Brain Vision Recorder
User Manual
Version 1.03
© Brain Products GmbH, 2001 - 2005
25-August-2005
The Vision Recorder software, frequently abbreviated to Recorder, is designed for use in
medical research. Brain Products GmbH does not grant warranty or assume liability for the
results of using the Recorder.
The content of this document is the intellectual property of Brain Products GmbH, and is
subject to change without specific notification. Brain Products GmbH does not grant warranty
or assume liability for the correctness of individual statements herein. Nor does Brain
Products GmbH enter into any obligation with regard to this document.
Any trademarks mentioned in this document are the protected property of their rightful
owners.
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Contents
1.
Product declaration .......................................................................................... 5
1.1. Product identification ....................................................................................... 5
1.2. Field of use ...................................................................................................... 5
2.
Introduction ....................................................................................................... 6
3.
Installation......................................................................................................... 7
4.
Getting started and handling ........................................................................... 8
4.1. First steps ........................................................................................................ 8
4.2. Setting up a workspace ................................................................................. 10
5.
Impedance measurement............................................................................... 14
6.
Viewing and recording data ........................................................................... 17
6.1. Controls ......................................................................................................... 17
6.2. Entering annotations ...................................................................................... 18
6.3. Blocking channels .......................................................................................... 20
6.4. DC offset correction ....................................................................................... 20
7.
Montages ......................................................................................................... 21
8.
Segmentation and averaging ......................................................................... 25
8.1. Entering parameters ...................................................................................... 25
8.2. Viewing and recording data ........................................................................... 29
9.
Program configuration ................................................................................... 32
9.1. Administrator ................................................................................................. 32
9.2. Preferences ................................................................................................... 33
10.
Amplifier-specific properties ......................................................................... 35
10.1. BrainAmp family............................................................................................. 35
10.1.1. Using the BrainAmp PolyBox ................................................................... 35
10.1.2. Impedance measurement ........................................................................ 36
10.1.3. Test signal ............................................................................................... 38
10.1.4. Configuring the digital port (marker port) ................................................. 39
10.1.5. Displaying the amplifiers connected ........................................................ 40
10.2. QuickAmp ...................................................................................................... 41
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10.2.1. Adapting sensors for the auxiliary (AUX) inputs ...................................... 41
10.2.2. Test signal ............................................................................................... 42
10.2.3. Configuring the digital port (marker port) ................................................. 42
10.3. National Instruments NI 6071e A/D converter card ....................................... 45
10.3.1. Installation ............................................................................................... 45
10.3.2. Configuration ........................................................................................... 45
10.3.3. Configuring the digital port (marker port) ................................................. 47
11.
OLE Automation ............................................................................................. 49
11.1. Application ..................................................................................................... 50
11.2. Acquisition ..................................................................................................... 51
11.3. CurrentWorkspace ......................................................................................... 51
11.4. License .......................................................................................................... 52
11.5. Licenses ........................................................................................................ 52
11.6. Menu.............................................................................................................. 52
11.7. Enumerator types .......................................................................................... 53
11.7.1. VisionRecorderMenuItem ........................................................................ 53
11.7.2. VisionRecorderState ................................................................................ 53
12.
Remote data access (RDA) ............................................................................ 54
13.
EEG file format ................................................................................................ 57
14.
Vision Video Recorder ................................................................................... 63
14.1. Installation ..................................................................................................... 63
14.2. Configuration ................................................................................................. 64
14.3. Combined EEG/video recording .................................................................... 65
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1. Product declaration
1.1. Product identification
Product designation:
Brain Vision Recorder
Manufacturer:
Brain Products GmbH
Stockdorfer Straße 54
D-81475 Munich
Germany
Permitted EEG amplifiers:
Brain Amp, Brain Amp MR,
BrainAmp DC, BrainAmp MR plus
QuickAmp, NI-6071e (AD card)
Classification in accordance with Directive 93/42/EEC (MDD) Appendix IX:
Class I with Recording Function
UMDNS number:
Software for Recording EEGs and Evoked
Potentials, 12-389
The CE mark confirms that the product fulfills all the basic safety requirements stipulated in
the Medical Devices Directive 93/42/EEC (MDD). 0123 is the number of the Notified Body
who issued the approval for the CE mark.
1.2. Field of use
The Vision Recorder is used to control EEG amplifiers and record EEG signals with the aid of
a personal computer.
This program is only allowed to be used by physicians or staff with adequate qualification.
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2. Introduction
In the Vision Recorder, you have bought a powerful and flexible recording program that is
characterized, in particular, by the following features:

The program is structured in such a way that different amplifiers can be controlled.

The program structure also enables new EEG formats to be integrated with the aid of
independent components.

The number of channels is only restricted by the amplifier that is in use. The internal
structure supports an unlimited number of channels.

Through implementation of OLE Automation, the Recorder can be controlled remotely
by other programs, and its internal state can be monitored.

While the EEG is being output, you can tap the digitized signals with programs of your
own. This technique is referred to as remote data access (RDA). Potential applications
for this include bio feedback and signal quality analyses. RDA operates across computer
boundaries.

Segmentation based on event markers is available to reduce the space required by EEG
files.

Averaging based on event markers is available to form evoked potentials during
recording.

The data can be filtered separately for display, for segmentation/averaging and for storage.
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3. Installation
The Vision Recorder generally functions parallel to other programs installed on your
computer without any problems. However, the Brain Products GmbH can only guarantee
error-free interaction for programs that have been tested accordingly. The tested programs are:
 Brain Vision Analyzer
 Microsoft Office XP
It is essential to use the setup.exe program for installation because the files are compressed on
the CD, and have to be unpacked and installed in a specific way.
System requirements



Windows NT as of version 4.0 or Windows XP with SP1
Minimum configuration: 1 GHz Intel Pentium III or compatible processor, 256 MB RAM,
graphics card with a resolution of 1024 x 768 pixels and 32,768 colors.
We recommend a monitor with a diagonal of at least 17". A 21" monitor should be used
when there are more than 32 channels.
1 Gbyte free hard disk space (further storage space depends on the amount of data that is
processed)
Installation
 Start Windows
 Insert the installation CD-ROM in one of your CD-ROM drives.
If your computer supports CD-ROM autostart, a menu will appear after a brief time to guide
you through the installation process.
Otherwise, take the following steps:
 Select Start > Run from the taskbar.
 Click the Browse button.
 Select your CD-ROM drive and the setup.exe file, and click the Open button.
 Now follow the instructions that the program outputs.
Before launching the Recorder, insert the USB dongle that is shipped with the product in one
of the USB ports available on the computer.
Now launch the Recorder by double-clicking the Vision Recorder icon on the desktop.
Alternately, select the Recorder via the taskbar: Start > Vision Recorder.
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4. Getting started and handling
4.1. First steps
Launch the Recorder.
After initial installation of the software a dialog box appears in which you can select an
amplifier. Select your amplifier here. Note that you must have administrator rights to do this.
Fig. 4-1: Dialog for selecting the amplifier
The program will now generate standard settings for your amplifier so you can check its
functionality immediately. Make sure the amplifier is connected and switched on. Then click
the following button on the toolbar (the bar beneath the menu bar):
Monitor
If everything is okay you should see how EEG curves are represented from left to right.
Fig. 4-2: Presentation of EEG curves
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If the message "The setup does not match the amplifier's capabilities!" appears, then the
current setup is invalid, i.e. the amplifier settings are not compatible with the amplifier. In this
case follow the instructions for setting up a workspace at the end of this chapter.
On the left, you see the channel names. The figures in percent shown in the figure are only
shown when a DC amplifier in the DC recording mode is connected. In this case the values
match the DC offset of the signal. An offset of 100% here corresponds to saturation at the
positive end of the recording level range. -100% corresponds to saturation at the negative end
of the recording level range.
At the bottom left there is a scaling bar which enables you to assess the signal size. If fewer
channels are displayed and there is enough space, a scaling bar is shown in front of every
channel.
Beneath the signals, separated by a gray line, the program displays time markers from the
amplifier's digital input.
With the toolbar, which is at the top beneath the menu, you can set the period to be displayed,
the number of channels to be shown simultaneously and other details.
You can obtain help on the functions of the toolbar by moving the mouse pointer to the
buttons or various elements on the bar. After a short time, a tooltip will appear. This is a small
yellow box containing brief information. The status bar, which is at the bottom of the program
window, gives you more detailed information at the same time.
The status bar also contains seven or eight boxes which are described here from left to right:








The first box shows the current program status (Monitoring, Saving etc.).
The second box shows the selected montage. You can find information on montages in the
"Viewing and recording data" chapter.
The third box shows the name of any EEG file that is open.
This is followed by a box showing the elapsed recording time of an open EEG file.
The next box shows the free disk storage space in hours. This information is also only
available if an open EEG file exists.
The next box shows utilization of the internal data buffer in percent.
As an option, the next box will show a battery icon and indicate the battery voltage of the
connected amplifier. The battery's charge state is shown on a color-coded basis, from
green through yellow to red. You should change the battery soon if the indicator shows
red.
The final box on the status bar shows the name of the current workspace (see below).
To terminate the Monitoring status, click the following button on the toolbar:
Stop Monitoring
The program is now in its idle state.
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4.2. Setting up a workspace
To define your recording parameters you have to create a workspace. A workspace stores
the location of your EEG files, amplifier parameters and more data. Select File > New
Workspace... from the menu.
Fig. 4-3: Start page of workspace dialog
You can define various settings here:

Raw File Folder:
This is where the generated raw data is stored.

Automatic Filename Generation:
If you enable this check box, the program proposes a file name when you are about to
save the file. This proposed file name consists of an optional prefix which can be entered
in the Prefix field and a consecutive number that is incremented internally. In the Min.
Counter Size field, you specify the minimum number of counter positions that you want to
appear in the file name. In the Current Number field you define the start number of the
internal counter. You can check the next file name that results from the inputs in the Next
Resulting Filename field.
Clicking the Next button brings up the second page of the dialog. It contains amplifierspecific inputs that we will examine here based on the BrainAmp parameters.
Before you specify settings for the BrainAmp, close all amplifiers used and click on the "Scan
for Amplifiers" button. Finally, you can fill in the following fields: Number of Channels,
Sampling Rate, Resolution (signal resolution in µV), Low Cutoff Filter and High Cutoff
Filter. The "Use PolyBox" makes it possible to activate the optional BrainAmp PolyBox. The
"Low Impedance" checkbox allows you to switch from an input impedance of over 100 MΩ
to 10 MΩ.
All of these parameters and their ranges depend on the currently selected amplifier.
If your amplifier supports individual settings per channel, you can define these individual
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settings in a table after enabling the Use Individual Settings check box. In this case, the Copy
Master Settings button enables you to transfer the parameters that were entered above to the
table. Then you only need to edit the channels that differ.
In the next column, you will find the type of amplifier. In the case of BrainAmp, we
distinguish between "EEG", "BIP" for bipolar channels (ExG amplifiers) and "AUX" for
sensor inputs (PolyBox)..
In the third column of the table you can assign physical channels to the logical channels
shown in the first column, providing your amplifier supports this. This is worthwhile, for
example, if you are operating with an electrode cap and do not want to use all the cap's
electrodes but, for example, just every other electrode.
Fig. 4-4: Amplifier parameters
For more information on the individual amplifier settings, see the section "Amplifier-specific
properties" below.
To get to the next page, press the Next button.
This page is used to set the filter parameters of the different software filter paths. There exist
three different filter paths:

Filtering of the saved raw data.
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
Filtering of all data that is used for segmentation/averaging.

Filtering of the displayed data.
Similar to amplifier page, you can choose individual settings for each channel or common
settings for all channels. You can also switch off complete filter paths by deactivating the
"Enable Filters" checkbox of the particular path.
Because the filters are realized in software you can choose any values. But you should not
choose frequencies equal or higher than half of the selected sampling frequency.
Fig. 4-5: Software filters
On the final page you have the option of setting segmentation/averaging parameters. The
options on this page are explained in the "Segmentation and averaging" chapter.
Clicking the Finish button brings up a dialog in which you are prompted to save the workspace file. Input a meaningful name and press the Enter key or click the Save button.
Select File > Edit Workspace... from the menu if you want to modify the workspace. Select
File > Open Workspace... to load another workspace.
If you want to use an existing workspace as a template for a new one, then load the required
workspace and then select File > New Workspace....
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Using the following toolbar button, you can look up the parameters for the current workspace
at any time – including in the course of recording.
Show Workspace Infos
The "Program configuration" chapter describes other settings that affect the program.
Amplifier-specific properties – such as test signal values and digital port settings – are given
in the "Amplifier-specific properties" chapter.
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5. Impedance measurement
If your amplifier has a built-in impedance measurement facility, then you can use it in
conjunction with this program.
To measure impedance, click the following button on the toolbar:
Impedance Check
A symbolic representation of a head appears. Various controls are located to the right of this.
If your electrodes are named 10-10 or 10-20, they are shown automatically on the head.
Otherwise they are arranged at the top right.
Fig. 5-1: Impedance measurement
You can change the electrode positions with the mouse. To do so, left-click an electrode, hold
the mouse button down and move the mouse.
The various controls are explained below:

Electrodes
Here, you can select various electrode groups that you want to measure. The groups and
their names depend on the amplifier that is being used. Clicking the Reset Positions button
resets the electrode positions.

Range (kOhm)
Here, you can set various impedance ranges, depending on the amplifier and the electrode
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group that you have selected. The impedances of the various electrodes are coded in
accordance with the color scale.

Zoom
If very many electrodes are being used, you can move the slider to select a section that
you want displayed. A red rectangle in the small electrode window defines the section in
the large window. You can move the rectangle with the mouse.
The "Settings" button takes you to a dialog box which allows you to define your own
measuring ranges, the colors used and the color steps and an optional background bitmap.
Figure 5-2: Setting the measuring ranges and colors
For each electrode group, you can select up to ten measurement ranges.
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It is also possible to define the colors used. Here you have the following three options:



A color gradient from green through yellow to red
A color gradient from blue through turquoise, green and yellow to red
A grayscale gradient from black to white.
Instead of a continuous color gradient between the minimum and maximum impedance value,
you can change the colors in steps ("Discrete Color Steps"). If you select this option, you can
enter the number of steps.
"Background Image" allows you to load and display any bitmap file with a representation of
the head in place of the default background. Please note that the horizontal position of the
electrode positions could change as a result. The reason for this is that with the default
background, an "isotropic" representation is used, i.e. any change to the height/width ratio of
the representation window is ignored (the head remains round). In contrast to this, the bitmap
always fills the entire window and the electrodes retain their relative positions on the bitmap.
If the selected bitmap file does not exist, or if it has an invalid format, the default background
is shown.
To stop impedance measurement, click the following button on the toolbar:
Stop Monitoring
If you have changed electrode positions, the program asks you whether you want to save these
changes. Electrode positions are assigned to the current workspace.
Also refer to the "Amplifier-specific properties" chapter for further options relating to your
amplifier's impedance measurement facility.
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6. Viewing and recording data
6.1. Controls
To view the data, select the Monitoring status by clicking the following button on the toolbar:
Monitor
You can change the display of data with various buttons on the toolbar.
The various buttons are described below.
Increase the time shown (alternately, use the Ctrl-(-) shortcut).
Reduce the time shown (alternately, use the Ctrl-+ shortcut).
Increase scaling (sensitivity; alternately, use the Ctrl- shortcut).
To scale individual channels differently (e.g. ECG channels) you can assign individual
scaling factors to them. The "Preferences" section of the "Program configuration"
chapter gives more details of this.
Reduce scaling (sensitivity; alternately, use the Ctrl- shortcut).
Reduce the number of channels shown.
Increase the number of channels shown.
Go to next channel group (only accessible when the number of channels has been
reduced).
Go to previous channel group (only accessible when the number of channels has been
reduced).
Turn baseline correction on/off. This only changes the baseline of the display – not the
data itself.
DC offset correction for DC amplifiers. This correction directly affects the data
(alternative: Ctrl-D).
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To start recording, click the following button:
Start / Resume Recording
A dialog box appears in which you can enter a comment that is stored in the EEG file.
Furthermore, a file name is proposed that you can change or accept.
To interrupt recording, click the following button:
Pause
While the program is in Pause mode you can also measure impedance without the EEG file
being closed.
Recording can be resumed by clicking the Start/Resume button again. Stop recording by
clicking the following button:
Stop Recording
Note that you can only end the program when you have explicitly stopped recording and then
clicked the following button to exit the Monitoring status.
Stop Monitoring
You can also view and save test signals if the connected amplifier supports this. Click the
Test Signal button to do this:
Test Signal
The test signals can be saved in the current EEG file.
The "Amplifier-specific properties" chapter gives more details on the shape and size of the
test signal.
6.2. Entering annotations
You can enter annotations that are shown at the bottom as markers and are included in the
recording (type: Comment). You have two options: on-the-spot annotations and predefined
annotations.
You enter on-the-spot annotations by pressing the following button:
Annotation
Alternately use the Ctrl-A shortcut.
A marker containing with three question marks appears in the lower marker area. A dialog
box also appears in which you can enter an annotation. Your input replaces the question
marks.
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Fig. 6-1: Dialog for on-the-spot annotation
Instead of an on-the-spot annotation, you can also predefine annotations and then output them
at the press of a key.
To do this you exit the Monitoring status and select Configuration > Predefined Annotations...
from the menu. If this menu item is not accessible, you do not have administrator rights and
your administrator has disabled access to this menu item. Read the "Administrator" section of
the "Program configuration" chapter for more details of this, or
get in touch with your system administrator.
Selecting this menu item brings up a dialog in which you can now input up to ten predefined
annotations. When you then press keys 1 to 0 in the Monitoring status, the predefined
annotations that are associated with them are displayed in the marker area.
Fig. 6-2: Dialog for predefined annotations
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6.3. Blocking channels
To block a channel, i.e. to suppress the signal received, click with the right mouse button on
the corresponding channel name. A context menu appears containing the
"Switch Off Channel <x>" option at the top of the menu. When you select this menu item, the
channel is blocked. The channel name and the curve now appear in red.
To reactivate the channel, open the context menu again. The option displayed now is
"Switch On Channel <x>".
6.4. DC offset correction
If you have a DC-coupled amplifier, then you can perform a DC offset correction with the
program. To do this, click on the DC Correction button:
You can also press Ctrl-D as an alternative. The DC offset is now corrected. The correction
affects the data. For this reason you should ensure that DC corrections are not performed in
important sections in the EEG.
The Recorder places a correction marker in the data to mark a DC correction in the data.
You can also set the Recorder so that DC correction is performed automatically as soon as a
channel exceeds or drops below a critical threshold value. You select this function by
selecting the menu item Configuration > Preferences and opening the DC Correction tab.
Figure 6-3: DC correction setup
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7. Montages
Montages enable channels to be reconnected on a software basis, i.e. new voltage references
are assigned to the channels.
They also serve to optimize the display of data, e.g. by combining frontal electrodes in one
montage and occipital electrodes in another one. In this case, when a montage is selected,
only those channels which have been assigned to it are displayed. The sequence of channels
can also be changed in a montage so that channels which were originally apart can be shown
next to each other. A channel can also occur multiple times in a montage.
A montage is used for visualization purposes only, i.e. the new data exists just temporarily
and the original data is not changed in any way.
Fig. 7-1: Start dialog for new montage
Choose Display Montage -> New.... from the menu in order to create a new montage. This
brings up a dialog in which you are asked about the type of reference to be used in the new
montage. There are three options:

Original. No new reference is calculated here. This type of montage is only used to group
channels or optimize their presentation as described above.

Average. The average reference is calculated here, i.e. the average of all selected channels
is used as the reference.

Bipolar. Bipolar connection. Differences between channels are formed.
Choose one of the reference options. To begin with, it may be better to take the easiest one –
the original reference.
Clicking the OK button takes you to the edit menu for electrodes. You will see two columns
titled Chn (+) and Chn (-) which indicate the channels and their reference channels. The
second column is not accessible unless you chose bipolar reference. On the right, the
obligatory OK and Cancel buttons are followed by others:

Insert Line: This button becomes accessible when you have written a text in the first field
of the first channel. If you click this button, the program inserts a line above the current
line.

Remove Line: With this button you can remove the current line providing it is not the last
line.
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
Insert Current Channels: This button is accessible when the montage list is empty.
Clicking it causes all channels in the current data window to be copied to the montage in
their original sequence. Then you may be able to define the required montage faster by
removing and inserting individual channels.

Remove All: This button becomes accessible when an entry has been completed. If you
click it, the entire content of the montage is removed following a question checking that
you really want to do so.

Arrange for Grid Views...: Clicking this button takes you to another dialog in which
channels can be assigned for grid views. Grid views are used when segmented or averaged
data is presented. This option is explained further below.
Fig. 7-2: Screen for editing montages
You can either type in the channel names or select them from the list boxes. When you have
completed the first 16 channels, you can access the next channels with the scroll bar.
As far as non-bipolar montages are concerned, the program inserts adequate names in the
reference channel input boxes.
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In a grid view, as used in segmentation/averaging, the channels are arranged in a grid pattern.
For the standard montage the grid is predefined. As far as other montages are concerned, you
can define the arrangement yourself under Arrange for Grid Views. Here you can input the
required number of rows and columns of the channel grid. Clicking the Refresh button
updates the grid that is being displayed. Now you can arrange the channels and the gaps using
your mouse.
Fig. 7-3: Grid definition dialog
When you have defined your montage, click the OK button. You are prompted to save the
montage. Input a suitable name and save the file.
To test your new montage, switch the Recorder to Monitoring status. Then click the Display
Montage menu. The number of items on the menu has increased as the name of your new
montage appears here now. Choose your new montage. The EEG is now displayed with the
montage. To revert to the default montage, choose it on the Display Montage menu.
If you have created a montage in which no electrodes of the current setup exist, then this
montage is not selectable during monitoring.
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If you want to modify an existing montage, select it under Display Montage > Edit... and edit
it. You cannot change the reference type for an existing montage. After editing, the program
asks you again which name you want to store the montage under. You can input a new name
in order to derive a new montage from an existing one in this way.
Fig. 7-4: Selecting keyboard shortcuts for montages
You can assign keyboard shortcuts to montages so that you can switch between them faster.
The montages are activated when you press the specified shortcuts. You can define these
shortcuts under Display Montage > Options.... The montages are assigned to the Ctrl-1 to
Ctrl-0 key combinations. Ctrl-1 is reserved for the default montage. As far as the other
combinations are concerned, you can select from existing montages.
If you defined one or more segmentation or averaging groups, as described in the
"Segmentation and averaging" chapter, you can select the montage from the active group
window in the same way by pressing the Ctrl-Shift-1 to Ctrl-Shift-0 shortcut.
Alternately, you can right-click in a data window to select a new montage.
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8. Segmentation and averaging
The Recorder can segment or average your data on the basis of event markers such as
stimulus and response markers.
Segmentation is always a preliminary stage to averaging, so the two are dealt with here in one
chapter.
You can store your segmented or averaged data in parallel to the raw data. You can also use
segmentation and averaging to ascertain whether a visibly evoked potential is formed at all. In
this case you do not store the segments or average.
It is also possible to save segmented data or the average only, and to dispense with raw data.
However, we advise you to save raw data if possible. Only if you do this do you have the
opportunity of changing your average parameters later.
8.1. Entering parameters
You can find the segmentation/averaging parameters under File > New Workspace... or File >
Edit Workspace... on the third page of the dialog box (press the Next button twice).
The first two pages of this dialog box are described in the "Getting started and handling"
chapter.
When setting the segmentation parameters you will see the term segmentation/averaging
group. A group describes segmentation based on one or more markers. Each group
independently defines all characteristics of segmentation/averaging. The data for each group
is displayed later in a separate window, and can be stored in separate files if you want to. You
can define up to 16 groups in total.
Now let's look at the various setting options.
First you can enable or disable segmentation/averaging with the Enable Segmentation /
Averaging option.
You use the Save Raw Data option to specify whether you want to save the raw data in
addition to segmented/averaged data.
You will also see two separate blocks in this dialog. The narrow block on the left enables you
to select, create, rename and delete groups. The large block on the right shows you the
parameters for the selected group.
You will see the following in the left-hand block:

Segment./Avg. Group
Here you select a group for editing.

New
This option is available to create a new group. A dialog appears in which you input the
name of the group and have the option of copying the settings from an existing group.

Rename
You use this option to rename the current group.
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
Remove
Here you can delete the current group.
Fig. 8-1: Segmentation/averaging parameters
The right-hand block contains various sections.
In the Markers section you can select the markers that describe the relevant segments for the
current group.
If you select Use All Markers, all markers that are sent by the amplifier are used in the course
of segmentation/averaging.
Alternately, the markers are used that are listed together with their type and description.
Press the Select button if you want to modify this list. This brings up a dialog in which you
can choose various markers. On the left there is a list named Types in which you select the
type of marker first. Then you can choose one or more markers under Descriptions.
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Fig. 8-2: Marker selection dialog
You add the markers to the Selected Markers list by clicking the Add button. If you want to
remove a marker from this list, then select it and click the Remove button.
Click the OK button when you have finished selecting markers. This takes you back to the
group dialog.
In the Interval Relative to Markers section you can set the relative positions of the segment
interval in one of two ways: Based on Time or Based on Data Points. You specify the Start
and End of the interval, or alternately the Duration of the interval instead of the end. When
defining an interval, make sure that it is not too big. The program will not include overlapping
segments in segmentation / averaging.
The Artifact Rejection section enables you to examine the individual segments that you want
to include in segmentation/averaging for various artifacts, or to carry out a quality check. All
segments that are detected as having artifacts are excluded from segmentation/averaging.
Four criteria are used to check for artifacts.

Gradient
The maximum permissible voltage gradient between two data points is defined here.

Difference
This describes the maximum permissible voltage difference between the smallest and
highest value in the range tested.

Amplitude
Here you can specify absolute voltage values for amplitude, i.e. the smallest and highest
permissible voltage in the range tested.

Low Activity
Here the program checks whether there is a minimum activity in a defined time. If, for
example, a period of 5 ms is specified here, the program checks whether, within the test
interval (described below), there is no change of voltage for the selected value over a
period of 5 ms.
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All these criteria are checked at an interval that you have to define. You can also disable
individual criteria, or all of them. Furthermore, you can exclude individual channels from
artifact checking. This is particularly advisable for ECG channels. Note that, here, you have to
select the untested channels and not the tested channels as in Vision Analyzer!
You can change the artifact detection parameters by clicking the Change button.
A further option is to manually reject artifacts ("Allow Manual Rejection with Space Bar"). If
this option is activated, you can subsequently reject any segment which has just been accepted
during segmentation / averaging by pressing the space bar. This is possible until the next
segment appears. If you have defined several segmentation/averaging groups, the rejection
refers to the segment of the group with the active window. All segments of the other groups
which form an intersection with respect to time with the rejected segment are also rejected.
However, only the most recently accepted segment in a group is checked.
In the next section (Average) you can define whether you want to segment or average the
data. If you opt for averaging, the Baseline Correction option is available in addition.
Baseline correction involves the adjustment of the baseline of every segment. The correction
is carried out right before averaging. The average voltage value of the prestimulus interval is
defined as the new zero value. In other words, the average of the points in the prestimulus
interval is ascertained, and this is subtracted from all points in the segment. This operation is
performed for all channels.
The next section (Miscellaneous) contains two options.

Limited Number of Segments
With this option you can limit the number of segments that you want to record during
segmentation or include in averaging.

Frame Color
Here you can select a frame color for the group in order to identify the associated data
window.
Finally, the Save Data section contains the following options for saving the group data:

Save Data
If you select this option, the data is stored when you press the Start button later when
viewing data.

File Name Prefix
Here, you specify the file name prefix, and can also use the $n placeholder. Wherever this
placeholder occurs, it is replaced later by the name of the raw file. The group name and a
file extension are added to the prefix that you enter here. The name that is formed is
shown under Resulting File Name.

Use Separate Folder
If this option is not selected, the previously defined raw data folder is used. Otherwise you
can select a separate folder (folder name) for the group here.
Now click the Finish button.
28
8.2. Viewing and recording data
If the program is still in the standard view, click the Monitor button on the toolbar:
Monitor
Fig. 8-3: Monitoring with averaging groups shown as well
The data view is now split up into two parts. On the left you see the familiar monitoring
window and on the right a separate data window for every segmentation or averaging group.
The data in this window is updated whenever a matching marker is found. The curves are
shown in red if the segment does not match the artifact criteria. This enables you to check the
criteria easily prior to acquisition.
If you have activated manual artifact rejection in the parameters, you can now use the space
bar during recording to subsequently reject segments which have not automatically been
identified as having artifacts.
You can change the ratio between the Monitor view and the segmentation windows by
dragging the bar between them to the left or right with the mouse. However, there is a limit
both on the left and on the right to prevent an area disappearing completely from the screen.
Beneath the group windows you see tabs that enable you to fetch a group window into the
foreground fast.
You can arrange the group windows with the three window control buttons below:
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29
Right-clicking in a data window enables you to select a new montage for this window.
At the top right there is a new toolbar with the following buttons that always relate to the
active group window. Their functions are the same as those of the main toolbar, but they are
explained here again. Note the difference in keyboard shortcuts (Ctrl-Shift-..., not Ctrl-...).
Increase scaling (sensitivity; alternately, use the Ctrl-Shift- shortcut).
To scale individual channels differently (e.g. ECG channels) you can assign individual
scaling factors to them. The "Preferences" section of the "Program configuration"
chapter gives more details of this.
Reduce scaling (sensitivity; alternately, use the Ctrl-Shift- shortcut).
Reduce the number of channels shown.
Increase the number of channels shown.
Go to next channel group (only accessible when the number of channels has been
reduced).
Go to previous channel group (only accessible when the number of channels has been
reduced).
Turn baseline correction on/off. This only changes the baseline of the display – not the
data itself.
Now we come to recording.
Fig. 8-4: Dialog to save data
Press the following button to start recording:
30
Start / Resume Recording
An extended Save dialog appears enabling you to overwrite the originally specified
parameters for the raw data and for every group.
As in the normal Save dialog, that is described in the "Viewing and recording data" chapter,
you can enter annotations (Comment). You can decide whether you want to save the raw data
and the various groups, the folder in which you want to store the data and the file name you
want to use.
You can input a base name for the raw file in the Base File Name field. The above-mentioned
$n placeholders in the filename fields of the segmentation or averaging groups are changed
accordingly.
Clicking the Save button puts the program in Save mode. The status fields in the individual
groups now show the number of segments (Total Segs) and the number of accepted segments
(Accepted Segs) in addition to the group status and the current montage. Furthermore, the
program shows the EEG filename and the remaining storage capacity in hours, minutes and
seconds. Note that this has to be interpreted as the capacity that would be available if the
respective group only were stored.
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9. Program configuration
9.1. Administrator
The Vision Recorder behaves differently, depending on whether you have logged in as an
administrator or as a normal user. All menu items are available to the administrator. Three
options are never available to normal users.
Configuration > Select Amplifier...
Here you can select the amplifier that needs to be controlled.
Configuration > Select Data Storage Type...
This menu item enables you to switch the EEG data output format. Only one format is
available in the current version.
Configuration > Administrator...
Selecting this brings up a dialog in which you can disable other options for normal users.
Fig. 9-1: Administrator dialog
You have the following options here:

Allow User Selecting Workspace
If this option is disabled, a normal user cannot select a workspace.

Allow User Editing / Creating Workspaces
This option defines whether a normal user can edit existing workspaces or create new
ones.

Allow User Editing Preferences
If this option is disabled, a normal user cannot set preferences. Preferences are dealt with
in the next section.

Allow User Editing Amplifier Specific Settings
All submenus beneath the Amplifier menu item can be enabled or disabled. The menu
items depend on the amplifier in question, and are explained in the "Amplifier-specific
properties" chapter.
32
Another option is Force 'Save As' Dialog when Monitoring Starts. If this option is enabled,
the Start button is activated internally whenever an EEG is displayed, causing the Save dialog
to appear.
9.2. Preferences
If you have administrator rights or if the administrator has not denied you access (see above),
then you can set various preferences.
To do this, stop monitoring and select Configuration > Preferences from the menu.
You now see three tabs: "Scaling", "DC Correction" and Remote Data Access.
Fig. 9-2: Dialog for setting scaling preferences
You can select the following under Scaling:

Polarity: Positive Down
This option defines the polarity of the displayed signal. If this option is enabled, positive
signals are shown facing down.

Start with Display Baseline On
If this option is enabled, baseline correction in the EEG display is enabled as standard.

Default Scaling
This is the scaling that is specified at the start of monitoring.

Set Individual Scaling Factors
Here you can enter individual channels that you want to display on a diminished basis.
This is, for example, desirable for ECG channels as they would otherwise extend far into
the signals of EEG channels. In the table, you enter the channels names and the associated
scaling factors by which you want to diminish display of the signals. This applies to the
display only, not to the data itself.
Under the "DC Correction" tab, you select whether or not automatic DC correction is to be
performed and at which threshold value (in percent) the correction will be performed. DC
correction is explained in the section "Viewing and recording data".
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Under the Remote Data Access tab, you enable or disable the RDA server. Refer to the
"Remote data access" chapter for more details of this.
34
10.
Amplifier-specific properties
This chapter describes amplifier-specific properties. In order to follow the descriptions given
here, you must have selected the amplifier in question.
10.1. BrainAmp family
10.1.1. Using the BrainAmp PolyBox
If you wish to use external sensors to measure temperature, skin conductivity etc. you can use
the BrainAmp PolyBox.
Please note the following:
The PolyBox inputs are not authorized for direct electrical contact with the test subject
as defined in EN ISO 60601-1.
Sensors which are not isolated from the patient (e.g. skin conductivity sensors) must therefore
not be used directly with the inputs.
In this event, use the Brain Products Optobox, which optically isolates the sensors and the
PolyBox.
To set the parameters for the sensors, select the menu item File > Edit Workspace. The
amplifier parameters are on the second page.
Figure 10-1: Amplifier Settings
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35
The BrainAmp system cannot automatically detect whether a PolyBox is connected. You
must therefore explicitly activate this by checking the "Use PolyBox" box. The PolyBox
inputs are labeled "AUX" (auxiliary) in the second column.
The PolyBox can only be used in combination with a minimum of one and a maximum of two
BrainAmps.
The PolyBox channels are always the last eight channels of the entire system. This means that
you can use physical channels 33 to 40 of a BrainAmp that is ready for operation, or channels.
65 to 72 in the case of two BrainAmps. If you have selected these channels under "Phys Chn."
then additional input columns will be available:

"Diff. Unit (Different Unit)"
If you check this box, you can use another unit such as "C" for Celsius

"Unit"
You enter the unit here.

"Gradient"
Here you enter the gradient in mV/unit, in the case of the unit "C", for example, mV/C.
Here, in our example, you describe the voltage difference in mV at a temperature change
of one degree Celsius. This value can also be negative.

"Offset"
The offset defines the zero point. In our temperature example, this is the voltage in mV
which the sensor returns at a temperature of 0 degrees Celsius.
10.1.2. Impedance measurement
In addition to the "Impedance measurement" chapter, you should note the following for the
BrainAmp:
There are three groups of electrodes that are measured separately: data electrodes, one reference electrode and one ground electrode. These groups are not completely independent of
each other so note the following sequence:

First apply all electrodes.

Then measure the data electrodes. You can choose from five ranges: 100, 50, 20, 10 and 5
k ohms. Start with the bigger range. If all electrodes are in a high-impedance state, check
how the reference and ground electrodes are connected.
If you want to define other measuring ranges, you can do so under "Settings" as described
above.

If the data electrodes have resistance values that are roughly correct, measure the
reference electrode. Here there is only a maximum measuring range from 0 to 10 k ohms.

Finally, measure the ground electrode. In this case as well there is only a maximum
measuring range from 0 to 10 k ohms.
You should also note that neither with bipolar inputs (ExG amplifiers) nor with the PolyBox
polygraphic sensors is it possible to measure input impedances.
36
Fig. 10-2: Options for measuring impedance
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10.1.3. Test signal
To record or display a test signal, attach the enclosed test signal generator to the amplifier via
the electrode input socket.
Clicking the program's Test Signal button generates and displays a signal with an amplitude
of 50µVpp (square wave) or 100µVpp (sine wave) .
Under Amplifier > Test Signal Values... you can select the signal shape (square waves or sine
waves).
Here, you can also define the frequency of the signal between 1 and 50 Hz.
Fig. 10-3: Dialog for entering test signal parameters
38
10.1.4. Configuring the digital port (marker port)
To record time-synchronous events such as stimuli or patient responses, the amplifier's PC
adapter card or USB adapter incorporates a 26-pole HD-sub socket. The socket contains 16
digital 1-bit inputs that are programmed separately from each other. The exact pinning of the
socket is given in the manual for the amplifier. The names D00 to D15 there relate to the bit
number. The first bit is identified as number 0.
Selecting Amplifier > Digital Port Settings... from the menu brings up the following settings
dialog:
Fig. 10-4: Dialog for digital port settings
You have various options here:
For each group of 8 bits you can define whether the signals are interpreted as high-active (5
volts = active) or low active (0 V = active). In addition, pulldown (high-active) or pullup
(low-active) resistors are applied at each input with a value of 4.9 k ohms to ground or 5 volts.
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39
In the table you can first define whether a bit is to be evaluated at all (Enabled field). For
every bit you can define which time marker types it is supposed to represent. It is also
possible to give several bytes a name of the same type. In principle, you are free in naming
the type but the Vision Recorder and Vision Analyzer use color coding for certain types. This
is why it is advisable to choose Stimulus and Response for stimulus and response inputs.
The description of the markers – that is the text that appears in the marker presentation of the
EEG view – is coded automatically. The following procedure is followed:
The first occurrence of the type in the table is weighted with value 1, the second occurrence
with value 2, the third with value 4 etc. For every data point, all set bits of a type are added
together according to this pattern. The resultant number is combined with the initial letter of
the type, resulting in the description.
Example:
Bits 8 to 15 are of the Response type. Setting bits 11 and 13 now results in a marker of the
Response type with description R 40. Bit 11 has value 8, and bit 13 has value 32. The total is
40.
A consequence of this logic is that only markers of different types can be detected at any one
time. If you want to record different responses simultaneously, you can do so by decoding the
number values again in the analysis, i.e. assigning a separate marker to every bit. Alternately,
you can assign a separate type to every bit in the table.
You can view the current state of the digital port for test purposes in the Current State field.
Another option in the dialog is Debouncing. If this is enabled, repetition of a marker of the
same type and same description is ignored for a period of 50 ms.
Note that trigger signals must be present at least for the period of a sampling point. This
means, for instance, that at a sampling rate of 1000 Hz, the minimum length of the trigger
signal is 1 ms. At 500 Hz, the minimum length is 2 ms etc.
10.1.5. Displaying the amplifiers connected
Select the menu item Amplifier > Connected Amplifiers... to determine which BrainAmp
amplifiers of which type are currently connected to your computer and are ready for
operation.
40
10.2. QuickAmp
10.2.1. Adapting sensors for the auxiliary (AUX) inputs
If you wish to use external sensors to measure temperature, skin conductivity etc. you can
carry out the appropriate adaptations in the Amplifier menu of the QuickAmp. Please note the
following:
The AUX inputs of the amplifier are electrically isolated from the power supply unit but not
from the standard EEG electrodes. It is therefore necessary to ensure that employed sensors
which have their own power supply isolate their signal output from this supply in accordance
with IEC60601-1. Otherwise it would be possible for impermissible currents to be routed
from the sensor output via the polygraphic inputs to the EEG electrodes. In this case, use the
Brain Products Optobox, which optically isolates the sensors and the amplifier.
To set the parameters for the sensors, select the menu item File > Edit Workspace. The
amplifier parameters are on the second page.
Figure 10-5 : Amplifier Settings
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41
The AUX channels are always the last four channels of an amplifier. This means that you can
use the physical channels 37 through 40 on the QuickAmp40, channels 69 through 72 on the
QuickAmp72 and channels 125 through 128 on the QuickAmp128. Once you have selected
these channels under "Phys Chn.", additional data entry columns become available.

"Diff. Unit (Different Unit)"
If you check this box, you can use a different unit, such as "C" for Celsius.

"Unit"
Specify the unit here.

"Gradient"
This field allows you to specify the gradient in mV/unit; with a unit "C", for example,
mV/C. In this example, you are describing the voltage difference in mV for a temperature
change of one degree Celsius. This value can also be negative.

"Offset"
The offset defines the zero point. In our temperature example, this is the voltage in mV
which the sensor returns at a temperature of 0 degrees Celsius.
10.2.2. Test signal
To record or display a test signal, click the program's Test Signal button. A rectangular signal
will be displayed.
Under Amplifier > Test Signal Values... you can select the signal amplitude. You can choose
between 50, 100, 200 and 500 µVpp.
Note that the test signal is not calibrated. It is simply an approximate value.
Fig. 10-6: Dialog for entering test signal parameters
10.2.3. Configuring the digital port (marker port)
To record time-synchronous events such as stimuli or patient responses, use digital ports
DIO0 to DIO7. The names DI00 to DI07 relate to the bit number. The first bit is identified as
number 0.
Selecting Amplifier > Digital Port Settings... from the menu brings up the settings dialog.
You have various options here:
You can define whether the signals are interpreted as high-active (5 volts = active) or low
active (0 V = active).
42
In the table you can first define whether a bit is to be evaluated at all (Enabled field). For
every bit you can define which time marker types it is to represent. It is also possible to give
several bytes a name of the same type. In principle, you are free in naming the type but the
Vision Recorder and Vision Analyzer use color coding for certain types. This is why it is
advisable to choose Stimulus and Response for stimulus and response inputs.
The description of the markers – that is the text that appears in the marker presentation of the
EEG view – is coded automatically. The following procedure is followed:
The first occurrence of the type in the table is weighted with value 1, the second occurrence
with value 2, the third with value 4 etc. For every data point, all set bits of a type are added
together according to this pattern. The resultant number is combined with the initial letter of
the type, resulting in the description.
Fig. 10-7: Dialog for digital port settings
Example:
Bits 4 to 7 are of the Response type. Setting bits 5 and 7 now results in a marker of the
Response type with description R 10. Bit 5 has value 2, and bit 7 has value 8. The total is 10.
A consequence of this logic is that only markers of different types can be detected at any one
time. If you want to record different responses simultaneously, you can do so by decoding the
number values again in the analysis, i.e. assigning a separate marker to every bit.
Alternatively, you can assign a separate type to every bit in the table.
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You can view the current state of the digital port for test purposes in the Current State field.
Another option in the dialog is Debouncing. If this is enabled, repetition of a marker of the
same type and same description is ignored for a period of 50 ms.
Note that trigger signals must be present at least for the period of a sampling point. This
means, for instance, that at a sampling rate of 1000 Hz, the minimum length of the trigger
signal is 1 ms. At 500 Hz, the minimum length is 2 ms etc.
44
10.3. National Instruments NI 6071e A/D converter card
You can also enable EEG analog amplifiers to be connected to the Vision Recorder using the
A/D converter card from National Instruments. The card converts the analog signals of the
amplifiers into digital signals. The Vision Recorder treats the card just like an amplifier.
N.B.:
The EEG amplifier used must ensure the prescribed electrical patient isolation at the
analog outputs. The A/D converter card does not provide any electrical isolation
between the inputs and the PC!
There is no facility here for measuring impedance or for feeding in an internal test signal.
Please refer to the documents "PCI E Series User Manual.pdf" and "SCB-100 100-Pin
Connector Block Installation Guide.pdf" in subfolder "NI6071e" of the Brain Vision CD for
further information about the A/D converter card.
10.3.1. Installation
Do not use the CD from National Instruments to install the A/D card. The drivers on this CD
are not compatible with the Brain Vision Recorder.
The Brain Products CD contains the correct drivers.
Installation procedure:



Install the Brain Vision Recorder program.
Power down the computer and install the A/D card in a free PCI slot.
Power up the computer again. When the Hardware Wizard prompts you for a driver
for the new hardware, insert the Brain Products CD.
10.3.2. Configuration
To select this A/D converter card, choose NI 6071e under Configuration > Select Amplifier.
Fig. 10-8: Amplifier drop-down box
To set the parameters for the A/D card, select File > Edit Workspace. The parameters for the
card are on the second page.
The names of the parameters used are from the nomenclature of National Instruments and
their meaning may differ from the terms used in neurophysiological research.
Vision Recorder User Manual
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Fig. 10-9: Parameter settings for the A/D card
You can choose the input mode. This must match your chosen wiring configuration. You have
three options here:

Differential
Every channel has its own reference. A total of 32 channels are available here.

Nonreferential Single-ended
Unipolar without a connection to ground. The reference point for all channels here is the
"AISENSE" terminal.

Referential Single-ended
Unipolar with connection to ground. The reference point for all channels here is the
"AIGND" terminal.
Please refer to section 4, pages 4-13 ff. of the document "PCI E Series User Manual.pdf" on
the Brain Vision CD for information about optimal wiring of the amplifier used.
In addition, you can specify the number of channels, sampling rate, and input polarity.
The maximum sampling rate depends on the number of channels. With up to 16 channels you
can sample at 2048 Hz, with 32 channels at 1024 Hz and with 64 channels at up to 512 Hz.
46
The input polarity indicates whether the EEG amplifier supplies a symmetrical or
asymmetrical output signal.
The A/D Range drop-down box allows you to specify the recording level range of your
amplifier.
Enter the amplification factor of your EEG amplifier in the Gain box.
If you do not know the gain, you can determine it empirically. To do this you require a
calibration signal which is fed into the amplifier. Choose a realistic gain, e.g. 1000, and then
record a short data sequence. Measure the values in the analysis software. You can now
correct the gain by comparing the actual value with what it should be.
Example:
Set the gain to 1000 and feed in a test voltage of 100µVpp. The voltage measured in the
Analyzer is 120 µVpp for example.
Correct the gain: new value = old value * 120 µV/100 µV = 1200.
Now enter the new value and repeat the test. The value of the signal feed and the measured
value should now match.
If you require individual settings for each channel, activate the Use Individual Settings
checkbox.
10.3.3. Configuring the digital port (marker port)
To record time-synchronous events such as stimuli or patient responses, use digital ports
DIO0 to DIO7. The names DI00 to DI07 relate to the bit number. The first bit is identified as
number 0.
Selecting Amplifier > Digital Port Settings... from the menu brings up the settings dialog.
You have various options here:
You can define whether the signals are interpreted as high-active (5 volts = active) or low
active (0 V = active).
In the table you can first define whether a bit is to be evaluated at all (Enabled field). For
every bit you can define which time marker types it is to represent. It is also possible to give
several bytes a name of the same type. In principle, you are free in naming the type but the
Vision Recorder and Vision Analyzer use color coding for certain types. This is why it is
advisable to choose Stimulus and Response for stimulus and response inputs.
The description of the markers – that is the text that appears in the marker presentation of the
EEG view – is coded automatically. The following procedure is followed:
The first occurrence of the type in the table is weighted with value 1, the second occurrence
with value 2, the third with value 4 etc. For every data point, all set bits of a type are added
together according to this pattern. The resultant number is combined with the initial letter of
the type, resulting in the description.
Vision Recorder User Manual
47
Fig. 10-10: Dialog for digital port settings
Example:
Bits 4 to 7 are of the Response type. Setting bits 5 and 7 now results in a marker of the
Response type with description R 10. Bit 5 has value 2, and bit 7 has value 8. The total is 10.
A consequence of this logic is that only markers of different types can be detected at any one
time. If you want to record different responses simultaneously, you can do so by decoding the
number values again in the analysis, i.e. assigning a separate marker to every bit.
Alternatively, you can assign a separate type to every bit in the table.
You can view the current state of the digital port for test purposes in the Current State field.
Another option in the dialog is Debouncing. If this is enabled, repetition of a marker of the
same type and same description is ignored for a period of 50 ms.
Note that trigger signals must be present at least for the period of a sampling point. This
means, for instance, that at a sampling rate of 1000 Hz, the minimum length of the trigger
signal is 1 ms. At 500 Hz, the minimum length is 2 ms etc.
48
11.
OLE Automation
As mentioned at the beginning of this manual, the Vision Recorder can be controlled remotely
via OLE Automation.
The program ID (ProgID) for external access to the Recorder is VisionRecorder.Application.
The Recorder incorporates a registered type library which is stored in Recorder.exe. The entry
for the type library in the Registry is Vision Recorder x.x Type Library where x.x stands for
the current version.
The recorder can also be controlled, for example, via a VB script batch file, as shown below:
' TestRecorder
' Create recorder object
Set Rec = CreateObject("VisionRecorder.Application")
Rec.Acquisition.ViewData()
Rec.Acquisition.StartRecording(Rec.CurrentWorkspace.RawFileFolder & "\TestData.eeg")
WScript.Sleep 5000 ' Analyzer Macro: use Wait 5
Rec.Acquisition.StopRecording()
Rec.Acquisition.StopViewing()
Rec.Quit
In this example, the Recorder is started, data is displayed and an EEG file named
TestData.EEG with a length of 5 seconds (5,000 milliseconds) is stored.
If you have the Vision Analyzer, you can also control the Recorder by means of an Analyzer
macro. The macro looks like this:
' TestRecorder
Sub Main
' Create recorder object
Set Rec = CreateObject("VisionRecorder.Application")
Rec.Acquisition.ViewData()
Rec.Acquisition.StartRecording(Rec.CurrentWorkspace.RawFileFolder & "\TestData.eeg")
Wait 5
Rec.Acquisition.StopRecording()
Rec.Acquisition.StopViewing()
Rec.Quit
End Sub
In this chapter, we will not deal with programming in depth but will just outline the
Application
CurrentWorkspace
Acquisition
Menu
Recorder's object model.
Fig. 11-1: The Recorder's object hierarchy
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The objects are described below in Visual Basic notation.
11.1. Application
Description
The Application object represents the program as a whole. It is the default object, which
means that the methods and properties of this object can be addressed directly, i.e. Version
corresponds to Application.Version, for example.
Methods
Sub Quit()
Terminates the program.
Properties
Acquisition As Acquisition
Write-protected
The Acquisition object
CurrentWorkspace As CurrentWorkspace
Write-protected
The current workspace
Menu As Menu
Write-protected
The Menu object
State As VisionRecorderState
Write-protected
The program status, see below for enumerator types
SubLicenses As Licenses
Write-protected
Lists the registered sub-licenses
Version as double
Write-protected
This specifies the current program version
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11.2. Acquisition
Description
This object controls recording.
Methods
Sub Continue()
This resumes interrupted recording
Sub DCCorrection()
This performs a DC correction
Sub Pause()
This interrupts recording
Sub StartRecording(FileName As String, [sComment As String]))
This starts recording to FileName
A comment can be specified as an option
Sub StopRecording()
This stops recording
Sub StopViewing()
This stops viewing of data, test signals or impedance measurements
Sub ViewData()
This displays data, starts monitoring.
Sub ViewTestSignal()
This displays test signals.
Sub ViewImpedance()
This displays impedance.
11.3. CurrentWorkspace
Description
This object represents the current workspace.
Methods
Sub Load(FileName As String)
This loads the specified workspace file FileName
Properties
FullName As String
Write-protected
Name of the workspace file including full path
Name As String
Write-protected
Base name of the workspace file without the folder and file name extension
RawFileFolder
Write-protected
Folder for raw data
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11.4. License
Description
This object describes a license/sub-license (e.g. a video sub-license).
Methods
Properties
ID As Long
Write-protected
Unique ID of the license
Description As String
Write-protected
Description of the license
11.5. Licenses
Description
This object is a list of "License" objects.
Methods
Properties
Count As Long
Write-protected
Number of licenses in the list
Item(Index As Long) As License
Default element, write-protected
On specifying the index (1-...), returns a "License" object.
11.6. Menu
Description
This object supports manipulation of menus.
Methods
Sub DisableMenuItem(MenuItem As VisionRecorderMenuItem)
This disables a menu option; the option to be disabled is specified in MenuItem
(see below for enumerator types)
Sub EnableMenuItem(MenuItem As VisionRecorderMenuItem)
This enables a menu option; the option to be enabled is specified in MenuItem
(see below for enumerator types)
Sub Reset()
This resets all manipulated menu options
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11.7. Enumerator types
The following sections describe the various enumerator types.
11.7.1. VisionRecorderMenuItem
Constants for the various menu items that can be addressed with the Menu object.
Enum VisionRecorderMenuItem
vrMiMonitoring = 32777,
vrMiImpedanceCheck = 32778,
vrMiTestsignal = 32779,
vrMiStartRecording = 32791,
vrMiPauseRecording = 32792,
vrMiStopRecording = 32793,
vrMiStop = 32780,
End Enum
11.7.2. VisionRecorderState
Constants for the various states of the program
Enum VisionRecorderState
vrStateOff = 0
vrStateMonitoring = 1
vrStateTestsignal = 2
vrStateImpedanceCheck = 3
vrStateSaving = 4
vrStateSavingTestsignal = 5
vrStatePause = 6
vrStatePauseTestsignal = 7
vrStatePauseImpedanceCheck = 8
' Idle state
' Viewing EEGs
' Test signal
' Impedance measurement
' Saving data
' Saving test signals
' Data saving pause
' Data saving pause
' Displaying test signals
' Data saving pause
' Displaying impedance
End Enum
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12.
Remote data access (RDA)
While it is being displayed, the EEG data can be passed via TCP/IP to other programs on the
local computer and to computers in a network. In the program, this is referred to as remote
data access (RDA). In this process, the Recorder acts as the server, and the program receiving
the data acts as a client.
Up to ten clients can be logged in to the RDA server at the same time.
This chapter describes the interface that enables you to implement your own online analysis
programs or bio feedback methods. In principle, you can use different programming
languages to do this. You can also develop and run a client program under Linux or other
operating systems. Our example RDAClient is a program that was developed with Microsoft
Visual C++ Version 6.0 under Windows. You can find the example project on the program
CD in the RDAClient folder. RDAClient establishes the connection to the server, and then
waits in a loop for data. When data arrives, it is stored in Brain Vision-compatible EEG files.
The name of the computer on which the Recorder is running is passed to the program as a
command line parameter. If this parameter is not specified, the local computer is examined.
There are two versions of the RDAClient. The 16-bit version works with amplifiers and A/D
converters with an A/D range of a maximum of 16 bits. The 32-bit version covers an A/D
range of up to 25 bits.
Before the RDA server can run it must have been enabled in the Recorder program under the
Configuration > Preferences... menu option (Remote Data Access tab).
A key term in programming via TCP/IP is socket. It is the combination of a TCP/IP address
and a port number. This combination describes a certain service on a computer. A known,
implicitly used service is, for example, the HTTP protocol on a Web server. This has port
number 80 by default. The Recorder's RDA server has two port numbers, 51234 and 51244.
The first port is intended for 16-bit data, the second port for 32-bit data.
The first task of the client program is to establish a connection to the server's RDA service
using the port number. This is done with standardized socket programming that we will not
explain here. However, you can find an example of it in the RDAClient.cpp or
RdaClient32.cpp file.
Then the client waits for data or messages to be sent from the server. The client itself never
sends data to the server.
Every received data block contains a header of the type RDA_MessageHeader. You can find
the declaration of this header and all other structures and constants in the RecorderRDA.h file.
The header consists of three parts:
uid is a 128-bit constant for unique identification.
nSize describes the total length of the block.
nType describes the type of this message. Four message types are in use at present: 1 means
the start of message (RDA_MessageStart), 2 means data block (RDA_MessageData) for
clients of the 51234 socket, 3 means end of message (RDA_MessageStop) and 4 means data
block (RDA_MessageData32) for clients of the 51244 socket. These different messages are
described below.
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RDA_MessageStart (nType = 1)
This message is sent by the server when it goes into Monitoring status.
If a client logs in during monitoring, it will also receive this message.
In addition to the header information about the number of channels (nChannels), data is sent
on the sampling interval in µS (dSamplingInterval), the sensitivity of the channels in µV
separately for each channel (dResolutions) and the channel names (sChannelNames). The size
of the dResolutions field is flexible and depends on nChannels. sChannelNames contains all
channel names in a string. The individual channel names are null-terminated.
The routine WriteHeaderFile(RDA_MessageStart* pMsg) in RDAClient.cpp shows how the
fields can be broken down.
RDA_MessageData (nType = 2)
This message is only received by clients that have logged in via port number 51234.
This message is used to transfer 16-bit data. It consists of the following elements:
nBlock specifies the current block number since the start of monitoring. The number can be
used to identify whether a block has not been processed fast enough, thus causing a data
overflow. An example of this is given in RDAClient.cpp.
nPoints specifies the number of data or sampling points in this block.
nMarkers defines the number of markers in this data block.
nData[] is the actual data as 16-bit signed integers. The number of values results from
nPoints and RDA_MessageStart.nChannels.
Markers is a data field with markers of the RDA_Marker type. The individual elements of this
field can have different lengths.
A marker of the RDA_Marker type consists of the following:
nSize = the size of the marker in bytes
nPosition = the relative position in the data block in sampling points (0 -...)
nPoints = the number of points covered by this marker (mostly 1)
nChannel = the channel number to which this marker has been assigned
(at present only –1 = all markers)
sTypeDesc = type and description of the marker as null-terminated text
You will find examples of dealing with data and markers in RDAClient.cpp in the routines
WriteDataBlock(RDA_MessageData* pMsg) and WriteMarkers(RDA_MessageData* pMsg,
ULONG nOffset, ULONG nExistingMarkers).
RDA_MessageStop (nType = 3)
This message consists of the header only, and indicates the end of monitoring.
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RDA_MessageData32 (nType = 4)
This message is only received by clients that have logged in via port number 51244.
Its layout is identical to that of RDA_MessageData with the exception of the fData[] field,
which replaces the nData[] field.
fData[] is the current data in the 32-bit IEEE floating point format. The number of values
results from nPoints and RDA_MessageStart.nChannels.
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13.
EEG file format
The current version of the Recorder supports the Vision Data Exchange Format only.
This format is described below.
An EEG consists of three files: the header file, the marker file and the actual data.
The header file describes the EEG. This file is an ASCII file with the extension ".vhdr". It will
normally be given the same base name as the raw data EEG that is described in it. The header
file is stored in the raw data folder of the workspace.
The format of the header file is based on the Windows INI format. It consists of sections of
different names containing keynames and assigned values. Here is an extract of a header file:
Brain Vision Data Exchange Header File Version 1.0
; Data created by the Vision Recorder
[Common Infos]
DataFile=000014.eeg
MarkerFile=000014.vmrk
DataFormat=BINARY
; Data orientation: MULTIPLEXED=ch1,pt1, ch2,pt1 ...
DataOrientation=MULTIPLEXED
NumberOfChannels=16
; Sampling interval in microseconds
SamplingInterval=2000
[Binary Infos]
BinaryFormat=INT_16
[Channel Infos]
; Each entry: Ch<Channel number>=<Name>,<Reference channel name>,
; <Resolution in "Unit">,<Unit>, Future extensions..
; Fields are delimited by commas, some fields might be omitted (empty).
Ch1=Fp1,,0.1
Ch2=Fp2,,0.1
Ch3=F3,,0.1
Ch4=F4,,0.1
Ch5=C3,,0.1
Ch6=C4,,0.1
Ch7=P3,,0.1
Ch8=P4,,0.1
Ch9=O1,,0.1
Ch10=O2,,0.1
Ch11=A1,,0.1
Ch12=A2,,0.1
Ch13=F7,,0.1
Ch14=F8,,0.1
Ch15=T7,,0.1
Ch16=T8,,0.1
The first line identifies the header file and is mandatory.
A semicolon at the beginning of a line identifies a comment which is ignored by the reader.
Blank lines are also ignored. A section is identified by a line with a term enclosed in square
brackets. The header extract above, for example, contains the [Common Infos] section. A
header file can contain any number of sections.
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The next lines show some keynames in this section and the values that have been assigned to
them. A keyname can only occur once in a section. Its meaning depends on the section in
which it occurs. There must be no blank before or after the assignment operator (equal sign).
Most predefined keynames have a predefined value which is used if a keyname is not found.
The various predefined sections with keynames, meaning and default values are listed below.
[Common Infos]
This section contains general information on the EEG file.
Keyname
Meaning
DataFile
MarkerFile
DataFormat
DataOrientation
DataType
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Name of the EEG file. If the name
does not contain a path, it is assumed
that the EEG file is in the same folder
as the header file. The placeholder $b
can be used in the name. It is replaced
by the base name of the header file
when the file is read in. Example:
The entry
DataFile=$b-EEG.dat
is interpreted for a header file named
Test.vhdr as
DataFile=Test-EEG.dat
Optional marker file containing a list
of markers assigned to the EEG. If no
path is specified explicitly, the marker
file is searched for in the folder in
which the header file is located. The
format of the marker file is explained
further below. Here, too, it is possible
to use the placeholder $b.
Possible values:
ASCII, BINARY
Possible values:
VECTORIZED
First the file contains all data points
for the first channel, followed by all
data points for the second channel etc.
MULTIPLEXED
Here, all channels for every data point
follow on from each other directly.
The data structure is multiplexed.
Possible values:
TIMEDOMAIN
The data is in the time domain.
FREQUENCYDOMAIN
The data is in the frequency domain.
Default value
None
A value must be specified
-
ASCII
MULTIPLEXED
TIMEDOMAIN
NumberOfChannels Number of channels in the EEG file.
None
A value must be specified
SamplingInterval
None
A value must be specified
The sampling interval is specified in
µs in the time domain and in hertz in
the frequency domain.
Averaged
This indicates whether the data set
which is to be read in has already
been averaged. This is particularly
relevant for the enabling and disabling
of transforms on the Transformations
menu.
Possible values:
YES
Yes, the data set represents data that
has been averaged.
NO
No, the data set represents data that
has not been averaged.
AveragedSegments This is the number of segments that
were included in averaging. This value
is only evaluated if Averaged=YES.
SegmentDataPoints If the data is segmented evenly, then
the number of data points per segment
can be specified here.
SegmentationType Like Averaged, this variable is
relevant for the enabling and disabling
of transforms on the Transformations
menu.
Possible values:
NOTSEGMENTED
The data set has not been segmented.
MARKERBASED
The data set has been segmented on
the basis of one or more marker
positions. All segments have the same
length.
FIXTIME
Segmentation was based on fixed
times. All segments have the same
length.
DataPoints
Number of data points in the EEG file.
NO
0
0
NOTSEGMENTED
0
If no predefined value has been
specified, the data is read to the end of
the file. As far as binary data is
concerned, the TrailerSize parameter
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can be set in the [Binary Infos] section
as an alternative.
Codepage
Codepage used in the header file.
ANSI
Possible values are:
UTF-8
ANSI
[ASCII Infos]
This section is only relevant if DataFormat in the [Common Infos] section was set to
ASCII.
Keyname
Meaning
Default value
DecimalSymbol
Decimal symbol that is used in the EEG Point (.)
file. This symbol can be a point or
comma. In the header file, the decimal
symbol is always a point.
SkipLines
Number of header lines to be skipped.
0
SkipColumns
Number of columns to be skipped at the 0
beginning of a line.
[Channel Infos]
This section lists the individual channels and their properties.
Keyname
Meaning
Ch<x>
Individual properties for the channel are
"x" stands for the specified with commas between them:
channel number, <Channel Name>,<Reference Channel
i.e. the keyname
Name>,<Resolution in
for the first
"Unit">,[<Unit>]
channel is Ch1,
Example:
Ch1=Fp1,,1
for the second
channel Ch2 etc. Here, the first channel is named Fp1.
The reference channel is assumed to be
the common reference channel because
no entry has been made. Resolution is
1 µV. Resolution is the value by which
the value of the data point is multiplied
to convert it to μV or to the selected
unit.
Default value
<Channel Number>,,1,µV
i.e. Ch1=1,,1,µV
for channel 1, for example
[Binary Infos]
This section is only relevant if DataFormat in the [Common Infos] section was set to
BINARY.
Keyname
Meaning
Default value
BinaryFormat
Possible values:
INT_16
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ChannelOffset
DataOffset
SegmentHeaderSize
TrailerSize
UseBigEndianOrder
IEEE_FLOAT_32
IEEE floating point format, single
precision, 4 bytes per value.
INT_16
16-bit signed integer
UINT_16
16-bit unsigned integer
Channel offset at which the data starts.
This offset is only relevant to vectorized
data. ChannelOffset and DataOffset can
be used simultaneously.
Size of the offset in the file at which the
actual data starts.
If the data is segmented evenly, the size
of the segment header can be input here
in bytes.
Size of the trailer of the EEG file in
bytes. This parameter can be specified as
an alternative to DataPoints in [Common
Infos] in order to stop reading in the data
before the end of the EEG file is
reached.
This only applies to integer formats. It
specifies whether big endian order is
used, i.e. whether the most significant
byte in a number is stored first
(Macintosh, Sun).
Possible values:
YES
Yes, big endian order is in use.
NO
No, little-endian order is in use
(corresponds to the Intel specification).
0
0
0
0
NO
The marker file is based on the same principle of sections and keynames as the header file.
The first line identifies the marker file and is as follows:
Brain Vision Data Exchange Marker File Version 1.0
The various predefined sections with keynames, meaning and default values are listed below.
[Common Infos]
This section contains general information on the marker file.
Keyname
Meaning
DataFile
Name of the EEG file. If the name does not contain a path, it is assumed that the
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Default value
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EEG file is in the same folder as the
marker file. This information is not
evaluated.
[Marker Infos]
The individual markers and their properties are listed in this section.
Keyname
Meaning
Default value
Mk<x>
Individual properties for a marker are
specified with commas between them:
-
Here, "x" stands
for the marker
number, i.e. the
keyname for the
first marker is
Mk1, for the
second marker
Mk2, etc.
<Type>,<Description>,<Position>,
<Points>,<Channel Number>,<Date>
Example:
Mk1=Time 0,,26,1,0
Here, the first marker has the type
"Time 0", no description, the position
is at data point 26, the length is 1 data
point, and the channel number is 0
which means that this marker relates
to all channels.
The date is optional. It is only evaluated
if the marker type is New Segment. The
date has the following format:
4 digits = Year
2 digits = Month
2 digits = Day
2 digits = Hour (24-hour system)
2 digits = Minute
2 digits = Second
6 digits = Microsecond
Consequently time is broken down to
the microsecond level.
The following specification
19990311140312003012
means
March 11, 1999, 14:03:12,003012
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14.
Vision Video Recorder
The Brain Vision Video Recorder – referred to in the following as Video Recorder for short –
is used for the synchronous recording of video data and EEG data in conjunction with the
Brain Vision Recorder.
As of version 1.03 of the Vision Recorder, you also install the Brain Products license file you
received with the product.
All settings for the Video Recorder are made in the Vision Recorder.
14.1. Installation
In order to use the Video Recorder, a Brain Vision Recorder with version number 1.02.0001
or higher must have been previously installed.
Make sure that you have a USB dongle with video option. Check this by starting the Vision
Recorder and choosing Help > About Recorder.
Fig. 14-1: Program info
If you have the appropriate USB dongle, the following line
"Vision Video"
will appear.
To install the Video Recorder, run the Setup program on the CD supplied and follow the
installation instructions.
Now install the codec supplied. A codec is used to compress the video data.
Finally, connect the video camera and switch it on.
Note that some video cameras with a video tape inserted switch over to standby mode after a
set time. Since we store the data directly in the computer, no video tape is required.
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14.2. Configuration
The Video Recorder is configured in the Vision Recorder under Configuration > Preferences.
If you have installed the Video Recorder correctly and you have a dongle with a video license,
you will see an additional tab named Vision Video.
Fig. 14-2: Video settings tab
You can switch on synchronous video recording here (Enable Vision Video).
Pressing the "Vision Video Recorder Settings" button takes you to the codec selection dialog
of the Video Recorder.
Fig. 14-3: Codec selection
This dialog box allows you to select different codecs.
Note that most codecs offered are not suitable for real-time recording so choose either the
codec supplied or one that you know is capable of doing the job.
Pressing the Codec Settings button takes you to a menu that depends on the codec currently
selected. There you can then set the optimum balance between image quality and video file
size. Experiment with different settings by recording part of an EEG in conjunction with the
Video Recorder and looking at the resulting quality and file size.
To diagnose errors, you can also select <None> for the codec. In this case the video data is
not compressed. Select this option for test purposes only!
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14.3. Combined EEG/video recording
Once you have enabled the video option and selected a suitable codec, choose the monitoring
mode in the Recorder with the following button:
Monitor
This brings up a window with EEG data as well as a video window in which the current video
data is displayed.
Fig. 14-4: Combined EEG/video display
If the video camera is not ready, the video window will show "Camera Not Connected!". If
the display is black, the most likely cause is that an incompatible codec has been selected. In
this case, select a different codec as described in the "Configuration" section.
You can move and resize the video window using the mouse.
Now record part of an EEG, for example 10 seconds. Make sure that the video image does not
disappear. A panning of the camera should also be visible after a short delay of less than a
second. If not, the codec used is not suitable.
A constant delay of the displayed video data of less than a second is however normal. This
does not result in any time difference between the video and the EEG when subsequently
replayed in the Vision Analyzer.
The video data is saved in the current raw data folder. A file with the extension
".VIDEOCONFIG" and the base name of the EEG file contains detailed information about the
video (names of video files, time, length etc.). The actual video data is saved to a file with the
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extension ".VISIONVIDEO". A new video file is created after every recording pause. It is
therefore possible for one EEG file to be associated with several video files.
You should always check the size of the video files generated. A value of 150 to 300 kbytes
per second is possible while maintaining good quality. If your video files have several
megabytes per second, either an unsuitable codec or no codec is selected.
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