SHOW_IMG
This program allows you to display images, and
was written for use with medical images such as
MRI, PET, and SPECT. These images currently must
have symmetric dimensions of 64, 128, 256 or 512.
They may be either 8- or 16-bit images, and may
be preceeded by a header of any size, provided
that the header is smaller than the image.
When you display a series of images, you may
use the LEFT mouse button to zoom a portion
of the window in a larger window; the zoom will
follow the mouse as you move it (use the RIGHT
button to remove the zoomed image). You can use
the MIDDLE mouse button to plot a histogram of
the selected image. Use the RIGHT mouse button
to a window to make it the current window; this
is useful when you are saving window contents to
disk (see below). These operations will work for ALL
currently displayed windows created using the
"Series" button (not for single images).
You can save the contents of the current window
to a file in GIF, BMP, PICT, JPEG or TIFF format.
See "Options" below.
Several options are available using the "Options"
button to call up a popup widget. These options
effect the display of subsequent images.
Several keyword options have been added to
facilitate the calling of Show_Img from other
modules.
Quick Start:
Set the environment variable IM to be a
directory which is often used for images:
setenv IM /dir/images
(optional)
In IDL, start the Show_Img program:
IDL> show_img
Enter the file specification for the
series of images you wish to view, in
the text widget below "Enter File Spec...":
eg. /dir/images/run5*.pet
Use "Mode" to change the window and image
size, and then select "Series" to display
the series. If the series contains more
images than can fit in the window, select
either "Continue" or "End".
Basic Operations:
Quit Viewer
Exit the program. Select "Delete Windows"
to remove windows, or "Leave_Windows" to
leave them onscreen.
Help
Display this help file. Requires the
program LHELP to display this .doc file.
Mode...
Choose the size and number of images to
be displayed simultaneously. The choices
are:
Images in Window
---------------4 x 4
8 x 6
4 x 3
8 x 6
Size of Images
-------------128 x 128
128 x 128
256 x 256
256 x 256
Mode
---1
2
3
4
1 x 1
2 x 1
3 x 2
256 x 256
256 x 256
256 x 256
5
6
7
1 x N
256 x 256
8
This option has no effect when you are
viewing a single image file with "Display
Image".
The 8x6, 256x256 mode puts images in a
scrollable window that fills most of the
screen.
The 1xN, 256x256 mode puts ALL of the
images in the series specified into a
scrollable window, with all images being
viewable using the horizontal scrollbar.
This is useful when comparing different
series of images.
Note that the last three modes are to
create windows compatible with display
modes on the IBM PC platform, for display
and print purposes.
Display...
Display Linear Combination:
-------------------------Various viewing options. The first is to
display a series of linear combinations
of two sets of images (the first image
minus the second). Select
"Display series as linear combination" to
do this. This is useful for checking the
registration in multiple-echo protocols.
Enter the file-specifications for the series
in the popup widget that appears. You will be
forced to use the mode (8x6 256x256).
The remaining options are for viewing a
single image file. Select "512x512" or
"256x256" to specify the size of the image.
Then specify which file to display using
the popup widget.
Displaying Single Image Files:
----------------------------Use the choices "Display image (512x512)" and
"Display image (256x256)" to display individual
images in the sizes specified. Note that the
mouse operations listed above do not work for
these windows.
Colors...
Use this to select different color tables
by selecting "Color Tables" (calls the IDL
routine XLOADCT), or to adjust the gray-scale
by selecting "Grayscale". Select "Palette colors"
to adjust the RGB color values for individual
color indices.
Options
[Popup widget]
Press this to bring up a popup widget which
will allow you to adjust display options.
The default settings are capitalized. The
currently enabled options are:
* Display Filenames? (YES/No)
* Set Colors on Display? (YES/No)
If set to YES, then when images are displayed
which require certain colors to be adjusted
the color palette will be updated. Set to NO
if you have adjusted colors yourself and do
not wish the colors to be adjusted automatically
when the next series is displayed.
* Restore Colors for Windows (Yes/NO)
All windows created while this option is set to
YES will have the current color-table assigned
to them when they are created. Thereafter whenever
the cursor enters a window its color-table will be
loaded, and when the cursor leaves the window the
previous color-table will be restored.
This option is useful when you want to display
several series having incompatible color-tables
simultaneously. Normally you could not view both
at the same time; now you can view each with its
appropriate color table, provided the cursor is
within the window.
When you update the gray-scale or adjust individual
colors using "Colors...", the new color-table will
be assigned to the current window (remember that you
can press the right mouse button within a window to
make it current). Note that this feature is NOT
enabled for loading new color tables using XLOADCT
(this is a limitation of XLOADCT, not SHOW_IMG).
You can turn this feature on when you start SHOW_IMG
by using the keyword /PRESERVE_COLORS (useful when
calling from another module).
* Multiple Windows For Series? (Yes/NO)
Normally when a window is filled the program will
pause until the user selects the "Continue" or "End"
button to either continue display or stop display
of the series. If you set this option to YES then
the entire series will be displayed using as
many windows as necessary. The window titles
will indicate the sequence of the windows.
This option is useful when you want to save multiple
windows to graphics files using the "Write Windows
to Files" option.
* Source of Filenames For Series (FILESPEC/Series)
This controls the source for the list of filenames
to display whenever you select the "Series" button.
When set to FILESPEC the file specification you
enter in the text widget is used. When set to
SERIES the program will use a list of filenames
entered individually using the menu choice
"Operations... : Create List of Filenames".
* Reverse Images Vertically (Yes/NO)
If set to YES then the images are reversed vertically
(their columns are reversed). This is for images that
appear "upside-down" relative to our usual orientation.
* Write Windows to Files (Yes/NO)
Selecting "Yes" for this option, you can save the
contents of one or more windows to graphics files of
the following formats:
TIFF, GIF, BMP, PICT, JPEG
This option will save the <next> window(s) created to
graphics files, while the "Operations" item to save
the current window to graphics file saves the <current>
window to a graphics file.
The JPEG format currently supports only grayscale images,
and defaults to "very good" image quality (meaning
QUALITY=75 in IDL's WRITE_JPEG() function call).
You will be prompted to choose from the above formats,
and then you will be asked to provide a base filename
to use for the output graphics files. If you have an
image series already displayed, then the first five
letters of their filenames will be displayed as a
suggestion. You can change the output directory for
these image files as well.
Each successive graphics file created will have an
image number added to the filename, and the appropriate
extension will be added. The image numbers will begin
with '001' and increment monotonically.
This option has been used, for example, to create single
graphics files for each image in a series of images, to
be printed later.
NOTE: If you are creating graphics files to be used with
Pizzaz Plus (IBM PC), use GIF files, as TIFF files seem to
lose resolution information when they get converted.
* Enable Uniform Scaling (YES/No/Manual)
When uniform scaling is enabled ("Yes", the default) the
maximum of the central image of a series is used as a common
scaling factor for all images of the series, so that the
images appear somewhat consistent in intensity.
When disabled ("No") each image is scaled according to its
own minimum and maximum values, which can lead to variations
in image intensity.
When "Manual" is selected then the user can specify the
common maximum value to use for uniform scaling, using the
slider below these buttons. Selecing this option will
activate this slider.
* Adjust scaling maximum [Slider]
The slider sets the maximum value to use
when scaling images. Show_img first determines
a reasonable scaling factor and then applies
it to subsequent images, resulting in the
images having consistent on-screen values.
If the images look too light or too dark
then adjust the slider appropriately.
This slider is only active when you have selected "Manual"
in the above option "Enable Uniform Scaling".
Operations...
Save Window Contents To File...
Formats:
BMP :
GIF :
PICT :
TIFF :
JPEG :
Microsoft Windows bitmap format
Graphics Interchange format
Macintosh graphics format
Tagged Image File Format
Joint Photographic Experts Group
You can save the "current" window contents to a
graphics file in PICT, TIFF, BMP, JPEG or GIF format
by selecting "Save Window Contents To File". If more
than one window is displayed, you can make one of them
"current" by pressing the RIGHT mouse button over
one of the images in the window. The title of the
window will change momentarily, verifying that this
is the current window. When you select a file format,
the title of the current window will have '(CURRENT)'
added to it, so that you can verify that you are saving
the contents of the correct window.
Currently the JPEG option only supports grayscale images,
and defaults to "very good" quality (meaning QUALITY=75
in IDL's WRITE_JPEG() function).
Create List of Filenames
This will bring up a popup widget in which you can enter
individual filenames for display. For Show_img to use this
list you must set the source of filenames to be "List"
within the "Options" popup widget.
Press "Done" to accept the list, or "Cancel" to abort.
If accepted, the program will verify whether all files
entered actually exist. You will be given the chance to
edit the list in the case of missing files.
Series
Use this to display a series of images. The source of
filenames used depends upon the setting of "Source of
Filenames For Series" within the "Options" widget (see
"Options" section above).
If the source of filenames is "Filespec", then the series
is designated by entering a file specification, using
wildcards, in the box below the instructions "Enter series
filespec below:".
If the source of filenames is "List", then the list of
filenames you entered (see "Operations..." above) will be
displayed.
If "Multiple Windows For Series" option is set to NO (the
default), then after all images are displayed or the screen
is filled, whichever comes first, you may select "End" to
discontinue displaying images, or select "Continue" to continue
the display of images. Unfortunately, other options (most notably
"Colors...") are not available "between screens"; you have to
select "End" or "Continue" first.
If "Multiple Windows For Series" is set to YES, then as many
windows as necessary will be created to display the entire series
of images.
Enter Series Filespec Below:
Use this when you want to display a series of images; type in
a file specification using wildcards (* or ?) which designates
the series you want to display. You must enter this BEFORE
selecting "Series".
Note that you can enter a file specification and then press
<return> to display the series using the current entry.
The initial entry in this text widget can be set using the
environment variable IM. Setting this to a commonly used
directory is often useful.
Delete:
Pressing this button deletes the most recently created imagedisplay window.
Continue / End:
When displaying more images than can fit into a single window,
the program will pause after each complete window is filled.
Pressing "Continue" will continue the display of images,
whereas "End" will discontinue the display. Note that these
options are useful only when "Multiple Windows for Series" is
set to NO in the Options widget.
------------------------------------------------------------------------Keywords
FILE=filespec
Set this to a file specification for a
series of image files. This Filespec will
appear in the file-specification text
widget. This is useful when calling from
other modules.
MODE=n
( n=1,2,3 or 4 )
This chooses the display mode (size and
number of simultaneous images). See option
"Mode" above for available modes and their
numbers.
NOCOLOR_TABLE
Set this to inhibit the loading of the
linear gray-scale (LOADCT, 0). This is
useful when calling from other modules
which adjust the color table themselves.
NOSCALE
Set this to force Show_img to display images
in original form, without any scaling
operations performed. If the display visual
is 8-bit, then the image must be 8-bit also.
This is useful when calling from other
modules, when image signal values must not
be changed.
PRESERVE_COLORS
Set this to enable event tracking for windows.
Each window created will have the current
color-table assigned to it, and whenever the
cursor enters this window its color-table will
be restored. See "Options" : "Restore Colors
for Windows" for more details.
This keyword also forces the following:
whenever the cursor is moved outside one of
the Show_img windows, the original color-table
(before Show_img was run) is restored. This is
useful when calling Show_img from other modules.
SCALE_MIN
Set this to the minimum value to use for
scaled images. This is useful if you have
reserved colors, say, from 0 to N, and want
gray-scale images displayed beginning with
color index N+1 (you would set SCALE_MIN=N+1).
This keyword activates the BOTTOM keyword in
the BYTE_SCALE routine.
Local routines required by Show_Img:
FILE_FIND.PRO
ASK.PRO
EDIT_TEXT.PRO
FILE_STRARR.PRO
ADJUST_COLORS.PRO
ZOOM2.PRO
STRETCH2.PRO
Example
show_img, mode=2
FILENAME.PRO
BYTE_SCALE.PRO
FILE_UTILS.PRO
WINDOW_TO_FILE.PRO
GRAYSCALE.PRO
FIND_PROCEDURE.PRO
GET_TEXT.PRO
DELETE_FILES.PRO
READ_IMG.PRO
BEEP.PRO
LHELP.PRO
ADJUST_PALETTE.PRO