PRESS RELEASE
Flexible, easy to use Machine Vision - meeting the fast changing consumer patterns
Today’s consumption behaviour has led to an increased need for rapid changes in the production
processes. There is a clear trend towards production of smaller series, with many different types of
objects sharing the production line, rather than mass production of a fewer number of types. This way of
production makes it important to quickly be able to introduce new product types.
Today’s consumers also place demands on perfectly manufactured goods, for example, a sticky bottle or
a skewed label will stay on the store shelf, unsold. This consumer pattern increases the pressure to
provide a fast and flexible production control process.
How do we meet these requirements, and, at the same time, increased productivity targets?
A key factor to success is flexible and easy-to-use quality inspection. The use of Machine Vision to
control and optimize productivity is rapidly growing, and indeed the technology continues to prove its
worth. Machine Vision has the potential to be every man's gear on the production floor, to help keep up
with the demanding production rate and targets. However, to do that, it needs to be very user friendly and
flexible enough for rapid adjustments; Vision sensors with focus on ease-of-use are a response to this
need.
One may think that a vision sensor would be easy to design because it is so easy to use. However, to
create a vision sensor that is user friendly, powerful and flexible clearly requires innovative skills. There
are several components within a vision sensor that contribute to its ease-of-use.
User interface – the base of usability
The most obvious component is the user interface. A configuration interface with an intuitive workflow,
simple tool icons and graphical feedback enable people, also without programming skills, to configure the
device. A user-friendly interface makes it easy to quickly adjust or add quality inspection for a new
product type in phase with changing consumer needs. To further increase the usability, the user interface
can also be available off-line, as an emulated device. Then, it is possible to fine-tune the inspection
configuration of an existing product type or simply add a configuration of a new one without disrupting
ongoing production.
Image quality – the core of Machine Vision
The most fundamental component to ease-of-use, and machine vision itself, is good image quality.
What, then, is good image quality? The straight answer is usually high resolution – or number of pixels
per millimeter. This is however only part of the truth.
The definition of a good image, when it comes to machine vision, is to secure a reliable and repeatable
extraction of the details of interest in the image. This is ensured by using the right illumination and optics
– this cannot be stressed too hard – to succeed with Machine Vision, make sure to use the proper
illumination and optics! With all the pixels and processing power in the world, the application will fail if it is
not possible to distinguish the important features in the image.
The most common "pit fall" for beginners is a careless set-up, not paying enough attention to the
illumination of the object and ignoring varying ambient lighting effects. Given this common problem, it is
important that the vision sensor can adapt to different illumination situations and optical variations without
compromising usability. Most vision sensors have an in-built white lighting. An innovative solution to the
problem stated above is to use this white light in combination with various front windows, resulting in red,
green, blue or white diffuse illumination. For a vision sensor with integrated IR-light, a front window with a
visible light block filter provides immunity against disturbing visible ambient lighting effects. All above
solutions are possible to realize without any additional needs for wiring or mechanical integration –
lighting flexibility at its simplest!
Smart algorithms – the power of vision sensors
The third main component that contributes to ease-of-use hides in the inspection tools’ analysis
algorithms and how these can be combined. A seemingly simple but extremely powerful "Locate and
Inspect" concept is a means to reach powerful simplicity. After “teach-in” of an object and configuration of
the needed inspections, this concept lets the vision sensor, in run-time, first locate the objects on the
production line, and then automatically perform the inspections relative to the found pose of the object.
This makes it extremely easy for a user to configure an application. Moreover, it also overcomes need for
expensive fixtures and complicated light switch trigger signal integration.
The core algorithm for the "Locate and Inspect" paradigm is an object locator tool. This tool needs to
detect an object and accurately measure its pose regardless of variations in position, rotation, scale, tilt,
illumination, reflections, and occlusion. The tool’s advanced matching algorithm furthermore needs to
perform at a very high speed, and on the limited computational resources found in a small vision sensor.
This calls for an optimized implementation, often on a purpose specific Digital Signal Processor (DSP)
and sometimes even utilizing the highly parallel computational abilities of a Field Programmable Gate
Array (FPGA).
The processing time of the algorithm should not only be low, it should also vary as little as possible for all
kinds of images. This gives a deterministic response time of the vision sensor, making it easy to integrate
into a real-time solution.
Vision Sensors as powerful as Smart Cameras
Complementing the flexible illumination concept and the smart algorithms, an easy-to-use calibration
feature increases the power and usability of the vision sensor even further. After a simple one-step
procedure, using a chess-patterned target, the vision sensor can be report values in true millimeters and
compensate for distorted images.
Vision sensors are increasingly supporting the trend of distributed communication, enabling centralized
control and result management. Standardized field bus protocols and web technologies are moving into
vision sensors, securing an easy handling even for communication and customized operator interface
designs.
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The border between vision sensors and smart cameras is becoming increasingly vague; the advantage of
the vision sensors in terms of solution cost and time saving due to ease of use persists.
Conclusion
The above discussion has mainly touched upon the usability of solving production problems with vision
sensors. Vision sensors with simple configuration interfaces, innovative illumination possibilities and
smart algorithms are indeed paving the way for Machine Vision to become every man's gear.
Usability and powerful simplicity is the key to keep up with the rapidly changing consumption patterns –
without compromising productivity.
SICK is one of the world's leading manufacturers of sensors and sensor solutions for industrial
applications. Founded in 1946 by Dr.-Ing. e. h. Erwin Sick, the company is headquartered in the German
town of Waldkirch, in the Breisgau region near the city of Freiburg. It is a technology and market leader,
maintaining a global presence with more than 50 subsidiaries and equity investments as well as
numerous representative offices. In the 2014 fiscal year, SICK had around 7,000 employees worldwide
and generated Group revenues of €1,099.8 million.
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