Viewpoint: Industrial imaging
@imveurope
www.imveurope.com
Dale Deering, senior program manager at Teledyne Dalsa, says lower cost of image processing onboard cameras is improving video performance
O
ne of the most significant trends in imaging today is the continued evolution of CMOS image sensors as
the technology of choice for general machine vision applications. A complementary trend is the reduction in the cost of processing image data within the camera – the price of FPGAs, microprocessors and memory continues to drop, while speed and capability continue to increase. Tese changes allow the inclusion of more image processing features which provide significant video performance improvements over vision products of the past. Some of the benefits of these
new features in machine vision cameras are highlighted below: High dynamic range – One
scenes of high contrast, where there is important detail in both the dark and bright areas of the image. Multi-exposure – Cycling mode also uses
Expect these
emerging feature for machine vision is the ability to take multiple synchronised exposures and either extract details of the image of choice or fuse the images into a single combined, high dynamic range image which provides higher contrast than is possible with a single image. Tis feature is very useful for
feature sets to continue to evolve, further increasing the utility of machine vision equipment
synchronised exposures. A unique set of exposures is established and then rapidly cycled to create a more detailed image. Te most common application of this feature is to image the same object with different colour LEDs to create a multispectral image. Tis can also be used to incorporate changes in the angle of illumination, different types of light sources, polarisation, or any combination of exposure types which help to meet the demands of the application. Colour correction –
Colour imaging can also benefit from the increased
processing capability within the camera. Colour accuracy can be enhanced with colour calibration to Gretag-Macbeth colour reference charts, and corrections for colour aliasing due to encoder speed mismatch are easily handled with sub-pixel
spatial corrections. Even more complex issues such as parallax distortion due to camera angle can be corrected within the camera. Data reduction – Numerous features in
machine vision cameras today target data reduction – the ability to transmit only the image data of interest, allowing for a reduction in hardware costs downstream. Of course the ideal example is the ‘smart’ camera, which uses a number of standard algorithms to extract specific data from the image and transmit only this data, like barcode identification, optical character recognition, or object position. For more complex applications, there are still useful ways to reduce the dataset. One of these features is known as area of interest, allowing the pre-determined extraction of a subset of one or more regions of the image data. Expect these feature sets to continue to evolve,
further increasing the utility of machine vision equipment to enable even more vision applications while optimising the capability of image processing algorithms to extract the best information possible from raw image data.
Marc Damhaut, CEO of Euresys, says advanced frame-grabbers will be needed in the future for higher resolution industrial imaging
T
he need for advanced frame-grabbing technologies continues to grow in the machine vision business. Te demand
is fulfilled by the availability of high-resolution and high-frame-rate sensors and cameras, which leads to more bandwidth-hungry systems. For example, high-resolution cameras with 25 megapixel sensors shooting at 72 frames per second are now commonly used to track the finest details. For 3D applications, four- megapixel cameras now deliver up to 500 images per second. New camera-frame grabber interfaces such as CoaXPress have been designed to answer that need. On the host computer side, it is fortunately
matched by the availability of the new PCIe 3.0 (also called PCIe Gen 3) interface. PCIe Gen 3, which provides roughly twice the transfer bandwidth of its predecessor, PCIe Gen 2, and four times more bandwidth than the original PCIe interface, is now common in server and desktop motherboards, and will soon be
standard in industrial computers as well. Te Coaxlink Quad G3, the first PCIe Gen 3 frame grabber, will be available from Euresys by the end of the year. New technologies are also making an
appearance on the soſtware side – GenICam (abbreviation for Generic Interface for Cameras) is a generic programming interface for all kinds of cameras and devices, now including frame grabbers. With the new Coaxlink series
of CoaXPress cards, Euresys fully embraces the GenICam standard. Te Coaxlink cards are delivered with a GenICam-compliant driver, including the GenTL interface, which provides the following advantages: because CoaXPress cameras and Coaxlink cards conform to the GenAPI standard, users can access the camera parameters and the Coaxlink frame grabber parameters
18 Imaging and Machine Vision Europe • Yearbook 2014/2015
2015 will be another interesting year for frame grabbers, with new technologies and applications
in exactly the same way, providing ultimate ease of use. Programmers do not have to study or use multiple programming interfaces. In addition, the naming of the Coaxlink parameters also follows the recommendations of the GenICam’s SFNC (Standard Feature Naming Convention). Designing applications that
work in a similar way with GigE Vision, USB3 Vision and CoaXPress cameras is possible. Tis allows system integrators
and inspection machine makers to upgrade a machine easily using a GigE Vision or USB3 Vision camera to CoaXPress when increased performances are required. I believe 2015 will be another interesting year
for frame grabbers, with new technologies and applications.
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