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Use the full potential of the Camera Link Base interface

Posted by Gretchen Alper on Tue, May 24, 2011

The current quality of high resolution and high speed CMOS sensors and corresponding industrial video cameras results in an increased demand on high speed interfaces.  

Choosing a fast CMOS sensor-based camera can offer performance advances, but often requires a frame grabber upgrade!  In the case of Camera Link 2-tap (Base) configurations there was only a costly step to Camera Link 4-tap (medium) frame grabber configurations.

Now there is a cost effective approach for system enhancements through Camera Link 3-tap solutions.  

The 3-tap configuration* uses bits that are unused in 2-tap configurations.  In a 2-tap configuration, the maximum transmission rate per cycle is 2x the number of bits – so for example, to transmit 8-bit video you can achieve a maximum of 16 bits per cycle; for 10 bits the maximum is 20 bits.  However, the maximum bandwidth for one Camera Link cable, is 24 bits, so the full potential is not utilized in a 2-tap configuration when using 8- or 10-bit pixel resolution.

The 3-tap solutions are ideal for 8-bit images.  When 10-bit images are required, the Look Up Table function (LUT) can be used.  This function allows for the 10-bit images to be compressed to 8-bit data for transmission over the 3-tap Camera Link interface and then decompressed back to 10-bit images again via the frame grabber.

By using a 3-tap configuration combined with the Look Up Table function (LUT), the cameras are able to effectively take full advantage of Camera Link cable bandwidth, and transmit 8- and 10-bit images at 1.5x the speed of a 2-tap configuration.  This is all without using special cables or frame grabbers.

Adimec has introduced two new cameras to our Quartz Qs series with that are designed to maximize the potential of the Camera Link® Base communication protocol through the use of a 3-tap configuration.  The four megapixel Qs-4A60 offers frame rates of up to 60 frames per second (fps), and the two megapixel Qs-2A120 delivers up to 114 fps.  The actual image acquisition can be done at higher frame speeds using the in-camera burst mode function, allowing the cameras to deliver 90 fps and 170 fps respectively.  These cameras will be demonstrated at the Image Sensing Show (ISS) June 8-10 in Yokohama, Japan

Adimec QUARTZ Qs

Frame grabbers supporting the Camera Link 3-tap configuration are now available from several manufacturers including AVAL DATA.

 

*The 3-tap configuration is a Camera Link Base configuration and is part of the official Camera Link standard. Like 2-tap it uses just one Camera Link cable.

Topics: Interface Technology

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