Camera Link

Camera Link (CL ) is an interface in industrial image processing. It is specified for fast image transfer. The standard is managed by the Automated Imaging Association (AIA).

Properties

The bit width per pixel may vary between 8 and 16 bit. The maximum pixel frequency is 85 MHz. If more data still to be transferred, this can result in parallel streams, so-called Taps happen.

Camera Link is available in three variants:

• Base (up to 24 bits per clock ) - eg: 255 MB / s at 3 taps of 8 bit
• Medium ( up to 48 bits per clock )
• Full (up to 64 bits per clock ) - eg: 680 MB / s with 8 taps

As a plug MDR -26 connector from 3M is defined. The greater range of medium - and full specifications is realized via a second connector / cable.

It can be transmitted both monochrome as well as color images.

In the Camera Link Specification 1.2 Power over Camera Link was taken. Ensure that cameras do not require their own power supply more.

Connection to PC

A CL camera is connected via a cable to the PC - CL, which must be equipped with a CL frame grabber. For communication from the PC to the camera several lines are available. Two of them form a normal RS- 232 UART interface. This is primarily used to configure and control the camera. Four other signals are freely configurable and thus camera specific. In general, a trigger is sent to the camera to control it from outside (eg from a light barrier) on the first of these four lines. This external trigger allows for a very short shutter delay ( latency ) of the camera.

The maximum cable length depends on the pixel clock, it rarely amounts to more than 10 meters. If longer cables are required, the signal at regular intervals must be strengthened.

History

The first version of Camera Link was published in 2000. Camera Link is based on the Channel Link Protocol by National Semiconductor. Version 1.1 was released in January 2004.

The big new feature of version 1.2 is Power over Camera Link.