Is it possible to acquire 8-tap/10-bit images with the NI PCIe-1433 card?

[EthanJ]

Hello all,

I am currently trying to acquire images from a camera that uses the Camera Link protocol. In order to acquire images at the maximum line rate for the camera, it must be run in the 8-tap/10-bit configuration. I am using an NI PCIe-1433 camera link frame grabber card and acquiring data using NI-IMAQ in LabVIEW.

The following KnowledgeBase article tells me that this is not possible: http://digital.ni.com/public.nsf/allkb/9B89C9FA43A6973A86257A62004658D5

However, it looks like 10-tap/8-bit data is possible with the PCIe-1433, which is the same total number of bits streamed per clock cycle as 8-tap/10-bit. By my interpretation, this means that the limitation is therefore not a hardware limitation (since the PCIe-1433 can receive 80 bits per clock cycle) but rather that there is no support programmed for 8-tap/10-bit mode. My understanding (which may be wrong) is that this support is built into the (.dat) bitstream files that are specified in the "AcquisitionBitstream" parameter of the camera configuration file. Is this interpretation correct? If so, is there any way to create a new bit stream file or obtain one from someone else that would support 8-tap/10-bit mode?

Regards,

Ethan

[AmitShachaf]

Hi Ethan,

8 Taps / 10 bit configuration generate a lot more data then 10 Taps / 8bit.

When you set the frame grabber to 8 Tap / 10bit you actually streaming into the Frame Grabber 8 Taps / 16bit.

Camera link interface is parallel interface. So the Camera Link chip on the NI PCIe-1433 can be configured to 8bit or 16bit.

When the camera is configured to 10bit interface it is actually using 16bit data path.

Data will be set on the lower bit of the 16bit data path.

For the Frame Grabber 4Taps / 10bit or 4Taps / 12Bits are exactly the same. Frame Grabber is using 16bits Data path for all those configurations.

[AmitShachaf]

Hi Ethan,

One more issue to consider when you are using the camera in 10bit configuration is the value of 10bit.

I am working now in my project with Imperx Bobcat that is configured to 12bit.

With the way we are working I am getting over 1000 Frame per second.

In this speed 12bit has almost no value. A/D on the sensor doesn't produce 12bit of good data out of a pixel. 8bit would probably give me the same information like the 12bit.

Seems to me you are setting the camera to really high speed.

I don't know your system. But I suggest to check with the vendor if there is any value for 10bit in this speed.

[EthanJ]

Thanks Amit,

My understanding is that the coercion of bit depths as multiples of 8 "under-the-hood" is only a limitation with how the NI frame grabber card handles the data after it has been received from the camera (and not how the camera is actually streaming data to the frame grabber). If this were the format that the camera were streaming data, then it would be streaming 8x16 = 128 bits per clock cycle, which is much larger than the 80 bits maximum that is supported by the Camera Link "Deca" configuration. As such, I figured it might be possible to achieve 8-tap/10-bit mode with a custom bit stream file, but perhaps the "multiple of 8" coercion is at a lower level on these cards than the bit stream files, making this impossible.

Ethan

[AmitShachaf]

Correct