FPGA-based implementation of Camera Link standard

[Shervin]

Greetings, I have an FPGA board that has JPEG 2000 images stored in it
memory and need to send the images to another device that has a Cemara Lin
standard-based interface. The Camera Link docuement explains the overal
communication protocol: for example for a basic interface there are 3 8-bi
pixel-data lines and 3 main control signals FVAL, DVAL, and LVAL. In m
case, the images that I have are in the following format: meta data + bye
of image data. In the case of basic interface, do I just load the imag
data 3 bytes at a time, put them in parallel on the pixel-data lines whil
the FVAL, DVAL, LVAL signals are raised until the end of image bytes? I
this the basic idea?

Thank you in advance for your time, look forward to your kind reponse.

-Shervin




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[Gabor]

On Nov 22, 11:56 am, "Shervin"
<Shervin.Mehryar@n_o_s_p_a_m.mdacorporation.com> wrote:

Greetings, I have an FPGA board that has JPEG 2000 images stored in its
memory and need to send the images to another device that has a Cemara Link
standard-based interface. The Camera Link docuement explains the overall
communication protocol: for example for a basic interface there are 3 8-bit
pixel-data lines and 3 main control signals FVAL, DVAL, and LVAL. In my
case, the images that I have are in the following format: meta data + byes
of image data. In the case of basic interface, do I just load the image
data 3 bytes at a time, put them in parallel on the pixel-data lines while
the FVAL, DVAL, LVAL signals are raised until the end of image bytes? Is
this the basic idea?  

Thank you in advance for your time, look forward to your kind reponse.

-Shervin

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Posted throughhttp://www.FPGARelated.com

It would be best to find out from the company that makes your
framegrabber
if they need any special formatting. Many times you need to keep a
constant
line size and frame size, which is not really appropriate for JPEG
images,
since their size depends on the complexity of the image. Some
framegrabbers
will drop any data that is sent beyond the length of the defined line
or
image width. Also if you are using the "base" Camera Link hardware
and
want to use three bytes, be aware that most framegrabbers only allow
this
for RGB mode, so the three bytes are regarded as one "pixel".

If you are making the logic for both ends of the interface you can
obviously do
anything you want. We have made cameras and framegrabbers that can
handle JPEG compressed images using a straightforward frame interface
that does not require LVAL to toggle. It's been a while since we did
this,
but as I recall we used a 2-tap mode (16 bits per clock) and used the
DVAL signal to indicate valid data because the rate data came from the
JPEG compression core was not constant.

Camera Link does not have any provisions for variable length frames,
so there's no standard way to do this.

HTH,
Gabor

 

[Shervin]

Thank you Gabor for your useful tips. I will try to bug the company fo
some more information and see if I can do anything about it.

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