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Forum: FPGA, VHDL & Verilog On live data processing with Altera FPGA Cyclone IV


von Enrique P. (flote21)


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Hello everybody,

I am inside of a project where I am in charge of the VHDL design using 
an ALTERA FPGA Cyclone IV. This FPGA has to control a RGB sensor and 
this RGB sensor provide the information of the pixel output through a 
LVDS interface. In my FPGA design I implemented a module in order to 
control the RGB sensor and receive the pixel output.

The value of 4 pixels are reveived in parallel with a frequency of 
150MHZ. Si I had to designe a module for interfacing the FPGA with the 
sensor. This module was implemented in a succesfully way because I am 
able to see the values of the pixels on real time thanks to the Signal 
TAP (it is like chipscope in xilinx). But in this point I need to do 
some kind of data processing on real time before send this data to the 
PC via Ethernet.

The data processing that I need to do consisits in adding up the RGB 
infomation. I mean, every 150MHZ I receive 4 pixels in parallel. Thanks 
to the known Bayer Pattern, it is possible to predict which pixels have 
information of Red, Green or Blue. Then I need to make small packages of 
32 pixels and adding up the values of the pixels with the same color and 
send the total value to the PC.

And it is in this point where I don¨t know exactly how to do programm in 
VHDL. I have nerver handle d on real time data with a FPGA and I have 
never made a data processing on real time, too. For this reason I would 
like to ask in this forum if someone could give me some tips or some 
good documentation to read to reach my target.

Thank you very much in advance.

: Moved by Moderator
von J. S. (engineer)


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You could take advantage of a consultant of FPGA-based image processing. 
I heard, there are some in this forum. :-)

Seriously: You allready explained the task, to to:

>adding up small packages of pixels
Requires an addeder or a field of adders in case of 2D-processing and 
some timing around that. Basically this will lead to a 
set/reset-accumulator.

There is nothing special about this. For common image processing, there 
would be things to to like:

deBayering, flat field correction, gain offset re-linearisation, pixel 
binning, lense distorsion correction and all of that in the right 
sequence.

von Enrique P (Guest)


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Thanks for your advise,

But I am a little bit afraid about the timming. If I have to make the 
"adding on real time, and I have to store the samples in a FIFO, in the 
mean time what i am reading the FIFO and process the data read, I am 
missing incoming data. Maybe I will need to implement a ring memory, 
right?

Other question is, how can I measure the LVDS channels with a normal 
Oscilloscope? Is it possible with the normal probes? Or I need special 
ones?

thanks.

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