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CMOS Camera - color interpolation and interface questions

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Sobakava

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CMOS Camera

I'm designing SXGA digital camera with a CMOS image sensor. PC interface will be IEEE 1394 or Cameralink(LVDS) I would like to
talk to guys who has experience in this field. Especially about
color interpolation of Bayer color filters and Firewire or Cameralink
interface.

Regards.
 

samsuffy

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Maybe, i can help you about Bayer filters
 

Sobakava

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Bayer Filter

Hi,

I found some articles and tips about bayer filter interpolation.
Some methods are very complicated and hard to implement
realtime. Some methods are simply averaging two neighbour
pixels.

First, I would like to ask: My sensor has 1280x1024 pixels
with bayer pattern. If I need to generate 8x8x8 RGB image,
how many pixels will be generated for each image? :)
I'm confused.

I plan to use a DSP or FPGA for color interpolation. Do you
know a real implementation?

Regards.
Sobak
 

visioneer

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Re: CMOS Camera

Sobakava said:
I'm designing SXGA digital camera with a CMOS image sensor. PC interface will be IEEE 1394 or Cameralink(LVDS) I would like to
talk to guys who has experience in this field. Especially about
color interpolation of Bayer color filters and Firewire or Cameralink
interface.

Regards.
U can find a good bayer pattern color interpolation here.

http://ise.stanford.edu/class/psych221/99/bjjiang/
http://ise.stanford.edu/class/psych221/99/tingchen/intro.htm

Visioneer
 

samsuffy

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Hi Sobakava,

a 8x8x8 RGB reconstruction from a 1280x1024 image creates (8+8+8)x1280x1024 bit array...
= 1280x1024 pixels of 24 bits
= 3.932.160 bytes :wink:

(this site explains some basics : http://www.micron.com/imaging/Technology/Color_Processing/index.html )

Indeed, the neighbours averaging is the simplest method. It give the worst results... Choose an algorithm in relation to your quality needs.

Most of algorithms may be implemented in Real-time with line FIFO or circular buffer. However, I've never had to do RT code.

According to your target application, you will need contrast correction or other calculation that needs the whole image... Maybe, you could implement complex color reconstruction and others calculatino on the driver level of your target platform (PC?...). A benefit of this solution is the amount of data to transfer, 3 times smaller !
 

mobile-it

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Re: CMOS Camera

How did you implement 1394? Can you give me some information?
 

Sobakava

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CMOS Camera

I used Texas Instruments IEEE1394 Link Layer and Physcal Layer chipset via 16bit CPU bus but, now my design is based on USB2.0.
 

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