image normalization

[Altera_Forum]

Hi 

 I am working on image image processing on cyclone II. if I have 8 bit data in YCbCr then  Is it possible to normalize an image by: current pixel / 255   If there is another option please suggest me, I am working on DSP Builder v6.0.  Thank You

[Altera_Forum]

/255 is rather hard work 

 /256 is a lot easier as it is just a right bit shift by 8. In FPGA there is no need to do any bit shifting like this.

[Altera_Forum]

--- Quote Start ---  /255 is rather hard work  /256 is a lot easier as it is just a right bit shift by 8. In FPGA there is no need to do any bit shifting like this.  --- Quote End ---     But at the same time I want data bus of the same width(before normalization and after normalization). Further, Is it possible to re-gain the same image on de-normalization?  Thank You Tricky

[Altera_Forum]

If all you are doing is /256 and want an 8 bit fractional, you actually do nothing at all. You just "pretend" you did a divide. In an FPGA there is no real bitshifting when dividing, you just append zeros depending on which way you shift. 

 So if you had 152, and then divide by 256, then multiply by 1.5 (answer = 228), you just do this:  input = 10011000 (152)  1.5 = 1.1  just append zeros to 1.5 (multiply by 256) = 110000000  Do the multiply.  You have 8 bits fractional and 8 bits integer. (because your source, 152 was all fractional bits) so you discard the 8 LSBs and you have your answer  so you have:  0 1 0 0 1 1 0 0 0 x 1 1 0 0 0 0 0 0 0 ------------------------------------- = 0 1 0 0 1 1 0 0 0 + 0 1 0 0 1 1 0 0 0 ------------------------------------- 0 1 1 1 0 0 1 0 0|0 0 0 0 0 0 0 0 --Integer Fraction 11100100 = 228