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Altera_Forum
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16 years ago

Implement Phase Correlation algorithm

I'm putting a Phase Correlation algorithm in FPGA. Two images in, window them with 2D Hamming. 2D FFT on each. Complex multiply the matrices with one being conjugated first. The magnitude taken of ...
Altera_Forum's avatar
Altera_Forum
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16 years ago

parrado

Thanks for the reply.

Yes, I implemented the scaling logic to shift the BFP FFT outputs by the exponents out so that all results are in correct relationship to each other.

I am a little confused by your integer divider example. I understand the representation of fractional bits by the multiplication by 2^7. However, when you say 32/73 would return Q=2 Rem=14, I would think the divider would return Q=0 Rem = 32.

I'll play around with my simulations.

I also had a major conceptual error in that algorithm. The output of the final divider (normalizing the correlation value) produces numbers that range 1.0 to -1.0. The Quotient out of the divider is not the value I'm really interested in. The remainder contains the fractional info that is supplying the phase shift between the two images. I'll have to use the quotient to know when the output is exactly 1.0 or -1.0 but all other values are in the remainder.

mmeyers