IPP Equivalent of MATLAB's im2col

Royi — Mon, 21 Apr 2014 12:33:19 GMT

Hello,

I want to apply an operation on a sliding window over an image.
Yet it is Spatially Variant hence cannot be executed ad a convolution.

My question is, does Intel IPP has something equivalent of MATLAB im2col function (And of course the opposite way col2im)?

Those are needed in order to Vectorize the operation and keep the highest performance.

Unless there are better more optimized way to engage vectorization when dealing with Spatially Variant filters.

Thank You.

hi Royi,

Igor_A_Intel — Wed, 23 Apr 2014 14:45:55 GMT

hi Royi,

it is possible, but I think will be too expensive, as requires several steps:

1) transpose an image - so columns become rows

2) create additional IppiSize structure with your sliding window width and height

3) define the new image (sliding window) step that is == your window width*sizeof(your data type)

4) one limitation of such approach - your image should be dense (step == width*sizeof(data type) or width*height of window < image width

for col2im you can use the same approach - transpose, etc. but I think that simple C-loop will be more efficient and doesn't have any limitations.

regards, Igor