sliding window to extract patchs

[haixpham]

Hi Delzac,
Do you know how to apply a sliding window, for example on image, to extract patches? I want to implement custom pooling op on each patch.

thx

[delzac]

I know tensorflow has this function called extract_image_patches that does sliding window for images.

But i haven't thought of a way to implement it in cntk. It might not be possible with the python API or might be so inefficient that it is not worth trying :(

Duplicate #3752

[delzac]

@haixpham Actually this might be what you are looking for! Found it in this cntk issue #2819. It creates a sliding window for image.

[delzac]

@haixpham Let me know if it works and how is the performance. I may add it in cntkx.

[haixpham]

the code from there does not work, it raises RuntimeError. I will spend time brainstorming on a solution.

[haixpham]

I ended up not extracting patches explicitly, and came up with an efficient implementation of median filter. Tested it and it works as intended. See my post on CNTK forum for details.

P.S: I will continue using CNTK in my work. Have tried other frameworks but CNTK is still the best with its current feature set, especially dynamic sequence axis. Would you mind if I join in developing cntkx?

[delzac]

It's great to hear that you managed to solve the problem, I definitely take a took at your implementation to learn from it!!

I'm personally still using CNTK because of the dynamic axis too! I would love to have you join in in developing cntkx, more than welcome!!! ❤️❤️❤️