What is the visionworks vxLaplacianPyramid internal logic?

[leef918]

I tested the vxLaplacianPyramid API and the image reconstruction result,compared to opencv implementation.

The Laplacian pyramid is dismatched ,and the reconstructed image is dismatched too.

I need help for this ,
Thanks
.

opencv

[AastaLLL]

Hi,

Is the black pyramid output from the VisionWorks?
If yes, could you share a source to reproduce this in our environment?

Thanks.

[leef918]

Hi,
The black image pyramid image is not PURE black,some pixel value is bigger than zero in the image ,and the pyramid can constructed the image ,but is not expected .

Here is the source file.
main_lap_pyr.cpp (4.8 KB) util.h (5.3 KB)

[leef918]

Hi,
I tested the images in the laplacian pyramid with opencv-python,the problem may be in the pyramid up phase,the interplation type is incorrect.
And I post here the raw image and reconstructed image from visionworks .
and the opencv implementation.
c2.py (1.5 KB)
the opencv’s result is similar to the NV’s visionworks’
– visionworks’result

–opencv-interplation-iner-nereast

–opencv-pyrup

–raw input image to visionworks

– laplacian pyramid levels’ images.

[AastaLLL]

Hi,

Based on the implementation, VisionWorks uses linear interpolation rather than the nearest neighbor.
Not sure why the result looks like an NN-based output.

Let us check this based on your source and get back to you later.
Thanks.

[AastaLLL]

Hi,

It seems that our VisionWorks doesn’t implement a lossless reconstruction so that the results will be different from the OpenCV.
If you want a lossless version, you can try to implement custom kernels as below:
https://www.khronos.org/registry/OpenVX/specs/1.1/html/da/d83/group__group__user__kernels.html

Thanks