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Thread: Need some advice on compression artifact

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    Need some advice on compression artifact

    I am working on a discrete wavelet compressor.

    Using the CDF 5,3 wavelet transform with one level, I take the following
    image:

    Click image for larger version. 

Name:	baboon.png 
Views:	183 
Size:	233.1 KB 
ID:	2953

    and I produce this image:

    Click image for larger version. 

Name:	baboon53.png 
Views:	159 
Size:	216.3 KB 
ID:	2954

    Now, the wavelet transform breaks an image into Low,Low, Low,High, High,Low and High,High bands where
    each band has x,y dimensions equal to half of image. I am writing the bands linearly into the original image buffer,
    so that is why the bands seem to be split in two.

    The artifact can be seen at the bottom of the third band: it looks like part of LL band is being writting to HL band.

    Any ideas on what could be causing this?

    Also, any ideas on how to debug this?

    Code can be found here:

    https://github.com/OpenCodec/ocldwt

    Thanks,
    Aaron
    Last edited by boxerab; 27th May 2014 at 21:08.

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