Compression of Spectral Images Using Spectral JPEG XL

Re:Compression of Spectral Images Using Spectral JPEG XL by rurban on Monday March 17, 2025 @06:54AM (#43387091)

I also really wanted to use libjxl, but abandoned it eventually. The encoder was horrible. Also instead of OpenEXR we store our multispectral images as TIFF, with lossless lzw:2 compression. Lot of work with TIFF, but in the end much more flexible

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Re:Compression of Spectral Images Using Spectral JPEG XL by fc417fc802 on Monday March 17, 2025 @07:53AM (#43387513)

It seemed like most of their issues were due to the lossy compression (ie wanting different parameters per sub-image). If they had opted for lossless JPEG XL wouldn't things have "just worked"?

Unrelated, I'd also be curious to know how their initial data transformation varies from that of your TIFF scheme.

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Re:Compression of Spectral Images Using Spectral JPEG XL by rurban on Monday March 17, 2025 @08:42AM (#43387913)

The jxl compression would compute a base for all sub-images and create better diffs amongst them. The current encoder doesn't support that yet.

With my tiff lzw:2 it only takes the diffs for 2 consecutive lines per each sub-image, which is a shame. But still 50% compression. With jxl it would compress down to 10% or more with a sub-image base.

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Re:Compression of Spectral Images Using Spectral JPEG XL by JyrkiAlakuijala on Monday March 17, 2025 @01:02PM (#43390531)

Lossy compression can be megabytes vs. tens or hundreds of megabytes per image kind of question, i.e., worth all the sweat it brings.

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Re:Compression of Spectral Images Using Spectral JPEG XL by tehjoker on Monday March 17, 2025 @07:26AM (#43387313)

what problem did you run into?

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Re:Compression of Spectral Images Using Spectral JPEG XL by tetrahedon on Monday March 17, 2025 @08:43AM (#43387924)

Did you consider other compression methods? For us, ZSTD is quite good for TIFF files.

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Re:Compression of Spectral Images Using Spectral JPEG XL by JyrkiAlakuijala on Monday March 17, 2025 @01:01PM (#43390511)

ZSTD/Tiff is quite far from JPEG XL in compression density. There are many technical reasons why this is the case.

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