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GreycLab / gmic-community

Community contributions to the G'MIC software
http://gmic.eu
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wavelet decompose not reversible #101

Closed orbisvicis closed 6 years ago

orbisvicis commented 7 years ago

Is this supposed to happen? This is the result after I recompose the wavelet decomposition:

gmic wavelet decompose recompose

This is gimp in rgb uint8_t mode.

dtschump commented 7 years ago

That is not really surprising. From a numerical point of view, the wavelet decomposition is not perfectly reversible, you'll always loose a bit of precision as IEEE floats cannot store all possible floats with full precision. The auto-level makes the difference very clear, but what is the range of the difference ? If the max error is less than 4-5, I'd say everything is normal.

orbisvicis commented 7 years ago

Yeah, auto-levels maps 0-3 to 0-255, so looks good. By the way, do you know how to get a similar effect in a much more straightforward manner? Looks like banding both parallel and perpendicular to the gradients, each type of band being a different (primary) color and overlapping additively (or similar).

Can make some interesting effects like:

logo light