Re: [Algorithms] Image compression

[Jon W. <jw...@gm...>]

Richard Fabian wrote:
> notable. I took the vertical gradient, horizontal gradient, and the
> _saddle_ (diagonal difference / Determinant), and these were then the
> values recorded for later use in the compression. This 2D approach
> made a small but significant difference in the compressability of the
>   

Isn't that basically a lifting process, based on a 2D predicted value? 
For previous approaches, I believe that the good-old lossless JPEG 
method used almost exactly that pre-process to determine deltas, and 
then used an entropy coder to code the deltas (instead of treating the 
deltas as something to separately compress using wavelets or whatever).
What kind of compression ratios are you seeing now, btw? And have you 
tried the smaller/embedded profiles of JPEG 2000 for comparison?

Sincerely,

jw



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