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   -> Volume 4, Issue 4


Question: Backend Compression Methods for Wavelet Transformed Images ?
 
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sev@gdstech.grumman.com (Sev Binello)
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PostPosted: Mon Dec 02, 2002 6:07 pm    
Subject: Question: Backend Compression Methods for Wavelet Transformed Images ?
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Question: Backend Compression Methods for Wavelet Transformed Images ?

Hi,
I am experimenting wavelet compression on IR, radar and visual images.
I have heard of some large compression ratios available via wavelet
compression, however, I do not seem to be able to attain such ratios
( i.e often hear of 100 : 1). Are there benchmarks available anywhere?
Are descriptions of the techniques used to compress the images
available?

Basically, I perform a wavelet transform on an image, and
iteratively transform the low-low pass image a variable number of times.
Then scale the coeeficients back to pixel values and then use various back
end compression methods on the transformed and scaled images.
I have tried both lossy (Vq, Adpcm) and lossless (LZW, ARIITHMETIC)
techniques, in addition to cascading the two. The compression ratios
I get are usually on a par with JPEG if not a little lower.

Comments and Suggestions Appreciated

Sev
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