Bruce- It is not clear to me what sort of "study" you would need to convince you, as the ISO standard for encoding data into the JPEG-2000 file format is by construction mathematically and numerically lossless process. (Indeed, "compression", i.e. throwing away bits so as to further reduce storage requirements, is actually not defined within the scope of the standard.) -mpg
________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Saturday, February 23, 2008 1:58 AM To: OSGeo Discussions Subject: RE: [OSGeo-Discuss] 'lossless' JPEG2000 IMO: Thanks for the reply Traian, I don't mean to be dismissive of this report, but I was hoping for something more definitive to prove that 'lossless' JPEG compressions did indeed protect the integrity of the data.. Perhaps its just my ignorance, but I was hoping for something along the lines of: - a study of a range of typical spatial 'imagery'. - evaluation of all spectral values for each pixel in each image before compression. - 'lossless' compression of the images - restoration of the compressed images - comparison of all spectral values for each pixel in each restored image against the original pre-compressed values. - definitive statement with reference to the study results. Bruce > > JPEG2K supports lossless via a reversible wavelet transform with > integral coefficients (which make it reversible, and so lossless). > Here is a reference: > > http://www.ece.uvic.ca/~mdadams/publications/pacrim2001.pdf > > > > Traian > Notice: This email and any attachments may contain information that is personal, confidential, legally privileged and/or copyright. No part of it should be reproduced, adapted or communicated without the prior written consent of the copyright owner. It is the responsibility of the recipient to check for and remove viruses. If you have received this email in error, please notify the sender by return email, delete it from your system and destroy any copies. You are not authorised to use, communicate or rely on the information contained in this email. Please consider the environment before printing this email.
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