[OSGeo-Discuss] 'lossless' JPEG2000

[Michael P. Gerlek]

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: discuss-bounces at lists.osgeo.org
[mailto:discuss-bounces at lists.osgeo.org] On Behalf Of
Bruce.Bannerman at dpi.vic.gov.au
	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 
	>   
	
	
	
	
	
	

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