Johan,

I have no problem with lossless compression, LZW etc. I do have a 
problem with people using "high quality" jpegs which might look the 
same, but introduce high frequency pixel level artifacts. 
Colocalization and other correlation dependent imaging methods can 
suffer. Resolution can suffer. As far as transfer rates, I am patient 
and have no problem waiting 20 min to download a gigabyte image file 
to my home office. Storage is an issue but I am of the opinion that 
it is especially important to keep at least two copies of the 
original unmanipulated data with at least one on a read only memory 
format such as a DVD. Patents (or academic reputations) can succeed 
or fail on being able to justify a claim.


>Mario wrote:
>...
>>  upon request. In fact, uncompressed raw image files should be provided
>>  to the reviewers of a paper. Might save a lot time. As for Catherine
>>  Verfaillie and colleagues, without knowing the details, it seems like
>>  a black eye on common sense on the part of U of Minn. sorry don't mean
>>  to offend but consider item 2.
>it's about time to get this straight (mario might have just a typo here,
>not claiming anything for him):
>
>        compression does NOT imply reduced image quality
>
>but it does for sure increase the speed of disk transfer, and if you
>know what you are doing, some but not all compression algorithms can
>*optionally* trade high frequency information (noise) for disk space.
>avoid using the terminology that "compression" destroys images because
>it confuses non-experts into thinking they should be storing the images
>uncompressed. there's a factor 2-10 to gain in disk space/speed for
>normal images.
>
>/Johan (who is very tired of re-teaching about compression)
>
>--
>--
>------------------------------------------------
>Johan Henriksson
>MSc Engineering
>PhD student, Karolinska Institutet
>http://mahogny.areta.org http://www.endrov.net


-- 
________________________________________________________________________________
Mario M. Moronne, Ph.D.

[log in to unmask]
[log in to unmask]
[log in to unmask]