Posted by
Jeff Brandenburg on
Jan 05, 2006; 8:27pm
URL: http://imagej.273.s1.nabble.com/Image-compression-tp3704130p3704131.html
Just now catching up on holiday email...
On Dec 22, 2005, at 8:33 PM, John T. Sharp wrote:
> I am starting a project measuring features of hand and foot x-rays on
> 400 to 600 sets ( 4 each set) so it is a rather large project. I'm
> estimating 250-350 hours. There is some controversy among colleagues
> who we also be participating as to wheter measurements are likely to
> be affected by transmitting the images in compressed TIFF format. I
> will be using the Microsoft Photo Editor to decompress them and then
> making the measurements with an ImageJ plugin.
>
> Would anyone with the engineering/math/computer science background
> sufficiently broad to know whether this "lossless"
> compression-decompression system will influence the measurements
> comment on this problem.
As others replied, "lossless" means lossless -- compressing losslessly,
then decompressing, should result in bit-for-bit identical files. My
limited Windows experience leads me to distrust any claims of
"lossless" image treatment in any Microsoft application, but I have no
evidence that Photo Editor does the wrong thing.
While it isn't directly relevant to the problem you describe, I
recently found this press release indicating that lossy JPEG
compression of mammography images can actually IMPROVE (!) diagnostic
accuracy:
http://news.uns.purdue.edu/UNS/html4ever/2005/
051220.Lucier.mammograms.html
If the standard JPEG compression algorithm can do this, one wonders
what specialized algorithms might be able to achieve...
--
-jeffB (Jeff Brandenburg, Duke Center for In-Vivo Microscopy)