Re: Image compression
Posted by
Gabriel Landini on
Jan 05, 2006; 10:08pm
URL: http://imagej.273.s1.nabble.com/Image-compression-tp3704130p3704132.html
On Thursday 05 January 2006 20:27, Jeff Brandenburg wrote:
> 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
Thanks for the link, Jeff.
Strange claim, isn't it?
However, what is reported there does not seem to be quantitative analysis of
images.
Instead it seems that the author reports on subjective visual assessment by
radiologist observers. That is a completely different issue. (specially
because there is a degree of subjectivity in visual perception).
It may be that the compression artifacts do not interfere with perception of
the features of interest, or (as hinted) that it removes some noise. But I
think that it is a very inefficient and unpredictable way of performing noise
reduction.
Still, I think that for quantitative image analysis, it is better to start
with loss-less compressed images. If necessary noise reduction and image
simplification can be achieved afterwards with more controlled methods than
the jpeg compression.
Cheers,
Gabriel