Hi,

I looked at jpeg2000 as a compression for diffraction images for
archiving purposes - it works well but is *SLOW*. It's designed with the
idea in mind of compressing a single image, not the several hundred
typical for our work. There is also no place to put the header.

Bzip2 works pretty much as well and is standard, but again slow. This is
what people mostly seem to use for putting diffraction images on the
web, particularly the JCSG.

The ccp4 "pack" format which has been around for a very long time works
very well and is jolly quick, and is supported in a number of data
processing packages natively (Mosflm, XDS). Likewise there is a new
compression being used for the Pilatus detector which is quicker again.
These two have the advantage of being designed for diffraction images
and with speed in mind.

So there are plenty of good compression schemes out there - and if you
use CBF these can be supported natively in the image standard... So you
don't even need to know or care...

Just my 2c on this one.

Cheers,

Graeme

-----Original Message-----
From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of
Maneesh Yadav
Sent: 18 August 2007 00:02
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] diffraction images images/jpeg2000

FWIW, I don't agree with storing image data, I don't think they justify
the cost of storage even remotely (some people debate the value of the
structures themselves....)...but if you want to do it anyway, maybe we
should use a format like jpeg2000.

Last time I checked, none of the major image processing suites used it,
but it is a very impressive and mature format that (I think) would be
suitable for diffraction images.  If anyone is up for experimenting, you
can get a nice suite of tools from kakadu (just google kakdu +
jpeg2000).

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