In order to support thumbnails, we will be adding JPEG
and JPEG 2000 support to CBFlib. There would then be no
reason why one could not use JPEG 2000 for diffraction
images as well, but I am not certain anything would
be gained in practice for those images over what the
ccp4 J. P. Abrahams pack_c.c compression offers. At the
DLS session of the most recent imgCIF workshop we
agreed to start a serious benchmarking project and will
include a careful comparison of timings of byte
offset versus ccp4 versus jpeg 2000 versus ... in
what we do.
-- Herbert
=====================================================
Herbert J. Bernstein, Professor of Computer Science
Dowling College, Kramer Science Center, KSC 121
Idle Hour Blvd, Oakdale, NY, 11769
+1-631-244-3035
[EMAIL PROTECTED]
=====================================================
On Mon, 20 Aug 2007, Winter, G (Graeme) wrote:
> 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).
>
