[Dcmlib] [Fwd: JPEG Lossy Identification Question]

[Mathieu Malaterre]

I need to add that to my TODO list

-------- Original Message --------
Subject: JPEG Lossy Identification Question
Date: 31 Oct 2006 10:17:16 -0800
From: Homer <eholmstr at gmail.com>
Organization: http://groups.google.com
Newsgroups: comp.protocols.dicom

Hello,

I've been noticing that some vendors are not providing the attribute
(0028,2110) at all which would identify that Lossy Compression was used
on the pixel data in the case where the transfer syntax used was a JPEG
Lossy based transfer syntax.

If I understand the DICOM standard correctly, if a JPEG Lossy transfer
syntax of any flavor is used then the attribute should be present and
populated with "01". I did see notes that its Type 3 under the general
description of the attribute for backward compatibility however in some
specific IOD's there are modules that state its a 1C. So for those
cases I'd expect to see a "01" in that attribute.

If my understanding above is correct, would it be safe to assume that
even in the case where the vendor didnt provide the attribute
(0028,2110) but they did use a Lossy transfer syntax then the pixel
data is Lossy? Therefore, during image review of the object a Lossy
icon could be displayed to reflect this assumption? After all, a Lossy
transfer syntax is lossy in itself right? (no critical need for the tag
to identify Lossy in this particular case, but the tag becomes extra
useful during transfer syntax conversions - to ILE or ELE from Lossy
for example)

Thanks!

Homer