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Information about JPEG-LS is easily found on Google and in a lot of DICOM chapters. However, there are links/pages/readings that mention JPEG-LL, too. However, i have taken a deeper look at the DICOM standard, not a chapter has ever mentioned anything about JPEG-LL, but in a lot of other conformance statements/forums/articles, JPEG-LL has been mentioned...

So, what is the difference between JPEG-LS and JPEG-LL?

Gary Tsui
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  • Why vote to close? This is seriously and directly related to programming and software development. It is a very crucial compression scheme for many, many, many different areas of applications. Here, i would like to reach out and ask for help regarding the difference between JPEG-LS and JPEG-LL. Because different literatures have notated them differently and i would like to know if anyone else could help with my question. – Gary Tsui Jul 25 '11 at 10:08
  • Whoever voted down needs some serious thoughts about what this question is about. This is about JPEG-LS and JPEG-LL, which plays a serious part of major jpeg compression. Whoever can answer this question will help anyone who has the similar question in the future, which i am sure they will have. If this question needs to be voted down, all other questions that are related to dicom/jpeg must be voted down too. – Gary Tsui Jul 25 '11 at 10:18
  • Thanks for the answers below. For the person who voted this question down or voted to close, please read the answers below and see them for yourself whether this is anyhow related to SO questions and of any research value. – Gary Tsui Jul 26 '11 at 01:36

2 Answers2

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I suppose JPEG-LL is the lossless version of the JPEG (usually called JPEG Lossless), with transfer syntax 1.2.840.10008.1.2.4.70, and it's the most common lossless compression. Anyway, it's not the best possible (it does not support signed pixel values, and its compression rates are about 2-2.5).

JPEG-LS is a completely different standard with transfer syntax 1.2.840.10008.1.2.4.80, developped by HP, which is faster and have better ratios than standard JPEG. However, it's not widely used.

ruslik
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I supposed JPEG-LL refers to ITU-T T.81, ISO/IEC IS 10918-1 aka JPEG lossless. While JPEG-LS refers to ITU-T T.87, ISO/IEC IS 14495-1.

Technically speaking JPEG-LL is exactly the same standard as the usual 8bits lossy jpeg as found on internet website. JPEG-LS is much much less common.

malat
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  • thanks for the answers. With regards to JPEG-LL being exactly the same standard as the usual 8-bits lossy jpegs, do you still have the source of info for that? I need to quote it somewhere. Billion thanks. – Gary Tsui Jul 26 '11 at 01:36
  • Yes, this is explained in ISO/IEC IS 10918-1 – malat Jul 28 '11 at 09:39
  • thanks, may i know if you have the link to ISO/IEC IS10918-1? thanks! – Gary Tsui Jul 28 '11 at 09:43
  • thanks for the help again; but i can't locate the free copies of that. Do you have access to free copies of that? thanks – Gary Tsui Jul 29 '11 at 01:47