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JPEG2000: Is It The Future Of Imaging?
LISNews writes: "EE Times has a cool story on the pending JPEG2000 standard and how it will change what we see on the Web. They are already thinking wireless: 'The killer app for JPEG2000 is a handheld device combining both Internet applications and wireless access.'" They're also thinking about migration from current formats, smooth degradeability and -- nice to hear -- Open Source acceptance. Try JPEG's own JPEG2000 page for more information and links.
We basicallycovered this all before. Not a whole lot new here!
/. too much to let it drift off course without saying something.
Good lord, I'm really getting tired of this! If you guys can't read and remember your own front page (as you've admitted you don't) then it means that you (as individuals) aren't picking topics that you (as a group) find essential reading -- and that's a terrible sign!
There's so much interesting stuff going on, but they seem to find the same old stories over and over, perhaps 1/3 of the accepted stories are retreads. CmdrTaco et al -- we love you, but maybe it's time to go to a community moderated article selection with occassional "automatically accepted" posts by you guys.
if you can't remember or even do a search on old topics when picking a new one, you are too overloaded to be doing a good job at the task of selecting topics.
There are so many other areas where we'd rather have you guys using your impressive talents!
At the very least, can we see a quarterly thread to select the "best-of" suggestions for improving SlashDot, the way we select questions for interviews? Call it a step towards RMS's view of community-based Open source, if you will, but repeats and other bad thread decisions serve no one, and I like
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If you can go to bed, knowing you did a valuable thing today, you're very lucky. If you can't... it's not bedtime
Last time Slashdot covered this story, the EE Times article had a very hyped-up comparison showing JPEG2000 to be dramatically better than plain JPEG. Upon closer examination, while JPEG2000 is better, the difference is not very dramatic, as this comparison shows.
If this technology is not free for free software implemenation, forever, then my advice is to avoid it like the plague. I hope they do release the technology for free, but even then some care is called for. After all, you definitely don't want to send a JPEG2000 image to a browser that doesn't properly support it. One can only hope that the browser support is better than that for, say PNG.
The idea of sending images at multiple resolutions, one for the screen and one for printing, is an excellent one. However, it's not fundamentally the responsibility of the image format, but rather of the hypertext protocol. The idea has been around for a while - the first time I saw it was in Ted Nelson's Xanadu proposal. Damn, the old guys stole all our best ideas! Again!
LILO boot: linux init=/usr/bin/emacs
We did a JPEG vs JPEG2000 comparison for a class project here. The improvement seems to be dramatic, especially at low bit rates.
Raph Leviens conclusions are interesting but they only tell half the story about Jpeg2000.
Getting better compression ratios is not the only objective of the Jpeg2000 standard. It has lots and lots of other features that make it attractive besides impressive compression ratios.
First a little overview of compression. Compression schemes can be fitted into a three step framework:
Transform->Quantization->Entropy Code.
The transform part is where the data is massaged into something that is more suitable for compressing. The aims of this step is to remove redundant information as much as possible. In images pixels are very redundant. Pixels close together have very often the same color.
The transform part of the current Jpeg is the DCT transform.
The second step is quantization. This is where we throw away information that we can live without.
Finally comes Entropy coding. This is where the actual compression takes place. Common values in the data are here represented
by short bitstrings and those who occur seldom get longer bitstrings. In current Jpeg this is Huffman coding.
Raph talks about downsampling the image before compressing. That is exactly what Jpeg2000 does. The transform part of Jpeg2000 is a multiresolution analysis of the image. It takes the original image and downsamples it to a very small image. Then it adds in layers the information needed to upsample it to a higher resolution and get a perfect reconstruction. This is nice for lots of reasons. We can tell the decoder to stop downloading more details of the image at any time. You don't have to download the whole image if you don't want to. Nice for low bandwith connections and mobile connections. You can also choose to progress to a compleatly lossless version.
But Jpeg2000 does even more. It segments the image into tiles. This gives you the possibility to download only the regions of the image you are interested in in high resolution (good for porno - you only get the tits!).
The current Jpeg has only one transform, the DCT transform. Jpeg2000 v1 will have two transforms to choose between: An floating point transform for high performance compression and an integer only transform for use on low-end devices. That transform also allows you to get a perfect reconstruction. In Jpeg2000 v2 you can even specify your own transform coefficients and by that adapt the transform step to the data you have.
So even though the Jpeg2000 standard has rate/distortion similar to current Jpeg (that is Raphs point) it offers other very attractive features such as progressive decoding (giving you almost any resolution you want), regions of interest and the possibility to only get parts of the image if you are on low-bandwidth links.
Thanks
Hrafnkell
.- CitizenC (User Info)
--Ben
If you don't want to read through specs and prefer a down-to-earth explanation of features etc, check this Designer article on JPEG2K and what it will mean to web design of future. Excellent stuff.
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Will the MPAA try to kill this technology. This would be a techology that could be used to send images from a movie or even an entire movie over the internet. This technology must certainly violate the DMCA. In fact most technology violates the DMCA. Beware the MPAA is doing time travel experiments. They are going to send the DMCA back in time to stop digital images, then before that the VCR then before that photocopies, bethen photography, bethen paintings, bethen pigments, bethen scratches on rocks, bethen rocks, bethen matter.
The DMCA and the evil machinations of the MPAA must be stopped before they destroy all creation.
We must destroy the MPAA so that there is a future in which images can be communicated freely.
134340: I am not a number. I am a free planet!
As a technical member of the JPEG2000 body, I have to say that sitting in and participating in the meetings was quite an interesting experience. As always, there were a number of technical issues to resolve, but the most heated and often most time was spent on IP issues. The comment in the article, warning about people holding IP crawling out of the woodwork if the standard is successful is definitely one to watch. While I have not been involved in the last couple of meetings, I'm still actively involved in following what has been happening technology wise. The benefit of wavelet compression is not so much in compression quality, but in features. From a file, one can get multiple resolutions, multiple quality levels, selective decoding of a specific region (random access), etc. This should be a benefit in the long run. The article touches on it briefly, but one down side to the new standard is that it is more resoure intensive than the current JPEG even PNG formats -- in memory and cpu power. I suspect it will be a while until we see wireless devices with the resources to handle the format in a general purpose manner. A custom ASIC solution is a possibility, but would a device like a Palm Pilot include one? What are the factors that lead to the improved quality and additional complexity? JPEG2000 is based upon wavelet compression. The standard allows for tiling images, but it is more typical that the whole image is compressed, for most applications. Unlike JPEG, where pixels are grouped into 8x8 blocks, wavelet schemes which operate upon the whole image have a lot more data to play with when it comes to throwing away (quantizing) information. If one were to attempt to use the standard with 8x8 tiles, well, it would not work very well. Because of this increase in data that is part of the working set, the amount of memory needed, when compared with JPEG is, in most cases, much greater. During the JPEG2000 process, a few companies proposed block-based wavelet solutions which would reduce this complexity without sacrificing feature set or even quality. However, they were not included due to concerns over the companies not making the IP available on a free and non-discriminatory basis. There has been a part-2 to JPEG2000 proposed that will allow for the inclusion of technologies which IP is not necessarily free. My question to the group here is, if JPEG2000 takes off and companies and individuals who have not previously declared IP come forward and want royalties, will the standard be hurt? Is there a place for a part-2 which contains IP which is not free? And, what applications does the community here see as being crucial for the adoption of JPEG2000? Good night and enjoy.. -jim