Comments on: Microsoft’s HD Photo not better than Jpeg 2000?

By: Ron M.

Ron M. — Wed, 29 Aug 2007 17:05:40 +0000

You might also want to look a the effect of device noise on compression efficiency. We found that minimally lossless J2K encoding primarily strips out noise from the image. The result is much more controlled than the Median filtering Photoshop offers. Wavelets at work, I guess…

You can confirm this via image differencing using the Photoshop Calculation… command and looking at the resultant Histogram. Even with high end-scan backs, file sizes can drop noticeably, sometimes by more a factor of 3 over losslessly encoded images.

Wouldn’t device noise show up as low-order bit effects, with variation due to color (via combining the relative noisiness of R, G, & B)channels?

By: Andrew Polar

Andrew Polar — Wed, 29 Aug 2007 14:52:29 +0000

I quickly ran 5 different programs to compress kodak image set. The result is on http://www.ezcodesample.com/pre_image_reduction.html
Microsoft WMP is called there HD Photo. The program obtained from Bill Craw blog. I provided also for comparisson my own implementation of Marticci median adaptive predictor with arithmetic coding suggested in 1990. For those who did not see this predictor I can say that it is few lines of ‘c’ code. Arithmetic encoders are available for free I used one of them (it is not even mine). This program that gives few percent less compression than JPEG2000 and better than WMP could be written in 1990 and have size near 500 lines if we ignore format manipulation code.

By: Andrew Polar

Andrew Polar — Tue, 28 Aug 2007 17:03:39 +0000

When image compression scientists are coming to the point of making scientifically proven test, they act as if they’ve never heard of statistics and hypotheses test. There is a big science about that. If corporation (or individual) A says that it achieved better result than B the hypothesis is formulated that says “B makes better compression than A”. The hypothesis must sound this way, not the other. Then statistician randomly collects image samples for testing (I say again randomly, it is important) at the size 30 images or more (less number is allowed but may raise questions and open debates). Then the test is conducted and recorded. Then mean and standard deviation is computed for results for A and B methods. Even if mean for A is really better this is not a prove yet. Then data are plugged into a formula (some standard error tables are used too) that tells what might be a probability that the result is obtained by chance. And if the probability of obtaining better result for A by chance is less than 5 percent the statistician conclude that “statement that B makes better compression than A” is not true. Sorry if someone see this as kind of weird logic, this is standard statistics that is used all over the planet. And it is level of community college not even university. I explained it here in some sort of common sense language, omitting details, tying to provide a concept so we can see that tests are not even close to what should be called scientific prove.

By: Piclab 2

Piclab 2 — Sat, 04 Nov 2006 08:15:24 +0000

Windows Media Photo…

Windows Media Photo - новый формат для хранения cжатых изображений, разработанный Microsoft. Утверждается, что этот формат обладает самым лучшим качест……

By: chAlx

chAlx — Fri, 27 Oct 2006 08:32:57 +0000

It would be great too to get some ’social comparation’ results. Such as:
- license politics and costs;
- cpu and memory performance;
- number of platforms technology [will be] available on;
- losless versions compare.

By: Sachin Garg

Sachin Garg — Tue, 24 Oct 2006 14:53:03 +0000

Yes, a third party test set will be better. Even better will be to have multiple public test sets from independent sources.

But till that happens, I will be happy if the first one comes from MS.

(In any case, intentionally or unintentionally, most algorithms are tuned towards the files commonly used for benchmarking)

By: Nick

Nick — Tue, 24 Oct 2006 10:27:31 +0000

A third party test set will be better. What if they include in it only such images on which their algorithm works better.