2011.07.29 18:53 "Re: [Tiff] Using photon lists rather than rasters", by Chris Cox
I didn’t say “new predictor” just “better”.
For a 1 bit image, CCIT predictors/compressors would be good.
For an 8 bit/channel image, the differencing predictor would help a lot on sparse data, then follow up with LZW compression.
For his data, combining multiple exposures to create a photon hit map (summed image) then applying predictors will give the best compression (by removing a lot of overhead).
But I don’t know if that is feasible for his project (for captures of non-mobile sources, it should be).
On 7/28/11 10:30 AM, "email@example.com" <firstname.lastname@example.org> wrote:
The idea about a better predictor to improve compression of niche scientific images is interesting. Along the same direction, Terry could really use the new compression type for that. Think about that: if it's a new predictor that nobody today knows how to decode, and if it's much more advanced than today's "TIFF predictor" (even though it is indeed a predictor in mathematical/pedantic terms), it doesn't hurt to make its own compression type. As for the photon images, it will require something superbly advanced algorithms, something that blends several existing advanced algorithms together that nobody has seen before. Like: multi-resolution (or progressive-resolution), some kind of CABAC (which is both context-sensitive and uses arithmetic coding), etc. That said, the larger TIFF community may try to compel you to (1) open source your implementation and (2) give up, or sign over all intellectual rights and copyrights of that specification, and for that matter (3) it still leaves you vulnerable to patent lawsuits while the larger TIFF community just sit and watch. Therefore, it's important to remember that ultimately you have to decide what to do with your invention; you may decide whether to open it or not. If in doubt, talk to your company or employer lawyer. Thanks,
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Date: Wed, 27 Jul 2011 16:57:30 -0700
Subject: Re: [Tiff] Using photon lists rather than rasters
Re: [Tiff] Using photon lists rather than rasters
Tagged Image File Format.
I would rather not see a TIFF “image” that is not an image and is not readable by other software.
TIFF already gets too much abuse with undocumented custom compression types that render the files useless.
In this case you are creating a vector display list, for which there are more appropriate types.
Personally, I’d just apply a better predictor to improve compression and keep the image data. If all you need are locations/centroids of photon hits – you could easily convert the image to a 1 bit/sample representation and compress that.
On 7/27/11 3:51 PM, "Terry L. Sprout" <Terry.Sprout@Agile-Automation.com <http://Terry.Sprout@Agile-Automation.com> > wrote:
Ryan Wong wrote the following message and accidently sent it directly to my email:
TIFF is a raster image format, not a vector image format. Inside a TIFF file, each page must contain exactly one raster image. It can contain vector annotations in metadata, but viewers are not required to render it. It will most likely be ignored by most TIFF viewers that do not understand it. A TIFF page can contain thumbnail images, which, like any other metadata, can be ignored by viewers that do not support it.
No matter how hard you try, no current software would be able to decode from your photons list. Even far into the future, mainstream software do not have a need to support “photon lists”, but they wi