PTA 6.2 - Almost full DNG Support !?!

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seigell
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Joined: Tue Mar 21, 2006 10:26 pm

PTA 6.2 - Almost full DNG Support !?!

Post by seigell » Thu Oct 24, 2013 6:46 pm

I made a "mistake" of not "developing" a set of DNG files to TIFFs before Starting a PTA Project with them.

To my surprise, PTAPicker and the Auto-Build / Auto-Optimizer handled the DNG Images successfully.
The Preview view was a bit odd, insisting on creating "horseshoes" of the horizontal single-row pano.
The Auto-Size function was incorrect, but possibly because the Step#2 FOV calculation was constantly wrong.
The only thing that kept me from making a "usable" pano was that the Control Point Viewer "was having none of it" - couldn't render images from the DNG files.

Is this a precursor to full DNG support, maybe ?? Or just an "almost" side-effect of a library used throughout most of the UI portions of PTA ??

maxlyons
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Re: PTA 6.2 - Almost full DNG Support !?!

Post by maxlyons » Sat Oct 26, 2013 9:23 am

seigell wrote:Is this a precursor to full DNG support, maybe ?? Or just an "almost" side-effect of a library used throughout most of the UI portions of PTA ??
I haven't studied the DNG format much, but I know that it is based on the TIFF file format. It sounds from your observation that the logic I coded to parse EXIF/TIFF metadata like focal length, (which is all written from scratch using no third party libraries) probably works with DNG files. At one point I tested that it works with Canon raw files (which, at the time I tested, were also very close to a TIFF format). I hadn't tested it, but I guess from your observation that PTAPicker was able to read the image data (my guess is that it read the raw, monochromatic sensor data which is all that would be needed to find features and pick reasonable control points). PTAPicker uses the OpenCV library, and I don't think OpenCV advertises that it can read DNG files, but perhaps it reads them as a one channel TIFF file...not sure. The optimizer doesn't care/know about the image file format...it just uses a series of numerical coordinates as input (the coordinates generated by PTAPicker). The preview and final rendering is done by PTAStitcher (which doesn't use OpenCV, but relies on LibTiff and my own code), and I'm sure that it won't generate a three color result from a DNG file without a lot more work.

I don't plan on adding support for DNG to PTAssembler. While I think it could be done, I feel it would be like adding a toaster to a bicycle...possible, but not very useful for most folks.

Max

seigell
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Joined: Tue Mar 21, 2006 10:26 pm

Re: PTA 6.2 - Almost full DNG Support !?!

Post by seigell » Sun Oct 27, 2013 12:25 pm

Parts of that reply are rather tantalizing to those of us who shoot with Canon DSLRs - but in general I understand why you wouldn't directly support any specific RAW format.

The early legacy of "works with Canon raw files" is now directly blocked by the File Select actions. The Add Files dialog has a hard filter for "jpg,bmp,tif", and the Drag/Drop action changes the ".cr2" file extension on dropped files to ".tif" (but fails to do likewise for dropped ".dng" files - so action seems "targetted" to replace some specific list of extensions).

This action of "change the .cr2 extension to .tif" matches up with the detection of "file not found" in RED in the Step#1 File List, but doesn't seem to have any mechanism orientated toward "Controlled Resolution" of that status. Were there possibly plans to augment this with such a "controlled resolution" such as being able to invoke an External Process (supported for Noise Reduction Preprocessing and Unspecified Postprocessing) for Source File Format Conversion ?? This could be as simple as invoking a Predefined Command String with placeholders for Source Filename and Destination Filename (Canon DPP and ImageMagick Convert, et al, support such processing), and then delaying the next Auto-Create actions until all Source Files are present.

Yes, this can readily be accomplished outside PTA - requiring batch Raw Conversion beforehand - but I'm trying to guess at your original intent for this featurette...

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