Forum : Advice & Critiques

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Topic: transparency and png support

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lec (Over 1 year ago)
Hi, I would like to know if Photosynth supports transparency in the images, png file format? Right now the background in my jpeg is black, I could not upload png's with transparency. I have a object which was photographed from different sides, different scales, and different parts of it. The rotation looks goofy as the photography was not done to photosynth standards (prior to photosynth's existence). There is no way for us to re-photograph it. Any thoughts?
TonyErnst (Over 1 year ago)
lec, right now photosynth only supports jpgs.  You could try converting your pngs to jpg and then see how it synths.
Nathanael (Over 1 year ago)
Tony, I believe he already has. Add me to the list of those who would really appreciate alpha layer support as a means of telling Photosynth what to ignore in its analysis, if not for presentation value.

In my Buzz Lightyear synth (I'll grant you, the model is very nearly textureless and I also got too many video frames with interlacing artifacts) I got a huge number of hits in the white areas surrounding Buzz due to jpg artifacts. It would have been much appreciated to be able to save a png version of all of the frames with the currently white background portions being painted transparent and saved in a lossless format.

There are a number of things I intend to try next time I try a similar synth which should improve the results, but again, they are a bit of a cheat compared to true alpha transparency.

Lastly, could you explain what happens when I make a copy of my RAW images and instead of converting them to jpg, simply rename the extension? They do synth.
K (Over 1 year ago)
I'm surprised that your RAW images synth.  What camera do you use?  The only thing that makes any sense is that the synther is using the embedded JPG that most RAW files have.  Can you point us to a synth where you did that?
K (Over 1 year ago)
I forgot to add that I also like the idea of being able to tell the synther to ignore some parts of the image.  It could help in your scenarios & also for dealing with scenes that have repeating patterns.
Nathanael (Over 1 year ago)
Ken, I use a Nikon D60 that shoots RAWs under the NEF extension. I actually tried the simple extension rename several times as I was too low on disk space at the time to store the original images plus the converted jpegs at 99% quality and still retain room for the synther to work.

I believe one or two such synths may have been mixed with actual jpegs from my brother and his girlfriend's cameras, but one of my synths that is completely pulled from the renamed NEFs is (hence the sideways thumbnail - I had rotated the images, however the photo editor did not update the embedded thumbnail accordingly).
Nathanael (Over 1 year ago)
After a quick glance, I realise that I actually did this a bit more than I remembered. The contents of the current pages 2 and 3 of my synths contain quite a few thumbnails with black horizontal bars along the top and bottom. Every one of those was completed using my "cheat". 

I'll list the collection IDs to fit them all in this post.


Out of curiosity, if deepzoomtools already exports PNG tiles (+ other formats) for use with Seadragon, why not allow Photosynth to use PNGs? Is it a licensing issue or something else entirely? Seems like analysing one format is pretty much like analysing the next to me.
Nathanael (Over 1 year ago)
Running a quick search confirms that you were dead right about the embedded JPGs.

Sadly the embedded jpeg in an NEF appears to be only "Basic" quality for size reasons. I wonder what is actually happening during a batch 'conversion' from NEF to JPG... I would hope not simple extraction of the embedded low quality JPG but that may, in fact, be the case, being that I'm a complete beginner with RAW and certainly did no calibration of my own when I have actually followed through with the proper conversion process.

In any case... back to transparency...

Also, (what kind of post would this be without more tangents?) on getsatisfaction long ago David mentioned that Photosynth supported TIFFs. I believe that was in the Microsoft Confidential preview, though, and it no longer appears to support anything other than JPG. I had heard that Photosynth was using HDPhoto/JPEG XR at some point. Was that only in the Tech Preview when HDView was being used to power the viewer?
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