Thursday, September 28, 2006

Panoramic views - Preliminary results

An interesting use of the data from GeoCam is to see how stitching algorithms are performing with data from our balloon flight. An algorithm developed by Matthew Brown does this automatically through the comparison of SIFT points and a RANSAC algorithm determining good fit. The software is available at the AutoStitch web page.

We first tried stitching five photos together and obtained a reduced file (200 KB as opposed to 5 times 3.2 MB)




We then went on using about 100-200 frames per panoramas and obtained the following views:






It seems evident that the payload wasn't turning at 1 rpm.























One of the apparent issues seems to be that the comparison for overlap between frames was based on cues from the clouds. Since we took photos at intervals of about 23 seconds, some of these clouds changed location and eventually allowed for some of the panoramas to be unduly stretched.

9 comments:

Basil said...

Cool! Any chance you could string that into frames of a time elapse movie and post it on Youtube?

Igor said...

We're looking into it. Thanks for the suggestion.

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Igor said...

Thanks for MEncoder docs reference, we'll look into.

Fabio:
thanks for the pointer on the 100%. We tried it but it takes a loooong time to get something with more than 20 images. We are looking into putting this on a bigger machine and see how far we can go.

With regards to why the panorama is doing this stretching, it may indeed be the case that this is a point issue as opposed to feature/line recongition issue. An example of this is in the last picture:
http://photos1.blogger.com/blogger/5955/293/1600/pano6.jpg
in the middle the line is cut in three. It may also be due to the fact that the panorama tried to merge views that were taken at a 20 degree angle. Thanks for trying to help us figure it out.

Anonymous said...

Is there a reason that a panoramic or other wide angle reflector was not used?

Igor said...

I think the answer to the last question is : weight. We were constrained to a 1 kg payload total.