Public Lab Research note


Creating Multispectral Imagery for California Beaches

by MicheleTobias | May 24, 2011 00:51 24 May 00:51 | #268 | #268

Over the last few weeks, I've been working on streamlining a workflow to stitch together photos taken from my hot air balloon near Santa Barbara, CA (one set is standard color photos and the other is infrared) into one image with four colors (red, green, blue, and IR). Pictured here are some preliminary results - a false color infrared image of the dunes. Some details need to be worked out, such as why the images lose so much resolution in the stitching process, but that will come with a little more work. I've used a combination of Hugin, Quantum GIS, and GDAL to make this image.


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6 Comments

Well done. How large is the input dataset? I look forward to following your work.

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The picture is just a piece of the final mosaic (about 7 photos shown). The whole thing was about 20 narrowed down from the 130 or so photos taken over the beach. The resolution is about 4 mm per pixel, when the panorama program doesn't reduce the resolution.

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Wow, fantastic resolution. What altitude did you fly from?

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Is there good ground reference imagery for this site? What are the coordinates?

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The jury's still out on the final flying height, but I think it was about 30 meters (so really low). There is no good imagery to use to reference this mosaic because the sand shifts so quickly and the plants are very hard to see in more traditional photos. That's why there are targets on the ground. Each of the black squares with the white cross were logged with a GPS to help georeference.

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I may have figured out why the images have such a reduced resolution. Some of the settings in the stitching program I used limited the size of the output file. Maybe once I work out all the kinks, I'll write up some instructions and tips for working with the program, Hugin.

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