Lens distortion removal can help "flatten" images with a "fisheye" or barrel distortion, and make it easier for them to be used in creating maps. 

This is especially helpful when using photos from smaller cameras like the #mobius-action-cam and most #gopro cameras.

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## Questions

[questions:lens-distortion]

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## Activities

[activities:lens-distortion]

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## Lens databases

Databases collecting lens geometries are available, for use with programs like this one:

http://www.agisoft.ru/products/lens/

### LensFun database

The LensFun database is an open source database of lens models for correcting distortion. It'd be great to get the Canon A490 and SD 1300 series in there, and the format is:

<script src="https://gist.github.com/1351843.js"> </script>

You can read more about how to calculate this and generate other types of camera model stuff here: 
http://lensfun.berlios.de/lens-calibration/lens-calibration.html