Quickcam Barrel Distortion

Notes: This is very old stuff (c. 1996). I'm sure that the quickcam drivers have been updated a LOT since back then, and cameras are better too. I would be happy to see this code used in a GIMP filter or in other open-source applications. Let me know if you're working on that.

Since leaving CMU, I've used the formula below in KPT5's RadWarp filter, published by MetaCreations and now Corel. This version remains GPL'ed.

Michael Herf
April, 2000

Annoucement! We have a code and binary release. Right click to get files:

QuickWarp Dev kit

Modified qcam-0.3 with quickwarp

Modified xfqcam with quickwarp

If you're a QuickCam owner, you may have noticed that the barrel distortion is quite pronounced. Look at an object at the edge of the camera window, and it's curved, like a barrel.

This is a simple warping module that precomputes a radial warp map of the form

Then it samples using fast bilinear interpolation. All this means that you can resample images on the fly as they arrive from the camera, with very little slowdown.

Raw quickcam image:Fixed QuickCam image:

Once again, that's: ``Broken''``Fixed''