Re: Applying calibrated geometrical distortion to an image ?

Posted by Albert Cardona-2 on
URL: http://imagej.273.s1.nabble.com/Applying-calibrated-geometrical-distortion-to-an-image-tp5001968p5001970.html

Alan,

Have a look here:

http://fiji.sc/wiki/index.php/Distortion_Correction

This is a protocol to calculate the distortion of your camera. The resulting transformation you could apply using Stephan Saalfeld's mpicbg library functions.

Albert

On Mar 3, 2013, at 3:33 AM, Alan Hewat <[hidden email]> wrote:

> I have a camera instrument with a fixed geometry that produces slightly distorted images.
>
> I want to determine the distortion correction field, by comparing the distorted image with the undistorted image, eg of a grid. I then want to apply that calibrated correction field to any image with the same camera, without user interaction. I need a precise automatic correction, since the user must measure positions within the corrected image.
>
> I tried http://biocomp.cnb.csic.es/~iarganda/SplineDeformationGenerator/ which allows a choice of distortion models with a small number of parameters. This works, but calibration requires an a priori choice of the type of distortion  (fisheye, barrel etc...) and then manual adjustment of the parameters to obtain what <b>appears</b> to be the least distorted image. It is too subjective, and difficult to obtain parameters that remove all distortion.
>
> Then http://biocomp.cnb.csic.es/~iarganda/bUnwarpJ/ looked promising. This determines the distortion field that will transform between an un-distorted and distorted image pair. But again it appears to be a manual process and I couldn't see from the tutorial how I could store the distortion field and automatically apply it to new images with the same distortion.
>
> I would have thought that calibrated distortion correction was a common need for many fixed geometry cameras, but couldn't find much more on the WWW. Any suggestions would be welcome.
>
> Alan.
>
>
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