Posted by
Stephan Saalfeld on
Apr 20, 2009; 6:47pm
URL: http://imagej.273.s1.nabble.com/Image-distortion-tp3692838p3692839.html
Dear Ian,
if the distortion is caused by an optical lens, you may try the
following approach:
http://www.erik-krause.de/index.htm?./verzeichnung/distort_en.htmthat uses the PanoTools
http://panotools.sourceforge.net/for estimating the lens-distortion model and rendering the corrected
image. It is not required to mark "lines", (manually marked) point
correspondences in the distorted and a (manually created?) undistorted
reference image will do fine. For microscopy images, choose a very low
FOV and fix it. Alternatively to PTGui, use hugin
http://hugin.sourceforge.net/If the distortion is not caused by an optical lens (not rotationally
symmetric) and your are too lazy to think about the distortion model,
you can give bUnwarpJ
http://biocomp.cnb.uam.es/~iarganda/bUnwarpJ/a try. If you lack an undistorted image, create it manually. If the
program fails distorting these images based on the image intensities,
you can select the corresponding dots manually and set the landmark
weight to 1.0. Make sure to constrain the distortion everywhere in the
image either by landmark-correspondences or corresponding image content.
Best regards,
Stephan
On Mon, 2009-04-20 at 16:19 +0100, Macdonald Iain Mr (ENV) wrote:
> Dear ImageJ users,
>
>
>
> I plan to use ImageJ for particle size analysis and for particle
> tracking of irregular shaped particles. In order to test my system I
> have taken an image of a fixed frequency grid distortion target. The
> grid distortion target is made up of 62.5 microns diameter dots at
> 125
> microns spacing. The grid has dots in both directions.
>
>
>
> The image after thresholding shows that distortion is occurring (the
> dots appear larger with distance from the center of the image). Could
> anyone please help me with either some advice on how this distortion
> can
> be accounted for, or even better provide me with some code which would
> correct this distortion.
>
>
>
> The plan is to apply the distortion correction to subsequent images of
> irregular shaped particles, from which size and other information can
> be
> obtained.
>
>
>
> Thanks in advance
>
>
>
> Iain MacDonald
>
>
>
>