Eliminate point of view effects on a surface before processing the image.

Hello,

I have some concrete cross-sections with fibers. The camera will be at a central position and due to point of view effects, the edges will be deformed. I made a chess board to use it first to take out the point of view effects with same size of the cross-sections (see the photo).

The procedure:

- Fix the camera and the specimens position. - Take the image of the chess board. - Take the images of specimens with out changing the positions. - Use the chess board image to develop a code to reverse the point of view effects.

My questions: What is the transformation which should be used to reverse the point of view effects? Is it implemanted on Matlab already? Is the transformation simply linear or not? Do you have any lectures regarding this?

Thank you.

Answer 1

[Florian Morsch]

If you have the camera calibration toolbox at you hand you can simply use that to calibrate your camera with the checkerboard.

With the camera parameters from the calibration you can then use undistortImage() ( https://de.mathworks.com/help/vision/ref/undistortimage.html ) to correct the lense distortion.

[Mohammad Sarhil]

Thanks, but this can not transform the image to 90 degree projection of the plan object.

[Florian Morsch]

For that you could try imwarp() ( https://www.mathworks.com/help/images/ref/imwarp.html ), the older variant imtransform() ( https://www.mathworks.com/help/images/ref/imtransform.html )

This could also help you: https://www.mathworks.com/help/images/ref/tformarray.html