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Original pixel position on undistorted image

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Miguel Lopes
Miguel Lopes on 9 Mar 2015
Answered: Dima Lisin on 10 Mar 2015
I successfully calibrated a camera with matlab.
I undistorted the image using [newfoto, newOrigin] = undistortImage(origfoto,cameraParams);
But now, given a pixel in the origfoto (x1,y1) I wanted to know the position (x2, y2) of this pixel in the newfoto (undistorted). This newfoto has the same size as the oiginal, but some information is lost (due to distortion).
I thought the newOrigin vector would do the trick, but since the newfoto is of the same size as the origfoto, it gives the vector [0,0], so I don't think this newOrigin variable is what I need.
How can I do it??
I also tried to undistort a picture of the same size with only 1 non black pixel and the undistorted result was 4 non black pixels, so I'm guessing there is no exact position, but I need the approximate position!

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Miguel Lopes
Miguel Lopes on 9 Mar 2015
So i managed to do this but in a real stupid way lol. Basically I create a foto with same size as the original one and only 1 white pixel in the position I want. Then I undistort the foto and find which pixel in the undistorted foto has the maximum value. This way is pretty accurate, but it's a really brute force way of doing this, so my question still stands! Thanks!

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Answers (1)

Dima Lisin
Dima Lisin on 10 Mar 2015
Hi Miguel,
As of R2014b, there is a function called undistortPoints that does what you need.
The newOrigin output is only useful when you set 'OutputView' to 'full' or 'valid', because that returns an image of a different size from the original, and thus moves the origin of the image coordinates.


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