Stereo Calibration of two cameras with different camera resolutions

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Mohammad
Mohammad on 4 Sep 2014
Commented: Image Analyst on 16 Sep 2019
Hi Everyone;
I have just started with camera calibration and found the awesome APP that MATLAB has to perform the calibration. Unfortunately, we cannot perform stereo calibration with it.
However, there is a matlab example that allows for stereo calibration but the problem I am having is that the resolutions of the two cameras I am using are different. One is high definition (1980X1080) and the other one is (512X412) so I cannot use the code from the example unless I try to modify the image.
So I am guessing I should kind of "cut out" the middle 512X412 of the 1980X1080 image to make the calibration? or would imsize work? Seems to modify the image too much.. Anyone has any idea on how this can be done or the camera calibration in general can be done?
Thanks; Ali

Accepted Answer

Shida
Shida on 23 Feb 2015
Hi, It's very normal to have to calibrate two cameras of different resolution when working in Multi-modal imaging. It's always the case that you have two different sensors with different technologies and highly unlikely that they have same resolution. Kinect is of course a very common example. Unfortunately, the official matlab app doesn't support this. There are some codes which make this possible for kinect 1 which you can google. But if you're looking for something with kinect 2, you can try first using the detectCheckerboardPoints from matlab for each set of images (check the matlab manual) and then when you have the points use : imagePoints = cat(4, poitnsRGB, pointsIR); Then feed these to the estimateCameraParameters (check the manual for more info). The catch is that I've done this for a HD camera and the kinect IR and I get terrible amount of error. I'm still trying to fix this. Worst case, one can use Kinect 1 with one of the available calibration codes.
Regarding what you said about cropping the images, that's a calibration sin ! If you look up info on how to calibrate cameras, they always tell you not to do that because that messes up everything.
Good luck.
  4 Comments
Yash Rathore
Yash Rathore on 5 Mar 2017
Hey Shida, I followed the same steps you provided, and it worked. Thanks a lot for sharing it. :)

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More Answers (2)

Image Analyst
Image Analyst on 4 Sep 2014
I'd buy another camera. Why complicate things when simply buying another camera will solve the problem?
  4 Comments
Walter Roberson
Walter Roberson on 25 May 2017
Hania Alhamad comments to Image Analyst
The answer is irrelevant. Some times there is a need to calibrate two cameras with different resolutions. and buying cameras won't solve the issue. like for example calibrating a thermal and a RGB.

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muhammet balcilar
muhammet balcilar on 14 Jul 2018
Yes, it is still problem to calibrate different resolution camera for stereo vision system. I had the same difficulties. However I just modifie some functions and prepare a demo. here you can find my demo.
  4 Comments
Image Analyst
Image Analyst on 16 Sep 2019
Maybe they're floating point images not in the range of 0-1 so you need to use [] in imshow():
imshow(floatingPointImage, []);

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