Stereo Calibration with Nikon D3400

160 views Asked by At

I am trying to calibrate Camera-Projector 3D System. First, I used Logitech C920 webcam and I got an acceptable results in term of calibration accuracy (0.8 reprojection error). However, colors and resolution were bad.

Now, I got a professional camera (Nikon D3400 18-55). I did not manage to get better calibration results than 5.5! I did the calibration using exactly the same projector, the same pattern and the same algorithm.

All settings are fixed in my Camera including Focus, Iso, Aperture, Optical zoom and shutter speed.

What did I miss? What are the possible causes of this problem?

I know that my question is a bit board but it seems that there is a stupid mistake that I have made so any clue is appreciated.

I do not think that it is matter but I am using Brown University 3D Scanning Software which uses OpenCV 2.4.9.

1

There are 1 answers

0
Dima On BEST ANSWER

First, your reprojection error is in pixels. What was the resolution of your webcam and your Nicon? I am guessing that the Nicon has much higher resolution, so the pixel size in much smaller. That would make the error in pixels higher, although 5.5 pixels still seems way too high.

The next thing I would worry about is lens distortion. What does the undistorted Nicon image look like? It may be that you do not have enough calibration points close to the edges of the image, which would mean that you are not estimating the distortion coefficients accurately. Or it may be that you have a wide-angle lens, and the distortion is simply too great for this camera model to handle.

So, what you should do is look at the undistorted Nicon image. If that looks strangely warped, then try capturing more calibration images with the pattern close to the edges of the image.

I am also confused by what you wrote about the colors and resolution being bad. Are you talking about undistorted or rectified images? Why would colors be bad?