Written by Alexander Velizhev
Attention! Verify your calibration pattern size. If you have entered wrong object dimentions detection will run incorrectly. It runs only with calibration patterns using odd x even (or even x odd) number of squares (i.e 5×6, 7×8, 10×7, etc).
- The white space (marked with red on the picture below) between the outer squares and the object boundary should be at least 1 square wide, like this:
Figure 1. Calibration pattern
All the squares must be clearly visible (unoccluded).
Use a tripod
Take 25 images and more
Use a paper size ".3" and more
Square size is 3-5 cm
The chessboard on the images must be located in the all places of the camera matrix
Figure 2. Point density
The chessboard must be plane
Take photos from these positions + from the top of the chessboard
Figure 3. Camera positions
The tilt angle is constant (for example 45 deg)
Figure 4. Tilt angle
Take photos with three camera positions
Figure 5. Tilts of the camera
Another thing is that I actually tested only on my images, so maybe my modifications won’t help other people to do their calibration. If so – send me your image sequences, I’ll try to tune up my method to work with them also.