Berak, thank you for your reply.
- The problem is that I am using infrared camera. This is probably the best picture I can get. I was only able to take this picture because of the long exposure time.
- What do you mean “doesn’t work for 90° invariance”?
- Understood
- Why is that? In this tutorial they used borders similar to mine. Some of their squares are not even whole.
The “error” you are referring that calibrateCamera() returns 0.303 in my case. I will try another calibration with all the suggestions and see how it works.