For different pictures taken by the same camera, the camera internal parameter matrix should be the same, while the distortion coefficients may have certain differences, but they are usually similar. The reasons are as follows:
1. The camera intrinsic parameter matrix represents the geometric characteristics of the camera, including focal length, principal point coordinates, etc. These parameters are inherent and will not change due to shooting different pictures.
2. The distortion coefficient describes the distortion error of the camera, which mainly comes from the lens manufacturing process. Ideally, the distortion parameters of the same camera are the same.
3. However, during the calibration process, due to the influence of independent variable conditions and noise, the calculated distortion coefficient will have errors, and the calibration results of different pictures will also have slight fluctuations.
4. But as long as the calibration conditions are sufficient, this fluctuation should be very small, and the distortion parameters of the same camera can be regarded as equal.
5. If the fluctuation is large, you need to check the calibration quality and obtain more complete calibration samples. So usually we can think that the internal parameter matrices of different pictures from the same camera are the same, and the distortion coefficients can be regarded as equal although there will be errors.
If a large difference is found in the application, the calibration effect needs to be re-evaluated.