Camera intrinsic calibration based on star points

Abstract

Aiming at the intrinsic calibration of infrared cameras with certain atmospheric absorption bands, this paper proposes intrinsic-parameter correction methods based on the angular invariance of the infrared-star calibration points. The four cases of inner product cosine invariant and outer product sine invariant under the image model with or without distortion are compared and analyzed. According to the experimental results, the outer product sine invariant has higher correction accuracy due to the higher linearity for small angles, while the image model without distortion is more sensitive to the noise of star-centroid extraction, and the intrinsic calibration error is large. In addition, the experiment also proved that the noise of the star-centroid extraction should be controlled within half a pixel as much as possible; otherwise the accuracy of the intrinsic calibration may be reduced when the distortion in the field of view is severe. Experiments show that the sine-invariant correction algorithm under the distortion model is very suitable for high-sensitivity infrared camera intrinsic calibration using star points as a large number of control points.