Fast and practical method for underwater stereo vision calibration based on ray-tracing.

The perspective camera model has difficulty handling refracted light in the underwater environment. To achieve accurate and convenient calibration in large underwater scenes, we propose a method based on the underwater refractive camera model in this paper. First, the initial values of the refraction parameters are solved using refraction coplanarity constraints. Then the initial values are optimized nonlinearly using co-point constraints, which simplifies the optimization process of existing methods. In the field of view of 200 ×200 , the experiment results show that the reconstruction accuracy of the proposed method can reach below 0.02 mm, and it is equally effective in the case of sparse calibration.