Head/eye calibration of a binocular head by use of single calibration point

The authors propose a new method for calibrating the head-to-eye relation of a binocular head with very high accuracy. This method consists of a closed-form solution for initial estimation and an iteration procedure for accuracy refinement. The closed-form solution is already quite accurate (more accurate than the existing method) when the number of calibration input data is large enough or when the amount of measurement noise is small. Using the closed-form solution as an initial estimate, the iterative method can be adopted to further improve the calibration accuracy. Instead of using the estimates of some transformation matrices as the calibration input data, which is needed in almost all the existing techniques, the proposed method needs only to measure the 3D coordinates of a single calibration point. This avoids the difficulty in finding a reliable extrinsic camera calibration technique. Also, during the calibration, the binocular head can be moved in a larger range while keeping the single calibration point in the viewfield of the camera, which in turn provides richer information for the head/eye calibration. According to their experiments, the proposed method achieved much higher accuracy than the existing techniques.