Calibration method of visual parameters for see-through head-mounted display

In the see-through head-mounted display (STHMD), which superimposes the virtual environment generated by computer graphics (CG) on the real world, the information given as a virtual environment has to exactly match with the real environment, because both environments are visible. This is one of the problems to be solved for practical use. We focused both on systematic errors of visual parameters caused in manufacturing process and differences between actual and supposed location of user´s eye on STHMD when in use. The former is required to be calibrated only once after the fabrication of STHMDs, whereas the latter has to be calibrated every time users start using STHMDs. We propose a calibration method which is suitable to properties of these causes of errors. In the method, the direct fitting of the virtual cursor drawn in the virtual environment onto targets in the real environment is performed. Then, based on the result of fitting, the least square method identifies values of the visual parameters which minimize differences between locations of virtual cursor in the virtual environment and targets in the real environment. Application of the method to the STHMD which we have made is reported