GPU Based Real-time Correction for Optical Distortions in Head-Mounted Displays

This paper presents a GPU-based real-time method to correct optical distortions in head-mounted displays (HMDs). The HMD to be corrected is a lightweight and wide field-of-view HMD system with free-form-surface (FFS) prism, in which the image distortion is not rectilinear and centrosymmetric. A special predistortion model is constructed to correct the distortion of the HMD. Although the distortion correction can be performed with an extensional optics system, the system will be too expensive and additional weight will be imposed to the HMD. With the method presented in this paper, each pixel in the original image is remapped to a new position with GPU and forms a predistortion image. The remapping process is based on a prior formatted distortion map, which is similar to the normal map used in the bump mapping process. The distortion map is an RGBA image that corresponds to the X and Y coordinates of a pixel offset from the original image. The remapping process accomplished by GPU is very fast. The performance of the proposed method is analyzed and validated via a demonstration system.