Joint gaze-correction and beautification of DIBR-synthesized human face via dual sparse coding
Gaze mismatch is a common problem in video conferencing, where the viewpoint captured by a camera (usually located above or below a display monitor) is not aligned with the gaze direction of the human subject, who typically looks at his counterpart in the center of the screen. This means that the two parties cannot converse eye-to-eye, hampering the quality of visual communication. One conventional approach to the gaze mismatch problem is to synthesize a gaze-corrected face image as viewed from center of the screen via depth-image-based rendering (DIBR), assuming texture and depth maps are available at the camera-captured viewpoint(s). Due to self-occlusion, however, there will be missing pixels in the DIBR-synthesized view image that require satisfactory filling. In this paper, we propose to jointly solve the hole-filling problem and the face beautification problem (subtle modifications of facial features to enhance attractiveness of the rendered face) via a unified dual sparse coding framework. Specifically, we first train two dictionaries separately: one for face images of the intended conference subject, one for images of “beautiful” human faces. During synthesis, we simultaneously seek two code vectors - one is sparse in the first dictionary and explains the available DIBR-synthesized pixels, the other is sparse in the second dictionary and matches well with the first vector up to a restricted linear transform. This ensures a good match with the intended target face, while increasing proximity to “beautiful” facial features to improve attractiveness. Experimental results show naturally rendered human faces with noticeably improved attractiveness.