In this paper, we propose a flexible gaze detection method using single PTZ (Pan-Tilt-Zoom) camera. In this method, a PTZ camera traces user's face and measures position of their viewing point, so they do not need to fix their head in front of camera. Furthermore, to realize accurate gaze detection, we employ elliptical iris template matching. To reduce calculation amount of iris template matching, we get rough gaze direction by simple method on ahead to decide ellipse shape. In this paper, we also adapt to variation of facial orientations, which will affect to detect viewing position and gaze direction. After several experiments, we examine accuracy of gaze detection and head tracking ability of this system.

Faces of a person performing freely in front of the camera can be captured in a sufficient resolution for facial parts recognition by the proposed camera system enhanced with a special PTZ camera. Head region, facial parts regions such as eyes and mouth and the borders of facial parts are extracted hierarchically by being guided by the irises and nostrils preliminarily extracted from the images of PTZ camera. In order to show the effectivity of this system, we proposed a possibility to generate the borders of facial parts of the face for the facial caricaturing and to introduce eye-contacting facial images which can eye-contact bilaterally with each other on the TV conference environment.

This paper presents a novel and practical face-assisted video coding scheme to enhance the visual quality of the face region in videophone applications. A low-complexity skin-color-based face detection and tracking scheme is proposed to locate the human face regions in realtime. After classifying the macroblocks (MBs) into the face and non-face regions, we present a dynamic distortion-weighting adjustment (DDWA) scheme to skip encoding the static non-face MBs, and the saved bits are used to compensate the face region by increasing the distortion weighting of the face MBs. The quality of the face regions will thus be largely enhanced. Moreover, the computation originally required for encoding the skipped MBs can also be saved. The experimental results show that the proposed method can significantly improve the PSNR and the subjective quality of face regions, while the degradation introduced on the non-face areas is relatively invisible to human perception. The proposed algorithm is fully compatible with the H. 263 standard, and the low complexity feature makes it well suited to be implemented for real-time applications.

An algorithm that detects the surface echo peak position in a radar echo range profile has been developed for the TRMM Precipitation Radar (PR). The purpose of the surface echo peak detection is to determine the range window in which "over-sample" data are collected. The surface echo position in the range profile is variable due to the systematic change of satellite geodetic altitude and surface topography. The dynamic control of the over-sample range window using the surface detection algorithm contributes significantly to the reduction of PR data rate that should be sent to the ground station. The algorithm employs an α-β tracking filter and has three functions; surface tracking, lock-off detection and tracking loop initialization. After the launch of the TRMM satellite, a series of initial check-out of the PR was conducted. The performance of the algorithm was evaluated through the initial check-out and two-years operation of the PR. The results indicate that the algorithm is working as expected and basically meets the specification; however, it is found that some functions such as the tracking loop initialization algorithm need to be improved.