*1: NHK Broadcast Engineering Department, *2: NHK Engineering Services, Inc., *3: Dai Nippon Printing Co.,Ltd., *4: Matsushita Electric Industrial Co., Ltd.

The deterioration of the picture quality of displayed moving pictures caused by dynamic false contour artifacts is a serious impediment to the obtaining of good picture quality on PDPs (plasma display panels). The artifacts arise from the sub-field method used to represent the gray scale. We propose a combination of two methods, time-compression of emission and weighted division of upper signal bits, to improve picture quality. Each technique has a separate and important role in the improvement of quality. We also propose an additional technique for reducing the frequency with which the artifacts appear. The proposed methods were evaluated by computer simulation and subjective testing. The results showed that these methods significantly improved the moving picture quality of a PDP and provided a picture of acceptable quality for viewing on an HDTV receiver. A high-quality 42-inch-diagonal PDP-HDTV receiver, the "Nagano Model", was developed using the methods proposed.

Information about camera operations such as zoom, focus, pan, tilt and dollying is significant not only for efficient video coding, but also for content-based video representation. In this paper we describe a high-precision camera operation parameter measurement system and apply it to image motion inferring. First, we outline the implemented system which is designed to provide camera operation parameters with a high precision required for image coding applications. Second, we calibrate the camera lens to determine its exact optical properties. A pin-hole camera model with the 2nd order radial lens distortion and a two-image calibration technique are employed. Finally, we use the pan, tilt and zoom parameters measured by the system to infer image motion. The experimental results show that the inferred motion coincides with the actual motion very closely. Compared to the motion analysis techniques that estimate camera motion from video sequences, our approach does not suffer from ambiguity, thus can provide reliable and accurate image global motion. The obtained motion can be applied to image mosaicing, moving object segmentation, object-based image coding, etc.

We examine the cardboard effect by varying such image acquisition parameters as lighting, inter-camera distances, lens focal length, and presence or absence of motion parallax and backgrounds in program production. Subjective evaluation tests show that binocular disparity calculated from camera separation, lens selection and convergence point are dominant factors. The cardboard effect can be effectively avoided or lessened by enhancing increasing the binocular parallax. In case of actual program production, it is practical to use standard lenses or ones close in focal length to standard lenses and to set camera separation around the same as the average eye separation of human eyes in order to mitigate the cardboard effect. When binocular disparity is small using lenses with long focal length, other cues such as motion parallax accompanied by the relative movement between subjects and cameras are effective.