For converting between television or high-definition television signals, which differ in line and field rates, standards conversion is necessary. The conventional standards converters unavoidably causes motion blurring, motion judder, and vertical detail flashing in the converted signal. To improve the conversion, a motion compensated technique is needed.
In this thesis we propose an efficient conversion method from motion compensated(MC) 3-branch HD-MAC to NTSC. MC 3-branch HD-MAC coding system has three modes(80,40 and 20ms modes) with motion compensation employed in the 40ms mode. The mode decision signal and motion information used in 40ms mode are transmitted via DATV channel. The proposed field rate conversion method uses only the DATV information without additional motion estimation. Nevertheless, it has as good a picture quality as field rate conversion using 3-step block matching method (block size 8×8). Also, the proposed method is applicable to the 100Hz field rate HDMAC system, which is studied in the Eureka project.
The line-rate conversion method uses a vertical FIR filter which has different cutoff frequency according to aspect ratio conversion method.
