Adaptive scan rate up-conversion system based on human visual characteristics

Current NTSC systems employ an interlaced scan scheme where visually annoying artifacts, such as line flickers, large area flickers, and edge flickers, are inevitably generated and more objectionable with a larger display. With the development of HDTV systems, how an NTSC signal can be displayed in an HDTV system has also become a problem. Accordingly, in order to solve these problems, many adaptive scan rate upconversion systems have been proposed. The proposed system consists of a modified edge directional line averaging (ELA) interpolation module and contrast enhancement module. The modified ELA interpolation module reduces the visually annoying artifacts induced by an interlaced scan scheme whereas the degradation in the contrast and details due to interpolation processing is compensated by the contrast enhancement module. Moreover, the proposed system is easy to implement and the VLSI architecture is very simple. This new system was mainly developed for doubling the scan rate in an NTSC system; however, it can also be used in the format conversion in an HDTV system.