Occlusion artifact removal in video frame rate up-conversion

Abstract

In the past, frame rate up-conversion (FRC) methods were commonly used in standards conversion. Today, FRC methods are used for digital video temporal resolution enhancement to improve the visual quality in large screen LCD and plasma TV sets. The increase in processing power of DSPs, FPGAs and ASICs enables high complexity algorithms in the design of FRC systems. In this paper, we propose a multi-stage motion vector (MV) post-processing algorithm with occlusion adaptive overlapped block motion compensation, which increases the temporal resolution without loss of spatial resolution and consistency. Hexagonal search block matching yields us unreliable MVs which are post-processed in the refinement stages in order to get a consistent MV field in spatial domain. Relations between neighboring MVs and the MV fields of 4 consecutive frames are utilized to detect occlusion regions. Overlapped block motion compensation (OBMC) is adapted to these problematic regions in order to reduce artifacts due to occlusion. Compared to existing methods, the developed algorithm achieves FRC with reduced loss of spatial resolution and reduced amount of artifacts.