Compressed motion picture signal expander with error concealment

Abstract

In a compressed motion picture signal expander, if the compressed motion picture signal includes an uncorrectable signal error, the resulting defective picture block can be replaced by a replacement picture block that blends in smoothly with the picture blocks surrounding it. Hence the picture error resulting from the uncorrectable signal error is concealed. The defective picture block resulting from a signal portion including an uncorrectable signal error is replaced by a replacement block produced by prediction from a past picture using the motion of the past picture. In this manner, the defective picture block can be replaced by the replacement picture block that blends smoothly with the surrounding picture blocks regardless of the existence of motion in the picture. When an uncorrectable signal error is detected, the expander determines whether or not the motion quantity represented by the motion vector of the picture block of the past picture corresponding to the defective picture block is larger than a predetermined value. If the motion quantity is large, the replacement picture block is generated by intra-picture interpolation, using the pixel values of the boundary pixels in the picture blocks surrounding the defective picture block. If the motion quantity is small, the replacement picture block produced by prediction block is used. In this manner, the error resulting from the uncorrectable signal can be concealed and rendered unnoticeable, regardless of the motion quantity represented by the compressed motion picture signal.

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