| 摘要 |
An overlay detection unit ( 300 ) for detecting whether a particular pixe of a first image of a display sequence of video images represents a part of a graphics over ay is disclosed. The overlay detection unit ( 300 ) comprises: first testing means ( 302 ) for to ting whether a first difference (D 11 ) between a first value of the particular pixel (P( 1 ,n)) second value of a corresponding pixel (P( 1 ,n-1)) of a second image of the display seqence of video images is less than a first predetermined threshold (T 1 ); second testing mean ( 304 ) for testing whether a second difference (D 22 ) between a third value of a second pixel (P( 2 ,n)), being located in spatial neighborhood of the particular pixel (P( 1 ,n)), and fourth value of a fourth pixel (P( 2 ,n-1)) of the second image, is less than second predetermined threshold (T 2 ); third testing means ( 306 ) for testing whether a third difference (D 12 ) etween the first value of the particular pixel (P( 1 ,n)) and the third value of the second pixel (( 2 ,n)) is less than a third predetermined threshold (T 3 ); and establishing means ( 308 ) for establishing that the particular pixel represents the part of the graphics overlay on bas s of the output of the testing means. |
