Accom

Kenneth A Woodhouse

Sohei Takemoto

John D Stern

Luigi C Gallo

According to a presently preferred embodiment of the invention, image enhancement apparatus for digital video images comprises a two-stage filter comprising a median filter and a recursive filter. The median filter operates in one, two, and three dimensions wherein the cluster of pixels framing the center pixel are ranked, and the median value of the pixel cluster is chosen as the correct pixel value. The pixel cluster configuration is selectable, as are the planes where the pixels are located. Multiple weights may be given to the appropriate median filter inputs. A motion detector is used to prevent replacement of each pixel by its pixel cluster median value when there is excessive motion. Finally an adjustable pixel-replacement threshold is defined. Each pixel must deviate from its median value before it is replaced by that value. In the presence of rapid motion in the picture, the operation of the median filter is reduced or halted by a properly derived motion signal according to the present invention, thus preventing motion artifacts from occurring.

Three-dimensional median and recursive filtering apparatus and method

A digital image compositing system (20) has background, foreground, key and mask busses (22), (24), (26), and (28). An analog key input (30) is connected to the key and mask busses (26) and (28) through an analog/digital (A/D) converter (32) by crosspoint switches (34). Four digital D1 video signal inputs (36) are connected to the busses (22-24) through additional crosspoint switches (34). The key and mask busses (26) and (28) are respectively connected to frame stores (38) and (40). A key processing toolkit subsystem (42) is connected to the output of the frame stores (38) and (40). A compositor subsystem (44) is connected to the background and foreground busses (22) and (24) and to the output of the key processing toolkit subsystem (42). A D1 program output (46) is connected to the output of the compositor subsystem (44) on program bus ( 48). A D1 key output (50) is connected to the output of key processing toolkit subsystem (42) on processed key bus (52). A D1 auxiliary output (54) is connected to program bus (48), background bus (22), foreground bus (24), processed key bus (52) and mask bus (28) by crosspoint switches (56). An analog output (58) is also connected to the busses (48), (22), (24), (52) and (28) by additional crosspoint switches (56) through D/A converter (60). A microprocessor (62) is connected to provide control signals for all of the functional elements of the system (20). A control keyboard and display (64) is connected to the microprocessor at (66). The microprocessor (62) is also connected to a video editor at (68).

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Menlo Park, CA, United States of America

Kenneth A Woodhouse