Television – Image signal processing circuitry specific to television – Noise or undesired signal reduction
Patent
1997-05-07
1999-09-28
Faile, Andrew I.
Television
Image signal processing circuitry specific to television
Noise or undesired signal reduction
348606, 348625, 382263, 382266, H04N 521
Patent
active
059596937
ABSTRACT:
A current pixel of a video image is adaptively filtered to provide stronger filtering when there is a high likelihood that noise is present. Weaker filtering is provided when the presence of a color and/or brightness edge is likely in the video image. Each pixel has luminance and chrominance amplitude values. In a filtering method, a current pixel is intermediate to first and second pixels in the video frame. Difference signals are determined based on the amplitude difference between the current pixel and first and second adjacent pixels. A plurality of available filters provide successively stronger filtering of the current pixel amplitude. One of the filters is selected for filtering the current pixel according to the difference signals. Secondary difference signals which indicate the amplitude difference between the current pixel and pixels which are adjacent to the first and second pixels are also considered in the selection process. The selection process may further be biased by a user-selectable control word. The scheme may also provide temporal filtering with successive video frames or images. Filtering with pixel interpolation may also be used.
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Nemiroff Robert
Patel Jay R.
Shumate John
Wu Siu-Wai
Brown Reuben M.
Faile Andrew I.
General Instrument Corporation
Hoppin Ralph F.
Lipsitz Barry R.
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