Adaptive field/frame filter for interlaced video signals
AssigneeMatsushita Electric Corporation of America
InventorsSaiprasad V. Naimpally, Hee-Yong Kim
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Abstract
A motion adaptive vertical filter is used to filter an interlaced video signal on a frame basis in areas of the image that are not in motion and on a field basis in areas that are in motion. A soft switch mixes the field filtered data and the frame filtered data in areas where there is relatively little motion to prevent artifacts which may be caused by abruptly switching between the two vertical filtering schemes. The frame vertical filter reduces the vertical resolution of still NTSC images to 180 cycles per picture height (CPH) while the field filter reduces the vertical resolution to 90 CPH.
Claims8
A motion adaptive video signal filtering system suitable for filtering an interlaced video signal in which a frame of video information is represented by first and second interlaced fields and each of said fields includes a plurality of lines of pixel values, said system comprising:
- field filtering means for processing corresponding ones of said pixel values on each of a plurality of successive lines of one of said fields to generate a field filtered video signal;
- frame conversion means for combining successive pairs of said first and second interlaced fields to generate successive frames of said video signal;
- frame filtering means for processing corresponding ones of said pixel values on each of a plurality of successive lines of one of the frames to generate a frame filtered video signal;
- motion detection means, responsive to differences in successive ones of the frames provided by the frame conversion means, for selectively combining the field filtered video signal and the frame filtered video signal to generate an output signal.
A method of motion-adaptively filtering an interlaced video signal in which a frame of video information is represented by first and second interlaced fields and each of said fields includes a plurality of lines of pixel values, said method comprising the steps of:
- A) processing corresponding ones of said pixel values on each of a plurality of successive lines of one of said fields to generate a field filtered video signal;
- B) combining successive pairs of said first and second interlaced fields to generate successive frames of said video signal;
- C) processing corresponding ones of said pixel values on each of a plurality of successive lines of one of the frames to generate a frame filtered video signal;
- D) calculating a measure of difference in magnitude of pixel values in corresponding areas of successive ones of the frames generated at step B);
- and
- E) selectively combining the field filtered video signal and the frame filtered video signal, response to the measured difference in magnitude, to generate an output signal.
Dependencies are inferred from the claim text.