Digital Video Filter Segmentation for Smear and Ringing Reduction

The patent segments the video signal processing into multiple independent filtering stages: a first filter processes horizontal direction signals to reduce smear effect, while a second filter processes vertical direction signals to preserve edge sharpness. This segmentation allows each filter to be optimized for its specific direction, resolving the contradiction between reducing smear and maintaining image clarity.

The patent applies different filtering characteristics to different spatial locations and directions within the video signal. The first filter applies stronger smoothing in the horizontal direction where smear is more problematic, while the second filter maintains sharper response in the vertical direction to preserve edge definition. This local differentiation of filtering quality resolves the contradiction between reducing smear effect and maintaining overall image clarity.

The patent divides the high-pass filtering function into two separate filters with different characteristics: the first filter provides gentle high-pass response to enhance sharpness without excessive overshoot, while the second filter provides complementary high-pass response to maintain edge definition. This segmentation distributes the sharpness enhancement across multiple stages, avoiding the harmful overshoot and ringing effects that would result from a single aggressive high-pass filter.

The patent merges the output signals from the first and second filters to produce the final processed video signal. By combining the results of two milder high-pass filtering operations, the system achieves the cumulative sharpness enhancement of high-pass filtering while avoiding the harmful overshoot and ringing effects that would occur with a single strong high-pass filter.