Two-dimensional self-adaptive comb filter and filtering method for eliminating high-frequency color crosstalk

Abstract

The invention discloses a two-dimensional self-adaptive comb filter for eliminating high-frequency color crosstalk, which comprises a row cache unit, a chroma demodulation and low-pass filtering unit, a first judgment unit, a second judgment unit, a third judgment unit, a fourth judgment unit and a self-adaptive processing unit. The invention also provides a two-dimensional self-adaptive comb filtering method using the filter, which comprises the following steps: detecting whether current points are positioned in a weak-color high-frequency region; for points positioned in the weak-color high-frequency region, selecting points having no correlation from input points, and enabling the points having no correlation to be subjected to comb filtering; otherwise carrying out vertical boundary judgment, selecting points having no vertical boundary, and enabling the points having no vertical boundary to be subjected to comb filtering; and carrying out the traditional comb filtering on points which are not positioned in the weak-color high-frequency region and have no vertical boundary. The two-dimensional self-adaptive comb filter and filtering method can effectively prevent the weak-color high-frequency region from producing high-luminance color crosstalk and affecting the image separating effect, and have no effect on other regions.

Description

technical field [0001] The invention relates to a digital filter and a comb filter method thereof, in particular to a two-dimensional comb filter with the function of eliminating high-frequency cross-color and a comb filter method thereof. Background technique [0002] A traditional color TV signal refers to a single signal that includes a luminance signal, a color difference signal, and all timing signals. Currently, there are three common color TV systems in the world: PAL (Phase-Alternative Line), NTSC (National Television Systems Committee) and SECAM (Sequential Color with Memory). The digital decoding of color TV signals refers to the use of ADC (analog-digital converter) to convert analog composite color TV signals into digital signals, and then digitally demodulate the signals to realize the separation of brightness signals and color difference signals. The incomplete separation of the luminance signal and the color difference signal will lead to the problem of brigh...

AI Technical Summary

Problems solved by technology

However, this adaptive algorithm is not perfect. It will cause serious crosstalk in the high-frequency luminance signal area where the color difference signal is zero, and the presence of weak color high-frequency luminance signals is quite common.

like figure 2 In the region indicated by the middle arrow, there is a high-frequency region with sharp changes in brightness in this region, and the high-frequency region is weakly colored (that is, the color difference component is very weak, and can basically be considered colorless), then there is a kind of The situation is that the amplitude of the chrominance signal as the crosstalk signal in the luminance is already large enough, so that the correlation judge will regard the crosstalk chrominance signal as an effective image chrominance signal, and the filter will naturally follow figure 1 The correlation judgment conditions shown in the figure process the crosstalk signal, and the result is that the crosstalk signal that should have been canceled out in the weighted average is instead selected and retained, resulting in serious bright-color crosstalk

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