CN103280174B - A kind of method eliminating color noise under weak signal of liquid crystal display - Google Patents

Abstract

The invention discloses a method for eliminating color noise under a weak signal of a liquid crystal screen, comprising the following steps: a. Setting a brightness threshold y, analyzing the brightness of an input signal point by point, and screening out the color noise which is lower than the brightness threshold y b. Extract the corresponding color brightness and color saturation for low-brightness pixels; c. Set the signal-to-noise ratio threshold s, if the signal-to-noise ratio of the input signal is higher than the signal-to-noise ratio threshold s, the color brightness and color saturation will not be processed; d, if the signal-to-noise ratio of the input signal is not higher than the signal-to-noise ratio threshold s, then according to the signal-to-noise ratio of the input signal, correspondingly adjust the low-brightness pixel Color saturation and color brightness, the adjusted value should be lower than the original value. The invention has the beneficial effect of not only maintaining image quality, but also eliminating color noise.

Description

A Method of Eliminating Color Noise under Weak Signal of LCD Screen

technical field

The invention belongs to the technical field of image processing, and in particular relates to a method for eliminating color noise under weak signals of a liquid crystal screen.

Background technique

The optical characteristics of the LCD screen are mainly expressed by color coordinates and color temperature. During the process of the input signal from 0-255 grayscale, the color coordinate parameters of the same LCD screen usually change. If the characteristics of the lamp tube and the polarizing film do not match, the optical spectrum of R, G, and B will behave differently in different gray scales, and the color coordinates of different gray scales will vary greatly. For LCD TVs produced with this kind of LCD screen, it is difficult to match the characteristics and change rates of R, G, and B under different gray scales, and the phenomenon of coloring appears obviously in dark gray scales. The deviation rate of the batch screen is higher. If the screening is not strict, this situation will be extremely common; especially when displaying a signal that is on and off, such as noise under a weak signal, you will find that the noise obviously appears in red, green or blue colors. Noise, the weaker the signal, the more noise and the larger the particles, the more obvious this phenomenon is, which seriously affects the viewing of TV programs.

There is no complete solution to this situation caused by the differences in the technology and raw materials of the LCD screen. The general method is to readjust the gamma of the LCD screen: either from the perspective of the movement, or from the perspective of the screen. . But this is not to solve the source of the problem, but to reduce the brightness of the low-gray-scale signal, so the dark field signal is too black in the case of no noise, and the layering of the image is deteriorated, which seriously affects the image quality.

Contents of the invention

Based on the deficiencies of the prior art, the purpose of the present invention is to propose a method for eliminating color noise under weak signal of the liquid crystal screen, so as to maintain the image quality.

The present invention is realized like this, a kind of method for eliminating the color noise under the weak signal of liquid crystal screen, comprises the following steps:

a. Set the brightness threshold y, analyze the brightness of the input signal point by point, and filter out low-brightness pixels that are lower than the brightness threshold y;

b. Extract the corresponding color brightness and color saturation for low-brightness pixels;

c. Set the signal-to-noise ratio threshold s, if the signal-to-noise ratio of the input signal is higher than the signal-to-noise ratio threshold s, the color brightness and color saturation will not be processed;

d. If the signal-to-noise ratio of the input signal is not higher than the signal-to-noise ratio threshold s, adjust the color saturation and color brightness of the low-brightness pixel correspondingly according to the signal-to-noise ratio of the input signal, and the adjusted value should be lower to the original value.

The beneficial effects of the present invention are as follows: from the technical solution of the present invention, it can be seen that for low-brightness signals, that is, low grayscale signals: when the signal-to-noise ratio of the input signal is high, the low-brightness signal is not processed, and the image quality of the signal Without any influence, of course, there will be no problem that the dark field signal is too black in the case of no noise, and the layering of the image will deteriorate; when the signal-to-noise ratio of the input signal is low, only the color saturation and color of the signal The brightness has been reduced to make it difficult for the naked eye to eliminate the phenomenon of color noise, but the brightness of the input signal has not been reduced, so there will be no noise-free dark field signals that are too black, and the layering of the image will not change. bad question. In a word, the present invention achieves the beneficial effect of not only maintaining image quality, but also eliminating color noise.

Description of drawings

Figure 1 is a flow chart of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, a method for eliminating color noise under weak signals on the LCD screen includes the following steps:

a. Set the brightness threshold y, analyze the brightness of the input signal point by point, and filter out low-brightness pixels that are lower than the brightness threshold y;

b. Extract the corresponding color brightness and color saturation for low-brightness pixels;

c. Set the signal-to-noise ratio threshold s, if the signal-to-noise ratio of the input signal is higher than the signal-to-noise ratio threshold s, the color brightness and color saturation will not be processed;

d. If the signal-to-noise ratio of the input signal is not higher than the signal-to-noise ratio threshold s, adjust the color saturation and color brightness of the low-brightness pixel correspondingly according to the signal-to-noise ratio of the input signal, and the adjusted value should be lower to the original value.

In this embodiment, the input signals are R, G, and B data, and the brightness of each pixel is calculated according to the brightness Y=0.3*R+0.6*G+0.1*B;

The brightness threshold is set to 64, so pixels under the gray scale with brightness Y<64 are confirmed as low-brightness pixels;

The signal-to-noise ratio threshold s is taken as 60db, so when the input signal signal-to-noise ratio>60db, the color brightness and color saturation will not be processed;

When the signal-to-noise ratio of the input signal is less than or equal to 60db, the color saturation and color saturation of low-brightness pixels can be adjusted correspondingly by multiplying the color saturation by the coefficient m and the color brightness by the coefficient n according to the signal-to-noise ratio of the input signal. Color brightness, where the coefficients m and n vary according to the signal-to-noise ratio of the input signal, both of which are less than 1; examples are as follows:

60db≧input signal-to-noise ratio>50db, the color saturation* coefficient of low-brightness pixels is 0.4, and the color brightness* coefficient is 0.4;

50db≧input signal-to-noise ratio>40db, the color saturation* coefficient of low-brightness pixels is 0.2, and the color brightness* coefficient is 0.2;

Signal-to-noise ratio≦40db, color saturation* coefficient of low-brightness pixels is 0.1, and color brightness* coefficient is 0.1.

When the above solution is implemented, degree classification and classification processing can also be performed according to the brightness difference of low-brightness pixels, so as to have better adaptability to the input signal.

The present invention is applicable to liquid crystal screens used as video display devices such as terminal displays or televisions. After implementing the scheme of the embodiment of the present invention, the color noise under weak signals is basically consistent with the normal viewing state, and the brightness and darkness levels are not affected, ensuring reliable Improve the picture quality effect of the image, make up for the defects caused by the process and material problems of the LCD screen, and ensure the consistency of the picture quality of batch products.

Claims (3)

1. a method for eliminating color noise under a liquid crystal screen weak signal, is characterized in that comprising the following steps: a. Set the brightness threshold y, analyze the brightness of the input signal point by point, and filter out low-brightness pixels that are lower than the brightness threshold y; b. Extract the corresponding color brightness and color saturation for low-brightness pixels; c. Set the signal-to-noise ratio threshold s, if the signal-to-noise ratio of the input signal is higher than the signal-to-noise ratio threshold s, the color brightness and color saturation will not be processed; d. If the signal-to-noise ratio of the input signal is not higher than the signal-to-noise ratio threshold s, adjust the color saturation and color brightness of the low-brightness pixel correspondingly according to the signal-to-noise ratio of the input signal, and the adjusted value should be lower to the original value. 2. a kind of method for eliminating the color noise under the weak signal of liquid crystal screen according to claim 1, is characterized in that in described step d, is by multiplying color saturation by coefficient m, color brightness multiplied by coefficient n Corresponding adjustments are made, wherein the coefficients m and n vary according to the signal-to-noise ratio of the input signal, and both are less than 1. 3. A method for eliminating color noise under a weak signal of a liquid crystal screen according to claim 1, further comprising performing degree classification and classification processing according to brightness differences of low brightness pixels.