KR200275424Y1 - Image quality control device of digital video signal - Google Patents

Abstract

The present invention relates to an image quality control apparatus for a digital video signal, and compares a digital data value for each of a luminance signal or a chrominance signal, which is a video signal of each unit pixel constituting the video screen, with a threshold set by a user. A comparator (10, 11, 12) for outputting the magnitude for the; An adder (20, 21, 22) for adding the variation value set by the user to the digital data value for the luminance signal or the color difference signal according to the comparison result in the comparison unit (10, 11, 12); A key input unit (50) for inputting and setting the threshold value and the change value desired by the user; The controller 40 variably sets the threshold value input through the key input unit 50 to the comparator 10, 11, 12, and variably sets the input change value to the adders 20, 21, 22. ); And a three primary color converter 30 for converting the luminance signal and the color difference signal output from the adders 20, 21, and 22 into three primary colors (RGB) signals, and outputting the same. By emphasizing the image on the subjects of a certain color, you can adjust the image sharpness to suit the user's visual taste as well as sharply classify the boundary by emphasizing the image according to the difference value of adjacent image data. This is a very useful design to get a clearer picture.

Description

Digital Video Signal Quality Control Device

The present invention relates to a device for controlling image quality of a digital video signal, and more particularly, a user can arbitrarily adjust a boundary between a subject included in an input video signal and a surrounding background, and a boundary between each subject. It relates to an image quality control device of a digital video signal.

The quality of a video CD player or a digital video disk player (DVD), which is a representative digital video player in use, depends largely on the performance of an MPEG decoder. As illustrated in FIG. 2, the apparatus for controlling image quality of a digital video signal of an MPEG decoder uniformly applies a predetermined variation to the value of luminance signal data Y constituting the digital video signal for each pixel to be input. An adder 60 for adding; A size adjusting unit 70 for setting a change value to be added by the adder 60 to a desired size; And a three primary color converter 80 which receives the calculated luminance signal data and the color difference signal data C _r and C _b and converts them into three primary color signals of red (R), green (G), and blue (B); It is configured to include.

In the image quality control apparatus of the digital video signal configured as described above, the digital video signal data, which is compressed and stored on a video CD or a digital video disk (DVD), is received in an uncompressed state. A pixel is a component for determining the bright and dark degree of an image, and a luminance component (Y) related to a black / white image, and a red image and a blue color (component) for determining a color of an image, respectively. blue) is composed of chrominance components (C _r , C _b ) associated with the image. Accordingly, the input digital image signal data also includes luminance signal (Y) data and chrominance signal (C _r , C _b ) data. Each of these data is composed of 8 bits in accordance with the MPEG regulation, and can be represented by a value between 0 and 255, that is, a value of 256 steps in total.

Of the luminance signal (Y) data and the color difference signal (C _r , C _b ) data, the color difference signal (C _r , C _b ) data is input directly to the three primary color converter 80 without a separate data processing process, the luminance Only signal Y data is input to the adder 60, and the set variation value is added and then input to the three primary color converter 80.

However, the brightness of a digital image used for a video CD or a digital video disk (DVD) is adjusted by the luminance signal (Y) component. When the pixel having the luminance signal data value of 127 is displayed as 130, 130 is displayed. Is displayed brighter, and when it is displayed as 125, the display is darker. If the variation value is set to +2 in the size adjusting unit 70, the adder 60 is added. When a luminance signal having a data value of 125 is input to the luminance signal having a data value of 127 to which the variation value +2 is added, the luminance signal is output to the trichromatic converter 80 so that the brightness of the screen becomes brighter. .

However, the conventional digital image signal quality control device configured and operated as described above, although it is possible to adjust the light and dark degree of the digital image screen by the above method, it is simply uniform throughout the entire screen. As the value is added, it was mainly used to adjust the level of the final composite signal in the design stage of the player rather than directly by the user, and thus it was impossible to control the user by this method. Even if it is provided to the user, it is difficult to satisfy the user's vision because the boundary between the subjects included in the image screen cannot be clearly distinguished by adjusting the overall brightness. Of course, it is possible to select and view the desired image quality by adjusting the screen of the TV, but this has a problem that the effect is extremely limited as a method of adjusting the brightness by adjusting the level of the composite signal (Composite Signal) high or low.

Accordingly, the present invention has been created to solve the above problems, and provides an image quality control apparatus for digital image signals that can more clearly distinguish subjects of arbitrary brightness and color included in the image signal by user adjustment. Its purpose is to

Another object of the present invention is to provide a device for controlling image quality of a digital video signal which enables a user to more clearly distinguish an image having an arbitrary brightness and color difference between subjects included in the video signal.

1 is a block diagram showing an embodiment of an image quality control apparatus of a digital video signal according to the present invention,

2 is a block diagram showing a conventional image quality control device for a digital video signal.

※ Explanation of code for main part of drawing

10,11,12: comparison unit 20,21,22,60: adder

30,80: three primary color converter 40: control unit

50: key input unit 70: size adjustment unit

According to an aspect of the present invention, an apparatus for controlling image quality of a digital video signal includes: key input means for variably setting an arbitrary threshold value and scale value for each of a luminance signal and a color signal; Threshold adjustment means for adjusting the thresholds of the luminance signal and the color signal, respectively, corresponding to the threshold set by the key input means; Scale adjusting means for adjusting the scales of the luminance signal and the color signal which are variably adjusted by the threshold value adjusting means to an arbitrary threshold value corresponding to the scale values set by the key input means, respectively; And control means for controlling the operation of the threshold adjustment means and the scale adjustment means.

In the apparatus for controlling image quality of a digital video signal according to the present invention configured as described above, a threshold value for a signal component that a user wants to adjust among the luminance signal component or the color difference signal component inputted first, and a scale value when it corresponds thereto is the key input. Means are input to the threshold adjusting means and the scale adjusting means, respectively.

Subsequently, the threshold value adjusting means compares the luminance component and the color component of the input image signal data with the set threshold value, and outputs the inputted value without adding up the set scale value if each component value of the image signal data is smaller than the set threshold value. If it is larger than the threshold value, the input video signal data is spread by outputting the scale value set by the scale adjusting means. Therefore, a video signal having a luminance component and a color component of a predetermined value or more is compared with the surrounding video. It is possible to distinguish clearly, so that the boundary of the subject in the image signal becomes clearer, so that the user can obtain the optimum sharpness by adjusting.

Hereinafter, a preferred embodiment of an image quality adjusting device for a digital video signal according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the apparatus for controlling image quality of a digital image signal according to the present invention includes a digital data value and a threshold set by a user for each of a luminance signal or a color difference signal, which is an image signal of each unit pixel constituting the image screen. A comparison unit (10, 11, 12) for outputting the magnitude of the threshold value; An adder (20, 21, 22) for adding the variation value set by the user to the digital data value for the luminance signal or the color difference signal according to the comparison result in the comparison unit (10, 11, 12); A key input unit (50) for inputting and setting the threshold value and the change value desired by the user; The controller 40 variably sets the threshold value input through the key input unit 50 to the comparator 10, 11, 12, and variably sets the input change value to the adders 20, 21, 22. ); And a three primary color converter 30 for converting and outputting a luminance signal and a color difference signal output from the adders 20, 21, and 22 into three primary color (RGB) signals.

Hereinafter, the operation of the apparatus for controlling image quality of a digital video signal according to the present invention configured as described above will be described in detail with reference to the drawings.

First, the user selects a signal and an adjustment method (absolute mode and relative mode) to be adjusted on the screen among the luminance signal or the chrominance signal constituting the video signal, and controls the desired threshold value and the variation value through the key input unit 50. When inputting to 40, the control unit 40 inputs and sets the input values to the comparing units 10, 11, 12 and the adders 20, 21, 22, respectively.

When the threshold value and the variation value are set, the comparator, in which the threshold value is set among the comparators 10, 11 and 12, is compared with the threshold value set for each data value of the input signal. For convenience of description, in order to adjust only the brightness on the screen, the user inputs and sets the threshold value 30 and the variation value 5 only for the comparator 12 and the adder 22, respectively. Assuming that the control method of is set to the absolute mode, the comparator 12 compares the data value of the input luminance signal with the set threshold, and if the relative mode is selected in the previous input step, the comparator 12 ) Compares the difference in luminance data values between adjacent pixel data in the luminance signal data input with the threshold value set above.

However, as described above, the luminance signal and the chrominance signal are each composed of 8 bits according to the MPEG specification, and can be represented by a value between 0 and 255. For example, the luminance signal data continuously input is 28, 30. Assuming that the input values are 32, 67, 69, and 70, the difference in data values between adjacent luminance signals is 2, 2, 2, 35, 2, and 1, respectively. ) Directly compares the luminance signal data inputted in the order of 28, 30, 32, 67, 69, and 70 with the set threshold 30, and continuously compares the difference value with the preset threshold 30 when the relative mode is set. In doing so, it is important to understand the magnitude of the threshold.

If the absolute mode is set, the comparison unit 12 inverts the comparison output with respect to luminance data of 32, 62, 69, and 70, and adds the set change value to the adder 22, and sets the relative mode. In the case where the difference between adjacent signals is 2, 2, or 2, which is less than or equal to the threshold value 30, the output of the comparator 12 is not inverted by the luminance signal data inputted so that the luminance is not added without changing the value for boundary division. The signal data is passed through the adder 22 as it is and then output to the three primary color converter 30.

However, in the relative mode, if the difference value is 35 and the threshold value is 30 or more, it is highly likely that the input luminance signal data display different subjects on the video screen or display the surrounding background of the subject, and the comparison unit The output of (12) is maintained inverted so that the adder 22 calculates a predetermined variation value 5 for the subsequent signal and outputs it to the three primary color converter 30.

Therefore, the luminance signal continuously input to the three primary color converter 30 after the addition process in the adder 22 finally has data values of 28, 30, 32, 72, 74, and 75, so that the subject The difference in the data value at the boundary line between the objects becomes larger than the difference value in the existing input signal, and the boundary between the objects becomes clearer. In addition, after the output of the comparator 12 is maintained inverted because the difference value exceeds the threshold in the relative mode as described above, the comparator 12 may invert the cumulative difference value of the luminance data input thereafter. As soon as the negative value (-35) of the difference value 35 at the time is reached, its output is restored to its original state so that the luminance data is not added.

If the difference value of the luminance data is +30 as described above, the signal is converted from a dark signal to a bright signal. Therefore, the set change value is added to the input signal after that, and if the difference value is -30, the bright signal is added. It is more preferable to subtract and output the signal value inputted afterwards so as to flexibly correspond to the boundary between the subjects.

The comparison unit 12 continuously compares the difference between the luminance signal data inputted, and when the difference becomes 30 or more again, i.e., the input data value is a larger value of 100 units or a lower value. In the case of a value of 30 units, the adder 22 adds or subtracts the signal input thereafter and outputs the result, thereby making it possible to clarify the boundary classification for all subsequent subjects.

The image quality control apparatus of the digital image signal according to the present invention constructed and operated as described above may be arbitrarily adjusted to suit the user's visual taste by emphasizing the image on a subject having a specified brightness or a specific color displayed on the image screen. In addition to controlling the sharpness of the image, it is a very practical design to obtain a clearer screen by sharply separating the boundary by emphasizing the corresponding image according to the difference value of adjacent image data.

Claims (1)

Key input means for variably setting arbitrary threshold and scale values for each of the luminance signal and the color signal; Threshold adjustment means for adjusting the thresholds of the luminance signal and the color signal, respectively, corresponding to the threshold set by the key input means; Scale adjusting means for adjusting the scales of the luminance signal and the color signal which are variably adjusted by the threshold value adjusting means to an arbitrary threshold value corresponding to the scale values set by the key input means, respectively; And And control means for controlling the operation of the threshold adjustment means and the scale adjustment means.