KR100748493B1 - Method for definition optimization through gamma adjustment - Google Patents

Abstract

The present invention relates to a method for improving image quality, and in particular, when connected to a third-party system, a gamma adjustment for adjusting the brightness and improving the image quality of PPI images by easily predicting and adjusting gamma of another system using a histogram. The purpose is to provide a picture quality optimization method. According to the present invention for video communication, a first step of calculating a camera gamma value and a display gamma value, and comparing and analyzing the calculated camera gamma value and the display gamma value with a company system to determine a connection between systems. In the second step, and as a result of the determination, when the system and the third party system are connected, the third step of applying the third party gamma corresponding to the third party system to adjust the brightness of the screen and improving the image quality and displaying the image on the PI screen; As a result of the determination, the four systems are connected to each other, and the fourth step of displaying the image on the PI screen by improving the brightness and image quality of the screen by applying the gamma as it is.

Description

How to optimize picture quality with gamma adjustment {METHOD FOR DEFINITION OPTIMIZATION THROUGH GAMMA ADJUSTMENT}

1 is a block diagram showing the configuration of a conventional video communication system.

Figure 2 is an exemplary view showing a conventional IP image.

3 is a graph illustrating a relationship between a conventional gamma-adjusted input and output image.

Figure 4 is a graph showing a histogram according to the system connection state of the present invention.

5 is a flow chart showing a sequence of the image quality optimization method through the gamma adjustment of the present invention.

The present invention relates to a method for improving image quality through gamma adjustment in video communication. In particular, in a video communication device, a gamma of another system can be easily predicted using a histogram and the display means The present invention relates to an image quality optimization method through gamma adjustment to optimize image quality.

FIG. 2 is a diagram illustrating a conventional PIP image. As shown in FIG. 2, in the case of video communication, PIP (PIP: Picture In Picture or below) is used to represent one's own image together with an image of a counterpart. Pi is displayed).

First, Figure 1 is a block diagram showing the configuration of a conventional video communication system in the above case, as shown in the system A (10) and system B (20) transmit and receive images with each other, where the system A 10, a camera 11 receiving an image and image data received from the camera 11 are compressed and transmitted to the codec unit 21 of the following system B 20, and the And a display unit 13 for receiving and restoring image data from the codec unit 21 and a display unit 13 for outputting an image received from the codec unit 12.

Similarly, the system B 20 compresses the camera 22 receiving the image and the image data received from the camera 22 and transmits the compressed image data to the codec unit 12 of the system A 10. A codec unit 21 for receiving and restoring image data from the codec unit 12 of the A 10 and a display unit 23 for outputting the image received from the codec unit 21 are configured as described above. The operation of the conventional device is as follows.

First, as shown in FIG. 2, an image input to the camera 11 of the system A 10 is fed back and displayed on a PIP (magnetic screen) screen, and from the codec unit 21 of the system B 20. The compressed and transmitted image data is restored by the codec unit 12 of the system A 10 and displayed on the PIP screen (relative screen).

On the contrary, the image inputted to the camera 22 of the system B 20 is fed back and displayed on the pizza screen, and the image data compressed and transmitted from the codec unit 12 of the system A 10 is transmitted to the system B 20. Is restored in the codec unit 21 and displayed on the PIP screen.

At this time, the cameras 11 and 22 receiving the image and the display units 13 and 23 outputting the image must be gamma adjusted based on Equation 1 below because of their nonlinear characteristics.

output =

output =

3 is a graph illustrating a relationship between an input image and an output image in a gamma-adjusted state according to Equation 1, and as shown in FIG. 3, an input image is output as it is and r> 1 In this case, the output image becomes brighter than the input image, and in the case of r <1, the output image becomes darker than the input image.

In general, in the case of a camera, an adjustment is made such that r <1, and the display device is adjusted so that r> 1, so that people feel visually that gamma adjustment is not made. Thus, in one system the gamma of the display device is the inverse of the camera gamma.

However, in case of video communication, the same company system is not necessarily connected to each other, but also connected to a system of a third party having the same communication protocol (for example, H.323 and H.324). In this case, since the gamma values adjusted by the camera and the display device are different for each system, there is a problem in that the brightness and the image quality deteriorate between the mother screen and the child screen in the PIP image.

Accordingly, the present invention was created to solve the above-mentioned conventional problems, and when connected to a third-party system, the gamma of another system is easily predicted using a histogram, and the gamma of the camera is adjusted using the predicted gamma. In addition, by adjusting the gamma of the display device, an object of the present invention is to provide a method for optimizing image quality through gamma adjustment to solve the difference in brightness of the PPI image and to improve the image quality through the adjusted gamma.

In order to achieve the above object, the present invention provides a first step of calculating a gamma value of a camera and a gamma value of a display when performing video communication, and comparing and analyzing the calculated camera gamma value and the display gamma value with a company system. The second step of judging the connection between the systems, and as a result of the determination, when the company's system and the third party's system are connected, the third party's gamma corresponding to the third party's system is applied to adjust the brightness of the screen and improve the image quality. The third step of displaying on, and as a result of the determination, it is characterized in that the system is connected to each other and the fourth step of displaying on the PPI screen by improving the brightness and image quality of the screen by applying its gamma as it is.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

First, in case of video communication through video communication connection, the camera's gamma value and the display device's gamma value are calculated, and the calculated camera gamma value and display value are compared with the company's system. It determines whether the system is a system of another A company or another B company, that is, a connection between the systems.

As a result of the determination, when the systems are connected to each other for video communication, the gamma of the camera is applied as it is, that is, the gamma of the camera and the gamma value of the display device correspond to each other, as shown in FIG. Will be able to send images.                     

In this case, obtaining a histogram from n frames transmitted from one system of the system to the other system forms a graph located at a constant brightness as shown in FIG.

In addition, as a result of the determination, when the system and the other A company's system is connected to perform video communication, the other company's gamma is applied, that is, by increasing the gamma of the camera as shown in FIG. It becomes less dark, and by making the display gamma smaller, it is less bright than the gamma of our system display.

Accordingly, when a histogram of n frames transmitted from another A company in the system is obtained, the mother screen appears bright in the image of the PI screen 30 shown in FIG. 4, and the child screen appears relatively dark. On the contrary, the parent screen appears dark in the image of the PI screen 30 appearing in another A company's system, and the child screen appears relatively bright.

In this case, when a histogram of n frames transmitted from another A company in the system is obtained, a graph located on a brighter side than the histograms connected to each other is formed as shown in FIG. 4.

In addition, as a result of the determination, when the video communication is connected to the company's system and the other B's system by applying the other B's gamma to reduce the gamma of the camera as shown in Figure 3 than the company's system camera gamma It is dimmed, and by increasing the display gamma, it is brighter than its system display gamma.

As a result, the parent screen appears dark in the PIP image appearing in the company's system, and the parent screen appears relatively bright, while the mother screen appears bright in the PIP image appearing in another B company's system, and the child screen appears relatively bright. .

In this case, when a histogram of n frames transmitted from another B company in the system is obtained, a graph located at a darker side than the histograms connected to each other is formed as shown in FIG. 4.

Therefore, in the case of the own system, if the histogram is obtained from n frames, it is possible to know whether the currently connected counterpart system is the own system or another A company or another B company.

As such, in order to further improve the brightness difference and image quality deterioration of the IP screen caused by the system connection between the company or between the company and the third party, the histogram is used to adjust the gamma value, that is, the camera gamma value or the display gamma value. The solution is possible by adjusting.

Then, if the other system is another A company, the video output on the parent screen of its own PI image is the image transmitted from another A company. Therefore, if the gamma value of the company's display device is used as it is, To solve this problem, to solve this problem, to reduce the gamma value of the display, the overall screen brightness is maintained at the same level, thereby improving the image quality.

In addition, the camera gamma value that is output on the child screen of the company's PI image is maintained as it is, and the camera gamma value is larger so that the image that is transmitted to the other party is not dark. By doing so, the overall screen brightness is maintained at a constant level in other A systems.

In addition, if the other system is another B company, the image output on the parent screen of its own PI image is from the other B company. Therefore, if the gamma value of the company's display device is used, it is darker than the child screen of the PI image. In order to solve this problem, the gamma value of the display device is increased to maintain the overall screen brightness at the same level, thereby improving image quality.

In addition, the camera gamma value that is output on the child screen of the company's PPI image is maintained as it is and transmitted to the other party, that is, the camera gamma value is made smaller so that the image displayed on the mother screen on another B company's system does not appear bright. By doing so, the overall screen brightness is maintained at a constant level in other B systems.

As described above, the present invention easily predicts the gamma of another system by using a histogram and compares the brightness difference and the image quality deterioration of the PIP image generated not only when the systems are connected to each other during video communication but also when connected to other systems. By adjusting the gamma adjustment, the brightness difference can be solved and the brightness is kept constant and the image quality is improved.

Claims (4)

In the case of video communication, a first step of calculating a gamma value and a display gamma value of a camera, and a second step of comparing and analyzing the calculated camera gamma value and a display gamma value with a company's system to determine a connection between systems; As a result of the determination, when the system and the third party system are connected, the third step of applying the third party gamma corresponding to the third party system to adjust the brightness of the screen and improving the image quality to display on the IP screen; The system is connected to each other, and the fourth step of displaying the image on the PI screen by improving the brightness and image quality of the screen by applying the gamma as it is, the image quality optimization method through gamma adjustment. The image quality optimization through gamma adjustment according to claim 1, wherein the PPI screen of the third step displays an image transmitted from a system of a third party on a mother screen and an image of the system itself is displayed on a child screen. Way. The method of claim 1, wherein in the third step, the third-party gamma is applied with a larger camera gamma value and a smaller display gamma value. The method of claim 1, wherein in the third step, application of gamma for a third party is performed by applying a small camera gamma and a large display gamma value.

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