KR100731385B1 - Image display apparatus and method for adjusting contrast and brightness - Google Patents

Abstract

The present invention provides an image display device and method which can adjust brightness and contrast in a limited saturation region and a cutoff region to a minimum, and as a contrast value higher than a previous contrast value is newly set, A first step of calculating and temporarily storing a virtual saturation region generated when adjusting the contrast in advance; Determining whether the virtual saturation region is greater than a predetermined limited saturation region when a video signal is input; If the virtual saturation region is not large as a result of the determination, a third step of increasing the contrast of the input video signal according to a high contrast value; And a fourth step of increasing brightness of the input video signal and reducing contrast when the virtual saturation region is large as a result of the determination.

Video Display, Video, Contrast, Brightness, Saturation, Cutoff

Description

Image display apparatus and method for controlling contrast and brightness

1A is a view showing adjustment characteristics of brightness in a conventional image display device.

Figure 1b is a view showing the adjustment characteristics of the contrast in a conventional video display device.

2 is a block diagram of an image display device for adjusting contrast and brightness according to an embodiment of the present invention.

3 is a flowchart illustrating a method of adjusting contrast and brightness in an image display device according to an embodiment of the present invention.

4 is a flowchart illustrating a method of adjusting contrast and brightness in an image display device according to another embodiment of the present invention.

5 is a flowchart illustrating a method of adjusting contrast and brightness in a video display device according to another embodiment of the present invention.

FIG. 6A is a signal characteristic diagram illustrating a method of adjusting contrast and brightness in FIG. 3. FIG.

6B is a signal characteristic diagram illustrating a method of adjusting contrast and brightness in FIG. 4.

FIG. 6C is a signal characteristic diagram illustrating a method of adjusting contrast and brightness in FIG. 5; FIG.

Explanation of symbols on the main parts of the drawings

100: TV receiver 101: Tuner

102: demodulation section 103, 111: A / D conversion section

104: demultiplexer 105: audio decoder

106: video decoder 107: speaker

108: audio processor 109: amplifier

110: display unit 111: image processing unit

112: control unit

The present invention relates to an image display device such as a television receiver, and more particularly, to an image display device and a method that can adjust brightness and contrast in a limited saturation region and a cut-off region. will be.

In addition to the rapid development of science and technology, the multimedia field combining various forms of information such as video and audio has become a digital form of information storage and existence in the rapid development of information and communication. Due to the development of MPEG technology, which is a compression standard for moving picture data for compressing digital video data that requires relatively large amounts of data, the size of digital video data is gradually getting smaller. Digital video and audio services have been provided in all fields, and digital devices for providing such services have emerged.

Among them, broadcasting and TV occupy an important place as an easy and effective information transmission medium in daily life, and thanks to the digital technology described above, video data and audio data are compressed and transmitted by MPEG technology, thereby adding a large amount of information. With the advent of digital TV, which can provide fast and reliable, more broadcasts can be easily enjoyed at home with clearer picture quality and more vivid sound. Accordingly, various techniques for providing clear image quality have been proposed. For example, Korean Patent Application Publication No. 2004-0107571 (published date: Dec. 23, 2004) discloses brightness and / or contrast of a screen based on a digital luminance signal. It is proposed a display device and a control method for automatically adjusting the. A brief description will be made of a signal conversion unit for converting an analog image signal into a digital luminance signal and a color difference signal, and outputting the digital luminance signal having a level exceeding a predetermined saturation period among the digital luminance signals of one frame. A control unit for increasing the contrast level if present and reducing the contrast level if there is no digital luminance signal having a level belonging to the saturation period among the digital luminance signals of one frame; And a frame buffer for temporarily storing the digital luminance signal and the color difference signal.

In order to adjust a video screen such as a TV according to the screen condition adjusting method as described above, the user must adjust the screen state by pressing a button in accordance with a predetermined control pattern using a remote controller or the like. When the brightness and contrast are adjusted in this way, the saturation region, which is the limit of the increase in the adjustment of the brightness and the contrast, becomes very wide, and the cutoff region, which is the limit of the decrease in the adjustment of the brightness, becomes very wide.

FIG. 1A is a view illustrating adjustment characteristics of brightness in a conventional image display device, and illustrates a state in which a saturation region and a cutoff region increase or decrease according to the increase and decrease of a horizontally moving brightness.

As shown in FIG. 1A, since brightness of one element of an image state displayed on an image display device corresponds to a constant value in a first order function, the brightness is moved horizontally on a coordinate plane composed of an input axis and an output axis during increase and decrease. Have Accordingly, when the brightness is increased to the maximum, the saturation region can be expanded to the output axis, and when the brightness is reduced to the minimum, the saturation region can be extended to the input axis.

Therefore, as the saturation region and the cutoff region, which are the limits of brightness increase and decrease, are widened, there is a problem that the brightness becomes worse.

FIG. 1B is a view illustrating a control characteristic of contrast in a conventional image display device, and illustrates a state in which a saturation region increases or decreases according to increase or decrease of contrast having a change in slope.

As shown in FIG. 1B, since the contrast, which is an element of the image state displayed on the image display device, corresponds to a slope in the linear function, the slope is changed on the coordinate plane formed by the input axis and the output axis during increase and decrease. Accordingly, when the contrast is maximized, the saturation region can be extended to the output axis. As a result, the wider the saturation region that becomes the limit of contrast increase and decrease, the worse the contrast.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an image display apparatus and a method which can adjust brightness and contrast in a limited saturation region and a cutoff region.

Another object of the present invention is to provide an image display device and a method which can improve brightness and contrast by interlocking and adjusting brightness and contrast in a saturation region and a cutoff region that are limited to a minimum.

The present invention for achieving the above object, the display means for displaying an image; Control means for controlling the setting of the contrast value and the brightness value of the input video signal and controlling the output of the video signal; And adjusts the contrast and brightness of the input video signal according to the contrast value and brightness value set by the control means and outputs the contrast to the display means. And image processing means for adjusting.

According to the present invention, as the contrast value higher than the previous contrast value is newly set, a first step of pre-calculating and temporarily storing the virtual saturation region generated when adjusting the contrast of the video signal; Determining whether the virtual saturation region is greater than a predetermined limited saturation region when a video signal is input; If the virtual saturation region is not large as a result of the determination, a third step of increasing the contrast of the input video signal according to a high contrast value; And a fourth step of increasing brightness of the input video signal and reducing contrast when the virtual saturation region is large as a result of the determination.

According to an embodiment of the present disclosure, a first step of pre-calculating and temporarily storing a virtual saturation region generated when a brightness value of a video signal is adjusted as a brightness value higher than a previous brightness value is newly set; Determining whether the virtual saturation region is greater than a predetermined limited saturation region when a video signal is input; If the virtual saturation region is not large as a result of the determination, a third step of increasing the brightness of the input video signal according to a high brightness value; And a fourth step of increasing brightness of the input video signal and reducing contrast when the virtual saturation region is large as a result of the determination.

According to an embodiment of the present invention, a first step of pre-calculating and temporarily storing a virtual cutoff area generated when adjusting a brightness of a video signal is set as a brightness value lower than a previous brightness value is newly set; Determining whether the virtual cutoff area is larger than a predetermined limited cutoff area when an image signal is input; A third step of reducing the brightness of the input video signal according to a lower brightness value if the virtual cutoff area is not large as a result of the determination; And a fourth step of reducing the contrast of the input video signal when the virtual cutoff area is large as a result of the determination.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a block diagram of a video display device for adjusting contrast and brightness according to an embodiment of the present invention, and shows an example of a television receiver according to the present invention.

Referring to FIG. 2, the television receiver 100 of the present invention includes a tuner 101 for tuning a plurality of broadcast channels received through different frequencies from a plurality of broadcast stations, and a broadcast signal received through the tuner 101. A demodulation unit 102 for demodulating a signal, an A / D conversion unit 103 for converting an analog broadcast signal demodulated by the demodulation unit 102 into a digital broadcast signal, and an A / D conversion unit 103. Demultiplexer 104 for separating the digital broadcast signal converted by the audio signal and the video signal, an audio decoder 105 for decoding the audio signal separated by the demultiplexer 104, and a demultiplexer 104 A baseband of a video decoder 106 for decoding the video signal separated by the < RTI ID = 0.0 > And audio processing unit 108 for converting into an electric signal, the electric signal by the width of the baseband output from the audio processing unit 108 increases and a amplifier 109 to output to a speaker 107.

The television receiver 100 of the present invention outputs a display unit 110 for displaying various images and OSD information and a video signal input from the video decoder 106 to the display unit 110, and outputs a predetermined signal. Controls channel tuning of the tuner 101 according to a channel tuning command input through an image processing unit 111 for adjusting contrast and brightness of an image signal according to a contrast value and a brightness value, and a remote controller (not shown). And a contrast value and a brightness value input by the user to the image processor 111, and a controller 112 for controlling the image processing of the image processor 111.

The image processor 111 adjusts the image signal according to the contrast value and the brightness value set by the controller 112, and controls the contrast and the brightness in a predetermined limited saturation region. The description will be described with reference to the accompanying flowchart and signal characteristics.

When the user inputs a contrast value and a brightness value using a remote controller or the like, the controller 112 sets the input contrast value and the brightness value to the image processing unit 111, and the image according to the newly set contrast value and brightness value. The image processor 111 is controlled to adjust the contrast and brightness of the signal.

3 is a flowchart illustrating a method of adjusting contrast and brightness in an image display device according to an exemplary embodiment of the present invention. When the contrast is set higher than before by a user, a process of adjusting contrast and brightness is performed. It is shown.

Referring to FIG. 3, when a user inputs a contrast value higher than a contrast value of a previously set video signal using a remote controller or the like to instruct its setting (S310), the controller 112 displays the input contrast value as an image processor 111. ), But sets a higher contrast value than before (S320).

In the state where the contrast value is set higher than before, the image processor 111 temporarily stores the virtual saturation area calculated by calculating a virtual saturation area that may be generated when adjusting the contrast of the image signal according to the high contrast value. (S330). In this process, since the virtual saturation region is determined according to the contrast value set in the image processor 111, the predetermined contrast value is changed every time it is newly changed and set by the user.

When the video signal is input from the video decoder 106 (S340), it is determined whether the virtual saturation region is larger than the preset limited saturation region as shown in FIG. 6A (S350). Here, the limited saturation region is set in advance in the image processing unit 111 for the purpose of the present disclosure, and the image processing unit 111 adjusts the contrast and the brightness in the limited saturation region.

If it is determined that the virtual saturation region is not large, the image processor 111 increases the contrast of the input image signal according to the contrast value set higher than before and outputs the contrast (S360). In this process, as shown in FIG. 6A, the image processor 111 increases the contrast as indicated by arrow A1 within a range not departing from the predetermined limited saturation region.

As a result of the determination, if the virtual saturation region is large, the image processing unit 111 increases the brightness of the image signal input within the predetermined limited saturation region and reduces the contrast (S370). In this process, as illustrated in FIG. 6A, the image processing unit 111 increases brightness and decreases contrast as indicated by arrow A2 within a range not departing from a predetermined limited saturation region.

4 is a flowchart illustrating a method of adjusting contrast and brightness in a video display device according to another embodiment of the present invention. When the brightness is set higher than before by a user, a process of adjusting contrast and brightness is performed. It is shown.

Referring to FIG. 4, when a user inputs a brightness value higher than a brightness value of a previously set video signal using a remote controller or the like to instruct its setting (S410), the controller 112 displays the input brightness value. It is set in the processing unit 111, but sets a higher brightness value than before (S420).

In this state in which the brightness value is set higher than before, the image processing unit 111 calculates the virtual saturation area that may be generated when adjusting the brightness of the image signal according to the brightness value set higher, and calculates the virtual saturation area in advance. Temporarily stores (S430). In this process, since the virtual saturation region is determined according to the brightness value set in the image processor 111, the predetermined brightness value is changed every time it is newly changed and set by the user.

When the video signal is input from the video decoder 106 (S440), it is determined whether the virtual saturation region is larger than the preset limited saturation region as shown in FIG. 6B (S450). Here, the limited saturation region is set in advance in the image processing unit 111 for the purpose of the present disclosure, and the image processing unit 111 adjusts the contrast and the brightness in the limited saturation region.

If it is determined that the virtual saturation region is not large, the image processor 111 increases the brightness of the input image signal according to the brightness value set higher than before and outputs the brightness of the input image signal (S460). In this process, as illustrated in FIG. 6B, the image processing unit 111 increases brightness as indicated by arrow A3 within a range not departing from a predetermined limited saturation region.

As a result of the determination, if the virtual saturation region is large, the image processing unit 111 increases the brightness of the image signal input within the predetermined limited saturation region and reduces the contrast (S470). In this process, as illustrated in FIG. 6B, the image processing unit 111 increases brightness and decreases contrast as indicated by arrow A4 within a range not departing from a predetermined limited saturation region.

FIG. 5 is a flowchart illustrating a method of adjusting contrast and brightness in a video display device according to another embodiment of the present invention. When brightness is set lower than before by a user, contrast and brightness are adjusted. The process is shown.

Referring to FIG. 5, when a user inputs a brightness value lower than a brightness value of a previously set video signal using a remote controller or the like to instruct its setting (S510), the controller 112 displays the input brightness value. It is set in the processor 111, but sets a brightness value lower than before (S520).

With the lower brightness value than before, the image processor 111 calculates a virtual cutoff area that may be generated when adjusting the brightness of the image signal according to the lower brightness value. Temporarily store (S530). In this process, since the virtual cutoff area is determined according to the brightness value set in the image processor 111, the predetermined brightness value is changed every time a new brightness value is set by the user.

When the video signal is input from the video decoder 106 (S540), it is determined whether the virtual cutoff area is larger than the preset limited cutoff area as shown in FIG. 6C (S450). Here, the limited cutoff area is set in advance in the image processing unit 111 for the purpose of the present disclosure, and the image processing unit 111 adjusts the contrast and the brightness in the limited cutoff area.

If it is determined that the virtual cutoff area is not large, the image processing unit 111 reduces the brightness of the input image signal according to the brightness value set lower than before (S560). In this process, as shown in FIG. 6C, the image processing unit 111 reduces brightness as indicated by arrow A5 within a range not departing from the predetermined limited cutoff area.

If the virtual cutoff region is large as a result of the determination, the image processor 111 reduces the contrast of the image signal input within the predetermined limited cutoff region and outputs the reduced signal (S570). In this process, as shown in FIG. 6C, the image processing unit 111 reduces the contrast as indicated by arrow A6 within a range not departing from the predetermined limited cutoff area.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the present invention, by adjusting the brightness and contrast in the saturation region and the cut-off region at least limited in the video display device, the brightness and contrast is improved, and thus the viewer can see a high quality video screen Can be provided to

Claims (10)

Display means for displaying an image; Control means for controlling the setting of the contrast value and the brightness value of the input video signal and controlling the output of the video signal; And Adjusting contrast and brightness of the input video signal according to the contrast value and brightness value set by the control means and outputting to the display means, the contrast and brightness in the limited saturation region and the limited cutoff region Image processing means Image display device comprising a. As the contrast value higher than the previous contrast value is newly set, a first step of temporarily calculating and temporarily storing a virtual saturation region generated when adjusting the contrast of the video signal; Determining whether the virtual saturation region is greater than a limited saturation region when an image signal is input; If the virtual saturation region is not large as a result of the determination, a third step of increasing the contrast of the input video signal according to a high contrast value; And A fourth step of increasing brightness of the input video signal and reducing contrast when the virtual saturation region is large as a result of the determination; Contrast and brightness control method comprising a. The method of claim 2, In the third step, the contrast and brightness control method characterized in that to increase the contrast of the video signal in the limited saturation region. The method of claim 2, In the fourth step, as a result of the determination, the brightness and contrast in the limited saturation region to adjust the contrast and brightness control method. A first step of pre-calculating and temporarily storing a virtual saturation region generated when adjusting the brightness of a video signal according to a new brightness value higher than a previous brightness value; Determining whether the virtual saturation region is greater than a limited saturation region when an image signal is input; If the virtual saturation region is not large as a result of the determination, a third step of increasing the brightness of the input video signal according to a high brightness value; And A fourth step of increasing brightness of the input video signal and reducing contrast when the virtual saturation region is large as a result of the determination; Contrast and brightness control method comprising a. The method of claim 2, In the third step, the brightness and brightness of the video signal in the limited saturation region is increased. The method of claim 2, In the fourth step, as a result of the determination, the brightness and contrast in the limited saturation region to adjust the contrast and brightness control method. A first step of pre-calculating and temporarily storing a virtual cutoff area generated when the brightness of the image signal is adjusted as a brightness value lower than the previous brightness value is newly set; Determining whether the virtual cutoff area is larger than a limited cutoff area when an image signal is input; A third step of reducing the brightness of the input video signal according to a lower brightness value if the virtual cutoff area is not large as a result of the determination; And A fourth step of reducing contrast of the input video signal when the virtual cutoff area is large as a result of the determination; Contrast and brightness control method comprising a. The method of claim 8, In the third step, the brightness and brightness control method of reducing the brightness of the video signal in the limited cut-off area. The method of claim 8, And in the fourth step, as a result of the determination, contrast is reduced within the limited cutoff region.

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