JP2002006825A - Video signal correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct an appropriate correcting process for video signals after having stored the video signals in a computer as digital data. SOLUTION: A picture quality correcting means 109, which corrects video data such as animation and TV video, is provided between a general purpose display controller 107 that is incorporated in a computer main body 100, and a display device 110. Having synthesized video signals and computer image signals, the region, in which video within the synthesized screen are displayed, is extracted and a correcting process is conducted by the means 109. Furthermore, by linking the correcting process to the time and operations so that the user feels no sense of incongruity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a video signal correction device for performing a correction process on a video signal before displaying the video signal captured by a computer system on a display device.

[0002]

2. Description of the Related Art A method for selectively correcting an input signal has been proposed as a technique for appropriately displaying a video signal in a liquid crystal display device, a computer display device, or the like.
For example, Japanese Patent Application Laid-Open No. Hei 5-188352 discloses a configuration in which a gamma correction circuit corrects a video signal and a normal computer output so that optimum display can be performed. In this case, a switch is switched depending on whether the signal is a video signal or not, and the correction process is enabled in the case of a video signal.

Further, Japanese Patent Application Laid-Open No. 6-208339 discloses a configuration in which a gamma correction is canceled and a color correction circuit for improving color reproducibility in accordance with the LCD is provided in order to improve the display quality of the LCD. ing. In this case, a correction process is applied to the video signal before the video signal and the computer image signal are superimposed.

[0004]

However, any of the image quality correction techniques corrects only the video signal. For example, the video signal is stored in an external storage device of a computer by using a video capturing device such as a video capture device. However, there is a problem in that after the image data is stored as digital data, correction processing on the video signal is not performed because all the data is processed as a computer image.

[0005] For this reason, for example, if the video data after the correction processing is taken into an external storage device, the display characteristics change when the video data is displayed not on a computer image but on another display device. Display quality may be degraded.

As described above, there is a need for the development of an image quality correction technique capable of performing an appropriate correction process on a video signal stored as digital data in a computer.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a video signal which can be appropriately corrected even after the video signal is stored in a computer as digital data. It is to provide a signal correction device.

Another object of the present invention is to provide a video signal correction device capable of performing the correction without giving the user a feeling of strangeness.

[0009]

SUMMARY OF THE INVENTION A video signal correction apparatus according to the present invention provides a video signal correction apparatus for transmitting a video signal such as a TV video signal and a moving image signal taken into a computer system to a display device.
What is claimed is: 1. A video signal correction device for performing a correction process on a video signal, comprising: an image synthesizing unit that superimposes the video signal and a computer image signal; A video area extracting means for extracting a portion to be extracted, an image quality correcting means for correcting the image quality of the area extracted by the video extracting means, and controlling the image synthesizing means, the video extracting means and the image quality correcting means. Control means for displaying an image on the display device.

The image quality correcting means may be an electronic chip built in a computer main body or a display device, or
A board or device that is connected to the computer body and the display device by a bus or cable.

The image quality correction means performs gradation correction according to the signal level.

The image area extracting means extracts an area where image data is displayed as a rectangular area of a specific color.

The image area extracting means is constituted by a program provided in advance so as to start execution when the computer system is started.

The control means is constituted by a TV picture display program or a moving picture display program.

The control means analyzes the characteristics of the TV image to be displayed and controls the image quality correcting means.

The control means switches the setting of the image quality correction means in conjunction with the channel switching or menu operation.

The control means switches the setting of the image area extracting means in conjunction with the operation of changing the image display size.

The control means switches the setting of the image quality correction device according to the data stored in the external storage device.
The stored data can be updated by a user operation.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a block diagram of a computer system using an image correction device of a first embodiment.

The computer system includes a computer main body 100, and a display device 110 and an input device 111 connected to the computer main body 100. The display device 110 includes a CRT, an LCD (Liquid Crystal Display), and the like. The input device 111 includes a keyboard, a mouse, and the like for operation.

The computer body 100 includes a CPU (Central Processing Unit) 101 for performing arithmetic processing, a chipset 102 for controlling the flow of data, a memory 103 for temporarily storing programs, data, and the like. External storage device 104 such as DVD or hard disk for storing
A tuner device 105 for extracting a desired signal from a radio signal input to an antenna, a capture device 106 for converting a video signal into a digital signal, a display controller 107 for controlling a display device 110, and data for display. And a picture quality correction chip 109 serving as a picture quality correction means for correcting the picture quality.

In this computer system, a TV video signal is displayed on the display device 110 as a video signal. Also, for example, the DV stored in the external storage device 104
The compressed moving image data such as D is displayed on the display device 110. When displaying a TV image signal, the CPU 101 executes a TV image display program as a control unit. When displaying moving image data, the CPU 101 executes a moving image display program as control means.

FIG. 2 is a block diagram of T in the computer system.
The flow of the TV video signal when the V video display program is activated is shown.

When the TV image display program is started, it performs the following control. (1) A parameter for tuning a desired channel is set in the tuner device 105. (2) The capture device 10 is provided to the display controller 107.
An instruction is given to secure an area for storing the data sent directly from No. 6 and set on the video memory 108. (3) Capture desired data in the capture device 106 and sequentially transfer the data to the display controller 107.

Under this control, the TV video signal is transferred from the capture device 106 to the video memory 108 via the display controller 107. Display controller 1
07 is the video memory 1 in synchronization with the display clock.
A normal computer screen and a TV video are synthesized from the data of 08, and the obtained data is output to the display device 110 via the image quality correction chip 109.

FIG. 3 shows the flow of moving image data when the moving image display program is started in the computer system.

When the moving image display program is started, the compressed moving image data such as a DVD stored in the external storage device 104 is first loaded into the memory 103.
The compressed data fetched into the memory 103 is decompressed as frame-by-frame data by the CPU 101 by decompression logic incorporated in a program or implemented in a library format called at the time of execution, The data is transferred to the memory 108.

The display controller 107 synthesizes a normal computer screen and a moving image from the data in the video memory 108 in synchronization with the display clock, and displays the obtained data via the image quality correction chip 109. Device 110
Output to

Next, a case where the display controller 107 combines a TV image or a moving image with a computer screen will be described.

Normal computer image signals are RGB signals, which are the red (R), green (G),
It is represented as a luminance value of a pixel corresponding to each color of blue (B). On the other hand, a video signal such as a TV video signal and a moving image signal is a YUV signal represented in a data format different from a computer image signal, and a luminance signal Y
And the color difference signals Cb and Cr.
The relationship between the RGB signal and the YUV signal is expressed by the following equation.

Y = 0.290 × R + 0.5870 × G + 0.1140 × B (1) Cb = (− 0.1687) × R + (− 0.3313) × G + O.5000 × B (2) Cr = 0.5 × R + (− 0.4187) ) × G + (− 0.0813) × B (3) By using this equation, mutual conversion between the RGB signal and the YUV signal is possible.

FIG. 4A is an example of a TV image display screen displayed based on the TV image display program. FIG. 4B shows that the TV image is stored in the video memory 108.
3 conceptually shows the state stored in the.

As shown in FIG. 4B, the video memory 1
In the area to the left of 08, the normal computer screen is RG
It is stored in the B format (luminance level of each color of red, green and blue). In the area on the right side of the video memory 108, T
Video data such as V-video and moving images is stored in a YUV data format. Further, on a normal computer screen, an area (shown by oblique lines) to which an image is transmitted is formed of a specific same color that can be recognized by the display controller 107.

The display controller 107 determines that a portion composed of a specific same color is a region for video, converts a signal in YUV format into a signal in RGB format,
The image is output to the display device 110 via the image quality correction chip 109.

In the video signal correction device of the first embodiment, the image data correction chip 109 interposed between the display controller 107 and the display device 110 causes the video data in the hatched portion in FIG. Only the correction process is selectively performed.

Hereinafter, the selective image quality correction processing by the image quality correction chip 109 will be described. FIG. 5 is a block diagram illustrating the configuration of the image quality correction chip 109.

The image quality correction chip 109 is a video memory 1
08: an RGB-YUV conversion unit 201 that converts an RGB signal transmitted via the display controller 107 into a YUV signal; a correction operation unit 202 that performs luminance correction and the like;
A YUV-RGB conversion unit 203 that converts a YUV signal into an RGB signal, and a frame memory 20 that stores an image of one screen
4, a correction coefficient calculation unit 205 that calculates a correction coefficient from an input signal of one screen, a correction control unit 206 that controls the correction calculation unit 201, and an area register 207 that stores coordinate values of an area to be corrected. It has.

As described above, signals in RGB format are sent from the display controller 107 to the image quality correction chip 109. The image quality correction chip 109 converts this RGB signal into R
In the GB-YUV conversion unit 201, the above equations (1) to
Based on (3), the signal is converted into a YUV signal again and transferred to the frame memory 204 and the correction count calculation unit 205.

The frame memory 204 is composed of a FIFO (first in first out) memory for one frame. When a YUV signal of a certain coordinate (x, y) is input, the coordinate (x, It operates so that the signal of y) is output. The correction coefficient calculation unit 205 obtains, for example, an average value, a maximum value, and a minimum value of the signal levels from the data for one frame.

The correction control unit 206 determines whether or not the current signal is included in the correction target area based on the control signal sent from the CPU 101 and the coordinate values stored in the area register 207. Controls whether to perform correction calculation.

Next, the operation of software on the computer system for executing the image quality correction processing will be described.

In the following description, the image area monitor program as the image area extracting means realizes the image quality correction by periodically scanning the video memory 108. However, the image quality may be corrected by the apparatus. Good.

At the same time when the computer system is started, a video area monitor program, which is a resident program, starts.

The video display program secures a video data area in a surplus portion of the video memory 108 at the time of startup, and fills a portion corresponding to the video display area with a specific same color. When a rectangular area of the same color is secured in the video memory 108, the video area monitor program calculates the upper left coordinate value and the lower right coordinate value of the rectangular area, and stores the data in the area register 207 in the image quality correction chip 109. To transfer. Further, from the size of the target area, the number of pixels used for calculating the correction value is obtained and output to the correction control unit 206.

The correction control unit 206 counts the number of pixels in the horizontal direction and the number of pixels in the vertical direction of the display, and determines whether or not the coefficiented pixel is within the area stored in the area register 207. , And sends a control signal to the correction coefficient calculation unit 205. The correction coefficient calculation unit 205 calculates
Signal characteristics such as sum of signal levels, maximum value and minimum value are obtained.

When the number of coefficient pixels in the horizontal and vertical directions reaches the number of pixels used for calculating a correction value, the correction control unit 206 sends a signal to end the counting to the correction coefficient calculation unit 205. The correction coefficient calculation unit 205 obtains a correction coefficient and transfers it to the correction calculation unit 202.

FIGS. 6A and 6B show examples of the configuration of the correction coefficient calculation unit 205, respectively.

The correction coefficient calculator 20 shown in FIG.
Reference numeral 5 denotes an addition circuit 301 for adding an input signal, a register 302 for temporarily holding the addition result, a shift operation circuit 303 for obtaining an average after the addition operation, and a counter 304 for counting the number of additions. Have.

The number of additions of the counter 304 is set based on the data of the area register 207. Adder circuit 30
1 continues adding until the counter reaches 0. After the addition is completed, the added data is processed by the shift operation circuit 303 to obtain an average value.

The correction operation unit 202 includes a correction coefficient operation unit 20
The correction process is performed by multiplying the input signal by the correction coefficient given from 5.

FIG. 7 shows the conversion function of the correction operation unit 201,
This is shown by the change over time of the input luminance and the output luminance. In this case, the correction function is represented by the following equation (4).

Output signal = (Average output (128) / Average input) × Input signal (4) The signal subjected to the correction processing is finally inversely converted into an RGB signal by the YUV-RGB conversion unit 203 and displayed. Sent to the device 110. Thereby, an image with high contrast can be obtained.

FIG. 6A shows an example of the operation of the correction coefficient calculation unit 205 in which the input signals are sequentially added and the average is obtained at the end of the input. May be required. FIG. 6B shows a configuration example of such a correction coefficient calculation unit 205.

The correction coefficient calculating section 205 shown in FIG.
Are a maximum value detection circuit 401 and a minimum value detection circuit 402
And a counter 403 for controlling. The maximum value detection circuit 401 includes a comparator and a register, and executes detection of the maximum value until the counter becomes zero. The minimum value detection circuit 402 executes detection of the minimum value until the counter becomes zero.

In order that the obtained maximum value becomes the upper limit of the luminance,
Further, by converting the input signal so that the minimum value becomes the lower limit of the luminance, a high-contrast image can be obtained as in the case where the correction is performed using the average.

FIG. 8 shows the conversion function of the correction operation unit 201 in this case by the change over time of the input luminance and the output luminance. The correction function is represented by the following equation (5).

Output signal = [luminance range (256) / (maximum value-minimum value)] × input signal (5) In any case, after the computer image signal and the video signal are combined, , Only the video data is extracted and the image quality is corrected. Thus, the correction processing is performed on the video signal after being stored as digital data in the computer. In addition, it is possible to perform an appropriate correction process only on the video signal without affecting the computer image signal and without being affected by the computer image signal. As a result, for example, even when a display device such as an LCD having low gradation characteristics is used, a high-contrast high-quality image can be viewed.

<Embodiment 2> The video signal correction apparatus of Embodiment 2 changes the correction coefficient in synchronization with the switching of the screen so as not to give the user a strange feeling. In this method, the load of the CPU 101, the circuit of the image quality correction chip 109, and the like can be reduced by providing a function of transmitting data to the image area monitor program and the image quality correction chip 109 as an image area extraction unit.

This video signal correction device is different from the video signal correction device of the first embodiment in that the image quality correction chip 109
And the configuration of software related to the image correction chip is different.

FIG. 9 is a block diagram showing the configuration of the image quality correction chip 109 used in the video signal correction device according to the second embodiment.

The image quality correction chip 109 converts the RGB signals to Y
An RGB-YUV conversion unit 801 for converting into a UV signal, a correction operation unit 802 for performing luminance correction and the like,
It includes a YUV-RGB conversion unit 803 for converting to a B signal, an LUT buffer 804 for storing a correction table, a correction control unit 805 for controlling the correction calculation unit 802, and an area register 806 for storing area information.

FIG. 10 is a two-dimensional flag table in which the day of the week and the time are vertical components, and the broadcast station (channel) is a horizontal component, and is configured with correction flag values corresponding to each. This two-dimensional table is usually stored in the external storage device 104.

FIG. 11 shows the configuration of the LUT buffer 804. The LUT buffer 804 has an input level (0 to 0).
255) is a two-dimensional correction table using a vertical component and a flag value as a horizontal component, and has an output level corresponding to each. The correction table in FIG.
The output values corresponding to the input values (0, 10, 20, 30, 40,...) Of the buffer are shown. If the flag is 1 for the input 20, the output is 24, and if the input 20 is the flag, the flag is 5. If there is, the output is 40. Thus, the larger the value of the flag, the steeper the correction gradient.

FIG. 12 shows a change in control over time. When the TV image display program starts, the image area monitor program obtains area information (see step S1 in FIG. 12, the same applies hereinafter), and sets the obtained area in the area register 806 of the correction control unit 805 (step S2). ). When the TV video display program is started, the flag value is obtained from the flag table of FIG. 10 based on the channel information and the time information, and the obtained flag value is sent to the correction control unit 805 (step S3). The correction control unit 805 controls the correction table (L
A column corresponding to the transferred flag value is selected by the UT buffer 804), and an output signal is obtained from the input signal in the selected column by the correction operation unit 802 (step S4).

Further, when the display size of the screen is switched (step S5), the TV video display program executes
The control signal is sent to the image area monitor program, and the image area monitor program obtains the image area (step S
6) The obtained area is set in the area register 806 (step S7).

The TV video display program is 18:
At a fixed time such as 00, 18:15 (step S
8) When the channel is switched (step S9),
Alternatively, by adjusting the brightness (step S1
0), the correction control unit 805 selects a column corresponding to the transferred flag value from the correction table (LUT buffer 804) shown in FIG. An output signal is obtained from the input signal (steps S11 to S13).

Then, as in the case of the video signal correction device of the first embodiment, the image quality is corrected only in the video area.

Thus, an appropriate correction pattern is created in advance for an image shot under bright illumination such as a news program and an image including a lot of dark scenes such as a drama or movie. Since these correction patterns are switched in synchronization with the switching of the screen, the uncomfortable feeling felt by the user when performing the image quality correction by the TV video display program is remarkably reduced.

When the TV video display program ends, the contents of the area register 806 are invalidated, and the correction operation unit 802 is also invalidated (step S14).

FIG. 13 shows an example of a submenu displayed by the TV video display program. The submenu shown on the left is displayed when the channel switching button is pressed. The submenu shown in the center is displayed when the display size switching button is pressed. The submenu shown on the right is displayed when the image quality adjustment button is pressed.

When the user operates the image quality adjustment button to change the image quality adjustment level, the value of the flag in FIG. 11 is updated and transferred to the image quality correction control unit 206. This also facilitates adjustment according to preference. Further, the updated flag value is stored in the external storage device 104, so that the same setting value is stored at the next startup.

In the above embodiment, the image quality correcting means is constituted by the image quality correcting chip 109 which is an electronic chip. However, the image quality correcting means may be constituted by a board or a device connected to the computer main body and the display device by a bus or a cable. .

[0074]

As described above, according to the video signal correcting apparatus of the present invention, for example, a video signal input from a TV antenna, a video signal input from a video input terminal, a moving image signal stored in an external storage device, and the like. After the video signal is combined with the computer image signal, the image quality can be corrected only at the portion where the video signal is displayed in the composite screen. Even after the video signal is stored as digital data in the external storage device of the computer, the correction process for the video signal can be performed. Moreover, even though the video signal is synthesized with the computer image signal, it is possible to perform a correction process appropriate only for the video without affecting the computer image or being affected by the computer image.

Further, by switching the setting of the image quality correcting means in conjunction with the channel switching or the menu operation, automatic correction according to the characteristics of the TV image can be performed. Processing can be performed. In addition, it is possible to perform appropriate correction according to the atmosphere of the image.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a computer system using a video signal correction device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a data flow when a TV video display program is executed in the computer system.

FIG. 3 is a block diagram showing a data flow when a moving image display program is executed in the computer system.

FIG. 4A shows an example of a video display screen by a video display program, and FIG. 4B is a conceptual diagram of a video memory in which the video is stored.

FIG. 5 is a block diagram showing a configuration of an image quality correction unit used in the video signal correction device.

FIGS. 6A and 6B are block diagrams each showing a configuration example of a correction operation unit in the image quality correction and correction means;

FIG. 7 is an explanatory diagram of signal processing when correcting a video signal based on an average level.

FIG. 8 is an explanatory diagram of signal processing when a video signal is corrected based on a maximum value and a minimum value.

FIG. 9 is a block diagram of an image quality correcting unit used in the video signal processing device according to the second embodiment of the present invention.

FIG. 10 is a configuration diagram of a flag table used for the image quality correction unit.

FIG. 11 is a configuration diagram of a correction table used for the image quality correction unit.

FIG. 12 is a state transition diagram showing the operation of the image quality correction means.

FIG. 13 is an explanatory diagram of a submenu displayed by the TV video display program.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 computer main unit 101 CPU 102 chipset 103 memory 104 external storage device 105 tuner device 106 capture device 107 display controller 108 video memory 109 image quality correction chip (image quality correction means) 110 display device 111 input device 201 RGB-YUV conversion unit 202 correction operation Unit 203 YUV-RGB conversion unit 204 Frame memory 205 Correction coefficient operation unit 206 Correction control unit 207 Area register 301 Addition circuit 302 Register 303 Shift circuit 304 Counter 801 RGB-YUV conversion unit 802 Correction operation unit 803 YUV-RGB conversion unit 804 Correction Table 805 Correction control unit 806 Area register

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Rui Sakuta 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 5C058 AA06 BA07 BA21 BA24 BB25 5C082 AA01 AA02 BA12 BA27 BA41 CA12 CA54 CA55 CB01 CB05 DA51 DA87 MM10

Claims (10)

[Claims] 1. A computer system in which T is stored in a computer system.
What is claimed is: 1. A video signal correction device for performing a correction process on a video signal such as a V video signal and a video signal before transferring the video signal to a display device. Means, and a synthesized screen superimposed by the image synthesizing means,
Video area extraction means for extracting a portion where video data is displayed; image quality correction means for correcting the image quality of the area extracted by the video extraction means; image synthesis means, video extraction means and image quality correction means Control means for controlling the image signal to display the image on the display device. 2. The image quality correcting means according to claim 1, wherein the image quality correcting means is an electronic chip built in a computer main body or a display device, or a board or a device connected to the computer main body and the display device by a bus or a cable. Video signal correction device. 3. The video signal correction apparatus according to claim 1, wherein said image quality correction means performs gradation correction according to a signal level. 4. The video signal correction device according to claim 1, wherein the video area extracting unit extracts a region where the video data is displayed as a rectangular region of a specific color. 5. The video signal correction apparatus according to claim 1, wherein said video area extraction means is configured by a program provided in advance so as to start execution when a computer system is started. 6. The video signal display unit according to claim 1, wherein the control unit is configured by a TV video display program or a moving image display program. 7. The video signal correction device according to claim 1, wherein the control unit analyzes characteristics of the TV video to be displayed and controls the image quality correction unit. 8. The video signal correction device according to claim 7, wherein the control unit switches the setting of the image quality correction unit in response to a channel switch or a menu operation. 9. The video signal correction apparatus according to claim 7, wherein said control means switches the setting of the video area extraction means in conjunction with an operation of changing an image display size. 10. The video signal according to claim 7, wherein the control unit switches the setting of the image quality correction device based on data stored in an external storage device, and the stored data can be updated by a user operation. Correction device.