JP2004096556A - DISPLAY DEVICE, gamma CORRECTION METHOD, gamma CORRECTION PROGRAM AND COMPUTER READABLE RECORDING MEDIUM HAVING PROGRAM RECORDED THEREON - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform appropriate γ correction no matter what kind of γ correction is performed in a connected image signal generator. <P>SOLUTION: A display device for displaying image signals inputted from a personal computer comprises: a reception part (S01) for receiving the image signals from the personal computer connected to the display device; a γ value detection part (S02) for detecting the γ value of the image signals of a specified pattern on the basis of the image signals of the specified pattern received by a reception means; a correction value calculation part (S03) for calculating a correction value from the detected γ value and the γ value of the display device; and a monitor correction part for γ correcting the image signals received by the reception means according to the calculated correction value. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device, a γ correction method, a γ correction program, and a computer-readable recording medium storing the γ correction program, and in particular, a display for performing an appropriate γ correction on an image signal output from a connected image generation device. The present invention relates to a device, a gamma correction method executed by a display device thereof, a gamma correction program executed by the display device, and a computer-readable recording medium recording the program.
[0002]
[Prior art]
The display device has a response characteristic of a gradation in which the gradation of an output image changes exponentially without being directly proportional to the input voltage, and this response characteristic is represented by a γ value. The gamma correction is performed on the image signal in consideration of the response characteristics of the display device. When the display device is connected to a personal computer (image signal generation device) that generates an image signal, the personal computer executes γ correction in consideration of the γ value of the display device. Generally, in a personal computer, on the assumption that the γ value of the display device is, for example, 2.2, the image signal is γ-corrected so that the γ value of the γ-corrected image signal is 1/22. Outputting to the display device.
[0003]
However, there is no problem when a predetermined display device is connected to a personal computer, but when the display device is connected to a different personal computer, the γ value of the γ correction executed by the personal computer is not changed. May not correspond to the γ value. In such a case, the γ value of the image finally output from the display device does not become 1. For example, the case where the γ value of the γ correction executed by the personal computer is 1 / 2.5 and the γ value of the display device is 2.2.
[0004]
In order to solve this problem, Japanese Patent Application Laid-Open No. 2001-34245 describes a technique of adding image adjustment control information including a γ value of γ correction to an image signal output from a personal computer and outputting it to a display device. According to this, if the display device detects the γ value of the screen adjustment control information added to the image signal, it is possible to detect what γ correction has been executed by the personal computer.
[0005]
[Patent Document 1]
JP-A-2001-34245
[0006]
[Problems to be solved by the invention]
However, in the technology described in JP-A-2001-34245, it is necessary to provide a special image signal generator for adding the screen adjustment control information to the image signal on the personal computer side. Yes, existing personal computers cannot be used. For this reason, when the connected personal computer does not add the screen adjustment control information to the image signal and outputs the image signal, the personal computer cannot detect the γ value of the γ correction executed by the personal computer, and the display device has an appropriate gradation. Cannot display images.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and one of the objects of the present invention is to provide a method for appropriately performing gamma correction even when any gamma correction is performed by a connected image signal generator. To provide a display device capable of performing the following.
[0008]
Another object of the present invention is to provide a gamma correction that can perform a gamma correction suitable for output on a display device, regardless of the type of gamma correction performed by an image signal generator connected to the display device. Is to provide a way.
[0009]
Still another object of the present invention is to cause a display device to execute a gamma correction suitable for outputting on a display device even when any gamma correction is performed by an image signal generator connected to the display device. And a computer-readable recording medium on which a gamma correction program is recorded.
[0010]
[Means for Solving the Problems]
According to an aspect of the present invention, there is provided a display device for displaying an externally input image signal, wherein the display device includes an image signal generating device connected to the display device. Receiving means for receiving, the γ value detecting means for detecting the γ value of the image signal of the specific pattern based on the image signal of the specific pattern received by the receiving means, from the detected γ value and the γ value of the display device A calculating means for calculating a correction value; and gamma correcting means for gamma correcting the image signal received by the receiving means according to the calculated correction value.
[0011]
According to the present invention, the γ value of the image signal of the specific pattern is detected based on the image signal of the specific pattern received from the image signal generator connected to the display device. Therefore, it is possible to detect the γ value of the γ correction performed by the image signal generating device only by receiving the image signal of the specific pattern from the connected image signal generating device. Then, a correction value is calculated from the detected γ value and the γ value of the display device, and the image signal received from the image signal generating device is γ corrected according to the calculated correction value. As a result, it is possible to provide a display device that can perform appropriate gamma correction even when any gamma correction is performed by the connected image signal generating device.
[0012]
According to another aspect of the present invention, a gamma correction method is a gamma correction method for a display device that displays an image signal input from the outside, wherein the gamma correction method includes an image signal generation device connected to the display device. Receiving the signal, detecting the γ value of the image signal of the specific pattern received based on the received image signal of the specific pattern, and correcting the correction value from the detected γ value and the γ value of the display device. Calculating means for calculating, and gamma correcting the image signal received from the image signal generating device according to the calculated correction value.
[0013]
According to the present invention, there is provided a gamma correction method capable of performing gamma correction suitable for output on a display device even when any gamma correction is performed by an image signal generator connected to the display device. Can be provided.
[0014]
According to another aspect of the present invention, the gamma correction program is a gamma correction program that is executed on a display device that displays an image signal input from the outside, and is specified by an image signal generation device connected to the display device. Receiving the image signal of the pattern, detecting the γ value of the received image signal of the specific pattern based on the received image signal of the specific pattern, and from the detected γ value and the γ value of the display device Calculating means for calculating a correction value; and performing gamma correction on the image signal received from the image signal generator in accordance with the calculated correction value.
[0015]
According to the present invention, it is possible to cause the display device to execute the γ correction suitable for outputting on the display device even if any γ correction is performed by the image signal generating device connected to the display device. A gamma correction program and a computer-readable recording medium on which the gamma correction program is recorded can be provided.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed description thereof will not be repeated.
[0017]
FIG. 1 shows the appearance of a display device and an image signal generator connected thereto according to an embodiment of the present invention. As described below, the image signal generating device is configured by a general personal computer.
[0018]
Referring to FIG. 1, display device 200 is connected to personal computer 100 which is an image signal generating device. The display device 200 is a liquid crystal display device, a CRT, a plasma display, an electroluminescence or a field emission display. The personal computer 100 includes a CD-ROM (Compact Disc Read-Only Memory) drive 110, an FD (Flexible Disk) drive 112, a keyboard 106, and a mouse 108. A CD-ROM is mounted on the CD-ROM drive 110. An FD is mounted on the FD drive 112.
[0019]
An image signal of a specific pattern described later is recorded on the FD or CD-ROM, and is read by the FD drive 112 or the CD-ROM drive 110. Then, the read image signal of the specific pattern is output from the personal computer 100 to the display device 200.
[0020]
The personal computer 100 executes γ correction on the read image signal of the specific pattern. In the personal computer 100, a γ value for γ correction is predetermined. Here, for the sake of explanation, a description will be given assuming that correction is performed so that the γ value of the image signal after γ correction is 1/2. Some personal computers connected to the display device 200 do not execute the γ correction, but in such a case, it may be considered that the γ correction is performed when the γ value is 0.
[0021]
Since the operation of personal computer 100 itself is well known, detailed description thereof will not be repeated here.
[0022]
FIG. 2 is a functional block diagram showing functions of display device 200 according to the present embodiment. FIG. 2 also illustrates the functions of the personal computer 100 for explanation. Referring to FIG. 2, display device 200 includes a receiving unit 202 for receiving an image signal from personal computer 100, a storage unit 203 for storing monitor γ value 203a, and detecting a γ value of an image signal of a specific pattern. Value detection unit 201 for performing the correction, a correction value calculation unit 205 that calculates a correction value from the γ value of the image signal of the specific pattern and the monitor γ value, and a correction value that calculates the image signal received from the personal computer 100. And a display unit 211 for displaying a gamma-corrected image signal.
[0023]
The personal computer 100 includes an image signal generation unit 101 and a γ correction unit 102. The image signal generation unit 101 generates an image signal of an image created by application software started by the personal computer 100. An image recorded on a recording medium such as an FD or a CD-ROM is read by an FD drive 112 or a CD-ROM drive 110 to generate an image signal. Further, the image signal generation unit 101 can receive an image signal input to the personal computer 100 from another computer, a digital camera, a digital video camera, or the like connected to the personal computer. Such an image signal can be generated as long as the image signal is included. Then, the image signal generation unit 101 outputs the generated image signal to the γ correction unit 102.
[0024]
In particular, the image signal generation unit 101 generates an image signal of a specific pattern by reading the specific pattern 103 from an FD or a CD-ROM storing a specific pattern described later.
[0025]
The γ correction unit 102 performs γ correction on the input image signal. Here, the γ correction is a correction in consideration of the γ value of the display device 200, but the γ value is predetermined in the personal computer 100 and does not necessarily correspond to the γ value of the display device 200. . Here, a description will be given assuming that the γ value of the γ correction performed by the γ correction unit 102 is 1 / 2.5.
[0026]
FIG. 3 is a diagram illustrating an example of the specific pattern. Referring to FIG. 3, the specific pattern is such that each of the three primary colors of red (R), green (G), and blue (B) is represented in a band shape, and the gradation of each color is higher on the right side in the figure and on the left side in the figure. This is a low-profile pattern. In practice, the pattern is divided into a plurality of regions, and the gradation changes stepwise. This will be described more specifically.
[0027]
FIG. 4 is a diagram for explaining the divided areas of the specific pattern shown in FIG. Referring to FIG. 4, the specific pattern is divided into 48 in a vertical direction divided into three and in a horizontal direction divided into sixteen. The upper 16 areas R0 to R16 correspond to red (R), the middle areas G0 to G15 correspond to green (G), and the lower areas B0 to B15 correspond to blue (B). The gray scale is lower in the left area in the drawing, and higher in the right area. Specifically, the gray levels of the regions R0, R1, R3,..., R15 are 0, 16, 32,. The gradation is similarly defined for the regions G0 to G15 and the regions B0 to B15. As described above, the specific pattern defines the gradation for each position in the image. In particular, in the present embodiment, the pattern is such that the gradation gradually increases from left to right in the figure. Thus, in the display device 200, when an image signal of a specific pattern is input, it is possible to make the input voltage value correspond to each region. That is, the input voltages V0, V1, V2,..., V15 can correspond to the respective regions R0, R1, R2,. This input voltage is determined based on the relationship between the gradation and the input voltage when the γ value is 1.
[0028]
In this case, the region is divided into 16 equal parts, and each region is assigned each value of 16 equally divided gradations. However, the number of divisions is not limited to this, and the greater the number of divisions, the later-described γ value Detection accuracy can be improved. However, if the number of divisions is increased, the amount of calculation for γ detection is increased.
[0029]
FIG. 5 is a diagram illustrating another example of the specific pattern. Another specific pattern is different from the above-described pattern of the three primary colors of RGB only in that it is represented by a gray scale instead of the three primary colors. The other configuration does not differ from the above-described three primary color patterns, and thus the description will not be repeated. In the display device 200 according to the present embodiment, the specific patterns shown in FIG. 3 or FIG. 5 are input, and which specific pattern is input may be determined, for example, by using the OSD ( On
Specified by the user using the Screen Display function.
[0030]
Returning to FIG. 2, the receiving unit 202 of the display device 200 receives the image signal output from the personal computer 100. The image signal received by the receiving unit 202 is normally output to the monitor correction unit 207. However, when the input of the specific pattern is instructed by the OSD function and the execution of the γ value correction process is instructed, The received image signal of the specific pattern is output to the γ value detection unit 201.
[0031]
Upon receiving an image signal of a specific pattern from the personal computer 100, the γ value detection unit 201 detects a γ value of the image signal of the specific pattern. As described above, the input voltage is defined corresponding to each area of the specific pattern. The γ value detection unit 201 stores in advance voltages corresponding to each region of the specific pattern. The stored voltage value is a voltage value corresponding to the gradation of each area when an image signal of a specific pattern having a γ value of 1 is received. Then, the γ value of the image signal of the specific pattern is obtained by associating the voltage corresponding to each area of the specific pattern with the gradation of the received image signal.
[0032]
FIG. 6 is a diagram illustrating γ values of an image signal of a specific pattern output from a personal computer. FIG. 6 shows a graph in which the horizontal axis represents the input voltage (V) and the vertical axis represents the gradation (L). By plotting the gradation of each region of the specific pattern in correspondence with the input voltage defined corresponding to the region, the γ curve in the figure is obtained, and the γ value is obtained. As for the gradation for each area of the specific pattern, noise included in the image signal can be removed by extracting a plurality of sample values from one area of the image signal and using an average value or an intermediate value thereof. Therefore, the detection accuracy of the γ value can be improved. Further, if the number of divisions of the specific pattern in the gradation direction is increased, the number of points to be plotted is increased, so that the detection accuracy of the γ value can be improved. Hereinafter, the γ value detected by the γ value detection unit 201 is referred to as γ1.
[0033]
FIG. 7 is a diagram illustrating a γ curve of the display device 200 according to the present embodiment. The γ value (γ2) of the display device 200 was 2.2. For this reason, the curve has a curve in which the gradation changes slowly at a portion where the input voltage is low and changes sharply at a portion where the input voltage is high.
[0034]
FIG. 8 is a diagram illustrating a γ curve when an image signal received from a personal computer is output without γ correction. When a personal computer outputs an image signal that has been subjected to γ correction with a γ value (γ1) of 1 / 2.5 on a display device with a γ value of γ2 = 2.2, the total γ value is 2.2 / 2. .5 and not 1. Therefore, the display device 200 cannot accurately reproduce the gradation. In the present invention, the monitor correction unit 207 corrects the input image signal so that the total γ value becomes 1.
[0035]
Returning to FIG. 2, the correction value calculation unit 205 calculates a correction value from the monitor γ value 203a stored in the storage unit 203 and γ1 detected by the γ value detection unit 201. This correction value is represented by (1− (γ1 × γ2)) where the monitor γ value 203a is γ2. Since γ2 = 2.2 and γ1 = 1 / 2.5, the correction value is (1-2.2 / 2.5).
[0036]
The correction value calculated by the correction value calculation unit 205 is output to the monitor correction unit 207. The monitor correction unit 207 performs gamma correction on the image signal received from the personal computer 100 according to the received correction value. The γ correction is performed by using a conventionally known technique such as a method of changing a look-up table 209 included in the correction value calculation unit 205 according to a correction value or a method of changing an image signal received from the personal computer 100 according to a correction value. Can be used. Therefore, the detailed description will not be repeated.
[0037]
The γ value of the image signal output from the monitor correction unit 207 to the display unit 211 is 1 / 2.2 because the monitor γ value 203a is γ2 = 2.2. As a result, the image signal subjected to appropriate γ correction is input to the display unit 211, so that the gradation can be accurately expressed.
[0038]
Further, the γ value detection unit 201, the correction value calculation unit 205, and the monitor correction unit 207 of the display device 200 may be realized by hardware, or may be realized by executing software by a CPU. When the software is realized by executing the software on a CPU, the gamma correction program is stored in a memory such as a ROM of the display device 200, and the gamma correction program is executed by the CPU. Further, the ROM 215 may be detachably attached to the display device 200, and when the ROM 215 is mounted on the display device 200, the γ correction program stored in the ROM 215 may be read into the CPU of the display device 200 and executed. .
[0039]
The recording medium for storing the γ correction program is not limited to the ROM, but may be a magnetic tape, a cassette tape, an optical disk (MO (Magnetic Optical Disc) / MD (Mini Disc) / DVD (Digital Versatile Disc)), an IC card ( A fixed medium such as a semiconductor memory such as an optical card, a mask ROM, an EPROM, an EEPROM, and a flash ROM may be used.
[0040]
The program referred to here is a concept that includes not only a program directly executable by the CPU but also a program in a source program format, a compressed program, an encrypted program, and the like.
[0041]
FIG. 9 is a flowchart illustrating a flow of the γ value adjustment process performed by the display device 200 according to the present embodiment. The start of the γ value adjustment processing in the display device 200 is determined by the user selecting a menu for instructing the execution of the γ value adjustment process from the menu displayed on the display unit 211 by the OSD function of the display device 200. This is the case. Further, when the display device 200 starts the γ value adjustment process, the personal computer 100 reads the specific pattern from the FD or CD-ROM in which the specific pattern 103 is recorded, and the personal computer 100 reads the image signal of the specific pattern. Needs to be output to the display device 200.
[0042]
Referring to FIG. 9, display device 200 receives an image signal of a specific pattern from personal computer 100 (step S01). Then, regarding the received specific pattern image signal, the γ value of the specific pattern image signal (γ1 = １ ／ .2) is obtained by associating the gradation of each area with an input voltage predetermined for the area. 5) is detected (step S02).
[0043]
A correction value (1−γ1 × γ2) is calculated from the γ value of the display device 200 (γ2 = 2.2) and the γ value of the image signal of the detected specific pattern (step S03). The look-up table 209 used for the γ correction is changed based on the calculated correction value (step S04). Although the lookup table 209 is changed in step S04, the coefficient for correcting the received image signal may be changed according to the correction value. This ends the γ value adjustment processing.
[0044]
FIG. 10 is a flowchart illustrating a flow of a process in which the display device displays an image signal received from the personal computer. Referring to FIG. 10, when receiving an image signal from personal computer 100 (step S11), display device 200 performs γ correction using a look-up table changed according to the correction value (step S12). Then, the gamma-corrected image signal is displayed on the display unit 211 (step S13). As described above, since the look-up table 209 has been changed after performing the γ value adjustment processing, the changed look-up table 209 is used for an image signal input from the personal computer 100 thereafter. Is used to perform gamma correction. For this reason, an image can be displayed on the display unit 211 at an appropriate gradation.
[0045]
The γ value adjustment processing may be performed once when the display device 200 is connected to the personal computer 100 as an image signal generator. Therefore, it suffices to execute it once each time the display device 200 is connected to the image signal generating device.
[0046]
The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an appearance of a display device and an image signal generation device connected thereto according to an embodiment of the present invention.
FIG. 2 is a functional block diagram illustrating functions of a display device 200 according to the present embodiment.
FIG. 3 is a diagram illustrating an example of a specific pattern.
FIG. 4 is a diagram for explaining divided regions of a specific pattern.
FIG. 5 is a diagram showing another example of a specific pattern.
FIG. 6 is a diagram illustrating a γ value of an image signal of a specific pattern output from a personal computer.
FIG. 7 is a diagram illustrating a γ curve of the display device according to the present embodiment.
FIG. 8 is a diagram illustrating a γ curve when an image signal received from a personal computer is output without performing γ correction.
FIG. 9 is a flowchart illustrating a flow of a γ value adjustment process performed by the display device 200 according to the present embodiment.
FIG. 10 is a flowchart illustrating a flow of a process in which a display device displays an image signal received from a personal computer.
[Explanation of symbols]
Reference Signs List 100 personal computer, 101 image signal generation unit, 102 γ correction unit, 103 specific pattern, 106 keyboard, 108 mouse, 110 CD-ROM drive, 112 FD drive, 200 display device, 201 γ value detection unit, 203 storage unit, 203a Monitor γ value, 205 correction value calculation unit, 207 monitor correction unit, 209 look-up table, 211 display unit.

Claims (4)

A display device that displays an image signal input from the outside, a receiving unit that receives an image signal from an image signal generating device connected to the display device,
Γ value detecting means for detecting a γ value of the image signal of the specific pattern based on the image signal of the specific pattern received by the receiving means,
An arithmetic unit that calculates a correction value from the detected γ value and the γ value of the display device,
A gamma correction unit for performing gamma correction on the image signal received by the receiving unit according to the calculated correction value. A gamma correction method for a display device that displays an image signal input from the outside,
Receiving an image signal of a specific pattern from an image signal generator connected to the display device;
Detecting the γ value of the received specific pattern image signal based on the received specific pattern image signal,
An arithmetic unit that calculates a correction value from the detected γ value and the γ value of the display device,
Correcting the image signal received from the image signal generator according to the calculated correction value. A gamma correction program executed on a display device that displays an image signal input from the outside,
Receiving an image signal of a specific pattern from an image signal generator connected to the display device;
Detecting the γ value of the received specific pattern image signal based on the received specific pattern image signal,
An arithmetic unit that calculates a correction value from the detected γ value and the γ value of the display device,
Correcting the image signal received from the image signal generator according to the calculated correction value. A computer-readable recording medium on which the gamma correction program according to claim 3 is recorded.

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