JP2006145836A - Liquid crystal screen color tone correcting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a liquid crystal screen color tone correcting device capable of displaying an image on a liquid crystal monitor with a sharp color tone emphasizing video by properly correcting the image color tone of the liquid crystal monitor and adjusting the luminance of a back light. <P>SOLUTION: Image outputs of a plurality of AV devices are selected by an image output device selection section 3 and inputted to an image signal input section 4, an image signal color tone distribution detection section detects the distribution state of the image signal, and an image color tone correction signal arithmetic section 6 computes an image color tone correction signal according to the distribution state and outputs it to the liquid crystal monitor 2. The correction signal computed by the image color tone correction signal arithmetic section 6 is inputted to a back light luminance arithmetic section 13 to obtain a luminance adjustment signal of the back light corresponding to the color tone correction. A back light luminance adjustment section of the liquid crystal monitor 2 adjusts the luminance with the signal. When the image color tone correction signal is computed, color tone correction of an image and luminance adjustment of the back light in a variety of modes are related and performed adaptively to the kinds of image output devices, ambient lightness, and the state of screen division. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal screen color tone correction device that adjusts the color tone of an image displayed on a liquid crystal monitor screen and adjusts the luminance of a backlight to make the screen display clear.

  In recent years, with the widespread use of AV (Audio Visual) devices, monitors for displaying images of televisions and DVDs that receive various broadcasts have become indispensable in daily life. Therefore, liquid crystal monitors using liquid crystal display means that can save power and display images relatively clearly have been widely used.

  In this liquid crystal monitor, since the liquid crystal itself that constitutes the pixel does not emit light, it is necessary to irradiate the liquid crystal. Alternatively, there is a method of transmitting light from a light source arranged on the back side of the liquid crystal and viewing the transmitted light. However, many liquid crystal monitors employ a method of viewing the latter transmitted light.

  A cathode fluorescent lamp has been widely used as a backlight as a light source disposed on the back side of the liquid crystal as described above. The visibility of the image displayed on the LCD differs depending on the brightness of the backlight.If it is too dark, the color tone of the entire screen will be black and visibility will be poor, and conversely if it is too bright, the color tone of the entire screen will become white and visibility will be low. Becomes worse.

  Further, the brightness of the backlight at that time is also affected by the brightness of the surroundings, and when the surroundings are dark, it is desired that the brightness is reduced accordingly. As shown in the publication, the brightness of the backlight is adjusted by detecting the brightness of the surroundings. When adjusting the brightness of the backlight according to the ambient brightness as described above, for example, in the case of a monitor for a navigation device mounted on a vehicle without using a sensor for detecting the ambient brightness. It may be adjusted by detecting whether or not the vehicle lighting is turned on.

  On the other hand, the backlight for the liquid crystal screen uses mercury in the cathode fluorescent lamp as described above, and the use of mercury is restricted due to environmental problems in recent years. emitting diode) is used. In the backlight using this LED, light is emitted to the liquid crystal by evenly arranging it on the back surface of the liquid crystal. Therefore, the brightness of the backlight with respect to the liquid crystal can be performed individually, for example, a divided screen. In each of the above, it is possible to adjust the luminance of the backlight corresponding to the displayed image.

In order to display an image on the liquid crystal monitor as described above, when the image output signal from various AV devices is displayed on the monitor as it is, the color tone of the output image is often different depending on each device. In a dark screen, the image becomes almost black and cannot be seen, and on a bright screen the color becomes white and a fine image cannot be seen. For this reason, a γ (gamma) correction function that adjusts the brightness of an image according to an image signal input to the monitor may be installed. Similarly, the brightness of the backlight is adjusted according to the color tone of the input image signal, and as described above, the brightness is increased and brightened for dark screens, while the brightness is decreased for bright screens. It is also darkening.
JP-A-6-67159

  As described above, the LCD monitor adjusts the color tone according to the input image signal and also adjusts the backlight respectively, but these are individually adjusted, and comprehensive adjustment is performed. It wasn't. For this reason, when the color adjustment is performed to darken the image when the input image signal is brighter than the preset brightness, the backlight is adjusted to be brighter when the monitor is used in a bright environment. Becomes an extremely bright image and is difficult to see. The reverse case also occurs in the same way.

  Therefore, according to the present invention, when the color tone is corrected in accordance with the image signal displayed on the liquid crystal monitor, the brightness of the backlight is also adjusted in association with the screen, so that a screen having a clear color tone can be obtained. It is a main object of the present invention to provide a liquid crystal screen color tone correction apparatus.

  In order to solve the above problems, a liquid crystal screen color tone correction apparatus according to the present invention detects an image signal color tone distribution detection unit that detects a color tone distribution of an image signal input from an image output device, and a color tone detected by the image signal color tone distribution detection unit. An image tone correction signal calculating means for calculating the tone of the input image according to the distribution, and a backlight luminance calculating means for calculating the luminance of the backlight of the liquid crystal monitor based on the correction signal calculated by the image tone correction signal calculating means. And correcting the image of the liquid crystal monitor with the correction signal calculated by the image color correction signal calculating means, and adjusting the backlight of the liquid crystal monitor to the luminance of the backlight luminance calculating means.

  Another liquid crystal screen color correction device according to the present invention is the liquid crystal screen color correction device, wherein the image color correction signal calculation means performs a predetermined color correction corresponding to the image output device. The color tone of the image output device changed at the time of change is gradually corrected.

  According to another aspect of the present invention, there is provided a liquid crystal screen color tone correction device comprising ambient brightness detection means for detecting ambient brightness of a liquid crystal monitor in the liquid crystal screen color tone correction device, wherein the image color tone correction signal calculation means is a liquid crystal display. The color tone is corrected according to the brightness around the monitor.

  According to another aspect of the present invention, there is provided the liquid crystal screen color tone correction device according to the above-mentioned liquid crystal screen color tone correction device, which includes a time associated with the navigation device, a current position including a tunnel or tower parking position, or a relative position between the sun and the traveling direction. Environmental condition detection means for detecting an environmental condition is provided, and the image color correction signal calculation means corrects the color according to the environmental condition.

  According to another aspect of the present invention, there is provided a liquid crystal screen color correction device comprising a divided screen detection means for detecting a division state of the display screen of the liquid crystal monitor in the liquid crystal screen color correction device, and the image color correction signal calculation means comprises: An image color correction signal for each divided screen is calculated, and the backlight luminance calculating means calculates the luminance of the backlight of each divided screen in accordance with the image color correction signal for each divided screen.

  According to another aspect of the present invention, there is provided the liquid crystal screen color tone correction device according to the present invention, wherein the image color tone correction signal calculation means has a specific region in which the color tone distribution of the image signal detected by the image signal color tone distribution detection means is a specific region. Correction is performed to diffuse the dense portion, and at the same time, the backlight luminance calculating means calculates the luminance corresponding to the diffusion correction.

  According to another aspect of the present invention, there is provided the liquid crystal screen color correction device according to the present invention, wherein in the liquid crystal screen color correction device, in the image color correction signal calculation means, the color distribution of the image signal detected by the image signal color tone distribution detection means is unevenly distributed. In this case, correction for moving the unevenly distributed portion to the center is performed, and at the same time, the backlight luminance calculating means calculates luminance corresponding to the moving correction.

  Since the present invention is configured as described above, when correcting the color tone of an image in accordance with the image signal displayed on the liquid crystal monitor, the brightness of the backlight can also be adjusted in relation to the sharpness of the video. It is possible to obtain a screen with a simple color tone.

  An object of the present invention is to display an image signal color tone distribution detecting means for detecting a color tone distribution of an image signal input from an image output device, and to display the image signal color tone on a liquid crystal monitor. Based on the color distribution detected by the distribution detection means, the image color correction signal calculation means for calculating the color correction of the input image, and the backlight brightness of the liquid crystal monitor is calculated by the correction signal calculated by the image color correction signal calculation means. And a backlight luminance calculating means for correcting the image on the liquid crystal monitor with the correction signal calculated by the image tone correction signal calculating means and adjusting the backlight of the liquid crystal monitor to the luminance of the backlight luminance calculating means It was realized by doing.

  An embodiment of the present invention is shown in the functional block diagram of FIG. 1, and the functional block diagram is shown so that various aspects of the present invention can be implemented. This can be implemented by selecting and using a function. In addition, the function part which performs each function in the same figure can also be said to be a means which performs each function.

  In the liquid crystal screen color tone correction apparatus shown in FIG. 1, the liquid crystal screen color tone adjustment processing unit 1, which is the main function unit, selects and inputs an arbitrary image selected by the user from various AV devices. An example is shown in which a color tone correction calculation is performed, an appropriate backlight luminance is calculated in connection with the calculation, and output to the liquid crystal monitor 2. For this purpose, the liquid crystal screen color tone adjustment processing unit 1 is provided with an image output device selection unit 3, which can input image signals of AV devices A, B, and C, and a specific AV device according to a user's selection instruction. Is selected and output to the image signal input unit 4.

  For the image signal input by the image signal input unit 4, the color tone distribution of the input image signal is detected by a method such as creating a histogram representing the color tone distribution of the image signal by the image signal color tone distribution detection unit 5. In this color tone distribution, in addition to detecting the distribution of the entire image signal, for example, the signal distribution may be detected for each color of RGB or CMYK. In detecting the distribution of the image signal, a histogram indicating how many pixels (pixels) exist for each brightness ranging from dark to bright, which has been widely used in the past, can be used. .

  In the image tone correction signal calculation unit 6, a state in which the signal is concentrated on a specific tone portion is mainly checked based on the signal of the image signal tone distribution detection unit 5, and various correction modes set by the correction mode setting unit 11. Color tone correction is performed according to a specific mode. In this case, when the signal distribution is detected for each color as described above, the color tone correction can be performed for each color according to the distribution state of each color, and further after that, by combining them.

  For example, a signal from the image output device detection unit 7 is input to the image tone correction signal calculation unit 6 so that the color tone correction can be performed in various modes, and the image output device selection unit 3 selects the output device. Accordingly, for example, there is a color tone specific to each AV device when outputting a television image and when outputting a DVD image, and therefore, a correction value corresponding to each AV device is registered in advance in, for example, the correction mode setting unit 11 or the like. The correction value can be read out and used. Further, in the image output device detection unit, when the selection of the output device is changed by a user instruction or the like, the changed output device can be gradually changed to the correction value registered in advance.

  Further, in the navigation display environmental condition detection unit 8, when the liquid crystal color tone correction processing device is used in a vehicle and the navigation device is mounted on the vehicle, when displaying an image on a monitor that the navigation device normally includes, The display mode and backlight brightness are adjusted and changed between the display mode when the surroundings are bright and the mode when the surroundings are dark, so the status of the mode change depending on the environmental conditions, for example, lighting of the vehicle lights, cooperation with the navigation device The correction mode setting unit detects a correction value suitable for the mode detected by an environmental condition detection means for detecting an environmental condition such as a current time such as a tunnel or tower parking position or a relative position between the sun and the traveling direction. In accordance with the set value registered in No. 11, appropriate color tone correction is performed.

  Similarly, the ambient brightness detector 9 detects the ambient brightness of the liquid crystal monitor using a sensor signal for detecting brightness, and reads the correction value registered in advance as described above according to the brightness. To correct. In the vehicle monitor, the detection signal of the ambient brightness detection unit 9 can be used when detecting environmental conditions in the navigation display.

  In the split screen detection unit 10, for example, when the navigation device is displayed on the liquid crystal monitor 2, the screen is split into two to make one side a map screen, and the other side performs facility guidance display or right / left turn intersection guidance display, etc. The screen division state and the type of information displayed on each divided screen are detected, and the signal is output to the image color tone correction signal calculation unit 6 so that an appropriate color tone is obtained on each screen. The correction signal can be obtained by the same method as described above.

  In the example of the liquid crystal screen color tone adjustment processing unit 1 shown in FIG. 1, the image color correction signal calculation unit 6 displays an image having a color tone suitable for the liquid crystal monitor 2 in consideration of the signals of the various detection units as described above. For this purpose, an image color correction signal is calculated and output from the image color correction signal output unit 12 to the image color correction unit 21 of the liquid crystal monitor 2.

  The image tone correction signal calculated by the image tone correction signal calculation unit 6 is also output to the backlight luminance calculation unit 13, and a liquid crystal monitor that further displays an image according to the image tone correction as described above. The luminance of the backlight is calculated so that the screen can be displayed in an appropriate color tone. As described above, according to the present invention, the image of the screen displayed on the liquid crystal monitor is made clearer and easier to see by appropriately setting the luminance of the backlight in accordance with the color tone correction together with the color tone correction of the image. Can do.

  In the example shown in FIG. 1, the signal of the image signal tone distribution detection unit 5 is directly output to the backlight luminance calculation unit 13, and at least the luminance of the backlight is appropriately adjusted even when the image tone correction is not performed. To be able to. The backlight luminance signal calculated by the backlight luminance calculating unit 13 is output from the backlight luminance signal output unit 14 to the backlight luminance adjusting unit 22 of the liquid crystal monitor 2 to appropriately adjust the luminance of the screen of the liquid crystal monitor, The display image that has been subjected to the image color correction as described above is made to appear more clearly.

  The liquid crystal screen color tone correction apparatus including the above-described functional units can be caused to perform a predetermined function by sequentially operating according to the operation flow shown in FIG. In the example shown in FIG. 2, the detection signal of the image signal tone distribution detection unit 5 which is the most basic among the various functional units shown in FIG. 1 is used, and the processing is performed using the detection signal of the image output device detection unit 7. Although the example to perform is shown, it can carry out easily by adding the same operation | movement using each signal of the navigation display environmental condition detection part 8, the surrounding brightness detection part 9, and the division | segmentation screen detection part 10. it can. The operation flow of FIG. 2 will be described below with reference to the functional block diagram of FIG. 1 and an example of signal processing of FIG.

  In the example of the operation flow of the liquid crystal screen color correction processing shown in FIG. 2, first, an image signal is input to the liquid crystal screen color correction device according to the present invention (step S1), and then the image color signal distribution is detected. (Step S2). In these operations, the image signal of the AV device selected by the image output device selection unit 3 in the liquid crystal screen color tone adjustment processing unit 1 of FIG. 1 is input by the image signal input unit 4, and the image signal color tone distribution detection unit is detected by the image signal. 5 can be detected and generated by creating a tone distribution histogram of the image signal as shown in FIGS. 3 (a) (i) and 3 (b) (i), for example. In creating such a tone distribution histogram, various processing techniques widely used in the image processing field can be used.

  Next, an image tone correction signal is calculated based on the color tone signal distribution of the input image detected as described above (step S3). In this operation, the image tone correction signal calculation unit 6 in FIG. 1 arbitrarily sets an appropriate correction mode among various correction modes set in the correction mode setting unit 11, and performs a correction calculation according to the correction mode. Is done.

  In the image color tone correction, for example, in the example shown in FIG. 3A, when the input image signal distribution as shown in FIG. Therefore, if the image is output as it is, the entire screen becomes dark and difficult to see. Therefore, by utilizing the fact that there is a region with a low distribution level in the brighter part, the dense part is diffused in that part. The signal is as shown in the image correction output signal in FIG. As a result, the image has a clear color tone as a whole and can be easily viewed.

  Next, the backlight brightness corresponding to the image color tone correction as described above is calculated (step S4). This processing is performed by inputting the above-described signal calculated by the image tone correction signal calculation unit 6 in the backlight luminance calculation unit 13 of FIG. 1 and performing a predetermined luminance calculation. In the example of FIG. 3A, as a result of the image correction processing as shown in FIG. 3 (ii), the signal is diffused in the bright direction as a whole, so that the luminance of the backlight is made dark according to the diffusion amount. To calculate. At that time, adjustments such as brightness adjustment according to ambient brightness, which have been conventionally performed, are also taken into consideration.

  In the example shown in FIG. 3A, the example in which the tone distribution is concentrated in the darker side as shown in FIG. 3I is shown. Is similarly diffused to the darker side, and the brightness of the backlight is adjusted to be darkened by the amount of diffusion. If the tone distribution is concentrated in the middle portion, it can be diffused to the bright side and the dark side, and the backlight luminance can be processed so as not to change. In the present invention, as described above, by correcting the color tone of the image and appropriately setting the luminance of the backlight according to the color tone correction, the screen image displayed on the liquid crystal monitor is made clearer and easier to see. be able to.

  Thereafter, the image color tone correction signal and the backlight brightness adjustment signal calculated as described above are output to the liquid crystal monitor (step S5), and the liquid crystal monitor corrects the image color tone in accordance with the signals, and at the same time, the backlight. Adjust the brightness of the light. In the example of FIG. 1, the image color correction signal output unit 12 outputs a signal to the image color correction unit 21 of the liquid crystal monitor 2, and the backlight luminance signal output unit 14 is the backlight luminance adjustment unit of the liquid crystal monitor 2. This is done by outputting a signal to 22.

  In the example shown in FIG. 2, next, it is determined whether or not the image output device has been changed (step S6). If not changed, the procedure returns to step S1 and repeats the operation. Here, for example, when the user is trying to play a DVD and watch it while the television is currently being received and the image output device selection unit selects the input of the image, the image output device selection unit 3 The user's instruction is input, and the image from the DVD is input to the image signal input unit 4.

  At that time, image color correction corresponding to the changed output device and correction processing for gradually changing the backlight luminance to the set value are performed (step S7). Such correction processing is performed by gradually changing, for example, in 3 seconds from a correction value at the time of image output of a television stored in advance to a correction value at the time of image output of a DVD by the correction mode setting unit 11 of FIG. This is done by calculating the luminance of the backlight corresponding to the correction. Thereafter, it is determined whether or not the color tone correction by the device change has been completed (step S8), and when the above three seconds have not yet elapsed, the process returns to step S7 to repeat the above operation, and the color tone correction by the device change is performed. When it is determined that the process has been completed, the process returns to step S1 to repeat the operation.

  In the above-described embodiment, as an example of image tone correction, a mode of correction for diffusing a signal when the signal is concentrated in a specific brightness portion as shown in FIG. 3A has been shown. For example, as shown in FIGS. 3B and 3I, a signal present in a particularly dark portion is displayed on a liquid crystal monitor and the image is crushed and becomes black. Since this is a signal of a certain region, the signal is moved in the brighter direction by the amount of the collapsed region, and the moving signal portion that is not displayed on the monitor in the brighter side is deleted, and as a result, the signal shown in FIG. Correction may be performed so as to obtain a tone distribution histogram state as shown. At that time, since the entire image signal moves in the bright direction, the luminance of the backlight is reduced by the corresponding amount so that the image on the monitor screen can be clearly seen.

  In the above-described embodiment, the input image signal is individually corrected for a specific color or all the colors of RGB and CMYK, for example, and the overall color tone correction is performed. good. Furthermore, in a liquid crystal monitor using many light emitting elements such as LEDs without using a cathode fluorescent lamp as a backlight, the present invention is applied to an arbitrary part of the monitor screen so as to display an easy-to-see screen as a whole. Also good.

  The liquid crystal screen color tone correction apparatus according to the present invention can be widely used for all liquid crystal monitors, and particularly the brightness of the surroundings changes greatly like the monitor mounted on a vehicle, or the brightness of the backlight is changed depending on the ambient brightness. It can be suitably used for a liquid crystal monitor that needs to be largely changed.

FIG. 7 is a functional block diagram for implementing the present invention in various modes. It is an operation | movement flowchart of one Example of this invention. An example in which the image color tone correction and the backlight luminance adjustment according to the present invention are performed in association with each other will be described. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal screen color tone adjustment processing part 2 Liquid crystal monitor 3 Image output equipment selection part 4 Image signal input part 5 Image signal color tone distribution detection part 6 Image color tone correction signal calculation part 7 Image output equipment detection part
8 Navigation display environment condition detection unit 9 Ambient brightness detection unit 10 Divided screen detection unit 11 Correction mode setting unit 12 Image color tone correction signal output unit 13 Backlight luminance calculation unit 14 Backlight luminance signal output unit 21 Image color tone correction unit 22 Back Light brightness adjustment section

Claims (7)

Image signal tone distribution detecting means for detecting the tone distribution of the image signal input from the image output device;
An image tone correction signal calculation means for performing a correction calculation of the color tone of the input image based on the tone distribution detected by the image signal tone distribution detection means;
A backlight luminance calculating means for calculating the luminance of the backlight of the liquid crystal monitor based on the correction signal calculated by the image tone correction signal calculating means,
Correcting an image of the liquid crystal monitor with a correction signal calculated by the image tone correction signal calculating means, and adjusting a backlight of the liquid crystal monitor to a luminance of the backlight luminance calculating means, apparatus.   The image color tone correction signal calculation means performs predetermined color tone correction corresponding to an image output device, and gradually corrects the color tone of the image output device changed when the image output device is changed. Item 2. The liquid crystal screen color tone correction apparatus according to Item 1.   2. The ambient brightness detection means for detecting the brightness around the liquid crystal monitor, and the image color tone correction signal calculation means corrects the color tone according to the brightness around the liquid crystal monitor. LCD screen color tone correction device.   Environmental condition detection means for detecting the environmental condition of the time associated with the navigation device, the current position including the position of the tunnel or tower parking, or the relative position of the sun and the traveling direction, and the image tone correction signal calculation means, 2. The liquid crystal screen color tone correction apparatus according to claim 1, wherein the color tone is corrected according to environmental conditions.   The image display apparatus includes a divided screen detecting unit that detects a division state of the display screen of the liquid crystal monitor, the image color correction signal calculating unit calculates an image color correction signal for each divided screen, and the backlight luminance calculating unit is divided into each divided screen. 2. The liquid crystal screen color tone correction apparatus according to claim 1, wherein the brightness of the backlight of each divided screen is calculated according to each image color tone correction signal.   In the image tone correction signal calculation means, when the color tone distribution of the image signal detected by the image signal tone distribution detection means is concentrated in a specific area, correction is performed to diffuse the dense portion and simultaneously the backlight luminance calculation 2. The liquid crystal screen color tone correction apparatus according to claim 1, wherein the means calculates a luminance corresponding to the diffusion correction. In the image color tone correction signal calculating means, when the color tone distribution of the image signal detected by the image signal color tone distribution detecting means is unevenly distributed to one side, correction is performed to move the unevenly distributed portion to the center and simultaneously the backlight luminance calculation The liquid crystal screen color correction device according to claim 1, wherein the means calculates a luminance corresponding to the moving correction.

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