JP5946281B2 - Image processing apparatus, image display system, and image display method - Google Patents

Image processing apparatus, image display system, and image display method Download PDF

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JP5946281B2
JP5946281B2 JP2012012861A JP2012012861A JP5946281B2 JP 5946281 B2 JP5946281 B2 JP 5946281B2 JP 2012012861 A JP2012012861 A JP 2012012861A JP 2012012861 A JP2012012861 A JP 2012012861A JP 5946281 B2 JP5946281 B2 JP 5946281B2
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image
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luminance
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JP2013152335A (en
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上野 雅史
雅史 上野
吉山 和良
和良 吉山
宮田 英利
英利 宮田
張 小▲忙▼
小▲忙▼ 張
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シャープ株式会社
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  The present invention relates to an image processing device, an image display system, and an image display method, and more particularly to an image processing device, an image display system, and an image display method for displaying one or more images on a plurality of display devices. .

  In recent years, display devices have been increased in size and resolution, and liquid crystal display devices are widely used as information display devices and digital signage display devices that are viewed by many people.

  However, the screen size of the liquid crystal display device is limited by the manufacturing process, and a large-screen liquid crystal display device is generally expensive. Therefore, a so-called multi-display device in which a plurality of liquid crystal display devices are arranged adjacent to each other in a planar shape (in some cases, in a linear shape) may be used. This multi-display device is widely used for digital signage and the like because a large screen can be obtained at low cost.

  A liquid crystal display device used for such applications is generally required to have high visibility, and is often arranged outdoors such that visibility is likely to be lowered. For this reason, various brightness correction methods for improving visibility have been used.

  For example, in Japanese Patent Application Laid-Open No. 2007-248935, a correction value corresponding to the brightness and saturation of an input video obtained by converting a video input signal is calculated, and input based on the calculated correction value and ambient illuminance. A configuration of an image processing apparatus that corrects brightness and saturation of a video is disclosed. With this configuration, the image quality and visibility of the displayed video can be improved.

JP 2007-248935 A

  However, in the case of a multi-display device, one image is typically divided and displayed by a plurality of liquid crystal display devices. For this reason, when the correction method described in Japanese Patent Application Laid-Open No. 2007-248935 is applied to the multi-display device as it is, the correction amount differs for each liquid crystal display device, and images having different luminance are displayed in each of the plurality of liquid crystal display devices. May be. In that case, since the luminance distribution in one image becomes non-uniform, there arises a problem that the display mode is uncomfortable.

  In order to avoid this problem, it is conceivable to perform the correction on the one image displayed on a plurality of liquid crystal display devices. However, since there are cases where a large number (for example, 9 to 25) of liquid crystal display devices are provided, the data amount of all the display images constituting the one image becomes enormous in that case. Therefore, the configuration for correcting this is not realistic because very high-speed processing is required.

  Accordingly, a configuration in which the above correction is performed on input image data that is original data of a displayed image can be considered. However, when generating a plurality of images to be displayed on each liquid crystal display device by enlarging the input image data (increasing the resolution), each display image is displayed in order to be displayed on the plurality of display devices. Various image processing based on edge processing and frequency characteristics is often performed. Such image processing needs to be performed on the input image before the correction for improving the visibility. If the above-described image processing is applied to the corrected input image, for example, the gradation of the input image after correction may be lost, so the image including the enlargement process (resolution conversion process) Inconvenience occurs in processing, and as a result, display failure may occur.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to perform a correction for improving visibility without causing a display defect in a display device configured to display at least one image by a plurality of display devices arranged so as to be adjacent to each other. The present invention provides an image processing apparatus, an image display system, and an image display method.

A first invention is an image processing device for outputting output image data representing each image displayed on each display screen in a plurality of display devices arranged linearly or in a plane based on input image data. ,
An image resolution conversion unit that converts an input image represented by the input image data into a display resolution for display on the display screen and outputs the image as enlarged image data;
An enlarged image represented by the enlarged image data output from the image resolution conversion unit is displayed on a display screen of the plurality of display devices in consideration of a frame region located at a boundary between the plurality of display devices. into a plurality of images to be displayed respectively, to generate a plurality of divided image data by display luminance plural image data in the periphery of the frame region representing the plurality of images respectively is corrected so as to increase An image division output unit for output;
A correction data calculation unit that calculates and outputs luminance correction data according to the image so that the luminance of the displayed image increases based on the input image data;
An image signal processing unit that outputs output image data obtained by correcting the luminance of the image represented by the divided image data based on the luminance correction data output from the correction data calculation unit,
When the input image includes a plurality of different images, the correction data calculation unit, for each of the plurality of images, based on the image, an area in the enlarged image corresponding to the image Calculate and output brightness correction data so that the brightness of the image displayed at
The image signal processing unit, when the input image includes a plurality of different images,
A division including at least a part of one image in the enlarged image corresponding to any one of the plurality of images in the input image among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the luminance of the image based on the luminance correction data calculated by the correction data calculation unit for the one image in the input image,
At least each of two or more images in the enlarged image corresponding to any two or more images in the plurality of divided images in the input image among the plurality of divided images represented by the plurality of divided image data. The brightness of the two or more images in the divided image including a part is corrected based on two or more brightness correction data respectively calculated by the correction data calculation unit for the two or more images in the input image. Thus, the output image data is generated.

According to a second invention, in the first invention,
The correction data calculation unit
Calculating a value indicating a frequency distribution of pixel luminance included in the input image data, calculating the luminance correction data based on the calculated value ;
When a plurality of different images are included in the input image, a value indicating a frequency distribution of pixel luminance in the region is calculated for each region of the plurality of images, and the value is calculated based on the calculated value. Luminance correction data is calculated .

According to a third invention, in the second invention,
Based on the value indicating the frequency distribution, the correction data calculation unit may increase the luminance of the pixel to be displayed when the frequency distribution is biased toward the low luminance side than when the frequency distribution is biased toward the high luminance side. Set the gain value, output the set gain value as the brightness correction data,
The image signal processing unit outputs the output image data based on a value obtained by multiplying the brightness of an image represented by the divided image data by the gain value.

According to a fourth invention, in the third invention,
The correction data calculation unit determines whether or not a value obtained by multiplying at least a part of luminance of the input image by the set gain value exceeds a maximum luminance value that can be displayed on the display device. When the number or ratio of pixels determined to exceed exceeds a predetermined threshold, the set gain value is decreased , and the number or ratio of pixels determined to exceed exceeds the threshold Confirms the set gain value as the gain value to be multiplied with the luminance of the image represented by the divided image data.

A fifth invention is the fourth invention,
The correction data calculation unit resets a gain value obtained by reducing the set gain value by a predetermined reduction amount as a new gain value, and further performs the resetting for at least part of the luminance of the input image. It is determined whether or not a value obtained by multiplying the obtained gain value exceeds a maximum luminance value that can be displayed on the display device, and if the number or ratio of pixels determined to exceed exceeds a predetermined threshold value, reduced only the set gain value quantified, until it is determined not to exceed the predetermined amount is reduced the set gain, to repeatedly to make the determination, the pixel is determined as the excess If the number or proportion of equal to or less than the threshold value, to determine the set gain value, as the gain value to be multiplied to the luminance of the image represented by the divided image data And features.

According to a sixth invention, in the first invention,
The correction data calculation unit receives a signal including information for image adjustment from the outside, and calculates the luminance correction data based on the input image data and based on information included in the signal.

A seventh invention is an image processing device for outputting output image data representing each image displayed on each display screen in a plurality of display devices arranged in a line or a plane based on a plurality of input image data. There,
An image resolution converter that converts a plurality of input images represented by the plurality of input image data into a display resolution for display at a predetermined position on the display screen, and outputs the image as enlarged image data;
The plurality of enlarged images represented by the enlarged image data output from the image resolution conversion unit are regarded as images synthesized to be displayed at the positions on the display screen, respectively, and the plurality of display devices taking into account the frame area located at the boundary between, divided on the display screen of the plurality of display devices to a plurality of images to be displayed respectively, the frame area of the plurality of image data representing the plurality of images, respectively An image division output unit that generates and outputs a plurality of divided image data by correcting the display luminance to increase around
For each input image of the plurality of input images, luminance correction data is calculated and output based on the input image so that the luminance of the image displayed in the enlarged image region corresponding to the input image increases. A correction data calculation unit;
An image signal processing unit that outputs output image data obtained by correcting the luminance of the image represented by the divided image data based on the luminance correction data output from the correction data calculation unit,
The image signal processor is
The luminance of the divided image including at least a part of one enlarged image corresponding to any one input image in the plurality of input images among the plurality of divided images represented by the plurality of divided image data is represented by the 1 By correcting the input image based on the brightness correction data calculated by the correction data calculation unit, the output image data is generated,
In a divided image including at least a part of each of two or more enlarged images corresponding to any two or more input images in the plurality of input images among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the brightness of the two or more enlarged images based on the two or more brightness correction data respectively calculated by the correction data calculation unit for the two or more input images. It is characterized by doing.

An eighth invention is a system for displaying an image corresponding to the input image data on a plurality of display screens arranged in a line or plane based on the input image data,
An image resolution conversion unit that converts an input image represented by the input image data into a display resolution for display on the display screen and outputs the image as enlarged image data;
An enlarged image represented by the enlarged image data output from the image resolution conversion unit is displayed on a display screen of the plurality of display devices in consideration of a frame region located at a boundary between the plurality of display devices. into a plurality of images to be displayed respectively, to generate a plurality of divided image data by display luminance plural image data in the periphery of the frame region representing the plurality of images respectively is corrected so as to increase An image division output unit for output;
A correction data calculation unit that calculates and outputs luminance correction data according to the image so that the luminance of the displayed image increases based on the input image data;
An image signal processing unit that outputs output image data in which the luminance of the image represented by the divided image data is corrected based on the luminance correction data output from the correction data calculation unit;
A plurality of display units including the plurality of display screens for displaying images based on the output image data;
When the input image includes a plurality of different images, the correction data calculation unit, for each of the plurality of images, based on the image, an area in the enlarged image corresponding to the image Calculate and output brightness correction data so that the brightness of the image displayed at
The image signal processing unit, when the input image includes a plurality of different images,
A division including at least a part of one image in the enlarged image corresponding to any one of the plurality of images in the input image among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the luminance of the image based on the luminance correction data calculated by the correction data calculation unit for the one image in the input image,
At least each of two or more images in the enlarged image corresponding to any two or more images in the plurality of divided images in the input image among the plurality of divided images represented by the plurality of divided image data. The brightness of the two or more images in the divided image including a part is corrected based on two or more brightness correction data respectively calculated by the correction data calculation unit for the two or more images in the input image. Thus, the output image data is generated.

In a ninth aspect based on the eighth aspect ,
Each of the plurality of display devices included in the plurality of display devices including the plurality of display units receives a signal including information for image adjustment from the outside, and is represented by the plurality of divided image data based on the information included in the signal An image adjustment processing unit that performs a correction process on a corresponding divided image of the divided images;
The image signal processing unit is included in each of the plurality of display devices, receives corresponding luminance correction data from the correction data calculation unit, and correction processing is performed by the image adjustment processing unit based on the received luminance correction data. For the corresponding divided image, output image data whose luminance is corrected is generated and output to the corresponding display unit.

A tenth invention is the ninth invention,
The image signal processing unit corrects the received luminance correction data according to the correction processing performed by the image adjustment processing unit, and the image adjustment processing unit performs correction processing based on the corrected luminance correction data. Output image data whose luminance has been corrected is generated with respect to the corresponding divided image subjected to the above, and is output to the corresponding display unit.

In an eleventh aspect based on the ninth aspect ,
The plurality of display devices are daisy chain connected by at least a signal line for transmitting the luminance correction data.

A twelfth aspect of the invention is an image display method for outputting output image data representing each image displayed on each display screen in a plurality of display devices arranged in a line or plane based on input image data. ,
An image resolution conversion step of converting the input image represented by the input image data into a display resolution for display on the display screen and outputting the enlarged image data;
The enlarged image represented by the enlarged image data output in the image resolution conversion step is displayed on the display screen of the plurality of display devices in consideration of a frame region located at a boundary between the plurality of display devices. into a plurality of images to be displayed respectively, to generate a plurality of divided image data by display luminance plural image data in the periphery of the frame region representing the plurality of images respectively is corrected so as to increase An image division output step to output;
A correction data calculation step of calculating and outputting luminance correction data corresponding to the image so that the luminance of the displayed image increases based on the input image data;
An image signal processing step of outputting output image data obtained by correcting the luminance of the image represented by the divided image data based on the luminance correction data output in the correction data calculating step,
In the correction data calculating step, when the input image includes a plurality of different images, an area in the enlarged image corresponding to the image based on the image for each of the images. Calculate and output brightness correction data so that the brightness of the image displayed at
In the image signal processing step, when the input image includes a plurality of different images,
A division including at least a part of one image in the enlarged image corresponding to any one of the plurality of images in the input image among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the luminance of the image based on the luminance correction data calculated by the correction data calculation step for the one image in the input image,
At least each of two or more images in the enlarged image corresponding to any two or more images in the plurality of divided images in the input image among the plurality of divided images represented by the plurality of divided image data. The brightness of the two or more images in the divided image including a part is corrected based on the two or more brightness correction data respectively calculated by the correction data calculation step for the two or more images in the input image. Thus, the output image data is generated.

According to the first aspect, the luminance correction data corresponding to the image is calculated based on the input image data so that the luminance of the displayed image is increased, and the luminance of the input image is calculated based on the luminance correction data. Output image data obtained by correcting the brightness of the image represented by the divided image data output from the image division output unit is output, which is typical in a plurality of display devices arranged in a line or a plane. When one image is displayed, the visibility can be further improved without causing a display defect such as a video failure.
According to the first aspect, when the input image includes a plurality of different images, luminance correction data suitable for each image can be calculated. Thereby, according to the content of the image, for example, for a dark image, the luminance can be further increased, so that the visibility of the displayed image can be further improved for each region. In particular, when an image using an OSD having a large difference (average value) in luminance among a plurality of image areas is included, it is possible to prevent one luminance correction from affecting the other luminance correction. Therefore, the visibility of the displayed image can be further improved for each region.
Furthermore, according to the first aspect, the display luminance in the frame region located at the boundary between the plurality of display devices is 0, but the display luminance around the frame region is increased, so that the luminance distribution as a whole is natural. An image can be obtained.

  According to the second aspect of the invention, by using the frequency distribution of pixel luminance, the visibility can be further improved in an average or statistically suitable manner as a whole pixel with a simple configuration.

  According to the third aspect of the invention, when the frequency distribution is biased toward the low luminance side, the gain value is set so that the luminance of the pixel to be displayed is increased compared to when the frequency distribution is biased toward the high luminance side. A dark image can be made easier to see and visibility can be further improved.

  According to the fourth aspect of the present invention, when the number or ratio of pixels determined to exceed the maximum displayable luminance value exceeds a predetermined threshold, the gain value is set to be smaller, so that a video failure, etc. Visibility can be further improved while suppressing display defects.

According to the fifth aspect, when the number or ratio of the pixels exceeds the threshold value, the gain value is continuously set to a small value until it does not exceed the threshold value. Therefore, the display defect such as video failure corresponds to the threshold value. Visibility can be further improved while reliably suppressing to the following.

  According to the sixth aspect of the invention, since the brightness correction data is calculated based on information for image adjustment from the outside, suitable brightness correction can be performed according to the external situation, particularly the ambient brightness. it can. This can further improve the visibility.

According to the seventh aspect, according to the plurality of images represented by the plurality of input image data, the visibility of the displayed image can be further improved for each image.
Further, according to the seventh aspect, the display luminance in the frame area located at the boundary between the plurality of display devices is 0, but the display luminance around the frame area is increased, so that the luminance distribution as a whole is natural. Can be obtained.

According to the eighth aspect , the same effect as that of the first aspect can be achieved in the image display system.

According to the ninth aspect , after receiving a signal including information for image adjustment from the outside, and performing a correction process on the corresponding image based on the information included in the signal, the corrected image is displayed. On the other hand, luminance correction for improving visibility is typically performed based on the luminance correction data. Accordingly, since this luminance correction can be performed finally (finally), a suitable correction that does not affect the result of image adjustment can be performed, and the display quality can be improved.

According to the tenth aspect of the invention, the luminance of the image is corrected in accordance with the correction processing performed by the image adjustment processing unit, and the luminance correction is performed based on the corrected new luminance correction data. Display can be performed in a suitable display mode reflecting the image adjustment result based on the user's instruction. In this case, since the image adjustment result is uniformly reflected (with respect to the luminance correction data), the image quality does not become different in each liquid crystal display device, and the display quality can be maintained.

According to the eleventh aspect , the same brightness correction data can be shared by a plurality of display devices with a simple configuration.

According to the twelfth aspect , the same effect as that of the first aspect can be achieved in the image display method.

1 is a block diagram illustrating a configuration of a multi-display device according to a first embodiment of the present invention. It is a figure which shows simply the display screen displayed by nine liquid crystal display devices in the said embodiment. It is a figure for demonstrating the correction | amendment aspect of an image brightness | luminance when pixel brightness | luminance is distributed on the high gradation side by the histogram analysis in the said embodiment. It is a figure for demonstrating the correction | amendment aspect of an image brightness | luminance when pixel brightness | luminance is distributed on the low gradation side by the histogram analysis in the said embodiment. It is a flowchart which shows the flow of the setting process of the gain value in the said embodiment. It is a figure for demonstrating that visibility improves with the structure of the said embodiment. It is a block diagram which shows the structure of the multi-display apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the liquid crystal display device in the said embodiment. It is a block diagram which shows the structure of the multi-display apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the multi-display apparatus which concerns on the 4th Embodiment of this invention. It is a figure for demonstrating the example of the 1st display screen in the said embodiment. It is a figure for demonstrating the 2nd example of a display screen in the said embodiment. It is a figure for demonstrating the example of the 3rd display screen in the said embodiment. It is a block diagram which shows the structure of the multi-display apparatus which concerns on the 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<1. First Embodiment>
<1.1 Overall configuration and operation>
FIG. 1 is a block diagram showing a configuration of a multi-display apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the multi-display device 100 is an image display system including an image processing device 10 and nine liquid crystal display devices 61 to 69, and typically displays nine images. Display by one display screen. In the following, the image processing apparatus 10 will be described as an apparatus different from the liquid crystal display apparatuses 61 to 69, but may be incorporated in any of these cases. Further, the number of display devices is not limited, and the arrangement mode is not planar (matrix), but may be arranged linearly according to the shape of the input image and the display application, and there is basically no limitation.

  FIG. 2 is a diagram simply showing a display screen displayed by nine liquid crystal display devices. As shown in FIG. 2, the liquid crystal display devices 61 to 69 are arranged in a planar shape (matrix shape), three in the vertical direction and three in the horizontal direction, and typically one display with nine display screens. Display the screen. With such a configuration, the multi-display device 100 can provide a large screen at a low cost.

  Next, as shown in FIG. 1, the image processing apparatus 10 includes an image resolution conversion unit 11 that converts the image resolution of input image data Dp representing an input image given from the outside, and nine converted images. The image division output unit 13 to be divided, the histogram analysis unit 12 that performs the histogram analysis on the input image data Dp, and outputs the gain value G, and the output image data Da1 to Da9 whose visibility is improved based on the gain value G Is provided to the liquid crystal display devices 61 to 69.

  Note that the liquid crystal display devices 61 to 69 used in the present embodiment are dedicated display devices whose arrangement positions are predetermined for the multi-display device 100, respectively. A typical liquid crystal display device can also be used. In that case, various kinds of information such as the size of the frame area of the liquid crystal display device to be used are required, but a similar large screen can be obtained if the information can be appropriately input. In addition, a known display device capable of displaying the large screen can be used instead of the liquid crystal display device.

  The image resolution conversion unit 11 shown in FIG. 1 converts an input image having a predetermined resolution represented by input image data Dp given from the outside into the large screen, that is, the entire display screen of the nine liquid crystal display devices 61 to 69. The process of enlarging it for display at. For example, when the resolution of the input image is the same as the display resolution in each of the liquid crystal display devices 61 to 69, the input image may be enlarged three times in the vertical direction and three times in the horizontal direction. Doubled. When conversion is performed to increase the resolution (that is, when up-conversion is performed), various interpolation methods and correction methods are known so that the quality of the display image is not deteriorated. By using some of the well-known methods, conversion is performed to increase the resolution of the input image (9 times), and the converted enlarged image data Dpu is output.

  The image division output unit 13 provides nine pieces of divided image data that can be supplied to each liquid crystal display device so that the enlarged image data Dpu received from the image resolution conversion unit 11 is suitable for display on the liquid crystal display devices 61 to 69. Ds1 to Ds9 are generated. At this time, the liquid crystal display devices 61 to 69 do not form a seamless single display screen, but in practice, the liquid crystal display devices 61 to 69 are located at the positions of the boundary lines between the liquid crystal display devices 61 to 69 shown in FIG. It has a frame area of the size. Since there is no liquid crystal display element in this frame area, display is impossible. Therefore, if the magnified image represented by the magnified image data Dpu is simply divided into nine without considering the presence of the frame region, the image becomes unnatural as a whole when actually displayed. Therefore, division is performed in consideration of the frame area. Also, since the display brightness of the frame area is 0, an image with a natural brightness distribution as a whole can be obtained by increasing the surrounding brightness. As described above, the image division output unit 13 generates the divided image data Ds1 to Ds9 by cutting out the enlarged image data Dpu at an appropriate position in consideration of the frame area and further performing appropriate correction.

  The liquid crystal display devices 61 to 69 may be configured to be able to display one image seamlessly on nine display screens by arranging optical members such as prisms and fiber plates in the vicinity of the frame region. Also in this case, it is necessary to consider the frame area when generating an image to be displayed on each display screen.

  On the other hand, the histogram analysis unit 12 performs a histogram analysis on the input image data Dp before the image conversion by the image resolution conversion unit 11 is performed, and calculates and outputs a gain value G. Note that this histogram analysis is to analyze the luminance distribution state of the pixels included in the image and can be realized by various well-known methods, and thus the detailed analysis method will not be described.

  Here, the histogram analysis unit 12 changes the output gain value G depending on whether the luminance distribution obtained by the analysis is biased toward the high gradation side or the low gradation side. The operation of the histogram analysis unit 12 will be described with reference to FIGS.

<1.2 Operation of Histogram Analysis Unit>
<1.2.1 First Operation Example>
FIG. 3 is a diagram for explaining a correction mode of image luminance when pixel luminance is distributed on the high gradation side by histogram analysis. FIG. 4 is a diagram showing pixel luminance distribution on the low gradation side by histogram analysis. It is a figure for demonstrating the correction aspect of the image brightness | luminance in a case.

  In these drawings, a straight line A indicated by a one-dot chain line indicates a case where the input gradation and the output gradation are equal, that is, a case where correction is not performed. In this case, the gain value G is 1. Here, for convenience of explanation, when correction is not performed, it is assumed that the input gradation and the output gradation are in a correspondence relationship as indicated by a straight line A. Correspondence as shown by a predetermined characteristic curve C in FIG.

  In these drawings, a straight line B indicated by a two-dot chain line indicates a case where the output gradation is larger than the input gradation, that is, a case where correction for increasing the display luminance is performed to improve visibility. The gain value here is greater than 1.

  First, in FIG. 3, when the luminance distribution of a pixel whose input gradation has a peak in the vicinity of 80% is obtained, that is, when the pixel luminance is distributed on the high gradation side, the luminance of the image is increased to improve the visibility. Even if it is necessary to correct the image to be large, the image displayed on the liquid crystal display devices 61 to 69 has a high luminance as a whole, and thus the visibility is relatively high. Therefore, the gain value G is preferably set to be relatively small. In FIG. 3, G = about 1.2.

  On the other hand, in FIG. 4, when most of the pixel luminances are distributed up to about 20% of the input gradation, that is, when the pixel luminances are distributed on the low gradation side, the overall luminance of the image is increased. Without such correction, the visibility of images displayed on the liquid crystal display devices 61 to 69 is not improved. Therefore, it is preferable to set the gain value G to be relatively large. In FIG. 4, G = about 4.

  The luminance distribution shown in FIGS. 3 and 4 is merely an example in which the pixel luminance is distributed on the high gradation side and the low gradation side, respectively, and the value of the gain value G is only an example. It can be determined appropriately according to the characteristics of the liquid crystal display device and the external environment.

  Here, various configurations can be applied to such a method of setting the gain value G. For example, whether the luminance distribution obtained by histogram analysis is biased toward the high gradation side or the low gradation side. A method of determining which case (which is closer) and setting (selecting) a corresponding predetermined gain value is conceivable.

  However, in this case, since there are only two types of gain values G, in order to set a more appropriate gain value G, a feature value such as a peak value or an average value of the luminance distribution is calculated and corresponds to the feature value. The gain value G may be calculated by referring to a predetermined calculation formula or a predetermined correspondence table. Furthermore, the gain value G may be calculated using other parameters.

  Further, instead of uniquely calculating the gain value from the luminance distribution in this way, a configuration in which an appropriate value is calculated according to the content of the input image is also conceivable. That is, when the target gain value is set first and the input gradation is corrected by applying this target gain value, the gradation collapse or video failure caused by excessively correcting the gradation does not occur more than a predetermined number. In addition, a configuration for setting a suitable gain value is also conceivable. An example of the operation of the histogram analysis unit 12 will be described with reference to FIG.

<1.2.2 Second Operation Example>
FIG. 5 is a flowchart showing the flow of gain value setting processing in the present embodiment. In step S10 shown in FIG. 5, the histogram analysis unit 12 sets a target gain value that is the first reference. As described above, the target gain value determines whether the luminance distribution state of the pixel obtained by the histogram analysis is biased toward the high gradation side or the low gradation side, and is determined in advance corresponding to each. The target gain value may be determined, or a feature value such as a peak value or an average value of the luminance distribution may be calculated, and a target gain value corresponding to the feature value may be calculated.

  Next, in step S20, the histogram analysis unit 12 multiplies the target gain value by the luminance value (gradation value) of all or some of the pixels included in the input image represented by the input image data Dp. (That is, perform correction) and calculate the number of pixels or the ratio (hereinafter referred to as “error amount”) in which the obtained value exceeds the maximum gradation value (for example, 255) that can be displayed on the display device. Perform the process.

  The error amount is configured to be counted equally in all the pixels, but a configuration may be adopted in which a higher weight is assigned to a pixel having a gradation value close to the maximum gradation value. In other words, the total error amount may be calculated according to the difference from the gradation value of each pixel to the maximum gradation value.

  Subsequently, in step S30, the histogram analysis unit 12 determines whether or not the error amount obtained in step S20 is equal to or less than a predetermined limit amount (for example, 20% of the total number of pixels) in which video failure is allowable. If the limit amount is exceeded (No in step S30), a value obtained by subtracting a predetermined value from the target gain value is calculated as a new target gain value (step S40), and the new target gain value is calculated. Is used to calculate an error amount (S20), and these processes are repeated until the obtained error amount does not exceed the limit amount (S30 → S40 → S20 → S30).

  As a result of the determination in step S30, when the error amount is equal to or less than the limit amount (in the case of Yes in step S30), the histogram analysis unit 12 performs a process of determining the target gain value as the gain value G (step S50), The gain value calculation process is terminated.

  The gain adjustment unit 14 receives the nine divided image data Ds1 to Ds9 generated by the conversion processing in the image division output unit 13 and the gain value G calculated by the above processing in the histogram analysis unit 12 as described above, Correction for multiplying the divided image data Ds1 to Ds9 by a gain value G is performed. Thus, the output image data Da1 to Da9 corrected so that the visibility is improved based on the gain value G in the gain adjusting unit 14 is provided to the corresponding liquid crystal display devices 61 to 69, respectively.

  The functions of the image processing apparatus 10 as described above are realized by hardware including a predetermined logic circuit corresponding to each of the above components, but a computer having a storage unit such as a CPU (Central Processing Unit) and a semiconductor memory In the above, functions corresponding to the above-described components may be realized by predetermined software.

  As described above, if the gain value is calculated by the process as shown in FIG. 5 and applied to the luminance of each pixel of the display image, the error amount does not exceed the above limit amount, so that the video is broken to some extent. It is suppressed. Therefore, since the maximum gain value G that suppresses the video failure to some extent can be set, visibility can be greatly improved while suppressing the video failure to some extent.

  Here, when the correction using the gain value as described above is performed, the correction amount in the vicinity of the low gradation is relatively small (that is, the gradation is not greatly increased), so that the visibility is not improved. Seems also. Therefore, the effect of this embodiment will be described with reference to FIG.

<1.3 Effects of the present embodiment>
FIG. 6 is a diagram for explaining that the visibility is improved by the configuration of the present embodiment. According to the characteristic curve C indicating the relationship between the input gradation and the output gradation in the liquid crystal display device shown in FIG. 6, an easy-to-see display screen is obtained when the surrounding environment is not very bright such as indoors. Although it can be provided, the visibility is reduced in a bright environment such as outdoors.

  Here, an ideal curve E shown in FIG. 6 is a characteristic curve showing a relationship between an ideal input tone and an output tone when the human eye is adapted to the bright environment. However, since the display luminance in the liquid crystal display device cannot exceed the output gradation 100% (for example, gradation value 255), which is the display limit, it is actually necessary to perform display that realizes the ideal curve E. Can not. Therefore, by multiplying the characteristic curve C by the gain value G as described above, the characteristic curve D with improved visibility in this embodiment can be obtained.

  Here, the characteristic curve D displays a gradation (for example, a gradation value with an output gradation of 20% or less) that cannot be visually recognized in a bright environment. Therefore, it seems that the visibility is further improved when the low gradation portion is increased more greatly. However, even in a bright environment, by paying attention to the area displayed with this invisible gradation, the eyes adapt to the low luminance and can be visually recognized. For this reason, when the gradation value of the low gradation part is increased, the display state of the part may be perceived as abnormal (referred to as black floating). Therefore, since it is better not to greatly increase this portion, the display quality is improved, and it can be said that the correction mode as in this embodiment is more suitable for maintaining the display quality while improving the visibility.

  As described above, the image processing apparatus 10 included in the multi-display device 100 according to the present embodiment typically displays one image on the liquid crystal display devices 61 to 69 arranged so as to be adjacent in a matrix. Visibility can be further improved without causing display defects such as video failure.

  Further, by calculating a gain value using a frequency distribution of pixel luminance such as histogram analysis and performing luminance correction, visibility can be improved in an average or statistically suitable manner for the entire pixel. it can.

<2. Second Embodiment>
<2.1 Overall configuration and operation>
FIG. 7 is a block diagram showing a configuration of a multi-display apparatus according to the second embodiment of the present invention. As shown in FIG. 7, the multi-display device 200 is similar to the multi-display device 100 according to the first embodiment shown in FIG. 1, and includes an image processing device 20 and nine liquid crystal display devices 71 to 79. The image display system includes: typically, one image is displayed on nine display screens.

  However, unlike the image processing apparatus 10 according to the first embodiment, the image processing apparatus 20 according to the present embodiment does not include a gain adjustment unit, and the gain adjustment unit is included in the liquid crystal display devices 71 to 79. Each is provided.

  That is, as illustrated in FIG. 7, the image processing apparatus 20 includes an image resolution conversion unit 21 that performs the same operation as the image resolution conversion unit 11 in the first embodiment, and an image division similar to the image division output unit 13. Although the output unit 23 and the histogram analysis unit 22 similar to the histogram analysis unit 12 are provided, the components corresponding to the gain adjustment unit 14 in the first embodiment are provided in the liquid crystal display devices 71 to 79, respectively. . Hereinafter, the configuration of the liquid crystal display device 71 will be described in detail with reference to FIG. 8 as an example. In the following, the image processing device 20 will be described as a device different from the liquid crystal display devices 71 to 79, but may be incorporated in any of these cases.

<2.2 Configuration and operation of liquid crystal display device>
FIG. 8 is a block diagram showing a configuration of the liquid crystal display device 71. As shown in FIG. 8, the liquid crystal display device 71 receives the corresponding divided image data Ds1 from the image processing device 20 and performs image adjustment, and the adjusted image data Dc adjusted thereby. On the other hand, a gain adjustment unit 27 that performs gain adjustment based on the corresponding gain value G received from the image processing device 20, and a liquid crystal control unit 28 and a liquid crystal display unit 29 for displaying the output image data Dv that has been gain adjusted. Is provided.

  As shown in FIG. 8, the image signal adjustment unit 25 receives the corresponding divided image data Ds1 from the image processing device 20, and attaches to the remote controller or the case from the user via the image control unit 26. User instruction information UC for image adjustment (by operating a switch or the like) is received. The adjustment mode of the image specified by the user instruction information UC is an adjustment mode set in advance so as to be suitable for the use and display mode of the image tone mode (for example, dynamic, standard, PC, cinema, etc.) as in a general video display device. Mode) setting, brightness adjustment, contrast adjustment, color temperature adjustment, and color balance adjustment.

  Such image adjustment is also possible in the liquid crystal display devices 61 to 69 in the first embodiment, and may be actually performed. In the first embodiment, after gain adjustment in the gain adjustment unit 14. Since the above-mentioned image adjustment is performed on the image, it is natural that the gain adjustment cannot be finally performed on the image after the image adjustment. On the other hand, in the configuration of the present embodiment, gain adjustment can be performed finally (finally), so that suitable gain adjustment can be performed so as not to affect the adjustment result. However, when correction is performed such that the pixel brightness is increased by the above adjustment, even if a suitable gain adjustment is performed, the amount of increase in brightness may actually be too large. In this regard, in the first embodiment, the user can further adjust the amount of increase in pixel brightness by further adjusting, and therefore the configuration of the first embodiment may be more suitable.

  The image control unit 26 functions as an input / output interface with the outside, and provides the gain adjustment unit 27 with the gain value G received from the image processing apparatus 20. Further, the image control unit 26 transmits common control information Cs including user instruction information UC and external environment information so that the liquid crystal display devices 71 to 79 can share the common control information Cs. This point will be described later.

  Here, instead of placing the gain value G in a state unrelated to the image adjustment result, a configuration in which the image adjustment result is reflected in the gain value G is also conceivable. In order to realize this configuration, it is difficult to determine the gain value G from the enlarged image as described above, and it is formed when the gain value is determined in each display device (the gain adjusting unit 27 thereof) (large The luminance distribution of the image (displayed on the screen) becomes uneven and is not appropriate.

  Therefore, in order to uniformly reflect the result of the image adjustment with respect to the change (correction) of the gain value G, a change amount (for example, a change ratio) of the gain value G corresponding to the image adjustment mode is previously set in each liquid crystal display device. The gain values after being changed (corrected) in all the liquid crystal display devices are set to be the same in 71 to 79 so as to be the same. This configuration corresponds to a modification of the above embodiment.

  For example, when the adjustment mode of the image specified by the user instruction information UC is “dynamic” in the above-described image adjustment mode, correction that increases the pixel luminance is performed, which is close to the correction mode based on the gain value that improves the visibility. It is possible that Therefore, for example, an example in which the gain value G is uniformly multiplied by 0.8 can be considered.

  With the configuration of the modified example as described above, it is possible to set a gain value that uniformly reflects the image adjustment result, and particularly when the image adjustment yields the same result as the gain value setting for improving visibility. Therefore, it is possible to set a suitable gain value and perform display in a suitable display mode reflecting the image adjustment result by the user. In this case, since the image adjustment result is uniformly reflected (with respect to the gain value), the display quality can be maintained without different image brightness in each liquid crystal display device. For this reason, there is no need for further adjustment as in the case of the first embodiment, and the amount of increase in pixel luminance does not become too large as in the case of the second embodiment. I can say that.

<2.3 Information sharing operation between liquid crystal display devices>
Further, as described above, the image control unit 26 transmits the common control information Cs including the user instruction information UC and the external environment information so as to be shared by the liquid crystal display devices 71 to 79. For example, when user instruction information UC is received in one of the liquid crystal display devices 71 to 79, the same user instruction is transmitted by transmitting the common control information Cs including the information to all the liquid crystal display devices 71 to 79. Share information UC. When a plurality of items are received, by predefining the priority relationship (for example, by defining the last user instruction information UC), one user instruction information UC is shared.

  In order to share the user instruction information UC among such liquid crystal display devices 71 to 79, each needs to be connected by a signal line capable of transmitting the information, and the configuration is typically the simplest. It is preferable that they are connected by a daisy chain method. Then, information can be easily shared with a small number of signal lines. Here, it is preferable that the image processing device 20 is also connected to the liquid crystal display devices 71 to 79 by a daisy chain method. Then, the gain value G can be similarly transmitted to the liquid crystal display devices 71 to 79 with a simple configuration. Note that the above connection method is an example, and a known signal transmission network such as a wireless LAN method may be used.

<2.4 Effects of this embodiment>
As described above, in the present embodiment, in addition to the effects of the first embodiment, the gain adjustment unit 27 can finally (finally) perform gain adjustment, and is thus specified by the user instruction information UC. Since the result of the image adjustment is not affected, a suitable gain adjustment can be performed. Therefore, the display quality can be prevented from being lowered by the gain adjustment.

<3. Third Embodiment>
<3.1 Overall configuration and operation>
FIG. 9 is a block diagram showing a configuration of a multi-display apparatus according to the third embodiment of the present invention. As shown in FIG. 9, the multi-display device 300 is similar to the multi-display device 100 according to the first embodiment shown in FIG. 1, and includes an image processing device 30 and nine liquid crystal display devices 61 to 69. The image display system includes: typically, one image is displayed on nine display screens.

  That is, as illustrated in FIG. 9, the image processing apparatus 30 includes an image resolution conversion unit 31 that performs the same operation as the image resolution conversion unit 11 in the first embodiment, and an image division similar to the image division output unit 13. An output unit 33 and a gain adjustment unit 34 similar to the gain adjustment unit 14 are provided, but unlike the histogram analysis unit 12, the histogram analysis unit 32 in the present embodiment receives external information from various sensors and input devices not shown. Is is received, and the gain value Gc is determined based on the external information Is. Hereinafter, the contents of the external information Is and the operation of the gain adjusting unit 34 will be described in detail. In the following, the image processing device 30 will be described as a device different from the liquid crystal display devices 61 to 69, but may be built in any of these cases, and the same applies to the following embodiments. And

<3.2 Operation of Histogram Analysis Unit>
The determination method of the gain value Gc in the histogram analysis unit 32 shown in FIG. 9 is almost the same as the determination method of the gain value G in the histogram analysis unit 12 described in the first embodiment and the point of using the external information Is. Since it is the same content, description is abbreviate | omitted about the same point.

  The external information Is refers to information that should affect image display, including external environment information and user instruction information UC in the second embodiment. For example, ambient light information indicating ambient brightness acquired by a light sensor (not shown), brightness setting information specified by a user's operation input (for a remote controller, etc.), ambient brightness given via an internal timer or the Internet The time, date, weather information, etc. for predicting the height can be considered as examples. In order to improve the visibility, it is necessary to increase the luminance of the display image as the surrounding brightness increases. Therefore, the histogram analysis unit 32 refers to the brightness (including prediction) information indicated by the external information Is, and increases the gain value G as the surroundings become brighter. If it does so, visibility can be improved more.

  Further, information other than brightness, for example, whether or not visibility needs to be improved is detected by a human sensor that detects whether or not there is a person around, and the gain value G is determined according to the detection result. It may be set. For example, when it is detected that there is no person, the gain value G is set small, and when it is detected that there is a person in the distance, in order to increase the attractiveness (so that the visibility is increased). If the gain value is set to a large value and it is detected that there is a person only nearby, the gain value should not be set too large in order to improve the visibility of detailed expressions (to achieve a higher quality display). It is also conceivable that the histogram analysis unit 32 performs the operation. In this way, the gain value G can be suitably set according to the external situation (for example, the presence or absence of a person viewing the display).

<3.3 Effects of this embodiment>
As described above, in this embodiment, in addition to the effects of the first embodiment, the histogram analysis unit 32 can set a suitable gain value G according to the external situation, particularly the ambient brightness. This can further improve the visibility.

<4. Fourth Embodiment>
<4.1 Overall configuration and operation>
FIG. 10 is a block diagram showing a configuration of a multi-display apparatus according to the fourth embodiment of the present invention. As shown in FIG. 10, the multi-display device 400 is similar to the multi-display device 100 according to the first embodiment shown in FIG. 1, and includes an image processing device 40 and nine liquid crystal display devices 61 to 69. In this case, a plurality of images are displayed on a large screen composed of nine display screens.

  That is, as illustrated in FIG. 10, the image processing apparatus 40 includes an image resolution conversion unit 41 that performs the same operation as the image resolution conversion unit 11 in the first embodiment, and an image division similar to the image division output unit 13. And an output unit 43.

  However, unlike the gain adjustment unit 14, the gain adjustment unit 44 of the present embodiment improves visibility by using a plurality of gain values Ga individually set corresponding to a plurality of input image areas. Unlike the histogram analysis unit 12, the area-specific histogram analysis unit 42 according to the present embodiment performs correction to improve, and is different from the histogram analysis unit 12 in that the gain value Ga for each area is output from the configuration of the first embodiment. It is very different. Hereinafter, the operations of the area-specific histogram analysis unit 42 and the gain adjustment unit 44 will be described in detail.

<4.2 Operation of Histogram Analysis Unit by Area>
In the present embodiment, as described above, a plurality of images corresponding to a plurality of image areas are included in the input image represented by the input image data Dp. For example, the following first to third examples can be considered for the arrangement of the images. Hereinafter, each will be described with reference to FIGS. 11 to 13. In addition to the following examples, various display modes are conceivable, and in this embodiment, a mode in which a plurality of image areas are arranged may be used.

  FIG. 11 is a diagram for explaining a first display screen example in the embodiment. As shown in FIG. 11, the configuration of the large screen formed by the display screens of the liquid crystal display devices 61 to 69 is the same as the screen shown in FIG. 2 described in the first embodiment. In FIG. 1, the first to fourth divided display images 601 to 604 are displayed instead of one image. The divided display images 601 to 604 are images having different contents, and four images are synthesized at appropriate positions by an input image data generation device (not shown). Since the divided display images 601 to 604 are not related to the contents, the display luminances of the divided display images 601 to 604 are different from each other, but to some extent (as one image) in one divided display image. Uniform luminance distribution. Therefore, in order to improve the visibility of each image, it is preferable to perform a histogram analysis for each image and calculate a gain value for each image.

  FIG. 12 is a diagram for explaining a second display screen example in the embodiment. As shown in FIG. 12, the configuration of the large screen formed by the display screens of the liquid crystal display devices 61 to 69 is the same, but this large screen is not a single image but an entire large image. Are displayed so as to include a small insertion image 605. Such a display mode is also called PinP (Picture in Picture). The inserted image 605 is an image having a content different from that of the entire image including the inserted image 605 and is synthesized so as to be inserted at an appropriate position of the entire image by an input image data generation device (not shown). Since the inserted image 605 is not related to the content of the entire image, the display luminance is different, but the luminance distribution is uniform to some extent (as one image) in each image. . Therefore, in order to improve the visibility of each image, it is preferable to perform a histogram analysis for each image and calculate a gain value for each image.

  Further, FIG. 13 is a diagram for explaining a third display screen example in the embodiment. As shown in FIG. 13, the configuration itself of the large screen formed by the display screens of the liquid crystal display devices 61 to 69 is the same, but this large screen is not a single image but a single image. The item display image 606 is displayed so as to be included in such a manner that it is superimposed on the image. Such a display mode is also called OSD (On Screen Display). This item display image 606 is an image having a content different from that of the entire image including the item display image 606. The input image data generation device or the present image processing device 40 (not shown) displays the item display image 606 as a display image for the user interface. It is overwritten and synthesized at an appropriate position. The item display image 606 is not related to the contents of the entire image and is basically a computer composite image, and thus the display brightness differs greatly. As a uniform image). Therefore, in order to improve the visibility of each image, it is preferable to perform a histogram analysis for each image and calculate a gain value for each image.

  As described above, when a plurality of images having different luminance distribution states are included in the input image, the area-specific histogram analysis unit 42 determines the histogram for each image in order to improve the visibility of each image. An analysis is performed to calculate a plurality of gain values Ga corresponding to each. The histogram analysis method and the gain value calculation method are the same as those in the first embodiment, and are different only in that they are performed separately for each image. Therefore, description of the calculation method is omitted.

  Here, the area-specific histogram analysis unit 42 also calculates which area (position) of the input image represented by the input image data Dp is a plurality of image areas that are to be subjected to histogram analysis. Output as position information Ia.

  Here, since the display positions of the divided display images 601 to 604 shown in FIG. 11 are determined in advance, the area-specific histogram analysis unit 42 does not need to particularly calculate and output the positions. In addition, when the item display image 606 shown in FIG. 13 is output by an image synthesis output unit (not shown) in the image processing apparatus 40, the area-specific histogram analysis unit 42 can receive the position. Good. Furthermore, if the insertion position of the insertion image 605 shown in FIG. 12 can be received from an external device, it may be output as it is. However, if the position information cannot be received, the area-specific histogram analysis unit 42 detects the boundary portion of each image with a known differential filter or the like, and calculates the position of each image area in the entire input image. For such image position detection or region detection, any method such as well-known pattern recognition analysis may be applied in addition to the method of detecting the boundary portion.

  Note that the area-specific histogram analysis unit 42 does not perform histogram analysis on the enlarged image represented by the enlarged image data Dpu converted by the image resolution conversion unit 41, but here is the target of the histogram analysis. The position of each image area in the magnified image is calculated (typically, a three-fold coordinate value according to the magnification) and is output as area position information Ia. The plurality of gain values Ga and area position information Ia calculated as described above are given to the gain adjusting unit 44. The operation of the gain adjusting unit 44 will be described.

<4.3 Operation of gain adjustment unit>
The gain adjustment unit 44 multiplies the pixel luminance (pixel gradation) in the area by the gain value Ga calculated for each area of the input image corresponding to the plurality of images, thereby improving visibility. Make corrections to improve. This correction content is the same as that of the first embodiment, and is different from that of the first embodiment only in that the target is limited to the corresponding image area.

  Here, it is rare that the image area includes only one image area on the display screen of each of the liquid crystal display devices 61 to 69, and usually includes a plurality of image areas. That is, in a normal case, one image area is displayed over a plurality of display screens. Therefore, a plurality of gain values may be required for one display screen among the liquid crystal display devices 61 to 69. For example, the gain adjustment unit 44 is one image represented by the divided image data Ds, and one of the two image areas (for example, the first image) included in the image displayed on the one display screen. The pixel luminance in the area) is multiplied by the first gain value, and the pixel luminance in the other image area (for example, the second image area) is multiplied by the second gain value.

  Specifically, when the divided display images 601 to 604 shown in FIG. 11 are displayed on each display screen, since only the divided display image 601 is included in the display screen of the liquid crystal display device 61, the corresponding gain value is Although the display screen of the liquid crystal display device 62 includes the divided display images 601 and 602, the corresponding gain value is two.

  Thus, in the image represented by the divided image data Ds, which gain value is multiplied by which part of the pixel luminance can be easily calculated from the area position information Ia. That is, for example, since the image represented by the divided image data Ds1 is predetermined to be disposed at the upper left position shown in FIG. 11, the arrangement of the image with respect to the enlarged image represented by the enlarged image data Dpu. The position is predetermined. Therefore, from the position in the enlarged image of each image area indicated by the area position information Ia, it is easily calculated which gain value is multiplied by which part of the pixel luminance in each image indicated by the divided image data Ds1 to Ds9. Can do.

<4.4 Effects of the present embodiment>
As described above, in the present embodiment, in addition to the effects of the first embodiment, when an input image includes a plurality of images, a gain value suitable for each image can be set. Thereby, according to the content of the image, for example, for a dark image, the luminance can be further increased, so that the visibility of the displayed image can be further improved for each region.

  Further, in the case of an image using OSD as shown in FIG. 13, since the difference in luminance (average value) in a plurality of image areas is large, one luminance correction affects the other luminance correction. In particular, the visibility of the displayed image can be improved for each region by the configuration that is performed individually.

<5. Fifth Embodiment>
<5.1 Overall configuration and operation>
FIG. 14 is a block diagram showing a configuration of a multi-display apparatus according to the fifth embodiment of the present invention. As shown in FIG. 14, this multi-display device 500 is similar to the multi-display device 400 according to the fourth embodiment shown in FIG. 10, and includes an image processing device 50 and nine liquid crystal display devices 61 to 69. The image display system includes a plurality of input image data provided to the image processing apparatus 50.

  That is, as illustrated in FIG. 14, the image processing apparatus 50 includes an image resolution conversion unit 51, an area-specific histogram analysis unit 52, an image division output unit 53, and a gain adjustment unit 54 similar to those in the fourth embodiment. However, one input image does not include a plurality of image areas, but differs in that one display image is formed by four images corresponding to the four input image data Dp1 to Dp4.

  In addition, the image resolution conversion unit 51 outputs enlarged image data Dpu1 to Dpu4 representing four enlarged images obtained by enlarging the input images represented by the input image data Dp1 to Dp4, respectively, in the fourth embodiment. It is different from the case of form.

  That is, the image resolution conversion unit 51 displays four input images having a predetermined resolution represented by the input image data Dp1 to Dp4 on the large screen, that is, the entire display screens of the nine liquid crystal display devices 61 to 69. Perform the process of enlarging. Of course, by simply compositing four input images, if the size is suitable for display on the entire display screen, enlargement processing is not necessary, but here, appropriate enlargement processing is performed. And

  Here, it is not necessary to perform the process of combining the images into one enlarged image. The image division output unit 53 easily divides the divided images represented by the divided image data Ds1 to Ds9 by synthesizing a plurality of corresponding regions at appropriate positions from the four enlarged images appropriately enlarged. It is because it can produce | generate.

  As described above, the operations of the image resolution conversion unit 51 and the image division output unit 53 are slightly different from those in the fourth embodiment, but the image displayed on the entire display screen is the same as the example shown in FIG. Therefore, the histogram analysis processing and gain value calculation processing in the area-specific histogram analysis unit 52, the gain value multiplication processing in the gain adjustment unit 54, and the like are the same as in the fourth embodiment. As described above, since the display positions of the divided display images 601 to 604 shown in FIG. 11 are determined in advance, the area-specific histogram analysis unit 52 determines the position in the same manner as the area-specific histogram analysis unit 42. It is not necessary to calculate and output the area position information Ia.

<5.2 Effects of this embodiment>
As described above, in the present embodiment, the same effects as in the first and fourth embodiments can be achieved. That is, the visibility of the displayed image can be further improved for each region.

10, 20, 30, 40, 50 ... image processing apparatus 11, 21, 31, 41, 51 ... image resolution conversion unit 12, 22, 32 ... histogram analysis unit 13, 23, 33, 43, 53 ... image division output unit 14, 27, 34, 44, 54 ... gain adjusting unit 25 ... image signal adjusting unit 26 ... image control unit 28 ... liquid crystal control unit 29 ... liquid crystal display unit 42, 52 ... area-specific histogram analysis units 61-69, 71-79 ... Liquid crystal display device 100-500 ... Multi-display device

Claims (12)

  1. An image processing device that outputs output image data representing each image displayed on each display screen in a plurality of display devices arranged linearly or in a plane based on input image data,
    An image resolution conversion unit that converts an input image represented by the input image data into a display resolution for display on the display screen and outputs the image as enlarged image data;
    An enlarged image represented by the enlarged image data output from the image resolution conversion unit is displayed on a display screen of the plurality of display devices in consideration of a frame region located at a boundary between the plurality of display devices. into a plurality of images to be displayed respectively, to generate a plurality of divided image data by display luminance plural image data in the periphery of the frame region representing the plurality of images respectively is corrected so as to increase An image division output unit for output;
    A correction data calculation unit that calculates and outputs luminance correction data according to the image so that the luminance of the displayed image increases based on the input image data;
    An image signal processing unit that outputs output image data obtained by correcting the luminance of the image represented by the divided image data based on the luminance correction data output from the correction data calculation unit,
    When the input image includes a plurality of different images, the correction data calculation unit, for each of the plurality of images, based on the image, an area in the enlarged image corresponding to the image Calculate and output brightness correction data so that the brightness of the image displayed at
    The image signal processing unit, when the input image includes a plurality of different images,
    A division including at least a part of one image in the enlarged image corresponding to any one of the plurality of images in the input image among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the luminance of the image based on the luminance correction data calculated by the correction data calculation unit for the one image in the input image,
    At least each of two or more images in the enlarged image corresponding to any two or more images in the plurality of divided images in the input image among the plurality of divided images represented by the plurality of divided image data. The brightness of the two or more images in the divided image including a part is corrected based on two or more brightness correction data respectively calculated by the correction data calculation unit for the two or more images in the input image. By doing so, the output image data is generated.
  2. The correction data calculation unit
    Calculating a value indicating a frequency distribution of pixel luminance included in the input image data, calculating the luminance correction data based on the calculated value;
    When a plurality of different images are included in the input image, a value indicating a frequency distribution of pixel luminance in the region is calculated for each region of the plurality of images, and the value is calculated based on the calculated value. The image processing apparatus according to claim 1, wherein brightness correction data is calculated.
  3. Based on the value indicating the frequency distribution, the correction data calculation unit may increase the luminance of the pixel to be displayed when the frequency distribution is biased toward the low luminance side than when the frequency distribution is biased toward the high luminance side. Set the gain value, output the set gain value as the brightness correction data,
    The image signal processing unit outputs the output image data based on a value obtained by multiplying the brightness of an image represented by the divided image data by the gain value, respectively. Item 3. The image processing apparatus according to Item 2.
  4.   The correction data calculation unit determines whether or not a value obtained by multiplying at least a part of luminance of the input image by the set gain value exceeds a maximum luminance value that can be displayed on the display device. When the number or ratio of pixels determined to exceed exceeds a predetermined threshold, the set gain value is decreased, and the number or ratio of pixels determined to exceed exceeds the threshold The image processing apparatus according to claim 3, wherein the set gain value is determined as the gain value to be multiplied with the luminance of the image represented by the divided image data.
  5.   The correction data calculation unit resets a gain value obtained by reducing the set gain value by a predetermined reduction amount as a new gain value, and further performs the resetting for at least part of the luminance of the input image. It is determined whether or not a value obtained by multiplying the obtained gain value exceeds a maximum luminance value that can be displayed on the display device, and if the number or ratio of pixels determined to exceed exceeds a predetermined threshold value, Decrease the set gain value by a fixed amount and reduce the set gain by the predetermined amount until it is determined not to exceed, and repeat the determination, and the number of pixels determined to exceed the predetermined value. Alternatively, when the ratio is equal to or less than the threshold value, the set gain value is determined as the gain value to be multiplied with the luminance of the image represented by the divided image data. Wherein, the image processing apparatus according to claim 4.
  6.   The correction data calculation unit receives a signal including information for image adjustment from the outside, and calculates the luminance correction data based on the input image data and information included in the signal. The image processing apparatus according to claim 1.
  7. An image processing device that outputs output image data representing each image displayed on each display screen in a plurality of display devices arranged in a line or plane based on a plurality of input image data,
    An image resolution converter that converts a plurality of input images represented by the plurality of input image data into a display resolution for display at a predetermined position on the display screen, and outputs the image as enlarged image data;
    The plurality of enlarged images represented by the enlarged image data output from the image resolution conversion unit are regarded as images synthesized to be displayed at the positions on the display screen, respectively, and the plurality of display devices taking into account the frame area located at the boundary between, divided on the display screen of the plurality of display devices to a plurality of images to be displayed respectively, the frame area of the plurality of image data representing the plurality of images, respectively An image division output unit that generates and outputs a plurality of divided image data by correcting the display luminance to increase around
    For each input image of the plurality of input images, luminance correction data is calculated and output based on the input image so that the luminance of the image displayed in the enlarged image region corresponding to the input image increases. A correction data calculation unit;
    An image signal processing unit that outputs output image data obtained by correcting the luminance of the image represented by the divided image data based on the luminance correction data output from the correction data calculation unit,
    The image signal processor is
    The luminance of the divided image including at least a part of one enlarged image corresponding to any one input image in the plurality of input images among the plurality of divided images represented by the plurality of divided image data is represented by the 1 By correcting the input image based on the brightness correction data calculated by the correction data calculation unit, the output image data is generated,
    In a divided image including at least a part of each of two or more enlarged images corresponding to any two or more input images in the plurality of input images among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the brightness of the two or more enlarged images based on the two or more brightness correction data respectively calculated by the correction data calculation unit for the two or more input images. An image processing apparatus.
  8. A system for displaying an image corresponding to the input image data on a plurality of display screens arranged in a line or plane based on the input image data,
    An image resolution conversion unit that converts an input image represented by the input image data into a display resolution for display on the display screen and outputs the image as enlarged image data;
    An enlarged image represented by the enlarged image data output from the image resolution conversion unit is displayed on a display screen of the plurality of display devices in consideration of a frame region located at a boundary between the plurality of display devices. into a plurality of images to be displayed respectively, to generate a plurality of divided image data by display luminance plural image data in the periphery of the frame region representing the plurality of images respectively is corrected so as to increase An image division output unit for output;
    A correction data calculation unit that calculates and outputs luminance correction data according to the image so that the luminance of the displayed image increases based on the input image data;
    An image signal processing unit that outputs output image data in which the luminance of the image represented by the divided image data is corrected based on the luminance correction data output from the correction data calculation unit;
    A plurality of display units including the plurality of display screens for displaying images based on the output image data;
    When the input image includes a plurality of different images, the correction data calculation unit, for each of the plurality of images, based on the image, an area in the enlarged image corresponding to the image Calculate and output brightness correction data so that the brightness of the image displayed at
    The image signal processing unit, when the input image includes a plurality of different images,
    A division including at least a part of one image in the enlarged image corresponding to any one of the plurality of images in the input image among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the luminance of the image based on the luminance correction data calculated by the correction data calculation unit for the one image in the input image,
    At least each of two or more images in the enlarged image corresponding to any two or more images in the plurality of divided images in the input image among the plurality of divided images represented by the plurality of divided image data. The brightness of the two or more images in the divided image including a part is corrected based on two or more brightness correction data respectively calculated by the correction data calculation unit for the two or more images in the input image. By doing so, the output image data is generated.
  9. Each of the plurality of display devices included in the plurality of display devices including the plurality of display units receives a signal including information for image adjustment from the outside, and is represented by the plurality of divided image data based on the information included in the signal An image adjustment processing unit that performs a correction process on a corresponding divided image of the divided images;
    The image signal processing unit is included in each of the plurality of display devices, receives corresponding luminance correction data from the correction data calculation unit, and correction processing is performed by the image adjustment processing unit based on the received luminance correction data. The image display system according to claim 8, wherein the output image data whose luminance is corrected is generated for the corresponding divided image and is output to the corresponding display unit.
  10.   The image signal processing unit corrects the received luminance correction data according to the correction processing performed by the image adjustment processing unit, and the image adjustment processing unit performs correction processing based on the corrected luminance correction data. 10. The image display system according to claim 9, wherein the output image data in which the luminance is corrected is generated for the corresponding divided image subjected to the processing, and is output to the corresponding display unit.
  11.   The image display system according to claim 9, wherein the plurality of display devices are daisy chain connected by at least a signal line that transmits the luminance correction data.
  12. An image display method for outputting output image data representing each image displayed on each display screen in a plurality of display devices arranged linearly or planarly based on input image data,
    An image resolution conversion step of converting the input image represented by the input image data into a display resolution for display on the display screen and outputting the enlarged image data;
    The enlarged image represented by the enlarged image data output in the image resolution conversion step is displayed on the display screen of the plurality of display devices in consideration of a frame region located at a boundary between the plurality of display devices. into a plurality of images to be displayed respectively, to generate a plurality of divided image data by display luminance plural image data in the periphery of the frame region representing the plurality of images respectively is corrected so as to increase An image division output step to output;
    A correction data calculation step of calculating and outputting luminance correction data corresponding to the image so that the luminance of the displayed image increases based on the input image data;
    An image signal processing step of outputting output image data obtained by correcting the luminance of the image represented by the divided image data based on the luminance correction data output in the correction data calculating step,
    In the correction data calculating step, when the input image includes a plurality of different images, an area in the enlarged image corresponding to the image based on the image for each of the images. Calculate and output brightness correction data so that the brightness of the image displayed at
    In the image signal processing step, when the input image includes a plurality of different images,
    A division including at least a part of one image in the enlarged image corresponding to any one of the plurality of images in the input image among the plurality of divided images represented by the plurality of divided image data. The output image data is generated by correcting the luminance of the image based on the luminance correction data calculated by the correction data calculation step for the one image in the input image,
    At least each of two or more images in the enlarged image corresponding to any two or more images in the plurality of divided images in the input image among the plurality of divided images represented by the plurality of divided image data. The brightness of the two or more images in the divided image including a part is corrected based on the two or more brightness correction data respectively calculated by the correction data calculation step for the two or more images in the input image. And generating the output image data.
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