Display system, display method, display controller, and image signal processing method of display controller

Abstract

A display system is provided with: a first decoding unit that decodes a first video signal and outputs a second video signal; an analysis unit that analyzes the second video signal and acquires a brightness distribution in at least a portion of an analysis range; a first determination unit that determines a first gamma curve on the basis of the brightness distribution; an encoding unit that outputs a third video signal obtained by encoding the second video signal using the first gamma curve; a second determination unit that determines a second gamma curve on the basis of the third video signal and gamma curve information; a second decoding unit that outputs a fourth video signal obtained by decoding the third video signal using a second gamma curve; and a display unit that displays an image on the basis of the fourth image signal.

Description

Technical Field

[0001] The present invention relates to a display system, a display method, a display controller, and an image signal processing method for a display controller. Background Art

[0002] Conventionally, in an LED (Light Emitting Diode) display system, usually, an LED controller unit and an LED panel unit are formed of different housings, and a structure capable of coping with a situation where the installation locations of the respective housings are separated is also available. Between the LED controller unit and the LED panel unit, they are mostly connected by a cable such as a LAN (Local Area Network) cable, and its transmission rate is usually 1 Gbps. Therefore, the data capacity that can be transmitted between the LED controller unit and the LED panel unit by one cable is limited.

[0003] In an LED display system, according to characteristics such as high brightness of elements, high-contrast performance can be achieved. On the other hand, sometimes a decrease in image quality is perceived in an image in a low-brightness portion. In the case of a display in which there is transmission between a controller unit and a panel unit, including not only an LED display system but also an LCD (Liquid Crystal Display) monitor, an OLED (Organic Light-Emitting Diode) monitor, etc., a decrease in image quality is perceived in an image in a low-brightness portion. The decrease in image quality can be prevented by increasing the amount of data (number of bits) per pixel.

[0004] However, as described above, the data capacity that can be transmitted in a transmission path such as a cable is limited. Therefore, when the amount of data per pixel is increased, the display area of an image that can be covered by one cable becomes smaller. Therefore, in order to prevent a decrease in image quality by increasing the amount of data per pixel, the number of cable connections increases, and as a result, the cost of the product becomes high and the usability also deteriorates.

[0005] The following technique is disclosed in Patent Document 1 below: After performing gamma processing on an image signal generated by an imaging device, image processing is performed, and after performing inverse gamma processing on the image signal after the image processing, the image signal is sent to a display. In this technique, in gamma processing, for a low-brightness portion, a characteristic represented by a straight line is used as a conversion characteristic instead of a curve to perform conversion of the image signal. Thereby, the loss of data in the low-brightness portion is alleviated, and therefore, it is possible to suppress a decrease in image quality in the low-brightness portion without increasing the amount of data per pixel.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-156721 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, in the technology of Patent Document 1 described above, although the loss of data in the processing (gamma processing) performed before the image processing of the image signal is considered, the loss of data in the processing (inverse gamma processing) performed after the image processing is not considered. Therefore, in order to suppress the deterioration of image quality, there is room for improvement in the processing performed after the image processing of the image signal.

[0011] In view of the above problems, an object of the present invention is to provide a display system, a display method, a display controller, and an image signal processing method for a display controller that can suppress the deterioration of image quality caused by the data capacity of a transmission path.

[0012] Means for Solving the Problems

[0013] In order to solve the above problems, a display system according to one aspect of the present invention includes: a first decoding unit that decodes an input first image signal and outputs a second image signal; an analysis unit that analyzes the second image signal and obtains a luminance distribution within at least a part of an analysis range of the second image signal; a first determination unit that determines a first gamma curve for encoding the second image signal based on the luminance distribution; an encoding unit that outputs a third image signal obtained by encoding the second image signal using the determined first gamma curve; a second determination unit that determines a second gamma curve for decoding the third image signal based on the third image signal and gamma curve information indicating the first gamma curve used for encoding; a second decoding unit that outputs a fourth image signal obtained by decoding the third image signal using the determined second gamma curve; and a display unit that displays an image based on the fourth image signal.

[0014] A display method according to one embodiment of the present invention is executed by a computer and includes the following processes: a first decoding process for decoding an input first video signal and outputting a second video signal; an analysis process for analyzing the second video signal to obtain a luminance distribution within at least a part of an analysis range of the second video signal; a first determination process for determining a first gamma curve for encoding the second video signal based on the luminance distribution; an encoding process for outputting a third video signal obtained by encoding the second video signal using the determined first gamma curve; a second determination process for determining a second gamma curve for decoding the third video signal based on the third video signal and gamma curve information indicating the first gamma curve used for encoding; a second decoding process for outputting a fourth video signal obtained by decoding the third video signal using the determined second gamma curve; and a display process for displaying an image based on the fourth video signal.

[0015] A display controller according to one embodiment of the present invention includes: a decoding unit for decoding an input first video signal and outputting a second video signal; an analysis unit for analyzing the second video signal to obtain a luminance distribution within at least a part of an analysis range of the second video signal; a determination unit for determining a gamma curve for encoding the second video signal based on the luminance distribution; and an encoding unit for outputting a third video signal obtained by encoding the second video signal using the determined gamma curve.

[0016] An image signal processing method of a display controller according to one embodiment of the present invention is executed by a computer and includes the following processes: a decoding process for decoding an input first video signal and outputting a second video signal; an analysis process for analyzing the second video signal to obtain a luminance distribution within at least a part of an analysis range of the second video signal; a determination process for determining a gamma curve for encoding the second video signal based on the luminance distribution; and an encoding process for outputting a third video signal obtained by encoding the second video signal using the determined gamma curve.

[0017] Advantages of the Invention

[0018] According to the present invention, it is possible to suppress a reduction in image quality caused by the data capacity of a transmission path. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a block diagram showing an example of the configuration of a display system according to the first embodiment.

[0020] Figure 2 FIG. is a block diagram showing an example of the functional configuration of a display controller according to the first embodiment.

[0021] Figure 3 This is a diagram showing an example of a gamma curve for encoding an image signal in the first embodiment.

[0022] Figure 4 This is a block diagram showing an example of the functional structure of a display module in the first embodiment.

[0023] Figure 5 This is a diagram showing an example of a gamma curve for decoding an image signal in the first embodiment.

[0024] Figure 6 This is a sequence diagram showing an example of the processing flow in a display system of the first embodiment.

[0025] Figure 7 This is a flowchart showing an example of the detailed processing flow of the analysis processing and decision processing in the first embodiment.

[0026] Figure 8 This is a flowchart showing an example of the detailed processing flow of the analysis processing and decision processing in a modification of the first embodiment.

[0027] Figure 9 This is a diagram showing an example of a histogram in a modification of the first embodiment.

[0028] Figure 10 This is a block diagram showing an example of the structure of a display system in the second embodiment.

[0029] Figure 11 This is a diagram showing an example of the structure of a display in the second embodiment.

[0030] Figure 12 This is a diagram showing an example of an image displayed on the display in the second embodiment.

[0031] Figure 13 This is a block diagram showing an example of the functional structure of an analysis unit in the second embodiment.

[0032] Figure 14 This is a block diagram showing an example of the functional structure of an analysis unit in a modification of the second embodiment.

[0033] Figure 15 This is a block diagram showing an example of the functional structure of a display controller in the third embodiment.

[0034] Figure 16 This is a block diagram showing an example of the functional structure of a display module in the third embodiment.

[0035] Figure 17 This is a block diagram showing an example of the functional structure of a display controller in the fourth embodiment.

[0036] Figure 18 It is a block diagram showing an example of the functional structure of the display module of the fourth embodiment.

[0037] Figure 19 It is a block diagram showing an example of the structure of the display system of the fifth embodiment. Detailed Embodiments

[0038] Embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, a display system for a display to display an image will be described.

[0039] The display system is a system (display monitor system) that transmits between a display unit (such as a panel) of a display for displaying an image and a controller of the display.

[0040] The display is, for example, an LCD (Liquid Crystal Display) monitor, an OLED (Organic Light-Emitting Diode) monitor, an LED (Light Emitting Diode) monitor, or the like.

[0041] In addition, in the display system, the display unit and the controller may be provided above in one housing, or may be provided in different housings respectively. Further, in the display system, other devices such as a module may be provided between the display unit and the controller. In this case, the display unit, the controller, and other devices may all be provided in one housing, or may be provided in different housings respectively, or may be arbitrarily combined and provided in any number of housings. That is, as long as it is a structure in which transmission occurs during the period from the image signal input to the controller to reaching the display unit, the structure of the display system is not particularly limited.

[0042] In addition, the transmission between the display unit and the controller may be performed by a wired connection in which the display unit and the controller are connected by a cable such as a LAN (Local Area Network) cable, or may be performed by a wireless connection using a wireless communication connection.

[0043] <<1. First Embodiment>>

[0044] Refer to Figures 1 to 9 , and the first embodiment will be described. In the first embodiment, an example in which one image is displayed on a display having one display unit will be used as an example to describe the embodiment. For example, it is a case of using only one display such as an LCD monitor or an OLED monitor.

[0045] In addition, in the first embodiment, an example of the display unit and the controller being respectively provided in different housings, with other devices provided between the display unit and the controller, and the other devices being provided in the same housing as the display unit will be used to illustrate the embodiment.

[0046] <1-1. Structure of the display system>

[0047] Refer to Figure 1 To describe the structure of the display system of the first embodiment. Figure 1 It is a block diagram showing an example of the structure of the display system of the first embodiment.

[0048] As Figure 1 shown, the display system 1 of the first embodiment includes a control terminal 10, a source device 20, a display controller 30, a display 40, and a display module 50.

[0049] (1)Control terminal 10

[0050] The control terminal 10 is a terminal for controlling the display of images in the display 40. The control terminal 10 is, for example, a PC (Personal Computer), a smart phone, a tablet terminal, etc. The control terminal 10 is connected to the display controller 30 in a communicable manner by a wired connection or a wireless connection.

[0051] When the user inputs information for controlling the display of images, the control terminal 10 outputs (sends) the input information to the display controller 30.

[0052] (2)Source device 20

[0053] The source device 20 is a device that outputs an image signal. The source device 20 is, for example, a PC, an image output device, etc. The source device 20 is connected to the display controller 30 in a communicable manner by a wired connection or a wireless connection. The source device 20 and the display controller 30 are, for example, wired-connected by a cable such as an HDMI (High Definition Multimedia Interface) (registered trademark) cable.

[0054] The source device 20 outputs (sends) an image signal to the display controller 30.

[0055] (3)Display controller 30

[0056] The display controller 30 is a device that converts the input image signal into an image signal for displaying an image on the display 40. The display controller 30 is connected to the control terminal 10, the source device 20, and the display 40 in a communicable manner by a wired connection or a wireless connection.

[0057] The display controller 30 processes the video signal based on the information received from the control terminal 10 and the video signal received from the source device 20, and outputs (transmits) the processed video signal to the display 40.

[0058] (4) Display 40

[0059] The display 40 is a display device that displays an image based on the input video signal. The display 40 is connected to the display controller 30 in a communicable manner by a wired connection or a wireless connection.

[0060] The display 40 displays an image based on the video signal received from the display controller 30.

[0061] As Figure 1 shown, the display 40 includes a display module 50.

[0062] (5) Display module 50

[0063] The display module 50 is assembled with a display unit such as a panel and a screen that constitute the display, and a processing unit such as a driver or a controller that performs processing for displaying an image. The display module 50 is connected to the display controller 30 in a communicable manner by a wired connection or a wireless connection.

[0064] The display module 50 performs processing for displaying the video signal received from the display controller 30 through the processing unit, and displays the image on the display unit after the processing.

[0065] <1-2. Functional Structure of Display Controller>

[0066] The structure of the display system 1 of the first embodiment has been described above. Next, with reference to Figures 2 to 3 , the functional structure of the display controller 30 of the first embodiment will be described. Figure 2 is a block diagram showing an example of the functional structure of the display controller 30 of the first embodiment.

[0067] As Figure 2 shown, the display controller 30 includes a decoding unit 310 (first decoding unit), a signal processing unit 320, an analysis unit 330, a determination unit 340 (first determination unit), an encoding unit 350, a switching unit 360, and a formatter unit 370.

[0068] (1) Decoding unit 310

[0069] The decoding unit 310 has a function of decoding a video signal. The decoding unit 310 decodes the video signal (first video signal) input from the source device 20 and outputs a video signal (second video signal).

[0070] The decoding unit 310 restores the input video signal to a video signal (linear data) with linear characteristics by decoding to match the gamma curve of the video signal. In decoding, the decoding unit 310 converts the input video signal into a video signal with a bit width wider than that of the input video signal. For example, the decoding unit 310 converts a 10-bit video signal into a 16-bit video signal.

[0071] After decoding, the decoding unit 310 outputs the video signal to the signal processing unit 320.

[0072] (2)Signal processing unit 320

[0073] The signal processing unit 320 has a function of performing signal processing on the video signal. The signal processing unit 320 performs signal processing such as color adjustment on the video signal (second video signal) input from the decoding unit 310. In signal processing, the bit width of the video signal can be changed. For example, the signal processing unit 320 can convert the 16-bit video signal input from the decoding unit 310 into a 14-bit video signal, an 18-bit video signal, etc. The changed number of bits is not particularly limited.

[0074] After signal processing, the signal processing unit 320 outputs the video signal (second video signal) on which signal processing has been performed to the analysis unit 330.

[0075] (3)Analysis unit 330

[0076] The analysis unit 330 has a function of analyzing the video signal. The analysis unit 330 analyzes the video signal (second video signal) input from the signal processing unit 320 and obtains the luminance distribution within at least a part of the analysis range of the video signal. In the first embodiment, for the display 40 having one panel, one video based on the input video signal is displayed, so the analysis range is the entire video signal (entire frame).

[0077] After analysis, the analysis unit 330 outputs the obtained luminance distribution to the determination unit 340.

[0078] In the analysis, the analysis unit 330 first obtains the luminance value of each pixel of the input video signal.

[0079] After obtaining, the analysis unit 330 determines the luminance level of each pixel based on the obtained luminance value. Specifically, the analysis unit 330 assigns each pixel to a corresponding luminance level by comparing the obtained luminance value with a preset reference luminance value. At this time, the analysis unit 330 counts and records the number of pixels assigned to each luminance level (hereinafter, also referred to as "number of pixels").

[0080] The analysis unit 330 can obtain the luminance distribution within the analysis range of the image signal by assigning luminance levels to all pixels. The luminance distribution is represented, for example, by the number of pixels assigned to each luminance level.

[0081] The reference value is set, for example, by dividing the range of values that the luminance value can take into multiple regions. In the first embodiment, as an example, when the number of bits is 10, the range of values that the luminance value can take is set to 0 to 1023, and the reference luminance value is set by dividing this range into three regions. For example, among the reference luminance values, 0 to 255 is set as the value for determining that the luminance level is level 1, 256 to 511 is set as the value for determining that the luminance level is level 2, and 512 to 1023 is set as the value for determining that the luminance level is level 3.

[0082] In addition, the number of bits, the range of values that the luminance value can take, the number of regions for dividing this range, and the values of the reference luminance value are not limited to the above examples. For example, the number of bits is not limited to 10 bits, and the reference luminance value is set in the same way in the case of 8 bits or 12 bits, etc.

[0083] (4)Decision unit 340

[0084] The decision unit 340 has the function of determining the gamma curve for encoding the image signal. The decision unit 340 determines the gamma curve (first gamma curve) for encoding the image signal (second image signal) based on the luminance distribution obtained by the analysis unit 330.

[0085] After the determination, the decision unit 340 outputs the image signal to the encoding unit 350, and outputs the gamma curve information to the switching unit 360 and the formatter unit 370. The gamma curve information output here is the information indicating the gamma curve determined by the decision unit 340 to be used for encoding the image signal.

[0086] Among the gamma curves for encoding, gamma curves corresponding to the ratio of pixels with low luminance within the analysis range are prepared. For example, in the first embodiment, 3 types of gamma curves for encoding are prepared.

[0087] The first type is the gamma curve for encoding used when the ratio of pixels with low luminance within the analysis range is high (that is, the number of pixels of level 1 is large). The second type is the gamma curve for encoding used when the ratio of pixels with low luminance within the analysis range is medium (that is, the number of pixels of level 2 is large). The third type is the gamma curve for encoding used when the ratio of pixels with low luminance within the analysis range is low (that is, the number of pixels of level 3 is large).

[0088] Here, refer to Figure 3 A description will be given of the gamma curve for encoding the image signal. Figure 3It is a diagram showing an example of a gamma curve for encoding an image signal in the first embodiment.

[0089] Figure 3 The gamma curve GC1 shown in the graph of (a) is the gamma curve for encoding corresponding to level 1. The gamma curve GC1 is set to have a smaller gamma value than other gamma curves.

[0090] Figure 3 The gamma curve GC2 shown in the graph of (b) is the gamma curve for encoding corresponding to level 2. The gamma curve GC2 is set to have a larger gamma value than the gamma curve GC1 and a smaller gamma value than the gamma curve GC3.

[0091] Figure 3 The gamma curve GC3 shown in the graph of (c) is the gamma curve for encoding corresponding to level 3. The gamma curve GC3 is set to have a larger gamma value than other gamma curves.

[0092] The determination unit 340 determines the gamma curve for encoding the image signal from the acquired luminance distribution based on the ratio of pixels with low luminance in the analysis range. The determination unit 340 determines the ratio of pixels with low luminance in the analysis range by comparing the number of pixels in each luminance level represented by the acquired luminance distribution with the number of reference pixels (hereinafter, also referred to as "reference pixel number").

[0093] For example, in the first embodiment, when any one of the number of pixels in luminance levels 1 and 2 is equal to or more than the reference pixel number and the number of pixels in level 1 is equal to or more than the number of pixels in level 2, the determination unit 340 determines that the ratio of pixels with low luminance in the analysis range is high.

[0094] In addition, when any one of the number of pixels in luminance levels 1 and 2 is equal to or more than the reference pixel number and the number of pixels in level 1 is less than the number of pixels in level 2, the determination unit 340 determines that the ratio of pixels with low luminance in the analysis range is medium.

[0095] In addition, when the number of pixels in luminance levels 1 and 2 is less than the reference pixel number, the determination unit 340 determines that the ratio of pixels with low luminance in the analysis range is low.

[0096] When the ratio of pixels with low luminance in the analysis range is high, the determination unit 340 determines to use a gamma curve whose gamma value is set smaller than that in the case where the ratio of pixels other than those with low luminance in the analysis range is high ( Figure 3 gamma curve GC1).

[0097] In addition, when the ratio of pixels with low luminance within the analysis range is medium, the determination unit 340 determines to use a gamma curve ( Figure 3 gamma curve GC2) in which the gamma value is set larger compared to the case where the ratio of pixels with low luminance within the analysis range is high, and the gamma value is set smaller compared to the case where the ratio of pixels with low luminance within the analysis range is low.

[0098] In addition, when the ratio of pixels with low luminance within the analysis range is low, the determination unit 340 determines to use a gamma curve ( Figure 3 gamma curve GC3) in which the gamma value is set larger compared to the case where the ratio of pixels with low luminance within the analysis range is medium.

[0099] (5) Encoding unit 350

[0100] The encoding unit 350 has a function of encoding an image signal. The encoding unit 350 outputs an image signal (third image signal) obtained by encoding the image signal (second image signal) input from the determination unit 340 using the gamma curve (first gamma curve) determined by the determination unit 340. In the encoding, the encoding unit 350 converts the input image signal into an image signal with a bit precision smaller than the bit width of the image signal. For example, the encoding unit 350 converts a 16-bit image signal into a 10-bit image signal.

[0101] After encoding, the encoding unit 350 outputs the image signal to the switching unit 360.

[0102] In addition, in the first embodiment, not only the gamma curve determined by the determination unit 340 is used, but also encoding using each separately prepared gamma curve is performed in parallel. Therefore, as Figure 2 shown, the encoding unit 350 includes a plurality of processing units 351. For example, a plurality of processing units 351 corresponding to the number of gamma curves prepared for encoding are provided.

[0103] In the encoding unit 350, for each of the plurality of processing units 351-1, 351-2,..., the same image signal is encoded using different gamma curves. In the case of the first embodiment, since three gamma curves GC1 to GC3 are prepared, three processing units 351 are prepared. The first processing unit 351 performs encoding using the gamma curve GC1. The second processing unit 351 performs encoding using the gamma curve GC2. The third processing unit 351 performs encoding using the gamma curve GC3.

[0104] (6) Switching unit 360

[0105] The switching unit 360 has a function of switching multiple video signals. Based on the gamma curve information input from the determination unit 340, the switching unit 360 switches which of the multiple video signals output from each processing unit 351 of the encoding unit 350 is output to the subsequent block.

[0106] After the switching, the switching unit 360 outputs the video signal to the formatter unit 370.

[0107] For example, in the first embodiment, when the gamma curve information represents the gamma curve GC1, the switching unit 360 switches to output the video signal encoded using the gamma curve GC1.

[0108] When the gamma curve information represents the gamma curve GC2, the switching unit 360 switches to output the video signal encoded using the gamma curve GC2.

[0109] When the gamma curve information represents the gamma curve GC3, the switching unit 360 switches to output the video signal encoded using the gamma curve GC3.

[0110] (7) Formatter unit 370

[0111] The formatter unit 370 has a function of processing the video signal according to the format of the transmission path between the display controller 30 and the display module 50. The formatter unit 370 processes the video signal input from the switching unit 360 according to the format of the transmission path. Also, in order to transfer the information of the gamma curve used for encoding the video signal to be output to the display module 50, the formatter unit 370 performs a process of embedding the gamma curve information input from the determination unit 340 into the video signal input from the switching unit 360.

[0112] After the processing, the formatter unit 370 outputs the video signal to the display module 50.

[0113] <1-3. Functional structure of the display module>

[0114] The functional structure of the display controller 30 in the first embodiment has been described above. Next, with reference to Figures 4 to 5 The functional structure of the display module 50 in the first embodiment will be described. Figure 4 is a block diagram showing an example of the functional structure of the display module 50 in the first embodiment.

[0115] As Figure 4 shown, the display module 50 includes a format decoding unit 510, a determination unit 520 (second determination unit), a decoding unit 530 (second decoding unit), a switching unit 540, and a display unit 550.

[0116] (1)Format decoding unit 510

[0117] The format decoding unit 510 has a function of decoding the format of the video signal. The format decoding unit 510 decodes the format of the video signal (the third video signal) input from the display controller 30. Thereby, the format decoding unit 510 obtains the video signal and gamma curve information representing the gamma curve (the first gamma curve) used for encoding this video signal.

[0118] After decoding the format, the format decoding unit 510 outputs the video signal and the gamma curve information to the determination unit 520.

[0119] (2)Determination unit 520

[0120] The determination unit 520 has a function of determining the gamma curve for decoding the video signal. The determination unit 520 determines the gamma curve (the second gamma curve) for decoding the video signal based on the video signal (the third video signal) and the gamma curve information obtained by the format decoding unit 510.

[0121] After determination, the determination unit 520 outputs the video signal to the decoding unit 530 and outputs the gamma curve information to the switching unit 540. The gamma curve information output here is the gamma curve information input from the format decoding unit 510.

[0122] Among the gamma curves for decoding, gamma curves of the types corresponding to the gamma curve used for encoding in the display controller 30 are prepared. For example, in the first embodiment, three gamma curves for decoding are prepared.

[0123] The first is the gamma curve for decoding corresponding to the gamma curve used for encoding in the case where the ratio of pixels with low luminance in the analysis range is high (i.e., the number of pixels of level 1 is large). The second is the gamma curve for decoding corresponding to the gamma curve used for encoding in the case where the ratio of pixels with low luminance in the analysis range is medium (i.e., the number of pixels of level 2 is large). The third is the gamma curve for decoding corresponding to the gamma curve used for encoding in the case where the ratio of pixels with low luminance in the analysis range is low (i.e., the number of pixels of level 3 is large).

[0124] Here, refer to Figure 5 The gamma curve for decoding the video signal will be described. Figure 5 This is a diagram showing an example of the gamma curve for decoding the video signal in the first embodiment.

[0125] Figure 5 The gamma curve GC4 shown in the graph of (d) shown is the gamma curve for decoding corresponding to level 1. The gamma curve GC4 is set to have a larger gamma value than other gamma curves for decoding.

[0126] Figure 5 The gamma curve GC5 shown in the graph of (e) shown is the gamma curve for decoding corresponding to level 2. The gamma curve GC5 is set such that the gamma value is smaller than the gamma curve GC4 and larger than the gamma curve GC6.

[0127] Figure 5 The gamma curve GC6 shown in the graph of (f) shown is the gamma curve for decoding corresponding to level 3. The gamma curve GC6 is set such that the gamma value is smaller than other gamma curves for decoding.

[0128] The determination unit 520 determines to use a gamma curve (second gamma curve) for which a gamma value (second gamma value) that is the reciprocal of the gamma value set for the gamma curve represented by the acquired gamma curve information is set, based on the gamma value (first gamma value) set for the gamma curve represented by the acquired gamma curve information.

[0129] For example, in the first embodiment, if the gamma value represented by the gamma curve information is the gamma value of the gamma curve GC1, the determination unit 520 determines to use the gamma curve GC4, which is the reciprocal of the gamma value, for decoding.

[0130] Further, in the case where the gamma value represented by the gamma curve information is the gamma value of the gamma curve GC2, the determination unit 520 determines to use the gamma curve GC5, which is the reciprocal of the gamma value, for decoding.

[0131] Further, when the gamma value represented by the gamma curve information is the gamma value of the gamma curve GC3, the determination unit 520 determines to use the gamma curve GC6, which is the reciprocal of the gamma value, for decoding.

[0132] (3) Decoding unit 530

[0133] The decoding unit 530 has a function of decoding an image signal. The decoding unit 530 outputs an image signal (fourth image signal) obtained by decoding the image signal (third image signal) input from the determination unit 520 using the gamma curve (second gamma curve) determined by the determination unit 520.

[0134] After decoding, the decoding unit 530 outputs the image signal to the switching unit 540.

[0135] Further, in the first embodiment, not only the gamma curve determined by the determination unit 520 is used, but also decoding using each separately prepared gamma curve is performed in parallel. Therefore, as Figure 4 shown, the decoding unit 530 includes a plurality of processing units 531. For example, a plurality of processing units 531 corresponding to the number of gamma curves prepared for decoding are provided.

[0136] In the decoding unit 530, for each of the multiple processing units 531-1, 531-2, …, the same video signal is decoded using different gamma curves. In the case of the first embodiment, three gamma curves GC4 to GC6 are prepared, so three processing units 351 are prepared. The first processing unit 351 performs decoding using the gamma curve GC4. The second processing unit 351 performs decoding using the gamma curve GC5. The third processing unit 351 performs decoding using the gamma curve GC6.

[0137] (4)Switching unit 540

[0138] The switching unit 540 has a function of switching multiple video signals. The switching unit 540 switches which of the multiple video signals (fourth video signals) output from each processing unit 531 of the decoding unit 530 is output to the subsequent block based on the gamma curve information input from the determination unit 520.

[0139] After switching, the switching unit 540 outputs the video signal to the display unit 550.

[0140] For example, in the first embodiment, when the gamma curve information indicates that the gamma curve GC1 is used in the encoding of the display controller 30, the switching unit 540 switches to output the video signal decoded using the gamma curve GC4.

[0141] When the gamma curve information indicates that the gamma curve GC2 is used in the encoding of the display controller 30, the switching unit 540 switches to output the video signal decoded using the gamma curve GC5.

[0142] When the gamma curve information indicates that the gamma curve GC3 is used in the encoding of the display controller 30, the switching unit 540 switches to output the video signal encoded using the gamma curve GC6.

[0143] (5)Display unit 550

[0144] The display unit 550 has a function of displaying an image. The display unit 550 displays an image based on the video signal (fourth video signal) input from the switching unit 540.

[0145] <1-4. Process flow>

[0146] Above, the functional structure of the display module 50 of the first embodiment has been described. Next, with reference to Figures 6 to 7 The process flow of the first embodiment will be described.

[0147] (1)Process flow in the display system 1

[0148] With reference toFigure 6 Describe the process of the processing in the display system 1. Figure 6 It is a sequence diagram showing an example of the process of the processing in the display system 1 of the first embodiment. Figure 6 The processing shown is executed, for example, triggered by an operation for displaying an image on the display 40 being performed on the control terminal 10.

[0149] As Figure 6 shown, first, the source device 20 sends an image signal to the display controller 30 (step S101).

[0150] When an image signal is input from the source device 20, the decoding unit 310 of the display controller 30 performs decoding processing (step S102). In the decoding processing, the decoding unit 310 decodes the image signal input from the source device 20 and outputs the decoded image signal.

[0151] Next, the signal processing unit 320 of the display controller 30 performs signal processing (step S103). In the signal processing, the signal processing unit 320 performs color adjustment, etc. on the image signal input from the decoding unit 310 and outputs the processed image signal.

[0152] Next, the analysis unit 330 of the display controller 30 performs analysis processing (step S104). In the analysis processing, the analysis unit 330 analyzes the image signal input from the signal processing unit 320, obtains and outputs the luminance distribution in the image signal.

[0153] Next, the decision unit 340 of the display controller 30 performs decision processing (step S105). In the decision processing, the decision unit 340 determines the gamma curve for encoding the image signal based on the luminance distribution input from the analysis unit 330 and outputs the image signal and gamma curve information.

[0154] Next, the encoding unit 350 of the display controller 30 performs encoding processing (step S106). In the encoding processing, the encoding unit 350 encodes the image signal input from the decision unit 340 using different gamma curves in each processing unit 351 and outputs a plurality of encoded image signals.

[0155] Next, the switching unit 360 of the display controller 30 performs switching processing (step S107). In the switching processing, the switching unit 360 switches the image signal output to the subsequent block among the plurality of image signals output from each processing unit 351 of the encoding unit 350 based on the gamma curve information input from the decision unit 340 and outputs one image signal.

[0156] Next, the formatter unit 370 of the display controller 30 performs formatting processing (step S108). In the formatting processing, the formatter unit 370 processes the video signal input from the switching unit 360 and embeds the gamma curve information input from the determination unit 340 into the video signal.

[0157] Next, the formatter unit 370 sends the formatted video signal to the display module 50 (step S109).

[0158] When a video signal is input from the display controller 30, the format decoding unit 510 of the display module 50 performs format decoding processing (step S110). In the format decoding processing, the format decoding unit 510 decodes the format of the video signal input from the display controller 30, and obtains and outputs the video signal and the gamma curve information.

[0159] Next, the determination unit 520 of the display module 50 performs determination processing (step S111). In the determination processing, the determination unit 520 determines the gamma curve for decoding the video signal based on the video signal and the gamma curve information input from the format decoding unit 510, and outputs the video signal and the gamma curve information.

[0160] Next, the decoding unit 530 of the display module 50 performs decoding processing (step S112). In the decoding processing, the decoding unit 530 decodes the video signal input from the determination unit 520 using different gamma curves in each processing unit 531, and outputs a plurality of decoded video signals.

[0161] Next, the switching unit 540 of the display module 50 performs switching processing (step S113). In the switching processing, the switching unit 540 switches the video signal output from each processing unit 531 of the decoding unit 530 and output to the subsequent block based on the gamma curve information input from the determination unit 520, and outputs one video signal.

[0162] Next, the display unit 550 of the display module 50 performs display processing (step S114). In the display processing, the display unit 550 displays an image based on the video signal input from the switching unit 540.

[0163] (2) Detailed processes of the analysis processing and the determination processing

[0164] Refer to Figure 7 The detailed processes of the analysis processing and the determination processing will be described. Figure 7 is a flowchart showing an example of the detailed processes of the analysis processing and the determination processing of the first embodiment. In addition, in Figure 7In the process shown, the brightness level of pixels with brightness values from 0 to 255 is determined as level 1, the brightness level of pixels with brightness values from 256 to 511 is determined as level 2, and the brightness level of pixels with brightness values from 512 to 1023 is determined as level 3. Additionally, the number of pixels with brightness level 1 is represented as c1, the number of pixels with brightness level 2 is represented as c2, and the reference number of pixels is represented as T1.

[0165] As Figure 7 shown, first, the analysis unit 330 of the display controller 30 is initialized (step S201). In the initialization, the analysis unit 330 sets c1 = 0 and c2 = 0.

[0166] Next, the analysis unit 330 obtains the brightness value for each pixel of the video signal input from the signal processing unit 320 (step S202).

[0167] Next, the analysis unit 330 determines the brightness level for each pixel of the video signal based on the obtained brightness value for each pixel (step S203).

[0168] In the case where the brightness level is level 1 (step S203 / level 1), the analysis unit 330 incrementally counts the number of pixels of level 1 (c1 = c1 + 1) (step S204). After the incremental counting, the process proceeds to step S206. In the case where the brightness level is level 2 (step S203 / level 2), the analysis unit 330 incrementally counts the number of pixels of level 2 (c2 = c2 + 1) (step S205). After the incremental counting, the process proceeds to step S206. In the case where the brightness level is level 3 (step S203 / level 3), the analysis unit 330 proceeds the process to step S206.

[0169] When the process proceeds to step S206, the analysis unit 330 determines whether the determination of the brightness level has been completed for all pixels (step S206). If completed (step S206 / yes), the process proceeds to step S207. On the other hand, if not completed (step S206 / no), the process repeats from step S202.

[0170] When the process proceeds to step S207, the determination unit 340 of the display controller 30 determines the proportion of pixels with low brightness within the analysis range of the video signal (step S207).

[0171] Specifically, first, the determination unit 340 determines whether either the number of pixels c1 with a brightness level of level 1 or the number of pixels c2 with a brightness level of level 2 is equal to or greater than a reference number of pixels T1 (c1 ≥ T1 or c2 ≥ T1) (step S208). When either c1 or c2 is equal to or greater than T1 (step S208 / Yes), the process proceeds to step S209. On the other hand, when both c1 and c2 are less than T1 (step S208 / No), the process proceeds to step S212.

[0172] When the process proceeds to step S209, the determination unit 340 determines whether the number of pixels c1 with a brightness level of level 1 is equal to or greater than the number of pixels c2 with a brightness level of level 2 (c1 ≥ c2) (step S209). When c1 is equal to or greater than c2 (step S209 / Yes), the process proceeds to step S210. On the other hand, when c1 is less than c2 (step S209 / No), the process proceeds to step S211.

[0173] When the process proceeds to step S210, the determination unit 340 determines that the proportion of pixels with low brightness within the analysis range of the video signal is high, and determines to use the gamma curve GC1 (step S210).

[0174] When the process proceeds to step S211, the determination unit 340 determines that the proportion of pixels with low brightness within the analysis range of the video signal is medium, and determines to use the gamma curve GC2 (step S211).

[0175] When the process proceeds to step S212, the determination unit 340 determines that the proportion of pixels with low brightness within the analysis range of the video signal is low, and determines to use the gamma curve GC3 (step S212).

[0176] After determining the gamma curve, the Figure 7 processing shown above is ended.

[0177] <1-5. Variation Example>

[0178] The processing flow of the first embodiment has been described above. Next, a variation example of the first embodiment will be described.

[0179] In the above first embodiment, an example of determining the proportion of pixels with low brightness in the video signal based on the number of pixels of each brightness level and determining the gamma curve for encoding has been described. However, the present invention is not limited to this example. For example, the proportion of pixels with low brightness in the video signal can be determined based on the area of each brightness level in the histogram, and thus the gamma curve for encoding can be determined.

[0180] Here, refer to Figures 8 to 9, a process for determining the proportion of pixels of an image signal with low brightness based on the areas of each brightness level in a histogram and determining a gamma curve for encoding will be described. Figure 8 is a flowchart showing an example of the detailed processes of the analysis process and the determination process in a modification of the first embodiment. In addition, in Figure 8 the process shown, in the histogram, the area with brightness level 1 is represented as AR1, the area with brightness level 2 is represented as AR2, and the reference area is represented as T2.

[0181] Figure 9 is a diagram showing an example of a histogram in a modification of the first embodiment. Figure 9 In the histogram shown, the horizontal axis represents the brightness value and the vertical axis represents the frequency. Additionally, Figure 9 the area A1 shown is the area of the histogram including pixels with brightness level 1, and the area A2 shown is the area of the histogram including pixels with brightness level 2.

[0182] As Figure 8 shown, first, the analysis unit 330 of the display controller 30 performs initialization (step S301). In the initialization, the analysis unit 330 resets the determination result of the previous frame.

[0183] Next, the analysis unit 330 obtains the brightness value for each pixel of the image signal input from the signal processing unit 320 (step S302).

[0184] Next, the analysis unit 330 generates a histogram based on the obtained brightness value for each pixel (step S303). The analysis unit 330 generates, for example, a histogram as Figure 9 shown.

[0185] Next, the analysis unit 330 determines whether the generation of the histogram has been completed for all pixels (step S304). If it has been completed (step S304 / Yes), the process proceeds to step S305. On the other hand, if it has not been completed (step S304 / No), the process repeats from step S302.

[0186] When the process proceeds to step S305, the determination unit 340 of the display controller 30 calculates the area AR1 with brightness level 1 and the area AR2 with brightness level 2 in the histogram generated by the analysis unit 330 (step S305). When the analysis unit 330 generates Figure 9 the histogram shown, the determination unit 340 calculates the area of the histogram within area A1 as the area AR1 with brightness level 1, and calculates the area of the histogram within area A2 as the area AR2 with brightness level 2.

[0187] Next, the decision unit 340 determines the ratio of pixels with low luminance within the analysis range of the image signal (step S306).

[0188] Specifically, first, the decision unit 340 determines whether either the area AR1 with luminance level 1 or the area AR2 with luminance level 2 is equal to or greater than the reference area T2 (AR1 ≥ T2 or AR2 ≥ T2) (step S307). If either AR1 or AR2 is equal to or greater than T2 (step S307 / Yes), the process proceeds to step S308. On the other hand, if both AR1 and AR2 are less than T2 (step S307 / No), the process proceeds to step S311.

[0189] When the process proceeds to step S308, the decision unit 340 determines whether the area AR1 with luminance level 1 is equal to or greater than the area AR2 with luminance level 2 (AR1 ≥ AR2) (step S308). If AR1 is equal to or greater than AR2 (step S308 / Yes), the process proceeds to step S309. On the other hand, if AR1 is less than AR2 (step S308 / No), the process proceeds to step S310.

[0190] When the process proceeds to step S309, the decision unit 340 determines that the ratio of pixels with low luminance within the analysis range of the image signal is high, and decides to use the gamma curve GC1 (step S309).

[0191] When the process proceeds to step S310, the decision unit 340 determines that the ratio of pixels with low luminance within the analysis range of the image signal is medium, and decides to use the gamma curve GC2 (step S310).

[0192] When the process proceeds to step S311, the decision unit 340 determines that the ratio of pixels with low luminance within the analysis range of the image signal is low, and decides to use the gamma curve GC3 (step S311).

[0193] After determining the gamma curve, the Figure 8 processing shown ends.

[0194] In addition, in the above-described first embodiment, an example in which the determination unit 340 of the display controller 30 and the determination unit 520 of the display module 50 determine the gamma curve for decoding or encoding by selecting one gamma curve from among a plurality of gamma curves prepared in advance has been described. However, the present invention is not limited to this example. For example, the determination unit 340 and the determination unit 520 may calculate the gamma curve each time decoding or encoding is performed, and determine to use the calculated gamma curve for decoding or encoding. In this case, the determination unit 340 calculates the gamma curve for encoding based on the analysis result of the analysis unit 330. In addition, the determination unit 520 calculates the gamma curve for decoding based on the gamma curve information acquired by the format decoding unit 510.

[0195] Above, the modification example of the first embodiment has been described.

[0196] As described above, the display system 1 of the first embodiment includes: a decoding unit 310 (first decoding unit) that decodes the input first video signal and outputs a second video signal; an analysis unit 330 that analyzes the second video signal and obtains a luminance distribution within at least a part of the analysis range of the second video signal; a determination unit 340 (first determination unit) that determines a first gamma curve for encoding the second video signal based on the luminance distribution; an encoding unit 350 that outputs a third video signal obtained by encoding the second video signal using the determined first gamma curve; a determination unit 520 (second determination unit) that determines a second gamma curve for decoding the third video signal based on the third video signal and gamma curve information indicating the first gamma curve used for encoding; a decoding unit 530 (second decoding unit) that outputs a fourth video signal obtained by decoding the third video signal using the determined second gamma curve; and a display unit 550 that displays an image based on the fourth video signal.

[0197] According to this configuration, in the display system 1 of the first embodiment, after decoding the input video signal, the characteristics of the video signal are analyzed, the optimal gamma curve for decoding is determined based on the analysis result, and the video signal after image processing is encoded using the determined gamma curve, and then transmitted to the display unit. Thereby, it is possible to alleviate not only the data loss in the decoding process (gamma processing) performed before the image processing of the video signal, but also the data loss in the encoding process (inverse gamma processing) performed on the video signal after the image processing.

[0198] Therefore, the display system 1 of the first embodiment can suppress the degradation of the image quality caused by the data capacity of the transmission path.

[0199] <<2. Second Embodiment>>

[0200] The above describes the first embodiment. Next, refer to Figures 10 to 14 to describe the second embodiment. In addition, hereinafter, descriptions that overlap with the first embodiment will be appropriately omitted.

[0201] In the above first embodiment, an example of displaying one image on a display having one display unit was described, but the present invention is not limited to this example. In the second embodiment, an example of displaying one image on a display having multiple display units will be used to describe the embodiment. For example, it is a case of using a multi-display that combines multiple LED displays. In this case, in the display, one image is displayed by causing multiple divided images obtained by dividing one image to be respectively displayed on corresponding display units.

[0202] <2-1. Structure of the display system>

[0203] Refer to Figures 10 to 12 to describe the structure of the display system of the second embodiment. Figure 10 It is a block diagram showing an example of the structure of the display system of the second embodiment.

[0204] As Figure 10 shown, the display system 1a of the second embodiment includes a control terminal 10, a source device 20, a display controller 30a, a display 40a, a plurality of display modules 50a, and a plurality of chassis 60.

[0205] As Figure 10 shown, in the display system 1a, the display 40a includes a plurality of display modules 50a and a plurality of chassis 60. That is, the display system 1a includes a plurality of display units.

[0206] The display 40a is realized by physically connecting a plurality of display modules 50a-11, 50a-12,.... The plurality of display modules 50a-11, 50a-12,... are respectively housed in a plurality of chassis 60-11, 60-12,... and connected on this basis.

[0207] Here, refer to Figure 11 to describe the structure of the display 40a. Figure 11 It is a diagram showing an example of the structure of the display 40a of the second embodiment.

[0208] As Figure 11 shown, in the display 40a, m display modules are arranged vertically and n display modules are arranged horizontally in a matrix. That is, m×n chassis 60 are arranged. A display module 50a is housed in each chassis 60. That is, similar to the chassis 60, by arranging m×n display modules 50 in a matrix, one display 40a is constituted.

[0209] Here, with reference to Figure 12 the image displayed on the display 40a will be described. Figure 12 FIG. is a diagram showing an example of the image displayed on the display 40a of the second embodiment.

[0210] In the second embodiment, the image displayed on the display 40a is divided into a plurality of divided images according to the number of display units (display modules 50a) provided in the display 40a. Figure 12 FIG. shows Figure 11 an example of the division of the image displayed on the display 40a shown. Figure 11 The display 40a shown is composed of m×n display modules 50, and thus has m×n display units. Therefore, Figure 11 the image 70 displayed on the display 40a shown is divided into m divided images vertically and n divided images horizontally as Figure 12 shown. That is, the image 70 is divided into m×n divided images.

[0211] In this case, the display 40a displays each divided image 71 on the display unit of the corresponding display module 50a. For example, the display module 50a-11 displays the divided image 71-11, the display module 50a-12 displays the divided image 71-12, the display module 50a-1n displays the divided image 71-1n, the display module 50a-m1 displays the divided image 71-m1, and the display module 50a-mn displays the divided image 71-mn.

[0212] <2-2. Functional Structure of Display Controller>

[0213] Above, the structure of the display system 1a of the second embodiment has been described. Next, with reference to Figure 13 the functional structure of the display controller 30a of the second embodiment will be described. The functional structure of the display controller 30a of the second embodiment is the same as the functional structure of the display controller 30 of the Figure 2 first embodiment shown, but the function of the analysis unit is different.

[0214] Here, with reference to Figure 13 the functional structure of the analysis unit of the display controller 30a of the second embodiment will be described. Figure 13 FIG. is a block diagram showing an example of the functional structure of the analysis unit of the second embodiment.

[0215] As Figure 13 shown, the analysis unit 330a of the second embodiment includes a processing unit determination unit 3301, an analysis processing unit 3302, a memory unit 3303, a memory controller unit 3304, and an image memory unit 3305.

[0216] (1)Processing unit determination unit 3301

[0217] The processing unit determination unit 3301 has the function of determining the processing unit of the video signal. Based on control signals such as the vertical synchronization signal and the horizontal synchronization signal, the processing unit determination unit 3301 determines which divided image 71 displayed on which display module 50a the data of the video signal (the second video signal) input from the signal processing unit 320 corresponds to. After the determination, the processing unit determination unit 3301 outputs the video signal together with the determination result to the analysis processing section 3302.

[0218] (2)Analysis processing section 3302

[0219] The analysis processing section 3302 has the function of analyzing the video signal. The analysis processing section 3302 performs analysis processing on each divided image in the same manner as the analysis section 330 in the first embodiment. The analysis processing section 3302 uses the memory section 3303 to hold the count value during the analysis and the generated histogram, etc.

[0220] After the analysis, the analysis processing section 3302 outputs the analyzed video signal and the obtained luminance distribution to the memory controller section 3304.

[0221] (3)Memory section 3303

[0222] The memory section 3303 has the function of holding the data generated by the analysis processing of the analysis processing section 3302. For example, the memory section 3303 holds the count value generated during the analysis of the analysis processing section 3302, the generated histogram, etc.

[0223] (4)Memory controller section 3304

[0224] The memory controller section 3304 has the function of controlling the output of various information. The memory controller section 3304 causes the image memory section 3305 to temporarily hold the video signal and the luminance distribution so as to rearrange the video signal input from the analysis processing section 3302 into the transmission order from the display controller 30a to the display module 50a. After that, the memory controller section 3304 reads out the video signal and the luminance distribution from the image memory section 3305 in the transmission order and outputs them to the subsequent determination section 340.

[0225] (5)Image memory section 3305

[0226] The image memory section 3305 has the function of temporarily holding the video signal input from the memory controller section 3304. The image memory section 3305 outputs the requested video signal when it receives a request from the memory controller section 3304.

[0227] According to the above structure, the analysis unit 330a of the display controller 30a can analyze the image signal (second image signal) for each part corresponding to the divided image, and obtain a plurality of luminance distributions. Therefore, the determination unit 340 (first determination unit) can determine the gamma curve (first gamma curve) for encoding the image signal based on the plurality of luminance distributions for each part of the image signal (second image signal) corresponding to the divided image.

[0228] <2-3. Functional Structure of Display Module>

[0229] The functional structure of the display controller 30a of the second embodiment has been described above. Next, the functional structure of the display module 50a of the second embodiment will be described.

[0230] The display 40a of the second embodiment includes a plurality of display modules 50a. The plurality of display modules 50a are respectively Figure 4 The display module 50 of the first embodiment shown has a format decoding unit 510, a determination unit 520 (second determination unit), a decoding unit 530 (second decoding unit), a switching unit 540, and a display unit 550 in the same manner.

[0231] The image signal input from the display controller 30a to the display 40a side is processed by the display module 50a having a display unit 550 that displays the divided image represented by the image signal.

[0232] When an image signal is input from the display controller 30, each format decoding unit 510 obtains the image signal of the divided image part and the gamma curve information through format decoding processing, and outputs them to the determination unit 520.

[0233] Each determination unit 520 determines the gamma curve (second gamma curve) for decoding the image signal based on the image signal (third image signal) obtained by encoding a part (divided image part) of the image signal (second image signal) corresponding to the divided image displayed on the corresponding display unit 550, and the gamma curve information indicating the gamma curve (first gamma curve) used for encoding.

[0234] Each decoding unit 530 outputs the image signal (fourth image signal) obtained by decoding the image signal (third image signal) using the determined gamma curve (second gamma curve).

[0235] The switching unit 540 switches which of the plurality of image signals (fourth image signals) output from each processing unit 531 of the decoding unit 530 is output to the subsequent block based on the gamma curve information input from the determination unit 520.

[0236] The display unit 550 displays the segmented image based on the video signal (fourth video signal) input from the switching unit 540.

[0237] <2-4. Process flow>

[0238] The functional structure of the display module 50a of the second embodiment has been described above. Next, the process flow of the second embodiment will be described.

[0239] In the second embodiment, the processing is performed in the same manner as Figure 6 the process flow of the first embodiment shown, but a part of the processing is different. In the case of the second embodiment, before the analysis process in step S104, the determination process of the processing unit determination unit 3301 is performed. After the determination process, the analysis process of step S104 is performed by the analysis processing unit 3302. After the analysis process, the rearrangement process is performed by the memory controller unit 3304. After the rearrangement process, the determination process of step S105 is performed by the determination unit 340.

[0240] <2-5. Variation example>

[0241] The process flow of the second embodiment has been described above. Next, the variation example of the second embodiment will be described.

[0242] In the above-described second embodiment, an example in which the determination of the processing unit is performed by the analysis unit 330a and then the analysis process is performed has been described, but it is not limited to this example. For example, the analysis process can be performed after the rearrangement of the video signal. Thus, there is no need to perform the process of determining the processing unit, nor is there a need for the corresponding structure.

[0243] Here, with reference to Figure 14 the functional structure of the analysis unit of the display controller 30a in the variation example of the second embodiment will be described. Figure 14 is a block diagram showing an example of the functional structure of the analysis unit in the variation example of the second embodiment.

[0244] As Figure 14 shown, the analysis unit 330b of the variation example of the second embodiment includes a memory controller unit 3306, an image memory unit 3307, an analysis processing unit 3308, and a memory unit 3309.

[0245] (1)Memory controller unit 3306

[0246] The memory controller unit 3306 rearranges the video signal input from the signal processing unit 320 in the same manner as the memory controller unit 3304 of the above-described second embodiment. The image memory unit 3307 is used to temporarily hold the video signal.

[0247] After rearrangement, the memory controller unit 3306 reads out the video signal from the image memory unit 3307 in the transmission order and outputs the video signal to the analysis processing unit 3308.

[0248] (2)Image memory unit 3307

[0249] Similar to the image memory unit 3305 of the second embodiment described above, the image memory unit 3307 temporarily holds the video signal input from the memory controller unit 3306 and outputs the requested video signal when a request is received from the memory controller unit 3306.

[0250] (3)Analysis processing unit 3308

[0251] The analysis processing unit 3308 performs analysis processing for each divided image in the same manner as the analysis processing unit 3302 of the second embodiment described above. The analysis processing unit 3308 uses the memory unit 3309 to hold the count value, the generated histogram, etc. during the analysis.

[0252] After the analysis, the analysis processing unit 3308 outputs the analyzed video signal and the obtained luminance distribution to the subsequent determination unit 340.

[0253] (4)Memory unit 3309

[0254] The memory unit 3309 has a function of holding the data generated by the analysis processing of the analysis processing unit 3302. For example, the memory unit 3303 holds the count value, the generated histogram, etc. generated during the analysis processing of the analysis processing unit 3302.

[0255] In the case of this modification, before the analysis processing in step S104, the rearrangement processing is performed by the memory controller unit 3306. After the rearrangement processing, the analysis processing unit 3308 performs the analysis processing in step S104. After the analysis processing, the determination processing in step S105 is performed by the determination unit 340.

[0256] <<3. Third Embodiment>>

[0257] Above, the second embodiment has been described. Next, with reference to Figures 15 to 16 the third embodiment will be described. In addition, hereinafter, the descriptions overlapping with the first embodiment to the second embodiment will be appropriately omitted.

[0258] In the above-described first and second embodiments, the video signal input from the source device 20 is directly processed by the display controller 30, but this is not limited to this example. For example, the display controller 30 may also divide the input video signal into three video signals: R (Red), G (Green), and B (Blue), and process each video signal.

[0259] Here, refer to Figure 15 to describe the functional structure of the display controller of the third embodiment. Figure 15 FIG. is a block diagram showing an example of the functional structure of the display controller of the third embodiment.

[0260] As Figure 15 shown, the display controller 30b of the third embodiment includes a format decoding unit 305, a decoding unit 310, a signal processing unit 320, an analysis unit 330, a decision unit 340, an encoding unit 350, a switching unit 360, and a formatter unit 370.

[0261] In the decoding unit 310, the signal processing unit 320, the analysis unit 330, the decision unit 340, the encoding unit 350, and the switching unit 360, processing blocks for the R video signal (blocks with the R symbol added), processing blocks for the G video signal (blocks with the G symbol added), and processing blocks for the B video signal (blocks with the B symbol added) are respectively prepared.

[0262] The format decoding unit 305 performs processing to divide the video signal input from the source device 20 into an R video signal, a G video signal, and a B video signal. After the division, the format decoding unit 305 outputs the R video signal to the decoding unit 310R, outputs the G video signal to the decoding unit 310G, and outputs the B video signal to the decoding unit 310B. When the video signal is input in YUV data, the format decoding unit 305 performs conversion from YUV data to RGB data.

[0263] The decoding unit 310, the signal processing unit 320, the analysis unit 330, the decision unit 340, the encoding unit 350, and the switching unit 360 for each of the R, G, and B video signals perform respective processes in the same manner as in the first embodiment or the second embodiment described above.

[0264] The formatter unit 370 performs format processing on the video signals input from the switching units 360 for each of the R, G, and B video signals, and sends the processed video signals to the display module 50b.

[0265] Here, refer to Figure 16 to describe the functional structure of the display module of the third embodiment. Figure 16It is a block diagram showing an example of the functional structure of the display module according to the third embodiment.

[0266] As Figure 16 shown, the display module 50b according to the third embodiment includes a format decoding unit 510, a determination unit 520, a decoding unit 530, a switching unit 540, and a display unit 550.

[0267] In the determination unit 520, the decoding unit 530, and the switching unit 540, processing blocks for the R video signal (blocks with the R symbol attached), processing blocks for the G video signal (blocks with the G symbol attached), and processing blocks for the B video signal (blocks with the B symbol attached) are respectively prepared.

[0268] When the format decoding unit 510 inputs a video signal from the display controller 30b, it performs format decoding processing on each of the R, G, and B video signals. After the processing, the format decoding unit 510 outputs the R video signal and gamma curve information to the determination unit 520R, outputs the G video signal and gamma curve information to the determination unit 520G, and outputs the B video signal and gamma curve information to the determination unit 520B.

[0269] In the determination unit 520, the decoding unit 530, and the switching unit 540 for each of the R, G, and B video signals, each process is performed in the same manner as in the above-described first embodiment or second embodiment.

[0270] The display unit 550 displays an image based on the image signals input from the switching unit 540 for each of the R, G, and B video signals.

[0271] <<4. Fourth Embodiment>>

[0272] Above, the third embodiment has been described. Next, with reference to Figures 17 to 18 the fourth embodiment will be described. In addition, hereinafter, descriptions that overlap with the first to third embodiments will be appropriately omitted.

[0273] In each of the above-described embodiments, an example in which the encoding unit of the display controller and the decoding unit of the display module each include a plurality of processing units has been described, but it is not limited to this example. For example, the encoding unit of the display controller and the decoding unit of the display module may each include only one processing unit.

[0274] Here, with reference to Figure 17 the functional structure of the display controller in the case where the encoding unit of the display controller includes only one processing unit will be described. Figure 17 It is a block diagram showing an example of the functional structure of the display controller according to the fourth embodiment.

[0275] As Figure 17As shown, the display controller 30c of the fourth embodiment includes a decoding unit 310, a signal processing unit 320, an analysis unit 330, a determination unit 340, an encoding unit 350c, a formatter unit 370, and a gamma table generation unit 380.

[0276] After the determination process, the determination unit 340 outputs an image signal to the encoding unit 350c, and outputs gamma curve information to the formatter unit 370 and the gamma table generation unit 380.

[0277] Based on the gamma curve information input from the determination unit 340, the gamma table generation unit 380 generates a table (gamma table) representing the gamma curve for encoding the image signal.

[0278] The processing unit 351 of the encoding unit 350c encodes the image signal input from the determination unit 340 using the gamma curve represented by the gamma table generated by the gamma table generation unit 380.

[0279] Whenever the gamma curve for encoding is determined by the determination unit 340, the gamma table generation unit 380 updates the gamma table based on the gamma curve information input from the determination unit 340. Then, the processing unit 351 performs encoding based on the updated gamma table. By rapidly rewriting the gamma table by the gamma table generation unit 380, encoding processing using multiple gamma curves can be executed.

[0280] Here, with reference to Figure 18 the functional structure of the display module when the decoding unit of the display module has only one processing unit will be described. Figure 18 It is a block diagram showing an example of the functional structure of the display module of the fourth embodiment.

[0281] As Figure 18 shown, the display module 50c of the fourth embodiment includes a format decoding unit 510, a determination unit 520, a decoding unit 530c, a display unit 550, and a gamma table generation unit 560.

[0282] After the determination process, the determination unit 520 outputs an image signal to the decoding unit 530c, and outputs gamma curve information to the gamma table generation unit 560.

[0283] Based on the gamma curve information input from the determination unit 520, the gamma table generation unit 560 generates a table (gamma table) representing the gamma curve for decoding the image signal.

[0284] The processing unit 531 of the decoding unit 530c decodes the image signal input from the determination unit 520 using the gamma curve represented by the gamma table generated by the gamma table generation unit 560.

[0285] Whenever the gamma curve for decoding is determined by the determination unit 520, the gamma table generation unit 560 updates the gamma table based on the gamma curve information input from the determination unit 520. Then, the processing unit 531 performs decoding based on the updated gamma table. By rapidly rewriting the gamma table by the gamma table generation unit 560, decoding processing using multiple gamma curves can be executed.

[0286] <<5. Fifth Embodiment>>

[0287] The above describes the fourth embodiment. Next, refer to Figure 19 to describe the fifth embodiment. Figure 19 is a block diagram showing an example of the configuration of the display system of the fifth embodiment.

[0288] As Figure 19 shown, the display system 90 of the fifth embodiment includes a first decoding unit 910, an analysis unit 920, a first determination unit 930, an encoding unit 940, a second determination unit 950, a second encoding unit 960, and a display unit 970.

[0289] The first decoding unit 910 decodes the input first video signal and outputs a second video signal.

[0290] The analysis unit 920 analyzes the second video signal and obtains the luminance distribution within at least a part of the analysis range of the second video signal.

[0291] The first determination unit 930 determines a first gamma curve for encoding the second video signal based on the luminance distribution.

[0292] The encoding unit 940 outputs a third video signal obtained by encoding the second video signal using the determined first gamma curve.

[0293] The second determination unit 950 determines a second gamma curve for decoding the third video signal based on the third video signal and the gamma curve information indicating the first gamma curve used for encoding.

[0294] The second encoding unit 960 outputs a fourth video signal obtained by decoding the third video signal using the determined second gamma curve.

[0295] The display unit 970 displays an image based on the fourth video signal.

[0296] According to this structure, in the display system 90 of the fifth embodiment, after decoding the input video signal, the characteristics of the video signal are analyzed, the optimal gamma curve for decoding is determined based on the analysis result, and the processed video signal is encoded using the determined gamma curve, and then transmitted to the display unit. Thereby, it is possible to alleviate not only the data loss in the decoding process (gamma processing) performed before the image processing of the video signal, but also the data loss in the encoding process (inverse gamma processing) performed on the video signal after the image processing.

[0297] Therefore, the display system 90 of the fifth embodiment can suppress the deterioration of the image quality caused by the data capacity of the transmission path.

[0298] As described above, the embodiments of the present invention have been described. In addition, all or part of the functions of the display system, control terminal, source device, display controller, display, and display module in the above embodiments can also be implemented by a computer. In this case, it can also be implemented by recording a program for implementing this function on a computer-readable recording medium and causing a computer system to read and execute the program recorded on the recording medium. In addition, the "computer system" mentioned here includes hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to removable media such as a floppy disk, optical disk, ROM, CD-ROM, and storage devices such as a hard disk built into the computer system. Furthermore, the "computer-readable recording medium" can also include a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a telephone line, and a medium that holds a program for a certain time, such as a volatile memory inside a computer system that becomes a server or a client in this case. In addition, the above program can be a program for implementing a part of the foregoing functions, can also be a program that can implement the foregoing functions by combining with a program already recorded in the computer system, and can also be a program implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0299] As described above, the embodiments of the present invention have been described in detail with reference to the drawings, but the specific structure is not limited to the above structure, and various design changes and the like can be made without departing from the gist of the present invention.

[0300] Reference Numerals

[0301] 1, 1a, 90... display system, 10... control terminal, 20... source device, 30, 30a, 30b, 30c... display controller, 40, 40a... display, 50, 50a, 50b, 50c... display module, 60... housing, 305... format decoding unit, 310, 310B, 310G, 310R... decoding unit, 320... signal processing unit, 330, 330a, 330b... analysis unit, 340... decision unit, 350, 350c... encoding unit, 351... processing unit, 360... switching unit, 370... formatter unit, 380... gamma table generation unit, 510... format decoding unit, 520, 520B, 520G, 520R... decision unit, 530, 530c... decoding unit, 531... processing unit, 540... switching unit, 550... display unit, 560... gamma table generation unit, 910... first decoding unit, 920... analysis unit, 930... first decision unit, 940... encoding unit, 950... second decision unit, 960... second encoding unit, 970... display unit, 3301... processing unit determination unit, 3302... analysis processing unit, 3303... memory unit, 3304... memory controller unit, 3305... image memory unit, 3306... memory controller unit, 3307... image memory unit, 3308... analysis processing unit, 3309... memory unit.

Claims

1. A display system comprising: A first decoding unit that decodes an input first video signal and outputs a second video signal; An analysis unit that analyzes the second video signal and obtains a luminance distribution within at least a part of the analysis range of the second video signal; A first determination unit that determines a first gamma curve for encoding the second video signal based on the luminance distribution; An encoding unit that outputs a third video signal obtained by encoding the second video signal using the determined first gamma curve; A second determination unit that determines a second gamma curve for decoding the third video signal based on the third video signal and gamma curve information indicating the first gamma curve used for encoding; A second decoding unit that outputs a fourth video signal obtained by decoding the third video signal using the determined second gamma curve; and A display unit that displays an image based on the fourth video signal.

2. The display system according to claim 1, wherein The first determination unit determines the first gamma curve for encoding the second video signal from the luminance distribution according to the ratio of pixels with low luminance within the analysis range.

3. The display system according to claim 2, wherein When the ratio of pixels with low luminance within the analysis range is high, the first determination unit determines to use the first gamma curve with a smaller gamma value set compared to the case where the ratio of pixels other than those with low luminance within the analysis range is high.

4. The display system according to claim 1, wherein The display system includes a plurality of the display units, In the case where an image is displayed by respectively displaying a plurality of divided images obtained by dividing one image on corresponding display units, The analysis unit analyzes the second video signal for each part corresponding to the divided image and obtains a plurality of the luminance distributions, The first determination unit determines the first gamma curve for encoding the second video signal for each part corresponding to the divided image of the second video signal based on the plurality of luminance distributions.

5. The display system according to claim 4, wherein The display system includes the second determination unit and the second decoding unit for each of the plurality of display units, Each of the second determination units determines the second gamma curve for decoding the third video signal based on the third video signal obtained by encoding a part of the second video signal corresponding to the divided image displayed on the corresponding display unit and the gamma curve information indicating the first gamma curve used for encoding, Each of the second decoding units outputs a fourth video signal obtained by decoding the third video signal using the determined second gamma curve.

6. The display system according to claim 1 or claim 5, wherein The second determination unit determines to use a second gamma curve with a second gamma value set, where the second gamma value is the reciprocal of the first gamma value, based on the first gamma value set for the first gamma curve represented by the gamma curve information.

7. The display system according to claim 1, wherein the display system further includes a signal processing unit that performs signal processing on the second video signal input from the first decoding unit and outputs the signal-processed second video signal to the analysis unit.

8. A display method executed by a computer, including the following processes: A first decoding process that decodes an input first video signal and outputs a second video signal; An analysis process that analyzes the second video signal and obtains a luminance distribution within at least a part of the analysis range of the second video signal; A first determination process that determines a first gamma curve for encoding the second video signal based on the luminance distribution; An encoding process that outputs a third video signal obtained by encoding the second video signal using the determined first gamma curve; A second determination process that determines a second gamma curve for decoding the third video signal based on the third video signal and gamma curve information representing the first gamma curve used for encoding; A second decoding process that outputs a fourth video signal obtained by decoding the third video signal using the determined second gamma curve; and A display process that displays an image based on the fourth video signal.

9. A display controller, including: A decoding unit that decodes an input first video signal and outputs a second video signal; An analysis unit that analyzes the second video signal and obtains a luminance distribution within at least a part of the analysis range of the second video signal; A determination unit that determines a gamma curve for encoding the second video signal based on the luminance distribution; and An encoding unit that outputs a third video signal obtained by encoding the second video signal using the determined gamma curve.

10. The display controller according to claim 9, wherein the determination unit determines the gamma curve for encoding the second video signal from the luminance distribution according to the ratio of pixels with low luminance in the analysis range.

11. The display controller according to claim 10, wherein when the ratio of pixels with low luminance in the analysis range is high, the determination unit determines to use a gamma curve with a smaller gamma value set compared to the case where the ratio of pixels other than those with low luminance in the analysis range is high.

12. The display controller according to claim 9, wherein in the case of displaying an image by separately displaying a plurality of divided images obtained by dividing one image on corresponding display units among a plurality of display units, the analysis unit analyzes the second video signal for each part corresponding to the divided image and obtains a plurality of the luminance distributions. The determination unit determines, for each part of the second image signal corresponding to the segmented image, the gamma curve for encoding the second image signal based on the plurality of luminance distributions.

13. The display controller according to claim 9, wherein the display controller further includes a signal processing unit that performs signal processing on the second image signal input from the decoding unit and outputs the second image signal subjected to the signal processing to the analysis unit.

14. An image signal processing method for a display controller, executed by a computer, comprising the following processes: A decoding process of decoding the input first image signal and outputting a second image signal; An analysis process of analyzing the second image signal to obtain a luminance distribution within at least a part of the analysis range of the second image signal; A determination process of determining a gamma curve for encoding the second image signal based on the luminance distribution; and An encoding process of outputting a third image signal obtained by encoding the second image signal using the determined gamma curve.

Images