JP2013085045A - Video display system, video supply device, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system which comprises a video supply device and a display device that are connected by a video signal interface and is used for display output of a video signal which has undergone linear signal processing.SOLUTION: De-gamma processing and part of linear signal processing is performed in a front-end box 40. A simple gamma circuit at the final stage of the signal processing encodes a 13-bit linear RGB signal into a 10-bit simple gamma RGB signal, and a simple de-gamma circuit is added to the input stage in a head-mounted display 10. Thereby, the front-end box 40 and the head-mounted display 10 are connected by a 10-bit video signal interface.

Description

  The technology disclosed in this specification relates to a video display system, a video supply device, and a display device that perform display and output after performing linear signal processing such as luminance adjustment, color temperature adjustment, and primary color point conversion on a video signal. In particular, the present invention relates to a video display system, a video supply device, and a display device that display and output a video signal subjected to linear signal processing on a head-mounted display mounted on a user's head.

  2. Description of the Related Art A display device that is worn on a head and views an image, that is, a head mounted display (HMD) is widely known. The head-mounted display has an optical unit for each of the left and right eyes, and is configured to be used in combination with headphones to control vision and hearing. When configured to completely block the outside world when worn on the head, the virtual reality at the time of viewing increases. The head-mounted display can also display different images for the left and right eyes, and can display a 3D image by displaying an image with parallax for the left and right eyes.

  A high-resolution display panel made of, for example, a liquid crystal or an organic EL (Electro-Luminescence) element can be used for the left and right eye display units of the head-mounted display. In addition, by setting an appropriate angle of view with the optical system and reproducing multi-channels with headphones, it is possible to reproduce a sense of realism as viewed in a movie theater. The head-mounted display is connected to an AV player such as a DVD player or a Blu-ray disc (BD) player, and is used for viewing content such as a movie (for example, see Patent Document 1). .

  By the way, the video signal is generally recorded as an 8-bit digital signal having a gamma characteristic. FIG. 8 illustrates the relationship between the luminance and the 8-bit digital video signal subjected to gamma processing. Even in video display devices such as TVs and monitors, most of the processing is performed with gamma processing applied. However, a part of signal processing such as luminance adjustment, color temperature adjustment, and primary color point conversion can be simplified by using a linear signal. For this reason, once the gamma-processed video signal is decoded, that is, after the gamma curve of the video signal is converted to a linear RGB signal (a signal in which the relationship between the data value and the luminance of the pixel is proportional) by degamma processing, the calculation is performed. There is a need to.

  FIG. 9 schematically shows a circuit configuration for performing linear signal processing after degamma processing. When an 8-bit video signal is input, the degamma circuit 901 performs degamma processing and converts it into a linear RGB signal. The primary color point conversion unit 902, the luminance adjustment unit 903, and the color temperature adjustment unit 904 each perform linear signal processing such as primary color point conversion, luminance adjustment, and color temperature adjustment on the linear RGB signal.

  The degamma process is a non-linear operation and has a heavy load, and therefore requires a dedicated degamma circuit. In addition, in order to correctly express a dark video signal with a linear RGB signal, it is necessary to perform bit extension such as 13 bits on the video signal. Therefore, an ideal video display system performs degamma processing on an 8-bit video signal reproduced from a recording medium and converts it into a 13-bit linear RGB signal, and further performs brightness adjustment, color temperature adjustment, primary color point conversion, and the like. After the linear signal processing is performed, the display is output.

  FIG. 10 schematically illustrates a configuration example of a video display system 1000 that performs linear signal processing on linear RGB signals that have been bit-extended by degamma processing and then outputs the display. When an 8-bit video signal is input to the degamma circuit 1001, the degamma circuit 1001 performs degamma processing to convert it into a linear RGB signal, and further expands the bit to 13 bits. Each of the primary color point conversion unit 1002, the luminance adjustment unit 1003, and the color temperature adjustment unit 1004 performs linear signal processing such as primary color point conversion, luminance adjustment, and color temperature adjustment on the 13-bit linear RGB signal. The video signal subjected to the linear signal processing in this way is displayed and output on the display panel 1005.

  Based on the above, let us consider an ideal video display system configuration method that has a head-mounted display or the like as a display device. This type of video display system includes a display device including a display unit and a display drive unit that drives the display unit, and a video supply device that supplies a video signal reproduced by a BD player or the like to the display device. And the display device are connected by a video signal interface. Before performing linear signal processing, it is necessary to perform degamma processing on the video signal. However, because degamma processing is heavy and the video signal is bit-extended after degamma processing, the degamma processing and where in the system It should be fully examined whether linear signal processing should be performed.

JP 2005-86328 A

  An object of the technique disclosed in this specification is configured by a display device and a video supply device that supplies a video signal to the display device. The video supply device and the display device are connected by a video signal interface, and brightness adjustment and color temperature are performed. It is an object to provide an excellent video display system, video supply device, and display device that can suitably display and output a video signal subjected to linear signal processing such as adjustment and primary color point conversion on a display device.

  A further object of the technology disclosed in the present specification is to convert the original video signal into a linear RGB signal that is degamma processed in consideration of the heavy load on the degamma processing and the bit extension of the video signal after the degamma processing. An object of the present invention is to provide an excellent video display system, video supply device, and display device capable of suitably performing linear signal processing.

The present application has been made in consideration of the above problems, and the technology according to claim 1
A degamma circuit that obtains a linear RGB signal by degamma processing the video signal, a first linear signal processing unit that performs a first linear signal processing on the linear RGB signal, and a linear after the first linear signal processing. A video supply device having a simple gamma circuit that encodes RGB signals to degenerate bits;
The video supply device is connected to the video signal interface of the degenerate bit length, and a simple degamma circuit for decoding the bit RGB degenerate linear RGB signal to the original bit length, and the linear RGB signal after the decoding A display device having a second linear signal processing unit for performing second linear signal processing, and a display unit for displaying and outputting linear RGB signals after the second linear signal processing;
Is a video display system.

  However, “system” here refers to a logical collection of a plurality of devices (or functional modules that realize specific functions), and each device or functional module is in a single housing. It does not matter whether or not.

  According to the technique described in claim 2 of the present application, in the video display system according to claim 1, the simple gamma circuit on the video supply device side performs gamma processing on the linear RGB signal by linear calculation, while the display The simple degamma circuit on the apparatus side is configured to de-gamma-process the gamma-processed linear RGB signal by linear calculation.

  According to a third aspect of the present application, in the video display system according to the first aspect, the simple gamma circuit on the video supply device side divides the input area into a plurality of gamma values for each divided input area. The linear RGB signal is encoded using an approximate gamma curve composed of line segments approximating the curve. On the other hand, the simple degamma circuit on the display device side encodes using an approximate degamma curve having characteristics opposite to those of the approximate gamma curve. The linear RGB signal is decoded.

  According to the technique described in claim 4 of the present application, the video display system according to claim 3 is characterized in that the input / output characteristics obtained by combining the simple gamma circuit and the simple degamma circuit are such that input / output is performed in a region where the signal level is small. Configured to match.

Further, the technique described in claim 5 of the present application is:
A degamma circuit that obtains a linear RGB signal by degamma processing the video signal;
A linear signal processing unit that performs first linear signal processing on the linear RGB signal;
A simple gamma circuit that encodes the linear RGB signal after the linear signal processing and degenerates the bit;
Is a video supply device.

  According to the technology described in claim 6 of the present application, the video supply device described in claim 5 is configured such that the simple gamma circuit performs gamma processing on the linear RGB signal by linear calculation.

  According to the seventh aspect of the present application, in the video supply device according to the fifth aspect, the simple gamma circuit divides the input area into a plurality of lines, and approximates a gamma curve for each divided input area. The linear RGB signal is encoded using an approximate gamma curve consisting of minutes.

Further, the technique described in claim 8 of the present application is:
A video signal interface connected to the video supply device;
A simple degamma circuit that inputs a linear RGB signal degenerated by the video supply device via the video signal interface and decodes it to the original bit length;
A linear signal processing unit that performs second linear signal processing on the decoded linear RGB signal;
A display unit for displaying and outputting linear RGB signals after the linear signal processing;
Is a display device.

  According to the technology described in claim 9 of the present application, the display device according to claim 8 is configured such that the simple degamma circuit performs degamma processing on the linear RGB signal subjected to gamma processing by linear calculation.

  According to the technique of claim 10 of the present application, the video supply device divides the input region into a plurality of linear RGB signals using an approximate gamma curve composed of line segments that approximate the gamma curve for each divided input region. Is encoded. The display device according to claim 8 is configured such that the simple degamma circuit decodes a linear RGB signal using an approximate degamma curve having a characteristic opposite to that of the approximate gamma curve.

  According to the technology described in claim 11 of the present application, the display device described in claim 8 is configured to be used by being directly mounted on a user's head, such as a head-mounted display.

  According to the technology disclosed in this specification, a video supply device and a display device that are connected by a predetermined video signal interface are configured to reduce luminance while reducing a signal processing load on a display device such as a head-mounted display. To provide an excellent video display system, video supply device, and display device capable of suitably displaying and outputting a video signal subjected to linear signal processing such as adjustment, color temperature adjustment, and primary color point conversion on a display device. it can.

  Other objects, features, and advantages of the technology disclosed in the present specification will become apparent from a more detailed description based on the embodiments to be described later and the accompanying drawings.

FIG. 1 is a diagram schematically showing the configuration of an image display system including a head-mounted display. FIG. 2 is a diagram illustrating a configuration example of a video display system according to an embodiment of the technology disclosed in this specification. FIG. 3 is a diagram showing an example of input / output characteristics of the simple gamma circuit. FIG. 4 is a diagram showing a configuration example of a simple gamma circuit. FIG. 5 is a diagram showing an input / output characteristic example of the simple degamma circuit. FIG. 6 is a diagram illustrating a configuration example of a simple degamma circuit. FIG. 7 is a diagram showing input / output characteristics in which the simple gamma circuit shown in FIG. 4 and the simple degamma circuit shown in FIG. 6 are combined. FIG. 8 is a diagram exemplifying a relationship between a gamma-processed 8-bit digital video signal and luminance. FIG. 9 is a diagram schematically showing a circuit configuration for performing linear signal processing after degamma processing. FIG. 10 is a diagram schematically illustrating a configuration example of a video display system 1000 that displays and outputs a video signal subjected to linear signal processing. FIG. 11 is a diagram schematically showing a configuration example of a video display system 1100 that performs all processes after degamma in the head mounted display 10. FIG. 12 is a diagram schematically showing a configuration example of a video display system that performs degamma processing and part of linear signal processing in the front end box 40.

  Hereinafter, embodiments of the technology disclosed in this specification will be described in detail with reference to the drawings.

  FIG. 1 schematically shows the configuration of an image display system including a head-mounted display. The illustrated system includes a head mounted display 10 main body, a Blu-ray disc playback device 20 that is a source of viewing content, and a high-definition display that is another output destination of the playback content of the Blu-ray disc playback device 20 (for example, An HDMI (High-Definition Multimedia Interface) compatible television (TV) 30 and a front end box 40 that processes an AV signal output from the Blu-ray disc playback apparatus 20 are configured.

  The front end box 40 corresponds to an HDMI repeater that performs, for example, signal processing and HDMI output when an AV signal output from the Blu-ray disc playback apparatus 20 is input via HDMI. The front end box 40 is also a two-output switcher that switches the output destination of the Blu-ray disc playback device 20 to either the head-mounted display 10 or the high-definition display 30. In the illustrated example, the front end box 40 has two outputs, but may have three or more outputs. However, the front end box 40 makes the output destination of the AV signal exclusive, and gives the highest priority to the output to the head mounted display 10.

  The Blu-ray disc playback apparatus 20 and the front end box 40 and the front end box 40 and the high-definition display 30 are respectively connected by HDMI cables. The front end box 40 and the head mounted display 10 can also be configured to be connected with an HDMI cable, but the AV signal may be serially transferred using a cable with other specifications. Good. However, it is assumed that the AV signal and power are supplied by a single cable connecting the front end box 40 and the head mounted display 10, and the head mounted display 10 also obtains driving power via this cable. be able to.

  The head mounted display 10 includes independent display units for the left eye and the right eye. Each display unit uses, for example, an organic EL element. Each of the left and right display units is equipped with a lens block composed of a wide viewing angle optical system with low distortion and high resolution.

  In the video display system shown in FIG. 1, the head mounted display 10 corresponds to a display device including a display unit and a display driving unit for driving the display unit, and the front end box 40 is a Blu-ray disc playback device. This corresponds to a video supply device that supplies the video signal reproduced at 20 to the display device, and the video supply device and the display device are connected by a predetermined video signal interface.

  Normally, the playback signal input from the Blu-ray disc playback apparatus 20 to the video display system is a video signal that has been subjected to, for example, 8-bit gamma processing. In an ideal video display system, as shown in FIG. 10, an 8-bit video signal is degamma processed and converted into a 13-bit linear RGB signal, and then brightness adjustment, color temperature adjustment, primary color point conversion, etc. are performed. Display output is performed after linear signal processing.

  Based on the above, let us consider again the ideal configuration method of the video display system shown in FIG. Before performing linear signal processing, it is necessary to perform degamma processing on the video signal. However, because degamma processing is heavy and the video signal is bit-extended after degamma processing, the degamma processing and where in the system It should be fully examined whether linear signal processing should be performed.

  FIG. 11 schematically shows a configuration example of a video display system 1100 that performs all processes after degamma within the head-mounted display 10. When the front end box 40 as a video supply device decodes the input video data by the decoder 1101 to obtain an 8-bit video signal, the preprocessing unit 1102 performs preprocessing such as scaling and noise reduction. The 8-bit video signal is transferred to the head mounted display 10 as it is. On the display device, that is, the head mounted display 10 side, the input 8-bit video signal is degamma processed by the degamma circuit 1103 and further bit-extended to obtain a 13-bit linear RGB signal. Thereafter, the 13-bit linear RGB signal is subjected to linear signal processing such as primary color point conversion, luminance adjustment, and color temperature adjustment by a primary color point conversion unit 1104, luminance adjustment unit 1105, and color temperature adjustment unit 1106, respectively, and then displayed. Displayed on panel 1107.

  As shown in FIG. 11, when processing after degamma is performed in the head mounted display 10, the amount of signal processing increases, leading to an increase in power consumption and heat generation, causing the following problems.

(1) Deterioration of the display unit is promoted by heat. In particular, when an organic EL element is used, the deterioration becomes significant.
(2) In the case of a device that is directly worn by the user, such as the head-mounted display 10, an increase in temperature is also a problem in terms of user safety and wearing comfort.

  On the other hand, in order to suppress the amount of signal processing performed in the head-mounted display 10, there is also a solution in which heavy degamma processing and at least a part of the linear signal processing are performed on the front end box 40 side. is there.

  FIG. 12 schematically shows a configuration example of a video display system 1200 that performs degamma processing and part of linear signal processing in the front end box 40. When the front end box 40 decodes the input video data by the decoder 1201 and obtains an 8-bit video signal, the front end box 40 performs preprocessing such as scaling and noise reduction by the preprocessing unit 1202, and then performs the degamma circuit 1203. When the degamma process is performed and the bit is expanded to obtain a 13-bit linear RGB signal, the primary color point conversion unit 1204 further performs a primary color point conversion process. Then, the 13-bit linear RGB signal after the primary color point conversion is transferred from the front end box 40 to the head mounted display 10. On the head mounted display 10 side, the 13-bit linear RGB signal is subjected to the remaining linear signal processing such as luminance adjustment and color temperature adjustment by the luminance adjustment unit 1205 and the color temperature adjustment unit 1206, and then the display panel 1207. Is displayed and output.

  In the system configuration example shown in FIG. 12, the amount of signal processing performed in the head mounted display 10 is reduced, but a 13-bit signal in which the space between the front end box 40 and the head mounted display 10 is expanded. It is necessary to connect with an interface. However, a general video signal interface such as DVI (Digital Video Interactive) or DisplayPort is limited to a bit length of about 10 bits. Thus, when the bit length is insufficient, an image quality problem that gradation expression is deteriorated occurs.

  On the other hand, in FIG. 2, the degamma processing and some linear signal processing are performed in the front end box 40, and the front end box 40 is a video signal interface limited to a bit length of about 10 bits. 2 shows a configuration example of a video display system 200 in which the head-mounted display 10 is connected.

  When the front end box 40 decodes the input video data by the decoder 201 and obtains an 8-bit video signal, the front end box 40 performs pre-processing such as scaling and noise reduction by the pre-processing unit 202 and then the de-gamma circuit 203. When the degamma process is performed and the bit is expanded to obtain a 13-bit linear RGB signal, the primary color point conversion unit 204 further performs a primary color point conversion process. The system configuration is the same as that shown in FIG. 12 in that the degamma processing and some linear signal processing are performed in the front end box 40. However, the difference is that a simple gamma circuit 205 is added to the final stage of signal processing in the front end box 40. The simple gamma circuit 205 encodes a 13-bit linear RGB signal into a simple gamma RGB signal and degenerates the signal to a 10-bit length.

  In addition, a simple degamma circuit 206 is added to the input stage of the head mounted display 10. The simple degamma circuit 206 decodes the input 10-bit simple gamma RGB signal into a linear RGB signal and restores it to the original 13 bits. Thus, the video display system can connect the front end box 40 and the head mounted display 10 with a 10-bit video signal interface. Thereafter, in the head mounted display 10, the remaining linear signal processing such as luminance adjustment and color temperature adjustment is performed on the linear RGB signal after decoding to 13-bit length by the luminance adjustment unit 207 and the color temperature adjustment unit 208. After being applied, display is output on the display panel 209.

  The original degamma process is a non-linear operation and is heavy. For this reason, when normal gamma processing and degamma processing are performed when a 13-bit linear RGB signal is encoded into a 10-bit RGB signal and further decoded into a 10-bit linear RGB signal, the inside of the head mounted display 10 Increases the amount of signal processing at the power source, leading to an increase in power consumption and heat generation.

  Therefore, in this embodiment, the front end box 40 and the head mounted display 10 are connected by a 10-bit video signal interface by introducing a simple gamma process and a simple degamma process that only require linear calculation. In addition, the amount of signal processing in the head mounted display 10 is suppressed, and an increase in power consumption and heat generation is prevented.

  In the configuration example shown in FIG. 2, in the linear signal processing for the linear RGB signal, the primary color point conversion unit is performed on the front end box 40 side, and the luminance adjustment and the color temperature adjustment are performed on the head mounted display 10 side. However, it is possible to replace the linear signal processing performed in each of the front end box 40 and the head mounted display 10 and to change the order of executing each linear signal processing.

  Hereinafter, the details of the simple gamma process performed by the simple gamma circuit 205 and the simple degamma process performed by the simple degamma circuit 206 will be described.

  In normal gamma processing, a bit length of a video signal can be reduced by converting a gamma input into a gamma output using a gamma curve composed of a power gamma. In the degamma process, the bit length of the video signal is restored to the original by using an operation opposite to that of the gamma process, that is, using a curve that is an inverse function of the original gamma curve.

  Gamma processing and degamma processing are non-linear operations and are heavily loaded. Therefore, in this embodiment, simple gamma processing and simple degamma processing are performed using an approximate gamma curve obtained by approximating a gamma curve with a plurality of line segments. Such simple gamma processing and simple degamma processing are linear operations and lightly loaded. Therefore, even if a simple degamma circuit is arranged at the input stage of the head-mounted display 10, there is no increase in power consumption or heat generation.

FIG. 3 shows an example of input / output characteristics of the simple gamma circuit 205. In the illustrated example, the input area is divided into five areas of 0 to 511, 512 to 1023, 1024 to 2047, 2048 to 4095, and 4096 to 8192, and each area has an inclination of 2 ⁰ , 2 ⁻¹ , 2 ⁻ in order. ³ Approximate the gamma curve with straight lines of 2 ^-5 and 2 ^-6 respectively. Therefore, the approximate gamma curve is represented by five line segments as shown in the following formula (1).

  FIG. 4 shows a configuration example of a simple gamma circuit 205 that realizes simple gamma processing according to the above approximate gamma curve. In the illustrated simple gamma circuit, the determination unit 401 first compares the 13-bit input signal IRGB with a threshold value, and in any region of 0 to 511, 512 to 1023, 1024 to 2047, 2048 to 4095, and 4096 to 8192. Depending on whether or not, m is divided into five cases of 0 to 4, and each variable i [m], o [m], a [m] is determined. The subtraction unit 402 subtracts i [m] from the input signal IRGB, and then the bit shift unit 403 performs bit shift to the lower order by a [m]. Further, the addition unit 404 adds o [m] and outputs the result.

  The above processing performed by the simple gamma circuit 205 is to obtain the output y by performing simple gamma processing on the input signal x in accordance with the following equation (2). The input / output characteristics are as shown in FIG.

FIG. 5 shows an input / output characteristic example of the simple degamma circuit 206. In the example shown in the figure, the input area is divided into five areas of 0 to 511, 512 to 767, 768 to 959, and 960 to 1024. In each area, the slope is 2 ⁻⁶ , 2 ⁻⁵ , 2 ⁻³ , 2 ^-1, respectively of 2 ⁰ linear approximate the Deganma curve. Therefore, the approximate degamma curve is represented by five line segments as shown in the following equation (3). This is exactly the reverse characteristic of FIG.

  FIG. 6 shows a configuration example of a simple degamma circuit 206 that realizes simple degamma processing according to the above approximate degamma curve. In the illustrated simple degamma circuit, the determination unit 601 first compares the 13-bit input signal IRGB with a threshold value, and in any region of 0 to 511, 512 to 767, 768 to 895, 896 to 959, and 959 to 1024. Depending on whether or not, m is divided into five cases of 0 to 4, and each variable i [m], o [m], a [m] is determined. Then, after subtracting i [m] from the input signal IRGB by the subtracting unit 602, the bit shift unit 603 performs bit shifting to the upper side by a [m]. Further, the adder 604 adds o [m] and outputs the result.

  The above-described processing performed by the simple degamma circuit 206 is to obtain the output y by performing simple degamma processing on the input signal x according to the following equation (4). The input / output characteristics are as shown in FIG.

  FIG. 7 shows input / output characteristics obtained by combining the simple gamma circuit 205 shown in FIG. 4 and the simple degamma circuit 206 shown in FIG. From the figure, it can be seen that the input and output match in the region where the signal level is low, and that the higher the signal level, the lower the match. This is because, as the signal level in the simple gamma circuit is larger, the component a [m] that determines the slope of the approximate gamma curve becomes larger, bit shift occurs, and gradation expression deteriorates. However, the human eye has high sensitivity in a region where the signal level is low, but is low in a region where the signal level is high, so that it can be perceived so that there is almost no deterioration.

  Both the simple gamma circuit shown in FIG. 4 and the simple degamma circuit shown in FIG. 6 do not require complicated processing such as a multiplier, and basically include only an adder and a bit shift. Therefore, it can be realized with a much smaller circuit than a normal degamma circuit.

Note that the technology disclosed in the present specification can also be configured as follows.
(1) A degamma circuit that obtains a linear RGB signal by degamma processing the video signal, a first linear signal processing unit that performs a first linear signal processing on the linear RGB signal, and the first linear signal processing. A video supply device having a simple gamma circuit that encodes a later linear RGB signal and degenerates the bit, and the video supply device is connected by the video signal interface of the degenerated bit length, and is based on the linear RGB signal that has been degenerated. A simple degamma circuit that decodes to a bit length of the second linear signal, a second linear signal processing unit that performs second linear signal processing on the decoded linear RGB signal, and a linear after the second linear signal processing An image display system including a display device having a display unit for displaying and outputting RGB signals.
(2) The video display according to (1), wherein the simple gamma circuit performs gamma processing on a linear RGB signal by linear calculation, and the simple degamma circuit performs degamma processing on the linear RGB signal subjected to gamma processing by linear calculation. system.
(3) The simple gamma circuit divides an input area into a plurality of parts, encodes a linear RGB signal using an approximate gamma curve composed of line segments approximating the gamma curve for each divided input area, and the simple degamma circuit includes: The video display system according to (1), wherein the encoded linear RGB signal is decoded using an approximate degamma curve having a characteristic opposite to that of the approximate gamma curve.
(4) The video display system according to (3), wherein input / output characteristics obtained by combining the simple gamma circuit and the simple degamma circuit match in input and output in a region where the signal level is low.
(5) A degamma circuit that obtains a linear RGB signal by degamma processing the video signal, a linear signal processing unit that performs a first linear signal processing on the linear RGB signal, and a linear RGB signal after the linear signal processing. A video supply device including a simple gamma circuit that encodes and degenerates bits.
(6) The video supply device according to (5), wherein the simple gamma circuit performs gamma processing on the linear RGB signal by linear calculation.
(7) The simple gamma circuit divides an input area into a plurality of parts, and encodes a linear RGB signal using an approximate gamma curve including a line segment that approximates the gamma curve for each divided input area. Picture supply device.
(8) A video signal interface connected to the video supply device, a simple degamma circuit that inputs a linear RGB signal degenerated by the video supply device via the video signal interface and decodes it to the original bit length, and the decoding A display device comprising: a linear signal processing unit that performs second linear signal processing on the linear RGB signal after being processed; and a display unit that displays and outputs the linear RGB signal after the linear signal processing.
(9) The display device according to (8), wherein the simple degamma circuit degamma-processes the gamma-processed linear RGB signal by linear calculation.
(10) In the video supply device, the input region is divided into a plurality of portions, and the linear RGB signal is encoded using an approximate gamma curve composed of a line segment that approximates the gamma curve for each divided input region, and the simple degamma circuit The display device according to (8), wherein the encoded linear RGB signal is decoded using an approximate degamma curve having a characteristic opposite to that of the approximate gamma curve.
(11) The display device according to (8), which is used by being directly attached to a user's head.

  As described above, the technology disclosed in this specification has been described in detail with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the scope of the technology disclosed in this specification.

  Although the present specification has mainly described the embodiment in which the technology disclosed in this specification is applied to a head-mounted display, the gist of the technology disclosed in this specification is limited to the configuration of a specific video display system. Is not to be done. The technology disclosed in this specification is similarly applied to various types of video display systems that are configured by a video supply device and a display device connected by a predetermined video signal interface and perform linear signal processing on the video signal. Can be applied.

  In short, the technology disclosed in the present specification has been described in the form of exemplification, and the description content of the present specification should not be interpreted in a limited manner. In order to determine the gist of the technology disclosed in this specification, the claims should be taken into consideration.

DESCRIPTION OF SYMBOLS 10 ... Head mounted display 20 ... Blu-ray Disc playback apparatus 30 ... Hi-vision display 40 ... Front end box 200 ... Video display system 201 ... Decoder 202 ... Pre-processing part 203 ... De-gamma circuit 204 ... Primary color point conversion part 205 ... Simple gamma circuit 206 ... Simple degamma circuit 207 ... Luminance adjustment unit 208 ... Color temperature adjustment unit 209 ... Display panel 401 ... Determination unit 402 ... Subtraction unit 403 ... Bit shift unit 404 ... Addition unit 601 ... Determination unit 602 ... Subtraction unit 603 ... bit shift unit 604 ... adder unit

Claims (11)

A degamma circuit that obtains a linear RGB signal by degamma processing the video signal, a first linear signal processing unit that performs a first linear signal processing on the linear RGB signal, and a linear after the first linear signal processing. A video supply device having a simple gamma circuit that encodes RGB signals to degenerate bits;
The video supply device is connected to the video signal interface of the degenerate bit length, and a simple degamma circuit for decoding the bit RGB degenerate linear RGB signal to the original bit length, and the linear RGB signal after the decoding A display device having a second linear signal processing unit for performing second linear signal processing, and a display unit for displaying and outputting linear RGB signals after the second linear signal processing;
A video display system comprising: The simple gamma circuit performs gamma processing on linear RGB signals by linear calculation,
The simple degamma circuit degamma-processes the gamma-processed linear RGB signal by linear calculation.
The video display system according to claim 1. The simple gamma circuit divides an input area into a plurality of parts, encodes a linear RGB signal using an approximate gamma curve composed of line segments approximating a gamma curve for each divided input area,
The simple degamma circuit decodes the encoded linear RGB signal using an approximate degamma curve having a characteristic opposite to that of the approximate gamma curve.
The video display system according to claim 1. The input / output characteristics combining the simple gamma circuit and the simple degamma circuit match the input / output in a region where the signal level is small.
The video display system according to claim 3. A degamma circuit that obtains a linear RGB signal by degamma processing the video signal;
A linear signal processing unit that performs first linear signal processing on the linear RGB signal;
A simple gamma circuit that encodes the linear RGB signal after the linear signal processing and degenerates the bit;
A video supply device comprising: The simple gamma circuit performs gamma processing on a linear RGB signal by linear calculation.
The video supply device according to claim 5. The simple gamma circuit divides an input area into a plurality of parts, and encodes a linear RGB signal using an approximate gamma curve composed of a line segment approximating a gamma curve for each divided input area.
The video supply device according to claim 5. A video signal interface connected to the video supply device;
A simple degamma circuit that inputs a linear RGB signal degenerated by the video supply device via the video signal interface and decodes it to the original bit length;
A linear signal processing unit that performs second linear signal processing on the decoded linear RGB signal;
A display unit for displaying and outputting linear RGB signals after the linear signal processing;
A display device comprising: The simple degamma circuit degamma-processes the gamma-processed linear RGB signal by linear calculation.
The display device according to claim 8. In the video supply device, the input region is divided into a plurality of segments, and the linear RGB signal is encoded using an approximate gamma curve composed of line segments that approximate the gamma curve for each divided input region,
The simple degamma circuit decodes the encoded linear RGB signal using an approximate degamma curve having a characteristic opposite to that of the approximate gamma curve.
The display device according to claim 8. Used directly on the user's head,
The display device according to claim 8.

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