Patent Publication Number: US-10791349-B2

Title: Frame generation apparatus, frame generation method, image synthesis apparatus, image synthesis method, signal generation apparatus, signal generation method, and image transmission system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Phase of International Patent Application No. PCT/JP2016/074158 filed on Aug. 18, 2016 which claims priority benefit of Japanese Patent Application No. JP 2015-230361 filed in the Japan Patent Office on Nov. 26, 2015. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a frame generation apparatus, a frame generation method, an image synthesis apparatus, an image synthesis method, a signal generation apparatus, a signal generation method, and an image transmission system. 
     BACKGROUND ART 
     These days, the amount of information of a video signal is dramatically improved, and an ultra-high resolution, ultra-high gradation baseband video signal is coming into wide use. For example, Super Hi-Vision, in which the number of effective pixels is 7680×4320 and the number of bits of each pixel element (R, G, or B, or Y, Cb, or Cr) of one pixel is 10 or 12, is promoted. Further, also further expansion of the dynamic range of a video image in the future is studied as seen in HDR, and it is also expected that a video signal in which the number of bits of each pixel element of one pixel is more than 12 (for example, the number of bits of each pixel element of one pixel is 16 or 24) will be handled. 
     For example, as a technology to transmit an ultra-high gradation video signal, a technology in which an ultra-high gradation video signal is transmitted using a plurality of 3G-SDI transmission paths is disclosed (for example, see Patent Literature 1). This Patent Literature 1 proposes, in a case where the number of bits of each pixel element is 16, dividing each pixel element into high-order 8 bits and low-order 8 bits and transmitting the high-order 8 bits and the low-order 8 bits while assigning these bits to different SG-SDI transmission paths. A reception apparatus receives these divided high-order 8 bits and low-order 8 bits using a plurality of transmission paths, synthesizes the pixel element divided in the high-order 8 bits and the low-order 8 bits, and reproduces an ultra-high gradation video signal. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2015-019182A 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     However, there may be a case where an ultra-high gradation video image is not handled by a receiver. As an example, there may be a case where tablet devices, mobile devices, and the like, of which the frequency of use is expected to continue to increase, cannot handle an ultra-high gradation video image, due to limitations on their throughput and power consumption, etc. Further, as another example, there may be a case where a video signal that a receiver displays does not need a considerable amount of information, in terms of the properties of the receiver. If, even in such a case, ultra-high gradation video images continue to be transmitted as they are or ultra-high gradation video images continue to be received as they are, wasteful power consumption is required. 
     Thus, it is desired to provide a technology by which, in a case where a video signal is divided and transmitted from a transmitter to a receiver via a plurality of transmission paths, the power consumption required by at least either one of the transmitter and the receiver can be reduced. 
     Solution to Problem 
     According to the present disclosure, there is provided a frame generation apparatus including: an image division section configured to divide a video signal into high-order bits and low-order bits for each pixel element; a frame generation section configured to generate a first frame including the high-order bits and a second frame including the low-order bits; and a transmission operation control section configured to cause an operation of a transmission section of transmitting the second frame to a receiver to stop in a case where information regarding the receiver is prescribed information. 
     According to the present disclosure, there is provided a frame generation method including: dividing a video signal into high-order bits and low-order bits for each pixel element; generating a first frame including the high-order bits and a second frame including the low-order bits; and causing an operation of a transmission section of transmitting the second frame to a receiver to stop in a case where information regarding the receiver is prescribed information. 
     According to the present disclosure, there is provided an image synthesis apparatus including: a pixel extraction section configured to extract high-order bits and low-order bits from, respectively, a first frame and a second frame including, respectively, the high-order bits and the low-order bits that are obtained by a video signal to be received by a receiver being divided for each pixel element in a case where the first frame and the second frame are received from a transmitter; an image synthesis section configured to synthesize the high-order bits and the low-order bits to restore the video signal; and a reception operation control section configured to make control so as to stop an operation of a reception section of receiving the second frame from the transmitter in a case where information regarding the receiver is prescribed information. 
     According to the present disclosure, there is provided an image synthesis method including: extracting high-order bits and low-order bits from, respectively, a first frame and a second frame including, respectively, the high-order bits and the low-order bits that are obtained by a video signal to be received by a receiver being divided for each pixel element in a case where the first frame and the second frame are received from a transmitter; an image synthesis section configured to synthesize the high-order bits and the low-order bits to restore the video signal; and making control so as to stop an operation of a reception section of receiving the second frame from the transmitter in a case where information regarding the receiver is prescribed information. 
     According to the present disclosure, there is provided a signal generation apparatus including: a pixel extraction section configured to extract high-order bits from a first frame including the high-order bits that are obtained by a video signal to be received by a receiver being divided for each pixel element in a case where the first frame is received from a transmitter; and a signal generation section configured to generate a video signal with a smaller size than the video signal on a basis of the high-order bits. 
     According to the present disclosure, there is provided an image transmission system including: a frame generation apparatus including an image division section configured to divide a video signal into high-order bits and low-order bits for each pixel element, a frame generation section configured to generate a first frame including the high-order bits and a second frame including the low-order bits, and a transmission operation control section configured to cause an operation of a transmission section of transmitting the second frame to a receiver to stop in a case where information regarding the receiver is prescribed information; and an image synthesis apparatus including a pixel extraction section configured to extract the high-order bits and the low-order bits from the first frame and the second frame, respectively, in a case where the first frame and the second frame are received from a transmitter, an image synthesis section configured to synthesize the high-order bits and the low-order bits to restore the video signal, and a reception operation control section configured to make control so as to stop an operation of a reception section of receiving the second frame from the transmitter in a case where information regarding the receiver is prescribed information. 
     Advantageous Effects of Invention 
     As described above, according to the present disclosure, a technology by which, in a case where a video signal is divided and transmitted from a transmitter to a receiver via a plurality of transmission paths, the power consumption required by at least either one of the transmitter and the receiver can be reduced is provided. Note that the effects described above are not necessarily limitative. With or in the place of the above effects, there may be achieved any one of the effects described in this specification or other effects that may be grasped from this specification. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram showing a configurational example of an ordinary system that transmits an ultra-high gradation video signal. 
         FIG. 2  is a diagram showing an example of a configuration of an image transmission system according to an embodiment of the present disclosure. 
         FIG. 3  is a diagram showing an example of a video signal according to the embodiment. 
         FIG. 4  is a diagram for describing an example of a technique of dividing a video signal into high-order bits and low-order bits for each pixel element (R, G, or B). 
         FIG. 5  is a diagram showing a configurational example of a frame (a first frame and a second frame) generated by a frame generation section. 
         FIG. 6  is a diagram for describing an example of a technique of synthesizing high-order bits and low-order bits for each pixel element (R, G, or B) to restore a video signal. 
         FIG. 7  is a diagram showing an example of a configuration of a modification example of the image transmission system. 
     
    
    
     MODE(S) FOR CARRYING OUT THE INVENTION 
     Hereinafter, (a) preferred embodiment(s) of the present disclosure will be described in detail with reference to the appended drawings. Note that, in this specification and the appended drawings, structural elements that have substantially the same function and structure are denoted with the same reference numerals, and repeated explanation of these structural elements is omitted. 
     Further, in the present specification and the drawings, a plurality of components having substantially the same functional configuration are distinguished by marking different numerals after the same reference character. However, in a case where it is not necessary to particularly distinguish each of a plurality of components having substantially the same functional configuration and the like, they are marked with only the same reference character. Further, like components of different embodiments are distinguished by marking different alphabet letters after the same reference character. 
     Note that the description is given in the following order. 
     1. Background 
     2. Configurational example of image transmission system 
     3. Conclusions 
     1. BACKGROUND 
     First, the background of the present embodiment is described. These days, the amount of information of a video signal is dramatically improved, and an ultra-high resolution, ultra-high gradation baseband video signal is coming into wide use. For example, Super Hi-Vision, in which the number of effective pixels is 7680×4320 and the number of bits of each pixel element (R, G, or B, or Y, Cb, or Cr) of one pixel is 10 or 12, is promoted. Further, also further expansion of the dynamic range of a video image in the future is studied as seen in HDR, and it is also expected that a video signal in which the number of bits of each pixel element of one pixel is more than 12 (for example, the number of bits of each pixel element of one pixel is 16 or 24) will be handled. 
     For example, as a technology to transmit an ultra-high gradation video signal, a technology in which an ultra-high gradation video signal is transmitted using a plurality of 3G-SDI transmission paths is disclosed (for example, see JP 2015-019182A).  FIG. 1  is a diagram showing a configurational example of an ordinary system that transmits an ultra-high gradation video signal. As shown in  FIG. 1 , the ordinary system that transmits an ultra-high gradation video signal includes a transmitter  80  and a receiver  90 , and the transmitter  80  includes an image generation section  801 , an image division section  802 , a 3G-SDI transmission section  803 , and a 3G-SDI transmission section  804 . Further, the receiver  90  includes a 3G-SDI reception section  903 , a 3G-SDI reception section  904 , an image synthesis section  902 , and an image display section  901 . 
     In the transmitter  80 , the image generation section  801  generates a video signal in which the number of bits of each pixel element is 16. The image division section  802  divides each pixel element of the video signal into high-order 8 bits and low-order 8 bits. The 3G-SDI transmission section  803  transmits the high-order 8 bits to the receiver  90 , and the 3G-SDI transmission section  804  transmits the low-order 8 bits to the receiver  90 . Subsequently, in the receiver  90 , the 3G-SDI reception section  903  receives the high-order 8 bits and the 3G-SDI reception section  904  receives the low-order 8 bits, the image synthesis section  902  synthesizes the high-order 8 bits and the low-order 8 bits to restore an ultra-high gradation video signal, and the image display section  901  reproduces and displays the ultra-high gradation video signal. 
     However, there may be a case where an ultra-high gradation video image is not handled by the receiver  90 . As an example, there may be a case where tablet devices, mobile devices, and the like, of which the frequency of use is expected to continue to increase, cannot handle an ultra-high gradation video images, due to limitations on their throughput and power consumption, etc. Further, as another example, there may be a case where a video signal that the receiver  90  displays does not need a considerable amount of information, in terms of the properties of the receiver  90 . If, even in such a case, ultra-high gradation video images continue to be transmitted as they are or ultra-high gradation video images continue to be received as they are, wasteful power consumption is required. 
     Thus, the present specification mainly proposes a technology by which, in a case where a video signal is divided and transmitted from the transmitter  80  to the receiver  90  via a plurality of transmission paths, the power consumption required by at least either one of the transmitter  80  and the receiver  90  can be reduced. Note that, in the present specification, an ultra-high gradation video image is envisaged as the video signal transmitted from the transmitter  80  to the receiver  90 , and a case where the number of bits of each pixel element is more than or equal to 16 and less than or equal to 24 is envisaged. However, the number of bits of each pixel element is not particularly limited. 
     Hereinabove, the background of the present embodiment is described. 
     2. CONFIGURATIONAL EXAMPLE OF IMAGE TRANSMISSION SYSTEM 
     Next, a configurational example of an image transmission system is described with reference to  FIG. 2 .  FIG. 2  is a diagram showing an example of the configuration of an image transmission system according to the present embodiment. As shown in  FIG. 2 , an image transmission system  1 A according to the present embodiment includes a transmitter  10  and a receiver  20 A. The transmitter  10  and the receiver  20 A are connected together via a cable  30 . The cable  30  includes a plurality of transmission paths. Note that the transmitter  10  can function as a “frame generation apparatus.” Further, the receiver  20 A can function as an “image synthesis apparatus.” 
     The transmitter  10  includes an image generation section  101 , an image division section  102 , a frame generation section  103 , a transmission section  104 , a transmission section  105 , a transmission operation control section  106 , and a device information reception section  107 . The image generation section  101  generates a video signal. Note that, although  FIG. 2  shows an example in which the image generation section  101  is incorporated in the transmitter  10 , the image generation section  101  may exist outside the transmitter  10 . 
       FIG. 3  is a diagram showing an example of a video signal according to the present embodiment. As shown in  FIG. 3 , the number of pixels in the horizontal direction in a video signal Im 10  is denoted by n, and the number of lines in the vertical direction in the video signal Im 10  is denoted by m. That is, the pixel number in the horizontal direction in the video signal Im 10  is set to integers of 0 to n−1, and the line number in the vertical direction in the video signal Im 10  is set to integers of 0 to m−1. 
     Further, as shown in  FIG. 3 , each pixel of the video signal Im 10  includes pixel elements (R, G, and B) or pixel elements (Y, Cb, and Cr), and the number of bits of each pixel element is L (16≤L≤24). In the following, a case where each pixel of the video signal Im 10  includes the pixel elements (R, G, and B) is mainly described. However, each pixel of the video signal Im 10  is not limited to the pixel elements (R, G, and B), and may be the pixel elements (Y, Cb, and Cr). 
     The image division section  102  divides the video signal Im 10  into high-order bits and low-order bits for each pixel element (R, G, or B). It is sufficient that the high-order bits have minimum data capable of bearing viewing in a case of being used for display, and the number of high-order bits is not particularly limited. Further, the low-order bits are the bits other than the high-order bits of the pixel element. A specific example will now be described with reference to  FIG. 4 . 
       FIG. 4  is a diagram for describing an example of a technique of dividing the video signal Im 10  into high-order bits and low-order bits for each pixel element (R, G, or B). The image division section  102  outputs high-order 12 bits of each pixel element (R, G, or B) (a total of 36 bits) to the frame generation section  103 . On the other hand, the image division section  102  outputs low-order bits of each pixel element (R, G, or B) to the frame generation section  103 . In this event, in a case where there is a set of low-order bits that does not reach 12 bits, the image division section  102  puts in 0 until reaching 12 bits, and outputs a set of low-order bits that has reached 12 bits to the frame generation section  103 . 
     The frame generation section  103  generates a first frame including the high-order bits and a second frame including the low-order bits.  FIG. 5  is a diagram showing a configurational example of a frame (the first frame and the second frame) generated by the frame generation section  103 . In  FIG. 5 , the whole of the N-th frame is shown as the N-th (N being an integer more than or equal to 0) frame, and a part of the N+1-th frame is shown as the N+1-th frame. 
     The frame generation section  103  generates a first frame that includes, in order, the high-order bits (12 bits) of each pixel element of the front-end line of the video signal Im 10  (the 0th line in the video signal Im 10 ), the high-order bits (12 bits) of each pixel element of the first line of the video signal Im 10  (the 1st line in the video signal Im 10 ), and the high-order bits (12 bits) of each pixel element of the lines following the above lines. 
     Further, the frame generation section  103  generates a second frame that includes, in order, the low-order bits (12 bits) of each pixel element of the front-end line of the video signal Im 10  (the 0th line in the video signal Im 10 ), the low-order bits (12 bits) of each pixel element of the first line of the video signal Im 10  (the 1st line in the video signal Im 10 ), and the low-order bits (12 bits) of each pixel element of the lines following the above lines. 
     Further, as shown in  FIG. 5 , the frame generation section  103  marks a frame start identifier (SYNC) on the head of the frame (the first frame and the second frame). Any one of prescribed codes at least not existing in the video signal (hereinafter, occasionally referred to as “special data”) is assigned to the frame start identifier. For example, the special data depend on the encoding of data transmitted and received through a transmission path  301  and a transmission path  302 . For example, in a case where ANSI 8b/10b conversion is used for the encoding of data transmitted and received through the transmission path  301  and the transmission path  302 , a K code may be assigned to the special data. For example, data in which a K code called K28.5 (0xBC) appears consecutively N bytes may be assigned to the frame start identifier. 
     Further, a blanking section exists on the rear side of each line. Here, among the special data, special data different from the special data assigned to the frame start identifier are assigned to the blanking section. 
     Note that the frame generation section  103  may perform encoding on the frame (the first frame and the second frame). Specifically, the frame generation section  103  may perform 8b/10b encoding on the frame (the first frame and the second frame). For example, the frame generation section  103  may substitute the frame start identifier of the frame (the first frame and the second frame) with corresponding special data, substitute the blanking section with corresponding special data, and substitute data other than these with 10-bit-based data. Further, the frame generation section  103  may convert the encoded frame from parallel data to serial data in order to change the frame to a form suitable for high-speed transmission. 
     Further, although the example shown in  FIG. 2  shows an example in which the generation of the first frame and the generation of the second frame are performed in the same frame generation section  103 , the generation of the first frame and the generation of the second frame may be performed in different frame generation sections  103 . 
     The transmission section  104  transmits the first frame to the receiver  20 A via the cable  30 . More specifically, the transmission section  104  transmits the first frame to the receiver  20 A via the transmission path  301 . For example, in a case where the transmission path  301  includes an optical fiber, the transmission section  104  transmits the first frame to the receiver  20 A via the transmission path  301  after converting the first frame to an optical signal. However, the type of the signal transmitted from the transmitter  10  to the receiver  20 A via the transmission path  301  is not limited. For example, the transmission section  104  may transmit the first frame to the receiver  20 A via the transmission path  301  by means of an electrical signal. 
     Further, the transmission section  105  transmits the second frame to the receiver  20 A via the cable  30 . More specifically, the transmission section  105  transmits the second frame to the receiver  20 A via the transmission path  302 . For example, in a case where the transmission path  302  includes an optical fiber, the transmission section  105  transmits the second frame to the receiver  20 A via the transmission path  302  after converting the second frame to an optical signal. However, the type of the signal transmitted from the transmitter  10  to the receiver  20 A via the transmission path  301  is not limited. For example, the transmission section  105  may transmit the second frame to the receiver  20 A via the transmission path  302  by means of an electrical signal. 
     The device information reception section  107  receives information regarding the receiver  20 A from the receiver  20 A via a transmission path  303 . Then, in a case where the information regarding the receiver  20 A is prescribed information, the transmission operation control section  106  causes the operation of the transmission section  105  of transmitting the second frame to the receiver  20 A to stop. By such a configuration, the operation of the transmission section  105  is stopped in the case where the information regarding the receiver  20 A is the prescribed information; thus, it becomes possible to reduce the power consumption required by the transmitter  10 . On the other hand, in a case where the information regarding the receiver  20 A is not the prescribed information, the operation of the transmission section  105  of transmitting the second frame to the receiver  20 A is allowed to continue. 
     Here, in a case where the transmission path  303  includes an optical fiber, the device information reception section  107  receives, from the receiver  20 A via the transmission path  303 , information regarding the receiver  20 A after being converted to an optical signal. However, the type of the signal transmitted from the receiver  20 A to the transmitter  10  via the transmission path  303  is not limited. For example, the device information reception section  107  may receive the information regarding the receiver  20 A from the transmitter  10  via the transmission path  303  by means of an electrical signal. 
     Further, the information regarding the receiver  20 A is not particularly limited. For example, the information regarding the receiver  20 A may include at least either one of a state of the receiver  20 A and a function of the receiver  20 A. For example, the information regarding the receiver  20 A includes a state of the receiver  20 A; and in a case where the state of the receiver  20 A is a prescribed state, the transmission operation control section  106  may cause the operation of the transmission section  105  of transmitting the second frame to stop. The prescribed state is not limited as long as it is a state not using the low-order bits in the receiver  20 A, and may be a low electric power mode. 
     Alternatively, the information regarding the receiver  20 A includes a function of the receiver  20 A; and in a case where the function of the receiver  20 A is a prescribed function, the transmission operation control section  106  may cause the operation of the transmission section  105  of transmitting the second frame to stop. The prescribed function is not limited as long as it is a function not using the low-order bits in the receiver  20 A, and may be a function of the number of receivable bits being below a threshold, may be a function of the number of connectable transmission paths being below a threshold, may be a function of being a mobile terminal, or may be a function of not having an ultra-high gradation mode. 
     Note that herein an example in which the transmission operation control section  106  causes the operation of the transmission section  105  of transmitting the second frame to the receiver  20 A to stop in the case where the information regarding the receiver  20 A is prescribed information is described. However, in the case where the information regarding the receiver  20 A is prescribed information, the transmission operation control section  106  may control the frame generation section  103  so as to stop the generation of the second frame, instead of causing the operation of the transmission section  105  to stop, or in addition to causing the operation of the transmission section  105  to stop. By such a configuration, the operation of the frame generation section  103  is lessened in the case where the information regarding the receiver  20 A is prescribed information; thus, it becomes possible to reduce the power consumption required by the transmitter  10 . 
     The receiver  20 A includes a reception section  204 , a reception section  205 , a reception operation control section  206 , a device information transmission section  207 , a pixel extraction section  203 A, a multiplexer  208 , an image synthesis section  202 , and an image display section  201 . 
     The reception section  204  receives the first frame via the cable  30 . More specifically, the reception section  204  receives the first frame via the transmission path  301 . For example, in a case where the transmission path  301  includes an optical fiber, the reception section  204  receives the light of the first frame that is transmitted by an optical signal from the transmitter  10 , and converts the light to an electrical signal. However, as mentioned above, the type of the signal transmitted from the transmitter  10  to the receiver  20 A via the transmission path  301  is not limited. For example, the reception section  204  may receive the first frame from the transmitter  10  via the transmission path  301  by means of an electrical signal. 
     The reception section  205  receives the second frame via the cable  30 . More specifically, the reception section  205  receives the second frame transmitted from the transmission section  105 , via the transmission path  302 . For example, in a case where the transmission path  302  includes an optical fiber, the reception section  205  receives the light of the second frame that is transmitted by an optical signal from the transmitter  10 , and converts the light to an electrical signal. However, as mentioned above, the type of the signal transmitted from the transmitter  10  to the receiver  20 A via the transmission path  302  is not limited. For example, the reception section  205  may receive the second frame from the transmitter  10  via the transmission path  302  by means of an electrical signal. 
     In a case where the information regarding the receiver  20 A is the prescribed information described above, the reception operation control section  206  makes control so as to stop the operation of the reception section  205  of receiving the second frame from the transmitter  10 . By such a configuration, the operation of the reception section  205  is stopped in the case where the information regarding the receiver  20 A is the prescribed information; thus, it becomes possible to reduce the power consumption required by the receiver  20 A. On the other hand, in a case where the information regarding the receiver  20 A is not the prescribed information, the operation of the reception section  205  of receiving the second frame from the transmitter  10  is allowed to continue. 
     The device information transmission section  207  transmits information regarding the receiver  20 A to the transmitter  10  via the transmission path  303 . Here, in a case where the transmission path  303  includes an optical fiber, the device information transmission section  207  converts the information regarding the receiver  20 A to an optical signal, and transmits the optical signal to the transmitter  10  via the transmission path  303 . However, the type of the signal transmitted from the receiver  20 A to the transmitter  10  via the transmission path  303  is not limited. For example, the device information transmission section  207  may transmit the information regarding the receiver  20 A to the transmitter  10  via the transmission path  303  by means of an electrical signal. 
     The pixel extraction section  203 A extracts the high-order bits of each pixel element from the first frame received by the reception section  204 . This will now be specifically described with reference to  FIG. 5 . Before extracting the high-order bits of each pixel element from the first frame, the pixel extraction section  203 A may convert the first frame from serial data to parallel data, and may decode the first frame converted to parallel data. Specifically, the pixel extraction section  203 A may perform 8b/10b decoding on the first frame. 
     For example, the pixel extraction section  203 A may substitute, of the first frame, the special data corresponding to the frame start identifier with the frame start identifier, and substitute the special data corresponding to the blanking section with the blanking section. On the other hand, the pixel extraction section  203 A may substitute also the remaining data of the first frame with 8-bit-based data. 
     Subsequently, the pixel extraction section  203 A detects the frame start identifier (SYNC) from the first frame. Since the frame start identifier is marked on the head of the first frame, the pixel extraction section  203 A may extract the high-order bits of each pixel element from the first frame on the basis of the position of the frame start identifier. More specifically, if the pixel extraction section  203 A has grasped the relative position of the high-order bits of each pixel element with respect to the position of the frame start identifier as a reference, the pixel extraction section  203 A may extract the high-order bits of each pixel element on the basis of this relative position. 
     Similarly, the pixel extraction section  203 A extracts the low-order bits of each pixel element from the second frame received by the reception section  205 . This will now be specifically described with reference to  FIG. 5 . Before extracting the low-order bits of each pixel element from the second frame, the pixel extraction section  203 A may convert the second frame from serial data to parallel data, and may decode the second frame converted to parallel data. Specifically, the pixel extraction section  203 A may perform 8b/10b decoding on the second frame. 
     For example, the pixel extraction section  203 A may substitute, of the second frame, the special data corresponding to the frame start identifier with the frame start identifier, and substitute the special data corresponding to the blanking section with the blanking section. On the other hand, the pixel extraction section  203 A may substitute also the remaining data of the second frame with 8-bit-based data. 
     Subsequently, the pixel extraction section  203 A detects the frame start identifier (SYNC) from the second frame. Since the frame start identifier is marked on the head of the second frame, the pixel extraction section  203 A may extract the low-order bits of each pixel element from the second frame on the basis of the position of the frame start identifier. More specifically, if the pixel extraction section  203 A has grasped the relative position of the low-order bits of each pixel element with respect to the position of the frame start identifier as a reference, the pixel extraction section  203 A may extract the low-order bits of each pixel element on the basis of this relative position. 
     Note that in the above an example in which the reception operation control section  206  causes the operation of the reception section  205  of receiving the second frame from the transmitter  10  to stop in the case where the information regarding the receiver  20 A is prescribed information is described. However, in the case where the information regarding the receiver  20 A is prescribed information, the reception operation control section  206  may control the pixel extraction section  203 A so as to stop the extraction of the low-order bits of each pixel element, instead of causing the operation of the reception section  205  to stop, or in addition to causing the operation of the reception section  205  to stop. By such a configuration, the operation of the pixel extraction section  203 A is lessened in the case where the information regarding the receiver  20 A is prescribed information; thus, it becomes possible to reduce the power consumption required by the receiver  20 A. 
     Further, although the example shown in  FIG. 2  shows an example in which the extraction of the high-order bits of each pixel element and the extraction of the low-order bits of each pixel element are performed in the same pixel extraction section  203 A, the extraction of the high-order bits of each pixel element and the extraction of the low-order bits of each pixel element may be performed in different pixel extraction sections  203 A. 
     In a case where the information regarding the receiver  20 A inputted from the reception operation control section  206  is prescribed information, the multiplexer  208  outputs “0” to the image synthesis section  202 . On the other hand, in a case where the information regarding the receiver  20 A inputted from the reception operation control section  206  is not the prescribed information, the multiplexer  208  outputs the low-order bits of each pixel element extracted by the pixel extraction section  203 A to the image synthesis section  202 . 
     The image synthesis section  202  synthesizes the high-order bits of each pixel element and the low-order bits of each pixel element to restore the video signal Im 10 .  FIG. 6  is a diagram for describing an example of a technique of synthesizing the high-order bits and the low-order bits for each pixel element (R, G, or B) to restore the video signal Im 10 . 
     As shown in  FIG. 6 , in a case where the low-order bits of each pixel element (R, G, or B) are inputted from the multiplexer  208 , the image synthesis section  202  synthesizes the high-order 12 bits of each pixel element (R, G, or B) (a total of 36 bits) and the low-order bits of each pixel element (R, G, or B) (a total of 36 bits), and outputs the result. The signal outputted in this event is, for example, a signal having the high-order bits and the low-order bits (an ultra-high gradation video signal). 
     On the other hand, in a case where “0” is inputted from the multiplexer  208 , the image synthesis section  202  synthesizes the high-order 12 bits of each pixel element (R, G, or B) (a total of 36 bits) and “0,” and outputs the result. The signal outputted in this event is a signal having only the high-order bits (a normal gradation video signal). 
     The image display section  201  displays a video image on the basis of a signal outputted from the image synthesis section  202 . Specifically, the image display section  201  reproduces a signal outputted from the image synthesis section  202 , and displays a video image. The image display section  201  may be, for example, display devices such as a liquid crystal display (LCD), a plasma display panel (PDP), an organic electro-luminescence (EL) display, and a projector, and the like. Note that, although  FIG. 2  shows an example in which the image display section  201  is incorporated in the receiver  20 A, the image display section  201  may exist outside the receiver  20 A. 
     3. CONCLUSIONS 
     As described hereinabove, according to the present embodiment, the frame generation apparatus  10  including the image division section  102 , the frame generation section  103 , and the transmission operation control section  106  is provided. Here, the image division section  102  divides a video signal into high-order bits and low-order bits for each pixel element. Further, the frame generation section  103  generates the first frame including the high-order bits and the second frame including the low-order bits. Then, in a case where the information regarding the receiver  20 A is prescribed information, the transmission operation control section  106  causes the operation of the transmission section  105  of transmitting the second frame to the receiver  20 A to stop. 
     By such a configuration, the operation of the transmission section  105  is stopped in the case where the information regarding the receiver  20 A is prescribed information; thus, it becomes possible to reduce the power consumption required by the transmitter  10 . 
     Further, according to the present embodiment, the image synthesis apparatus  20 A including the pixel extraction section  203 A, the image synthesis section  202 , and the reception operation control section  206  is provided. Here, a case where the first frame and the second frame including, respectively, high-order bits and low-order bits that are obtained by a video signal to be received by the receiver  20 A being divided for each pixel element are received from the transmitter  10  is envisaged. In such a case, the pixel extraction section  203 A extracts the high-order bits and the low-order bits from the first frame and the second frame, respectively. Further, the image synthesis section  202  synthesizes the high-order bits and the low-order bits to restore the video signal. Then, in a case where the information regarding the receiver  20 A is prescribed information, the reception operation control section  206  makes control so as to stop the operation of the reception section  205  of receiving the second frame from the transmitter  10 . 
     By such a configuration, the operation of the reception section  205  is stopped in the case where the information regarding the receiver  20 A is prescribed information; thus, it becomes possible to reduce the power consumption required by the receiver  20 A. 
     The preferred embodiment(s) of the present disclosure has/have been described above with reference to the accompanying drawings, whilst the present disclosure is not limited to the above examples. A person skilled in the art may find various alterations and modifications within the scope of the appended claims, and it should be understood that they will naturally come under the technical scope of the present disclosure. 
     For example, in the above, the receiver  20 A including both of the reception section  204  and the reception section  205  is described. Then, an example in which the pixel extraction section  203 A extracts the high-order bits of each pixel element from the first frame received by the reception section  204  and extracts the low-order bits of each pixel element from the second frame received by the reception section  205 , and the image synthesis section  202  synthesizes the high-order bits and the low-order bits to restore the video signal is described. However, the receiver  20 A may not include the reception section  204 , may not include the multiplexer  208 , and may not have partial functions of the pixel extraction section  203 A. 
       FIG. 7  is a diagram showing an example of the configuration of a modification example of the image transmission system. As shown in  FIG. 7 , an image transmission system  1 B according to the modification example includes a receiver  20 B in place of the receiver  20 A, and the receiver  20 B does not include the reception section  205 , includes a pixel extraction section  203 B in place of the pixel extraction section  203 A, and includes a signal generation section  209  in place of the image synthesis section  202 . The receiver  20 B can function as a “signal generation apparatus.” 
     The pixel extraction section  203 B extracts the high-order bits of each pixel element from the first frame, but the second frame is not inputted to the pixel extraction section  203 B. The pixel extraction section  203 B outputs “0” instead of the low-order bits of each pixel element to the signal generation section  209 . The signal generation section  209  generates a video signal with a smaller size than the video signal Im 10  on the basis of the high-order bits of each pixel element extracted by the pixel extraction section  203 B. 
     In the receiver  20 B, the reception section  205  does not exist, and furthermore the function of the pixel extraction section  203 B is made smaller than the function of the pixel extraction section  203 A; thus, a reduction in power consumption is achieved. Furthermore, the configuration of the receiver  20 B is made simpler than the configuration of the receiver  20 A; thus, the receiver  20 B can be manufactured at a lower cost than the receiver  20 A. 
     Further, for example, each of the image generation section  101 , the image division section  102 , the frame generation section  103 , and the transmission operation control section  106  may be mounted on a separate integrated circuit (IC), or a combination of any two or more of these may be mounted on the same IC. Further, for example, each of the multiplexer  208 , the reception operation control section  206 , the pixel extraction section  203 A (or the pixel extraction section  203 B), and the image synthesis section  202  (or the signal generation section  209 ) may be mounted on a separate IC, or a combination of any two or more of these may be mounted on the same IC. 
     Further, the effects described in this specification are merely illustrative or exemplified effects, and are not limitative. That is, with or in the place of the above effects, the technology according to the present disclosure may achieve other effects that are clear to those skilled in the art from the description of this specification. 
     Additionally, the present technology may also be configured as below. 
     (1) 
     A frame generation apparatus including: an image division section configured to divide a video signal into high-order bits and low-order bits for each pixel element; 
     a frame generation section configured to generate a first frame including the high-order bits and a second frame including the low-order bits; and 
     a transmission operation control section configured to cause an operation of a transmission section of transmitting the second frame to a receiver to stop in a case where information regarding the receiver is prescribed information. 
     (2) 
     The frame generation apparatus according to (1), 
     in which the information regarding the receiver includes at least either one of a state of the receiver and a function of the receiver. 
     (3) 
     The frame generation apparatus according to (2), 
     in which the information regarding the receiver includes a state of the receiver, and 
     the transmission operation control section causes the operation of the transmission section of transmitting the second frame to stop in a case where the state of the receiver is a prescribed state. 
     (4) 
     The frame generation apparatus according to (2), 
     in which the information regarding the receiver includes a function of the receiver, and 
     the transmission operation control section causes the operation of the transmission section of transmitting the second frame to stop in a case where the function of the receiver is a prescribed function. 
     (5) 
     The frame generation apparatus according to any one of (1) to (4), 
     in which the transmission operation control section controls the frame generation section so as to stop generation of the second frame in the case where the information regarding the receiver is the prescribed information. 
     (6) 
     The frame generation apparatus according to any one of (1) to (5), including: a device information reception section configured to receive the information regarding the receiver from the receiver. 
     (7) 
     The frame generation apparatus according to any one of (1) to (6), 
     in which the frame generation section marks a frame start identifier on a head of each of the first frame and the second frame. 
     (8) 
     The frame generation apparatus according to any one of (1) to (7), including: 
     a first transmission section configured to transmit the first frame; and 
     a second transmission section configured to transmit the second frame. 
     (9) 
     A frame generation method including: 
     dividing a video signal into high-order bits and low-order bits for each pixel element; 
     generating a first frame including the high-order bits and a second frame including the low-order bits; and 
     causing an operation of a transmission section of transmitting the second frame to a receiver to stop in a case where information regarding the receiver is prescribed information. 
     (10) 
     An image synthesis apparatus including: 
     a pixel extraction section configured to extract high-order bits and low-order bits from, respectively, a first frame and a second frame including, respectively, the high-order bits and the low-order bits that are obtained by a video signal to be received by a receiver being divided for each pixel element in a case where the first frame and the second frame are received from a transmitter; 
     an image synthesis section configured to synthesize the high-order bits and the low-order bits to restore the video signal; and 
     a reception operation control section configured to make control so as to stop an operation of a reception section of receiving the second frame from the transmitter in a case where information regarding the receiver is prescribed information. 
     (11) 
     The image synthesis apparatus according to (10), 
     in which the information regarding the receiver includes at least either one of a state of the receiver and a function of the receiver. 
     (12) 
     The image synthesis apparatus according to (11), 
     in which the information regarding the receiver includes a state of the receiver, and 
     the reception operation control section causes the operation of the reception section of receiving the second frame to stop in a case where the state of the receiver is a prescribed state. 
     (13) 
     The image synthesis apparatus according to (11), 
     in which the information regarding the receiver includes a function of the receiver, and 
     the reception operation control section causes the operation of the reception section of receiving the second frame to stop in a case where the function of the receiver is a prescribed function. 
     (14) 
     The image synthesis apparatus according to any one of (10) to (13), 
     in which the reception operation control section controls the pixel extraction section so as to stop extraction of the high-order bits and the low-order bits in the case where the information regarding the receiver is the prescribed information. 
     (15) 
     The image synthesis apparatus according to any one of (10) to (14), including: 
     a device information transmission section configured to transmit the information regarding the receiver to the transmitter. 
     (16) 
     The image synthesis apparatus according to any one of (10) to (15), 
     in which the pixel extraction section extracts the high-order bits and the low-order bits on a basis of positions of frame start identifiers marked on heads of the first frame and the second frame, respectively. 
     (17) 
     The image synthesis apparatus according to any one of (10) to (16), including: 
     a second reception section configured to receive the first frame; and 
     a second reception section configured to receive the second frame. 
     (18) 
     An image synthesis method including: 
     extracting high-order bits and low-order bits from, respectively, a first frame and a second frame including, respectively, the high-order bits and the low-order bits that are obtained by a video signal to be received by a receiver being divided for each pixel element in a case where the first frame and the second frame are received from a transmitter; 
     an image synthesis section configured to synthesize the high-order bits and the low-order bits to restore the video signal; and 
     making control so as to stop an operation of a reception section of receiving the second frame from the transmitter in a case where information regarding the receiver is prescribed information. 
     (19) 
     A signal generation apparatus including: 
     a pixel extraction section configured to extract high-order bits from a first frame including the high-order bits that are obtained by a video signal to be received by a receiver being divided for each pixel element in a case where the first frame is received from a transmitter; and 
     a signal generation section configured to generate a video signal with a smaller size than the video signal on a basis of the high-order bits. 
     (20) 
     An image transmission system including: 
     a frame generation apparatus including
         an image division section configured to divide a video signal into high-order bits and low-order bits for each pixel element,   a frame generation section configured to generate a first frame including the high-order bits and a second frame including the low-order bits, and   a transmission operation control section configured to cause an operation of a transmission section of transmitting the second frame to a receiver to stop in a case where information regarding the receiver is prescribed information; and       

     an image synthesis apparatus including
         a pixel extraction section configured to extract the high-order bits and the low-order bits from the first frame and the second frame, respectively, in a case where the first frame and the second frame are received from a transmitter,   an image synthesis section configured to synthesize the high-order bits and the low-order bits to restore the video signal, and   a reception operation control section configured to make control so as to stop an operation of a reception section of receiving the second frame from the transmitter in a case where information regarding the receiver is prescribed information.       

     REFERENCE SIGNS LIST 
     
         
           1 A,  1 B image transmission system 
           10  transmitter (frame generation apparatus) 
           20 A receiver (image synthesis apparatus) 
           20 B receiver (signal generation apparatus) 
           101  image generation section 
           102  image division section 
           103  frame generation section 
           104  transmission section 
           105  transmission section 
           106  transmission operation control section 
           107  device information reception section 
           201  image display section 
           202  image synthesis section 
           203 A,  203 B pixel extraction section 
           204  reception section 
           205  reception section 
           206  reception operation control section 
           207  device information transmission section 
           208  multiplexer 
           209  signal generation section 
           30  cable 
           301  transmission path 
           302  transmission path 
           303  transmission path 
         Im 10  video signal