Patent Publication Number: US-2017372140-A1

Title: Head mounted display and transmission control method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2016-123900, filed on Jun. 22, 2016, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The technology disclosed in embodiments is related to a head mounted display and transmission control. 
     BACKGROUND 
     In recent years, there has been proposed an augmented reality 
     (AR) technology for superimposing and displaying an object on an image-captured image by using a display device such as a head mounted display (HMD). The image-captured image is image-captured by an imaging device installed in, for example, the HMD and is transmitted to a terminal device coupled to the HMD. By using image processing, the terminal device recognizes whether or not an AR marker exists on a continuously acquired image-captured image, for example. Based on a result of the image processing, the terminal device generates a superimposition image obtained by superimposing, on an image-captured image, an object such as an AR content, for example, and transmits the superimposition image to the head mounted display, thereby causing the superimposition image to be displayed. 
     Related technologies are disclosed in, for example, Japanese Laid-open Patent Publication No. 2015-122707 and Japanese Laid-open Patent Publication No. 2015-146113. 
     SUMMARY 
     According to an aspect of the invention, a device includes a camera configured to capture an image, and a processor configured to determine whether the image acquired from the camera includes an area having a shape corresponding to a reference object, when the image includes the area, transmit image data corresponding to the image at a first frame rate to another device, and when the image does not include the area, transmit, to the other device, the image data at a second frame rate less than the first frame rate. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating an example of a configuration of a transmission control system of an embodiment. 
         FIG. 2  is a diagram illustrating an example of a hardware configuration of an HMD. 
         FIG. 3  is a diagram illustrating an example of an object data storage unit. 
         FIG. 4  is a sequence diagram illustrating an example of transmission control processing of an embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In some cases, image-captured images image-captured by an HMD include an image-captured image including no AR marker. The image-captured image including no AR marker is considered as an image that does not have to be carefully watched by a user, and is not requested to have a high image quality or a high frame rate, in some cases. Therefore, the image-captured image including no AR marker is transmitted to a terminal device by the HMD in the same way as an image-captured image including an AR marker, thereby consuming extra electric power related to image processing, in some cases. 
     In one aspect, an object of the technology disclosed in the embodiments is to reduce a load of image transmission to a terminal device by a head mounted display. 
     Hereinafter, based on drawings, embodiments of a head mounted display, a transmission control program, and a transmission control methods disclosed in the present application will be described in detail. Note that the present embodiments do not limit the disclosed technology. In addition, the following embodiments may be arbitrarily combined to the extent that these do not contradict. 
     Embodiments 
       FIG. 1  is a block diagram illustrating an example of a configuration of a transmission control system of an embodiment. A transmission control system  1  illustrated in  FIG. 1  includes an HMD  10  and a terminal device  100 . The HMD  10  and the terminal device  100  are wirelessly coupled to each other on a one-to-one basis, for example. In other words, the HMD  10  functions as an example of a display unit of the terminal device  100 . Note that while, in  FIG. 1 , as for a pair of the HMD  10  and the terminal device  100 , one pair is illustrated as an example, the number of pairs of the HMDs  10  and the terminal devices  100  is not limited and an arbitrary number of pairs of the HMDs  10  and the terminal devices  100  may be included. 
     The HMD  10  and the terminal device  100  are coupled to each other by a wireless local area network (LAN) such as, for example, Wi-Fi Direct (registered trademark) so as to be able to communicate with each other. Note that the HMD  10  and the terminal device  100  may be coupled to each other by a wired line. 
     The HMD  10  is attached by a user along with the terminal device  100  and displays a display screen transmitted by the terminal device  100 . As the HMD  10 , a transmissive type HMD for a single eye may be used, for example. Note that various types of HMD such as, for example, a both-eye type and an immersive type may be used as the HMD  10 . In addition, the HMD  10  includes a camera serving as an example of an imaging device. 
     The HMD  10  sequentially acquires an image-captured image image-captured by the imaging device and transmits, to the terminal device  100 , the acquired image-captured image at a specific transmission rate. In this case, the HMD  10  determines whether or not the acquired image-captured image includes a predetermined shape. In a case where the predetermined shape is included, the HMD  10  performs control for increasing the transmission rate. In other words, based on whether or not the acquired image-captured image includes the predetermined shape, the HMD  10  changes the frame rate of the image-captured image and transmits the image-captured image to the terminal device  100 . For this reason, the HMD  10  is able to reduce a load of image transmission to the terminal device  100  by the HMD  10 . 
     In addition, the HMD  10  acquires an image-captured image image-captured by the imaging device. The HMD  10  determines whether or not the acquired image-captured image includes a predetermined shape. In a case where the predetermined shape is included, the HMD  10  transmits, to the terminal device  100 , image data that corresponds to the acquired image-captured image and that has a first data amount. In a case where no predetermined shape is included, the HMD  10  transmits, to the terminal device  100 , image data that corresponds to the acquired image-captured image and that has a second data amount less than the first data amount. In other words, the HMD  10  transmits, to the terminal device  100 , image data encoded by changing a bit rate thereof, based on whether or not the acquired image-captured image includes the predetermined shape. For this reason, the HMD  10  is able to reduce a load of image transmission to the terminal device  100  by the HMD  10 . 
     The terminal device  100  is an information processing device to be attached and operated by the user, and a mobile communication terminal such as, for example, a tablet terminal or a smartphone, or the like may be used. Upon receiving image data from, for example, the HMD  10 , the terminal device  100  decodes the received image data. In addition, upon receiving AR marker detection information transmitted and associated with image data by the HMD  10 , the terminal device  100  performs, on the corresponding image data, recognition processing of an AR marker and superimposed display processing of an AR content, thereby generating a superimposition image. The terminal device  100  transmits the generated superimposition image to the HMD  10  and causes the superimposition image to be displayed. Note that, in a case where no AR marker detection information is associated with the image data, the terminal device  100  transmits the received image data to the HMD  10  without change and causes the received image data to be displayed. 
     Next, a configuration of the HMD  10  will be described. As illustrated in  FIG. 1 , the HMD  10  includes a communication unit  11 , a camera  12 , a display unit  13 , a storage unit  14 , and a control unit  15 . Note that, in addition to the functional units illustrated in  FIG. 1 , the HMD  10  may include functional units such as, for example, various types of input device or sound-output device. 
     The communication unit  11  is realized by a communication module such as, for example, a wireless LAN, or the like. The communication unit  11  is a communication interface that is wirelessly coupled to the terminal device  100  by, for example, Wi-Fi Direct (registered trademark) and that controls communication of information with the terminal device  100 . The communication unit  11  transmits, to the terminal device  100 , image data corresponding to an image-captured image input by the control unit  15 . In addition, the communication unit  11  receives, from the terminal device  100 , image data corresponding to a superimposition image or image data corresponding to image data received by the terminal device  100 . The communication unit  11  outputs the received image data to the control unit  15 . 
     The camera  12  is an imaging device to image-capture a predetermined shape associated with an AR content, in other words, an AR marker. The camera  12  image-captures an image by using, as an imaging element, a complementary metal oxide semiconductor (CMOS) image sensor, a charge coupled device (CCD) image sensor, or the like, for example. The camera  12  subjects, to photoelectric conversion, light-received by the imaging element and performs analog/digital (A/D) conversion thereon, thereby generating an image-captured image. The camera  12  outputs the generated image-captured image to the control unit  15 . 
     The display unit  13  is a display device for displaying various kinds of information. The display unit  13  corresponds to, for example, a display element of a transmissive type HMD in which a video picture is projected on a half mirror and through which the user is able to see an outside scene along with the video picture. Note that the display unit  13  may be a display element corresponding to an HMD of an immersive type, a video transmissive type, a retina projection type, or the like. 
     The storage unit  14  is realized by a storage device such as, for example, a semiconductor memory element examples of which include a random access memory (RAM) and a flash memory (Flash Memory). The storage unit  14  stores therein information used for processing in the control unit  15 . 
     A central processing unit (CPU), a micro processing unit (MPU), or the like executes a program stored in an internal storage device while using the RAM as a working area, thereby realizing the control unit  15 , for example. In addition, the control unit  15  may be realized by an integrated circuit such as, for example, an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). 
     Here, by using  FIG. 2 , a hardware configuration of the HMD  10  will be described.  FIG. 2  is a diagram illustrating an example of a hardware configuration of an HMD. As illustrated in  FIG. 2 , in the HMD  10 , a wireless unit  11   a , the display unit  13 , the storage unit  14 , a key input unit  31 , an audio unit  32 , an image processing unit  35 , and a sensor control unit  37  are coupled to a processor  15   a  serving as an example of the control unit  15  via a bus not illustrated, for example. 
     The wireless unit  11   a  is an example of the communication unit  11 . The storage unit  14  includes, for example, a read only memory (ROM)  14   a  and a RAM  14   b . While being a power button of the HMD  10 , for example, the key input unit  31  may include a button having another function. A speaker  33  and a microphone  34  are coupled to the audio unit  32 . The audio unit  32  controls inputting and outputting of sounds, for example. The camera  12  is coupled to the image processing unit  35 . Based on pieces of information such as focus, exposure, a gain, a brightness value (BV) value, and a color temperature, input by, for example, the camera  12 , the image processing unit  35  controls the camera  12  and performs image processing on an image-captured image input by the camera  12 . Various sensors  36  such as, for example, an acceleration sensor and a geomagnetic sensor are coupled to the sensor control unit  37 . The sensor control unit  37  controls the various sensors  36 . 
     Returning to the description of  FIG. 1 , the control unit  15  includes an acquisition unit  16 , a determination unit  17 , a conversion unit  18 , a transmission control unit  19 , and a reception control unit  20  and realizes or performs a function or an operation of information processing described below. Note that an internal configuration of the control unit  15  is not limited to the configuration illustrated in  FIG. 1  and may adopt another configuration as long as adopting a configuration for performing the after-mentioned information processing. 
     The acquisition unit  16  acquires an image-captured image input by the camera  12 . In other words, the acquisition unit  16  sequentially acquires an image-captured image-captured by the imaging device. The acquisition unit  16  outputs the acquired image-captured image to the determination unit  17 . In addition, the acquisition unit  16  determines whether or not a signal for power-off is input by, for example, the key input unit  31 , in other words, whether or not to terminate processing. In a case where the processing is not to be terminated, the acquisition unit  16  continues acquiring an image-captured image input by the camera  12 . In a case where the processing is to be terminated, the acquisition unit  16  performs shutdown processing on each of the units of the HMD  10 . 
     In a case where an image-captured image is input by the acquisition unit  16 , the determination unit  17  determines whether or not the input image-captured image includes a predetermined shape. Here, the predetermined shape is a shape of an AR marker and is a rectangle, for example. In a case of determining that the image-captured image includes the predetermined shape, the determination unit  17  generates AR marker detection information and outputs, to the conversion unit  18 , the generated AR marker detection information along with image-captured image while associating the generated AR marker detection information with the image-captured image. In a case of determining that the image-captured image includes no predetermined shape, the determination unit  17  outputs the image-captured image to the conversion unit  18  while generating no AR marker detection information, in other words, while associating no AR marker detection information with the image-captured image. 
     The conversion unit  18  is an encoder/decoder that performs encoding on an acquired image-captured image and that performs decoding on a received image data. In a case where an image-captured image associated with the AR marker detection information is input by the determination unit  17 , the conversion unit  18  performs encoding on the input image-captured image at a high bit rate. In addition, the conversion unit  18  performs encoding at a frame rate tailored to a frame rate (a transmission rate) at which the transmission control unit  19  transmits to the terminal device  100 , for example. Note that the conversion unit  18  may perform encoding at a frame rate different from a frame rate at which the transmission control unit  19  transmits to the terminal device  100 . By using a main profile (MP) and Level3 of H.264, the conversion unit  18  performs encoding on an image-captured image having the resolution of 720×480 while setting a bit rate and a frame rate to 10 Mbit per second (Mbps) and 30 frame per second (fps), respectively, for example. The conversion unit  18  outputs, to the transmission control unit  19 , image data that is obtained by performing encoding on the image-captured image and that has the first data amount while associating the AR marker detection information with the image data having the first data amount. 
     In a case where an image-captured image associated with no AR marker detection information is input by the determination unit  17 , the conversion unit  18  performs, on the input image-captured image, encoding at a low bit rate. In addition, in the same way as in a case of the high bit rate, the conversion unit  18  performs encoding at a frame rate tailored to a frame rate (a transmission rate) at which the transmission control unit  19  transmits to the terminal device  100  in a case where no AR marker is detected, for example. By using the MP and Level2.2 of H.264, the conversion unit  18  performs encoding on an image-captured image having the resolution of 720×480 while setting a bit rate and a frame rate to 4 Mbps and 10 fps, respectively, for example. The conversion unit  18  outputs, to the transmission control unit  19 , image data that is obtained by performing encoding on the image-captured image and that has a second data amount less than the first data amount. Note that the conversion unit  18  may add, to the image data having the second data amount, information informing that no AR marker is detected. 
     In a case where received image data is input by the reception control unit  20 , the conversion unit  18  performs decoding on the input image data and outputs the decoded image data to the display unit  13 , thereby causing the decoded image data to be displayed therein. The received image data is decoded by, for example, H.264 used in Miracast (registered trademark). 
     In a case where the image data that is associated with the AR marker detection information and that has the first data amount is input by the conversion unit  18 , the transmission control unit  19  transmits, to the terminal device  100  via the communication unit  11 , the input image data having the first data amount while increasing the frame rate. The transmission control unit  19  transmits, to the terminal device  100 , the input image data having the first data amount while increasing the frame rate to 30 fps, for example. In other words, in a case where the predetermined shape is included, the transmission control unit  19  performs control for increasing the transmission rate. In addition, in a case where the predetermined shape is included, the transmission control unit  19  transmits, to the terminal device  100 , the image data that corresponds to the acquired image-captured image and that has the first data amount. 
     In a case where the image data that is associated with no AR marker detection information and that has the second data amount is input by the conversion unit  18 , the transmission control unit  19  transmits, to the terminal device  100  via the communication unit  11 , the input image data having the second data amount while decreasing the frame rate. The transmission control unit  19  transmits, to the terminal device  100 , the image data having the second data amount while decreasing the frame rate to 10 fps, for example. In other words, in a case where no predetermined shape is included, the transmission control unit  19  performs control for decreasing the transmission rate. In addition, in a case where no predetermined shape is included, the transmission control unit  19  transmits, to the terminal device  100 , the image data that corresponds to the acquired image-captured image and that has the second data amount less than the first data amount. Note that each of the image data having the first data amount and the image data having the second data amount is image data corresponding to an image-captured image. 
     Note that, in place of the AR marker detection information to be associated with the image data having the first data amount, the transmission control unit  19  may associate, with the image data having the second data amount, information informing that no AR marker is detected. In addition, the transmission control unit  19  associates the AR marker detection information with the image data having the first data amount and may associate, with the image data having the second data amount, information informing that no AR marker is detected. In other words, the transmission control unit  19  may add, to the image data having the first data amount or the image data having the second data amount, a result of determination of whether or not the predetermined shape is included and may transmit, to the terminal device  100 , the image data having the first data amount or the image data having the second data amount. 
     By use of Miracast (registered trademark) utilizing Wi-Fi Direct (registered trademark), the reception control unit  20  receives image data from the terminal device  100  via the communication unit  11 , for example. The image data is image data corresponding to a superimposition image on which an AR content is superimposed or image data corresponding to image data received by the terminal device  100 . The reception control unit  20  outputs the received image data to the conversion unit  18 . 
     Subsequently, a configuration of the terminal device  100  will be described. As illustrated in  FIG. 1 , the terminal device  100  includes a communication unit  110 , a display operation unit  111 , a storage unit  120 , and a control unit  130 . Note that, in addition to the functional units illustrated in  FIG. 1 , the terminal device  100  may include various functional units included in a known computer, for example, functional units such as various input devices and sound-output devices. 
     The communication unit  110  is realized by a communication module such as a wireless LAN, or the like, for example. The communication unit  110  is a communication interface that is wirelessly coupled to the HMD  10  by, for example, Wi-Fi Direct (registered trademark) and that controls communication of information with the HMD  10 . The communication unit  110  receives, from the HMD  10 , image data corresponding to an image-captured image. The communication unit  110  outputs the received image data to the control unit  130 . In addition, the communication unit  110  transmits, to the HMD  10 , image data that is input by the control unit  130  and that corresponds to a superimposition image, or image data corresponding to the received image data. 
     The display operation unit  111  is a display device for displaying various kinds of information and is an input device that receives various operations from the user. The display operation unit  111  is realized, as the display device, by a liquid crystal display or the like, for example. In addition, the display operation unit  111  is realized, as the input device, by a touch panel or the like, for example. In other words, in the display operation unit  111 , the display device and the input device are integrated with each other. The display operation unit  111  outputs an operation input by the user, to the control unit  130 , as operation information. Note that the display operation unit  111  may display the same screen as that of the HMD  10  or may display a screen different from that of the HMD  10 . 
     The storage unit  120  is realized by a storage device such as, for example, a semiconductor memory element, examples of which include a RAM and a flash memory, or a storage device, examples of which include a hard disk and an optical disk. The storage unit  120  includes an object data storage unit  121 . In addition, the storage unit  120  stores therein information used for processing in the control unit  130 . 
     The object data storage unit  121  stores therein object data.  FIG. 3  is a diagram illustrating an example of an object data storage unit. As illustrated in  FIG. 3 , the object data storage unit  121  includes items such as an “object identifier (ID)” and “object data”. The object data storage unit  121  stores therein one record for each piece of object data, for example. Note that the object data storage unit  121  may store therein another item, for example, location information while associating the other item with object data. 
     The “object ID” is an identifier for identifying object data, in other words, an AR content. The “object data” is information indicating object data. The “object data” is a data file configuring the object data, in other words, the AR content, for example. 
     A CPU, a MPU, or the like executes a program stored in an internal storage device while using the RAM as a working area, thereby realizing the control unit  130 , for example. In addition, the control unit  130  may be realized by an integrated circuit such as, for example, an ASIC or an FPGA. The control unit  130  includes a reception control unit  131 , a conversion unit  132 , an AR processing unit  133 , and a transmission control unit  134  and realizes or performs a function or an operation of information processing described below. Note that an internal configuration of the control unit  130  is not limited to the configuration illustrated in  FIG. 1  and may adopt another configuration as long as adopting a configuration for performing the after-mentioned information processing. 
     Upon receiving, from the HMD  10  via the communication unit  110 , image data, in other words, image data corresponding to an image-captured image, the reception control unit  131  outputs the received image data to the conversion unit  132 . In addition, in a case where AR marker detection information is associated with the received image data, the reception control unit  131  extracts and outputs the AR marker detection information from the received image data and to the AR processing unit  133 . 
     In a case where the received image data is input by the reception control unit  131 , the conversion unit  132  performs decoding on the input image data and outputs the decoded image data to the AR processing unit  133 . The received image data is decoded by, for example, H.264. 
     In a case where image data corresponding to a superimposition image or image data corresponding to the received image data is input by the AR processing unit  133 , the conversion unit  132  performs encoding on the input image data so that the image data is able to be transmitted by using Miracast (registered trademark). The conversion unit  132  performs the encoding by using H.264, for example. The conversion unit  132  outputs the encoded image data to the transmission control unit  134 . 
     In a case where the decoded image data is input by the conversion unit  132 , the AR processing unit  133  determines whether or not the AR marker detection information corresponding to the image data is input by the reception control unit  131 . In other words, the AR processing unit  133  determines whether or not an HMD  10  side detects an AR marker. In a case where it is determined that the HMD  10  side detects an AR marker, the AR processing unit  133  performs AR marker recognition processing on the image data. The AR processing unit  133  references the object data storage unit  121  and superimposes, on the image data, object data corresponding to a recognized AR marker, in other words, an AR content, thereby generating a superimposition image. The AR processing unit  133  outputs, to the conversion unit  132 , image data corresponding to the generated superimposition image. 
     In a case where it is determined that the HMD  10  side detects no AR marker, the AR processing unit  133  outputs the input image data to the conversion unit  132  without change. In other words, the AR processing unit  133  outputs, to the conversion unit  132 , image data corresponding to the received image data. 
     In a case where the encoded image data is input by the conversion unit  132 , the transmission control unit  134  transmits the input image data to the HMD  10  via the communication unit  110 . In other words, by use of Miracast (registered trademark) utilizing Wi-Fi Direct (registered trademark), the transmission control unit  134  transmits, to the HMD  10 , the image data corresponding to the superimposition image or the image data corresponding to the received image data, for example. 
     Next, an operation of the transmission control system  1  of an embodiment will be described.  FIG. 4  is a sequence diagram illustrating an example of transmission control processing of an embodiment. 
     In a case where the user applies power, for example, the HMD  10  in the transmission control system  1  activates the camera  12  (step S 1 ). Upon being activated, the camera  12  starts outputting an image-captured image to the control unit  15 . The acquisition unit  16  in the HMD  10  starts acquiring the image-captured image input by the camera  12  (step S 2 ). The acquisition unit  16  outputs the acquired image-captured image to the determination unit  17 . 
     In a case where the image-captured image is input by the acquisition unit  16 , the determination unit  17  determines whether or not the input image-captured image includes a shape of an AR marker (step S 3 ). In a case where it is determined that the image-captured image includes the shape of an AR marker (step S 3 : affirmative), the determination unit  17  generates the AR marker detection information and associates the generated AR marker detection information with the image-captured image, thereby outputting, to the conversion unit  18 , the AR marker detection information along with the image-captured image. 
     In a case where the image-captured image associated with the AR marker detection information is input by the determination unit  17 , the conversion unit  18  performs encoding on the input image-captured image at a high bit rate (step S 4 ). The conversion unit  18  associates the AR marker detection information with image data that is obtained by performing the encoding on the image-captured image and that has the first data amount, and the conversion unit  18  outputs, to the transmission control unit  19 , the image data having the first data amount. 
     In a case where the image data that is associated with the AR marker detection information and that has the first data amount is input by the conversion unit  18 , the transmission control unit  19  increase a frame rate, thereby transmitting, to the terminal device  100 , the input image data having the first data amount (step S 5 ). 
     In a case where it is determined that the image-captured image does not include a shape of an AR marker (step S 3 : negative), the determination unit  17  outputs the image-captured image to the conversion unit  18  while associating no AR marker detection information with the image-captured image. 
     In a case where the image-captured image associated with no AR marker detection information is input by the determination unit  17 , the conversion unit  18  performs, on the input image-captured image, encoding at a low bit rate (step S 6 ). The conversion unit  18  outputs, to the transmission control unit  19 , image data that is obtained by performing the encoding on the image-captured image and that has the second data amount. 
     In a case where the image data that is associated with no AR marker detection information and that has the second data amount is input by the conversion unit  18 , the transmission control unit  19  decreases a frame rate, thereby transmitting, to the terminal device  100 , the input image data having the second data amount (step S 7 ). 
     Upon receiving the image data from the HMD  10  (step S 8 ), the reception control unit  131  in the terminal device  100  outputs the received image data to the conversion unit  132 . In addition, in a case where the AR marker detection information is associated with the received image data, the reception control unit  131  extracts and outputs the AR marker detection information from the received image data and to the AR processing unit  133 . 
     In a case where the received image data is input by the reception control unit  131 , the conversion unit  132  performs decoding on the input image data (step S 9 ) and outputs the decoded image data to the AR processing unit  133 . 
     In a case where the decoded image data is input by the conversion unit  132 , the AR processing unit  133  determines whether or not the HMD  10  side detects an AR marker (step S 10 ). In a case where it is determined that the HMD  10  side detects an AR marker (step S 10 : affirmative), the AR processing unit  133  performs, on the image data, processing corresponding to the AR marker (step S 11 ). In other words, the AR processing unit  133  references the object data storage unit  121  and superimposes an AR content on the image data, thereby generating a superimposition image. The AR processing unit  133  outputs, to the conversion unit  132 , image data corresponding to the generated superimposition image. 
     In a case where it is determined that the HMD  10  side detects no AR marker (step S 10 : negative), the AR processing unit  133  outputs, to the conversion unit  132 , image data corresponding to the received image data. 
     In a case where the image data corresponding to the superimposition image or the image data corresponding to the received image data is input by the AR processing unit  133 , the conversion unit  132  performs encoding on the input image data (step S 12 ). The conversion unit  132  outputs the encoded image data to the transmission control unit  134 . 
     In a case where the encoded image data is input by the conversion unit  132 , the transmission control unit  134  transmits the input image data to the HMD  10  (step S 13 ). 
     The reception control unit  20  in the HMD  10  receives the image data from the terminal device  100  (step S 14 ). The reception control unit  20  outputs the received image data to the conversion unit  18 . 
     In a case where the received image data is input by the reception control unit  20 , the conversion unit  18  performs decoding on the input image data and outputs the decoded image data to the display unit  13 , thereby causing the decoded image data to be displayed (step S 15 ). 
     The acquisition unit  16  determines whether or not to terminate the processing (step S 16 ). In a case of not terminating the processing (step S 16 : negative), the acquisition unit  16  returns to step S 2 . In a case of terminating the processing (step S 16 : affirmative), the acquisition unit  16  performs shutdown processing on each of the units in the HMD  10 , thereby terminating the transmission control processing. For this reason, the HMD  10  is able to reduce a load of image transmission to the terminal device  100  by the HMD  10 . In other words, the HMD  10  and the terminal device  100  are able to reduce power consumption. 
     In this way, the HMD  10  sequentially acquires an image-captured by the camera  12  serving as the imaging device and transmits the acquired image-captured image to the terminal device  100  at a specific transmission rate. In this case, the HMD  10  determines whether or not the acquired image-captured image includes a predetermined shape. In addition, in a case where the predetermined shape is included, the HMD  10  performs control for increasing the transmission rate. As a result, it is possible to reduce a load of image transmission to the terminal device  100  by the HMD  10 . 
     In addition, in a case where no predetermined shape is included, the HMD  10  performs control for decreasing the transmission rate. As a result, it is possible to reduce a load of image transmission to the terminal device  100  by the HMD  10 . 
     In addition, the HMD  10  acquires an image-captured by the camera  12  serving as the imaging device. In addition, the HMD  10  determines whether or not the acquired image-captured image includes a predetermined shape. In addition, in a case where the predetermined shape is included, the HMD  10  transmits, to the terminal device  100 , image data that corresponds to the acquired image-captured image and that has the first data amount. In addition, in a case where no predetermined shape is included, the HMD  10  transmits, to the terminal device  100 , image data that corresponds to the acquired image-captured image and that has the second data amount less than the first data amount. As a result, it is possible to reduce a load of image transmission to the terminal device  100  by the HMD  10 . 
     In addition, the HMD  10  adds, to the image data having the first data amount or the image data having the second data amount, a result of determination of whether or not the predetermined shape is included, thereby transmitting, to the terminal device  100 , the image data having the first data amount or the image data having the second data amount. As a result, in the terminal device  100 , it is possible to omit recognition processing of an image-captured image including no AR marker. 
     Note that while the bit rate and the frame rate of image data are increased or decreased in the above-mentioned embodiment, there is no limitation to this. Only the bit rate of image data may be increased or decreased or only the frame rate thereof may be increased or decreased, for example. 
     In addition, while the AR marker detection information is transmitted by the HMD  10  in the above-mentioned embodiment, there is no limitation to this. The terminal device  100  may detect the bit rate or the frame rate of received image data and may perform the AR marker recognition processing or generation of a superimposition image in accordance with the detected bit rate or frame rate, for example. For this reason, even in a case where the HMD  10  transmits no AR marker detection information, the terminal device  100  is able to determine whether or not to perform processing related to an AR marker. 
     In addition, individual illustrated configuration items of each of units do not have to be physically configured as illustrated. In other words, specific states of the distribution or integration of the individual units are not limited to these illustrated in the drawings, and all or part thereof may be functionally or physically distributed or integrated in arbitrary units, depending on various loads, various usage situations, and so forth. The conversion unit  18 , the transmission control unit  19 , and the reception control unit  20  may be integrated, for example. In addition, individual illustrated processing operations are not limited to the above-mentioned order and may be simultaneously implemented or may be implemented while changing an order, in so far as processing contents do not contradict one another. 
     Furthermore, all or an arbitrary part of various processing functions performed by the respective devices may be performed on a CPU (or a microcomputer such as an MPU or a micro controller unit (MCU)). In addition, it goes without saying that all or an arbitrary part of the various processing functions may be performed on a program analyzed and executed by the CPU (or the microcomputer such as an MPU or an MCU) or may be performed on hardware based on hard-wired logic. 
     Note that, by reading and executing the transmission control program, the HMD  10  explained in the above-mentioned embodiment is able to perform the same functions as those of the processing described in  FIG. 1  and so forth. By executing processes to perform the same processing operations as those of the acquisition unit  16 , the determination unit  17 , the conversion unit  18 , the transmission control unit  19 , and the reception control unit  20 , the HMD  10  is able to perform the same processing operations as those of the above-mentioned embodiment, for example. 
     These programs may be distributed via a network such as the Internet. In addition, these programs may be recorded in a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, or a DVD and may be read from the recording medium by a computer, thereby being executed. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. cm. What is claimed is: