Communication system, communication device, and control method and program thereof

Abstract

To provide a technique for reducing delay in topic generation.SOLUTION: A communication system for distributing a message generated by a distribution device to a communication device owned by a mobile object using a publish / subscribe-type communication method identifies the mobile object to generate identification information on the mobile object, generates a topic based on the identification information, subscribes the communication device to the topic generated based on the identification information on the mobile object in response to receiving a request for subscription registration including information specifying the mobile object from the communication device, and distributes information generated on the topic by the distribution device to the communication device subscribed to the topic.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication system, a communication device, and a control method and program thereof. [Background technology]

[0002] In recent years, a traffic system has been proposed that makes it possible to obtain traffic information using images and sensor information acquired by cameras and sensors installed near vehicle travel paths (Patent Document 1).

[0003] Meanwhile, the application of publish / subscribe asynchronous communication methods such as ROS (Robot Operating System) and MQTT (Message Queueing Telemetry Transport) is being considered as a communication method between a server and a terminal (Patent Document 2). The use of publish / subscribe asynchronous communication allows publishers and subscribers to communicate without being aware of each other. This has the advantage of ensuring the scalability of the communication system and simplifying the implementation of communication processing in each terminal. In publish / subscribe communication, topics are manually set, and publishers and subscribers distribute information via the set topics. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2007-293563 [Patent Document 2] Patent No. 6402077 Summary of the Invention [Problem to be solved by the invention]

[0005] Consider a case where road information obtained from cameras or sensors installed on roads is notified to vehicles via a topic using a publish / subscribe communication method. To notify road information using publish / subscribe communication, both the publisher and subscriber devices must hold the topic information in advance. In other words, if topic information is not shared in advance between the camera or sensor functioning as the publisher and the vehicle functioning as the subscriber, the road information obtained from the camera or sensor cannot be notified to the vehicle.

[0006] In a publish / subscribe communication system, once a topic is generated, publishers can generate and distribute information, and subscribers can receive the information. That is, once a topic is generated, a publisher can distribute (publish) road information for that topic, and once a subscriber (e.g., a vehicle) subscribes to that topic, it can receive the distributed road information. However, if the generation of a topic is delayed, there will be a delay between when road information is needed and when the generation and notification of road information actually begins for the vehicle, which can lead to issues such as a failure to obtain useful information. For example, in a configuration where topics are generated manually, topic generation may be delayed. Furthermore, if the radio wave conditions between the subscriber and the broker are poor, the subscriber's subscription registration will be delayed.

[0007] On the other hand, if the information published to a topic contains information other than the information required by the subscriber, the processing load of selecting the information increases on the subscriber side. To reduce the subscriber's computational resources, there is also the issue of dynamically generating topics specialized for information relevant to the subscriber. As described above, in order to obtain necessary road information and the like using communication devices carried by mobile objects such as vehicles and people as subscribers, it is desirable to generate topics at the required timing without delay and to register the communication devices as subscribers.

[0008] The present invention provides a technique for reducing the latency of topic creation. [Means for solving the problem]

[0009] A communication system according to one aspect of the present invention comprises the following arrangement: A communication system that distributes messages generated by a distribution device to communication devices owned by mobile objects using a publish / subscribe communication method, an identification means for identifying the moving object and generating identification information for the moving object; a generation means for generating a topic based on the identification information; a registration means for subscribing and registering the communication device to the topic generated based on the identification information of the mobile device in response to receiving a subscribe registration request including information identifying the mobile device from the communication device; a distribution unit that distributes information generated by the distribution device regarding the topic to the communication device that has been registered as a subscriber to the topic by the registration unit. 、 the identification unit generates the identification information based on detection of information capable of identifying the moving object in the image acquired by the distribution device; and The generating means generates the topic associated with the identification information based on the generation of the identification information. do. [Effects of the Invention]

[0010] According to the present invention, the latency of topic creation is reduced. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a communication system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a schematic diagram showing another example of the configuration of the communication system according to the present embodiment. [Figure 3] FIG. 2 is a block diagram showing an example of the functional configuration of a camera (publisher). [Figure 4] Block diagram showing an example of the functional configuration of a relay device (broker) [Figure 5]FIG. 2 is a block diagram showing an example of the functional configuration of a vehicle (subscriber). [Figure 6] FIG. 2 is a sequence diagram showing a communication procedure of the communication system according to the present embodiment. [Figure 7] FIG. 2 is a sequence diagram showing a communication procedure of the communication system according to the present embodiment. [Figure 8] FIG. 2 is a sequence diagram showing a communication procedure of the communication system according to the present embodiment. [Figure 9] 10 is a flowchart showing the operation of a camera (publisher). [Figure 10] 10 is a flowchart showing the operation of a topic management unit in a relay device (broker). [Figure 11] 10 is a flowchart showing the operation of a publish control unit in a relay device (broker). [Figure 12] 10 is a flowchart showing the operation of a vehicle (subscriber). [Figure 13] FIG. 10 is a diagram showing an example of an information table showing the correspondence between topic names and vehicle identifiers. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0013] FIG. 1 is a schematic diagram showing an example of the configuration of a communication system according to this embodiment. A camera 101 is installed to monitor the situation at an intersection and captures images of the intersection. The camera 101 functions as a publisher in a publish / subscribe system, generating information related to a topic from the captured image and transmitting the generated information to the topic. The camera 101 is an example of a publisher that generates information related to a topic and distributes it to the topic; the image capture function and distribution function may be provided by separate devices. The relay device 102 is a communication device that acts as a broker that relays and distributes communications in a publish / subscribe system. The vehicle 103 is a vehicle traveling on a road and is equipped with a communication device that functions as a subscriber. The wireless base station 104 wirelessly communicates with the camera 101 and the vehicle 103. The camera 105 has the same functions as the camera 101 and is installed at the intersection. The information server 106 functions as a publisher, generating and distributing traffic information and other information to the vehicle 103 and other vehicles. In FIG. 1, a camera 101 , a camera 105 , and a vehicle 103 can communicate with a relay device 102 and an information server 106 via a wireless base station 104 .

[0014] FIG. 2 is a schematic diagram showing another example of the configuration of the communication system according to this embodiment. Cameras 101 and 105 are installed at an intersection and have the same functions as those in FIG. 1. A vehicle 103 is equipped with a communication device capable of functioning as a subscriber and travels along a road. Relay device 102 in FIG. 2 is a communication device that has a short-range wireless communication function that covers the vicinity of the intersection and operates as a broker. Cameras 101 and 105 are connected to relay device 102 by wire. Furthermore, vehicle 103 and relay device 102 are connected via short-range wireless communication and are configured to be able to communicate with each other.

[0015] FIG. 3 is a block diagram showing an example of the functional configuration of the camera 101 according to this embodiment. In FIG. 3, the control unit 111 controls the operation of the camera 101. The control unit 111 includes, for example, one or more processors (e.g., a CPU) and memories (ROM, RAM), not shown, and executes programs stored in the memories to perform various controls. The imaging unit 112 captures an image of a subject and generates image data. The communication unit 113 communicates with external devices wirelessly or via a wired connection. The storage unit 114 stores the image data generated by the imaging unit 112 and stores information used by the control unit 111. The image analysis unit 115 analyzes the captured image data to detect moving objects and their identification information, and detects events related to a topic. The publishing unit 116 controls information related to a topic and notifies external devices via the communication unit 113. The communication unit 113 communicates with the relay device 102 via a wireless communication connection (FIG. 1) or a wired communication connection (FIG. 2). Note that part of the above-described configuration may be realized by the control unit 111, i.e., a CPU that executes a predetermined program stored in memory. For example, the image analysis unit 115 and the publishing unit 116 may be realized by the control unit 111, by dedicated hardware, or by a combination of these.

[0016] FIG. 4 is a block diagram showing an example of the functional configuration of the relay device 102 according to this embodiment. In FIG. 4, the control unit 121 controls the operation of the relay device 102. The control unit 121 has, for example, one or more processors (e.g., CPU) and memories (ROM, RAM), not shown, and performs various controls by executing programs stored in the memory. The topic management unit 122 generates topics and notifies external devices of the topics via the communication unit 123. The communication unit 123 communicates with external devices wirelessly or via a wired connection. For example, the communication unit 123 communicates with the wireless base station 104 via a wired connection and with the vehicle 103 via a wireless connection. The storage unit 124 stores information used by the control unit 121, the topic management unit 122, etc. The publish control unit 125 relays and distributes topic information. Note that part of the above-described configuration may be realized by the control unit 121, i.e., a CPU that executes a predetermined program stored in the memory. For example, the topic management unit 122 and the publish control unit 125 may be realized by the control unit 121, by dedicated hardware, or by a combination of these.

[0017] FIG. 5 is a block diagram showing an example of the functional configuration of a communication device (hereinafter simply referred to as the vehicle 103) mounted on the vehicle 103 according to this embodiment. In FIG. 5, a control unit 131 controls the communication functions of the vehicle 103. The control unit 131 has, for example, one or more processors (e.g., CPU) and memories (ROM, RAM), not shown, and performs various controls by executing programs stored in the memory. The display unit 132 displays information notified via topics and information from the control unit 131. The communication unit 133 performs wireless communication between the vehicle devices of the vehicle 103 and external devices (e.g., the relay device 102). The storage unit 134 stores information received via topics and information displayed on the display unit 132 by the control unit 131. The subscribe control unit 135 performs a subscribe process to acquire information from a publisher device. The location information processing unit 136 detects and stores the location, traveling direction, traveling speed, etc. of the vehicle 103. The location information may be acquired to determine a topic to select and whether or not to execute a subscription. Note that part of the above-described configuration may be realized by the control unit 131, i.e., a CPU that executes a predetermined program stored in memory. For example, the subscribe control unit 135 and the location information processing unit 136 may be realized by the control unit 131, or may be realized by dedicated hardware, or may be realized by a combination of these.

[0018] FIG. 6 is a diagram showing a communication operation sequence of the communication system of this embodiment. In FIG. 6, when the vehicle 103 travels and enters the imageable range of the camera 101 (imaging unit 112), the image analysis unit 115 of the camera 101 detects the vehicle 103 as a moving object from the captured image obtained from the imaging unit 112 (F301). The publishing unit 116 transmits vehicle detection information including identification information (vehicle identifier) ​​for identifying the vehicle 103 detected by the image analysis unit 115 to the relay device 102 via the communication unit 113 (F302). Note that in this embodiment, the vehicle 103 is also referred to as "vehicle A." Upon receiving the vehicle detection information, the topic management unit 122 of the relay device 102 determines a topic name for the detected vehicle and generates a topic (F303).

[0019] FIG. 13 is a diagram showing an example of an information table showing the correspondence between topic names and vehicle identifiers in this embodiment. The image analysis unit 115 acquires a vehicle number from an image of a license plate included in an image captured by the imaging unit 112, and uses this as a vehicle identifier to generate and transmit vehicle detection information. The topic management unit 122 generates a topic based on the vehicle identifier. In this embodiment, the vehicle number is used as the vehicle identifier, and the topic management unit 122 determines a topic name from the vehicle number according to a predetermined naming rule to generate a topic. In this case, the topic management unit 122 generates an information table as shown in FIG. 13, in which the vehicle number and the topic name are associated. Alternatively, the topic name may be determined from the vehicle number by referring to an information table in which the correspondence between vehicle numbers and topic names is registered in advance. In this case, a topic will not be generated for a vehicle number not registered in the information table.

[0020] The topic management unit 122 sets the generated topic in the publish control unit 125 (F304) and notifies the camera 101 of the generated topic (topic name) (F305). With the topic set, the publish control unit 125 becomes able to relay and distribute distributed information. That is, the publish control unit 125 transmits the information published to the topic to subscribers who have registered to subscribe to the topic. Furthermore, the camera 101, upon being notified of the topic, becomes able to publish information using the notified topic. When the image analysis unit 115 of the camera 101 detects an event related to the vehicle 103 from the captured image from the imaging unit 112 (F306), the publishing unit 116 generates information (event 1 information) including a message notifying the detected event. The publishing unit 116 publishes the generated information (event 1 information) to the relay device 102 using the topic name notified in F305 for the vehicle 103 (i.e., vehicle A) (F307).

[0021] Meanwhile, when the communication unit 133 of the vehicle 103 enters the communication range of the wireless base station 104, it executes wireless connection processing with the wireless base station 104, and becomes able to communicate with the relay device 102 via the wireless base station 104 (F308). When the wireless connection processing with the relay device 102 is completed, the subscribe control unit 135 transmits a request for subscribing to a topic related to the vehicle (vehicle 103) provided by the relay device 102 (F309). The subscribe registration request transmitted from the subscribe control unit 135 includes information for identifying the vehicle 103, and the publish control unit 125 uses this information to determine a topic to which the vehicle 103 is to be subscribed. For example, the subscribe registration request includes information about the vehicle number of the vehicle 103. In this case, the publish control unit 125 determines a topic name from the notified vehicle number by referring to the information table described with reference to FIG. 13, and performs subscription registration to the corresponding topic.

[0022] When the subscription registration is complete, the publish control unit 125 of the relay device 102 distributes (publishes) to the vehicle 103 information received from the camera 101 using a topic name related to the vehicle 103. For example, if information related to the vehicle 103 received from the camera 101 before the vehicle 103 was registered as a subscriber is stored in the storage unit 114, the information is transmitted to the vehicle 103 (F310). Furthermore, when the image analysis unit 115 detects the occurrence of an event related to the vehicle 103 (F311), the publishing unit 116 generates information (event 2 information) including a message notifying the detected event. The publishing unit 116 then publishes the information to the relay device 102 using the topic name notified in F205 (F312). The publish control unit 125 of the relay device 102 publishes the notified information to the vehicles 103 that have subscribed to the topic (F313). As indicated by F306 to F307 and F311 to F312, when the camera 101 is notified of the topic name related to the vehicle 103, it publishes information about an event related to the vehicle 103 regardless of the subscription state of the vehicle 103.

[0023] Thereafter, when the vehicle 103 moves out of the image capture range of the imaging unit 112 due to its movement, the image analysis unit 115 detects that the vehicle 103 is no longer present in the image capture range (F314). When the image analysis unit 115 detects that the vehicle 103 is no longer present in the image capture range, the publishing unit 116 notifies the relay device 102 of vehicle non-detection information indicating that the vehicle 103 is in a non-detection state (F315). In the relay device 102 that has received the notification that the vehicle 103 has entered an non-detection state, the topic management unit 122 requests the publish control unit 125 to unsubscribe from the topic related to the vehicle 103 (F316). The publish control unit 125 unsubscribes from the topic specified by this request, and notifies the vehicle 103 that has subscribed to the topic of unsubscription (F317). Note that after the vehicle 103 enters an undetected state, the image analysis unit 115 and publishing unit 116 of the camera 101 stop generating and distributing information related to the vehicle 103. Alternatively, for example, the topic management unit 122 of the relay device 102 may receive the vehicle undetected information (F315) and notify the camera 101 of the cancellation of the topic. Alternatively, the publishing control unit 125 may receive a publishing cancellation request (F316) and notify the camera 101 of the cancellation of the topic. The image analysis unit 115 and publishing unit 116 of the camera 101 that have been notified of the topic cancellation stop generating and distributing information related to the vehicle 103 corresponding to the topic for which the cancellation was notified.

[0024] While FIG. 6 illustrates a configuration in which the camera 101 publishes information via the broker function (topic management unit 122 and publish control unit 125) of the relay device 102, the camera 101 may also publish information to the vehicle 103. In this case, the broker function of the relay device 102 is incorporated into the camera 101, which is the publisher, and the relay device 102 having the broker function can be omitted. Also, some functions of the relay device 102, such as the function of the topic management unit 122, may be incorporated into the camera 101, which is the publisher. In the example of FIG. 6, a topic is always generated when the camera 101 detects the vehicle 103 as a moving object, but this is not a limitation. For example, whether to generate a topic may be determined based on individual information such as the type of moving object (vehicle or person) or the vehicle's license plate number. Furthermore, the determination conditions may be preprogrammed or arbitrarily changeable. Alternatively, a UI may be configured in which a video of the moving object and related information are displayed, allowing an operator or the like to select whether to generate a topic.

[0025] FIG. 7 is a diagram showing a sequence in the present embodiment when multiple cameras (camera 101 and camera 105) are installed at an intersection. While FIG. 6 shows an example in which one camera 101 is installed as a publisher, FIG. 7 shows an example in which two cameras 101 and 105 are installed as publishers. In FIG. 7, when a vehicle 103 travels and enters the image capture range of the camera 101 (imaging unit 112), the image analysis unit 115 detects the vehicle 103 as a moving object (F401). The publishing unit 116 transmits vehicle detection information indicating that the vehicle 103 has been detected to the relay device 102 (F402). Upon receiving the vehicle detection information, the topic management unit 122 of the relay device 102 determines a topic name based on the vehicle identifier included in the vehicle detection information and generates a topic related to the vehicle 103 (F403). The topic management unit 122 sets the generated topic in the publish control unit 125 so that information on the topic can be relayed and distributed (F404). The topic management unit 122 also notifies all communication devices (in this example, the cameras 101 and 105) that exist as publishers of the generated topic (topic name) (F405, F406). The cameras 101 and 105 that have been notified of the topic generate information about the vehicle 103 and publish it using the notified topic. In the example of FIG. 7, an event related to the vehicle 103 is detected by the camera 101 (image analysis unit 115) (F407). The publishing unit 116 of the camera 101 generates information including a message notifying of the detected event and publishes the generated information to the relay device 102 using the notified topic (F408).

[0026] On the other hand, when the vehicle 103 enters the communication range of the wireless base station 104, the communication unit 133 executes wireless connection processing with the wireless base station 104, and becomes able to communicate with the relay device 102 via the wireless base station 104 (F409). When the wireless connection processing is completed, the subscribe control unit 135 of the vehicle 103 transmits to the relay device 102 a request for subscription registration to a topic related to the vehicle 103 (F410). When the subscription registration is completed in the same manner as the procedure described above in FIG. 6, the publish control unit 125 of the relay device 102 becomes able to transmit to the vehicle 103 information published using the topic related to the vehicle 103. If there is information on the topic related to the vehicle 103 that was received and stored before the vehicle 103 was registered for subscription, the publish control unit 125 transmits the information to the vehicle 103. 10, information related to the vehicle 103 received from the camera 101 before the vehicle 103 was subscribed is stored in the storage unit 114 (F407, F408). Therefore, the publish control unit 125 transmits this information to the vehicle 103 (F411).

[0027] Thereafter (after subscription registration), when the camera 101 and the camera 105 detect an event related to the vehicle 103, they distribute information notifying the event, and the relay device 102 relays this information and distributes it to the vehicle 103. For example, in FIG. 10 , the image analysis unit 115 of the camera 105 detects that an event related to the vehicle 103 has occurred (F412). Then, the publishing unit 116 publishes information including a message notifying the detected event to the relay device 102 using the topic notified about the vehicle 103 (F413). The publishing control unit 125 of the relay device 102 transmits the received information to the vehicle 103 that has subscribed to the topic (F414). Similarly, the image analysis unit 115 of the camera 101 detects that an event related to the vehicle 103 has occurred (F415). Then, the publishing unit 116 of the camera 101 generates information including a message notifying the detected event and transmits the information to the relay device 102 using the topic notified about the vehicle 103 (F416). The publishing control unit 125 of the relay device 102 transmits the received information to the vehicles 103 that have subscribed to the topic (F417).

[0028] When the image analysis unit 115 of the camera 101 detects that the vehicle 103 has moved out of the imageable range (F418), the publishing unit 116 of the camera 101 notifies the relay device 102 that the vehicle 103 has entered an undetected state (F419). Similarly, when the image analysis unit 115 of the camera 105 detects that the vehicle 103 has moved out of the imageable range (F420), the publishing unit 116 of the camera 105 notifies the relay device 102 that the vehicle 103 has entered an undetected state (F421). When the relay device 102 receives notifications from both the camera 101 and the camera 105 that the vehicle 103 has entered an undetected state (vehicle undetection information), the relay device 102 cancels publishing to the topic related to the vehicle 103. That is, the topic management unit 122 notifies the publish control unit 125 of a request (publish unsubscription request) to unsubscribe the vehicle 103 (F422). Upon receiving this request, the publish control unit 125 notifies the subscribed vehicle 103 of the unsubscription (F423).

[0029] While Fig. 7 shows an example sequence in which a topic is generated when the vehicle 103 is detected by the camera 101 first, a topic is also generated in the same way when the camera 105 detects the vehicle 103 first. Note that a configuration may be adopted in which a topic is generated when both the camera 101 and the camera 105 detect the vehicle 103. Furthermore, Fig. 7 shows an example in which publishing to a topic is canceled when the vehicle 103 is determined to be in an undetected state by both the camera 101 and the camera 105, but publishing may also be canceled when either one of them becomes undetected.

[0030] 8 is a diagram illustrating an example of a sequence of a communication system in which an information server 106, which functions as a publisher and provides predetermined information to subscribers, is arranged in addition to a camera 101, which functions as a publisher. The information server 106 provides, for example, guidance information for guiding a vehicle and obstacle information.

[0031] 8, when the vehicle 103 travels and enters the image capture range of the imaging unit 112 of the camera 101, the image analysis unit 115 detects the vehicle 103 as a moving object (F501). The image analysis unit 115 transmits vehicle detection information including a vehicle identifier that identifies the detected vehicle 103 to the relay device 102 via the communication unit 113 (F502). Upon receiving the vehicle detection information, the topic management unit 122 of the relay device 102 determines a topic name based on the vehicle identifier and generates a topic related to the vehicle 103 (F503). The topic management unit 122 sets the generated topic in the publish control unit 125 (F504) and notifies the camera 101 and the information server 106 of the generated topic (F505, F506). Upon being notified of the topic, the publish control unit 125 becomes able to relay and distribute information distributed to the topic. The publishers (here, the camera 101 and the information server 106) that have been notified of the topic can publish information using the notified topic. The information server 106 generates information (guidance information in this example) related to the topic notified in F505 based on the information it holds (F507), and publishes the generated information to the relay device 102 using the topic (F508). Also, in FIG. 8, the image analysis unit 115 of the camera 101 detects an event related to the vehicle 103 (F509). The publishing unit 116 of the camera 101 generates information including a message notifying of the detected event, and publishes the information to the relay device 102 using the topic notified in F505 (F510).

[0032] On the other hand, when the vehicle 103 enters the communication range of the wireless base station 104, the communication unit 133 of the vehicle 103 executes wireless connection processing with the wireless base station 104, and becomes able to communicate with the relay device 102 via the wireless base station 104 (F511). When the wireless connection processing is completed, the subscribe control unit 135 of the vehicle 103 transmits a subscribe request to the topic related to the vehicle to the relay device 102 (F512). When the subscription registration of the vehicle 103 is completed according to the procedure described in FIG. 6, the publish control unit 125 of the relay device 102 transmits to the vehicle 103 the information published to the topic related to the vehicle 103. If information related to the vehicle 103 received from the information server 106 or the camera 101 before the vehicle 103 was registered as a subscriber is stored in the storage unit 114, the publish control unit 125 transmits the information to the vehicle 103. 8, the guidance information received from the information server 106 and the information received from the camera 101 are transmitted to the vehicle 103 (F513, F514). After subscribing, as in FIGS. 6 and 7, each time information about the vehicle 103 is published from the information server 106 or the camera 101, the publish control unit 125 of the relay device 102 transmits the information to the vehicle 103.

[0033] When the vehicle 103 moves and the camera 101 detects that the vehicle 103 has moved out of the imageable range (F515), the camera 101 notifies the relay device 102 that the vehicle has entered an undetectable state (F516). Upon receiving the notification that the vehicle has entered an undetectable state, the relay device 102 starts unpublishing the topic. That is, the topic management unit 122 notifies the publish control unit 125 of a request to unsubscribe from the topic related to the vehicle 103 (F517). The publish control unit 125 cancels the setting of the topic related to the vehicle 103 and notifies the vehicle 103 of the unsubscription (F518). The publish control unit 125 also notifies the information server 106 that the topic has been canceled (topic cancellation notification, F519), and causes the information server 106 to stop sending information to the topic. In cases where it is better to continue the topic and publish information even when the vehicle 103 leaves the imaging range of the camera 101, such as when the information handled by the information server 106 is wide-area information, the configuration may be such that the information from the information server 106 can be continued to be received. Note that the topic cancellation may be notified to the vehicle 103 from the topic management unit 122.

[0034] FIG. 9 is a flowchart illustrating the operation of the camera 101 functioning as a publisher in this embodiment. The flowchart in FIG. 9 shows processing executed by the camera 101 or the camera 105 to realize the operation of the camera 101 shown in FIGS. 6, 7, and 8. When a captured image is acquired by the imaging unit 112 in the camera 101 (EYS in S601), processing related to the captured image (S602 to S611) is executed. First, the image analysis unit 115 performs image analysis to detect a moving object from the acquired captured image (S602). In this example, a vehicle is used as the detected moving object. The image analysis unit 115 identifies the vehicle from the information on the type and vehicle number of the vehicle detected in S602, and determines whether a new vehicle has been detected (S603). If a new vehicle has been detected (YES in S603), the publishing unit 116 generates vehicle detection information including identification information (vehicle identifier) ​​for identifying the vehicle, and transmits the information to the relay device 102 (S604). Furthermore, if the image analysis in S602 results in a vehicle that was previously detected becoming undetectable (YES in S605), publishing unit 116 generates vehicle non-detection information including identification information (vehicle identifier) ​​that identifies the vehicle that has become undetected. Publishing unit 116 then transmits the generated vehicle non-detection information to relay device 102 (S606). Thereafter, publishing unit 116 cancels the setting of the topic in publishing unit 116.

[0035] If a topic has been set in the publishing unit 116 (YES in S608), the image analysis unit 115 performs image analysis processing on the captured image to detect an event related to the vehicle that corresponds to the set topic (S609). The topic set in the publishing unit 116 is a topic that was set in S613 and has not been released in S607. If an event is detected by the image analysis processing (YES in S610), the publishing unit 116 generates information for notifying the detected event and publishes it to the relay device 102 using the topic set for the related vehicle (S611). On the other hand, if a new topic has been notified (YES in S612) rather than the acquisition of a captured image (NO in S601), the publishing unit 116 sets the notified topic in the publishing unit 116. The publishing unit 116 determines whether the notified topic is the same as an existing topic, and sets the topic if it is determined to be a new topic.

[0036] FIG. 10 is a flowchart showing processing by the topic management unit 122 of the relay device 102 in this embodiment. The flowchart in FIG. 10 shows processing executed by the topic management unit 122 to realize the operations shown in FIGS. 6, 7, and 8. The topic management unit 122 determines whether vehicle detection information has been received from an external device (e.g., the camera 101) (S701). If vehicle detection information has been received (YES in S701), the topic generation processing of S702 to S704 is executed. In the topic generation processing, the topic management unit 122 determines a topic name based on the vehicle identifier included in the vehicle detection information received from the camera 101, and generates a corresponding topic (S702). At this time, the topic management unit 122 determines whether the received vehicle detection information is the same as vehicle detection information that has already been received, and generates a topic if it is determined to be new vehicle detection information. The topic management unit 122 performs publishing settings using the topic (topic name) generated in S702 (S703). In the publish setting, a publish function is set so that the publish control unit 125 can distribute information published to the topic generated in S702 to registered subscribers. This publish setting enables the publish control unit 125 to execute relay processing, which transmits information on the topic to subscribers who have registered to subscribe to the topic. Furthermore, the topic management unit 122 notifies the camera 101 (and / or camera 105, information server 106), which functions as a publisher, of the topic generated in S702 (S704). Furthermore, when the topic management unit 122 receives vehicle non-detection information from a publisher (for example, the camera 101) (YES in S705), it cancels the publish setting for the topic related to the vehicle identifier included in the vehicle non-detection information (S706).

[0037] FIG. 11 is a flowchart showing processing by the publish control unit 125 of the relay device 102. The flowchart in FIG. 11 shows processing executed by the publish control unit 125 to realize the operations shown in FIGS. 6, 7, and 8. The publish control unit 125 determines whether or not a publish setting instruction has been received from the topic management unit 122 (S801). If a publish setting instruction has been received (YES in S801), the publish control unit 125 sets the publish function so that information published regarding the topic specified by the instruction can be sent to subscribers (S802). Furthermore, if a publish unsubscribe request has been received from the topic management unit 122 (YES in S803), the publish control unit 125 unsets the topic specified by the notified publish unsubscribe request (S804). Then, the publish control unit 125 notifies vehicles corresponding to the topic of unsubscription (S805).

[0038] When the publish control unit 125 receives a subscribe registration request from a vehicle (YES in S806), it subscribes to the vehicle that sent the request (S807). The subscribe registration request includes information that identifies the vehicle that sent the request (for example, a vehicle license plate number). The publish control unit 125 subscribes to the identified vehicle to a topic corresponding to the vehicle. Thereafter, if there is information that has been published to the corresponding topic and stored in the storage unit 124, the publish control unit 125 transmits that information to the vehicle that was subscribed to in S807 (S808).

[0039] Furthermore, the publish control unit 125 determines whether information published to the set topic has been received from an external device (for example, the camera 101 (105) or the information server 106) (S809). If it is determined that the information published to the topic has been received (YES in S809), the publish control unit 125 determines whether the vehicle has subscribed to the topic (S810). If the vehicle has not subscribed to the topic (NO in S810), the publish control unit 125 stores the received information in the storage unit 124 (S811). The stored information is transmitted in S808 after the vehicle has subscribed. On the other hand, if the vehicle has subscribed to the topic (YES in S810), the publish control unit 125 transmits the information to the subscribed vehicles (S812).

[0040] 12 is a flowchart showing the processing performed when the vehicle 103 enters the communication range of the wireless base station 104 in this embodiment. The communication unit 133 of the vehicle 103 establishes a wireless communication connection with the wireless base station 104, and then establishes a wireless communication connection with the relay device 102 (S901). When the wireless communication connection with the relay device 102 is established (YES in S902), the subscribe control unit 135 requests the relay device 102 to subscribe (S903). More specifically, the subscribe control unit 135 transmits a subscribe registration request including identification information of the vehicle (e.g., vehicle number) to the relay device 102 so that the vehicle can receive information on topics related to the vehicle. Upon receiving the subscribe registration request, the relay device 102 subscribes to the vehicle as described in S807.

[0041] Thereafter, the control unit 131 of the vehicle 103 waits for information on the topic transmitted from the relay device 102 (information transmitted in S808 or S812) and receives it via the communication unit 133 (S904). The control unit 131 presents the information received in S904 to the user via, for example, the display unit 132. The control unit 131 maintains the information standby state until an unsubscribe notification is received from the relay device 102 (while the determination in S905 is NO). When an unsubscribe notification is received from the relay device 102 (YES in S905), this process ends, and the standby state for information distributed from the relay device 102 is canceled.

[0042] The present invention is not limited to the above-described embodiment, and various modifications can be made and applied to various embodiments without departing from the spirit and scope of the present invention. For example, in the above embodiment, a vehicle is used as an example of a moving object, but this is not limiting. For example, the moving object may be a person. In this case, the image analysis unit 115 of the camera 101 may identify the person through facial recognition, for example, and notify the relay device 102. The topic management unit 122 generates a topic name based on the person's recognition information and sets the topic in the publish control unit 125. Furthermore, the publish control unit 125 subscribes the person's mobile phone to the topic through communication with the person's mobile phone and distributes information. In such a communication system, the person's mobile phone number can be used as the person's recognition information.

[0043] In the above embodiment, the camera 101, which is the publisher, recognizes the moving object by analyzing the captured image acquired by the imaging unit 112, but the present invention is not limited to this. For example, the moving object (vehicle) may be identified by wireless communication such as that used in ETC (Electronic Toll Collection System) gates.

[0044] As described above, according to the embodiment, by transmitting and receiving information between a publisher and a subscriber via a dynamically generated topic, it becomes possible to notify the subscriber of highly relevant information without delay. This makes it possible to realize an information notification system that is more efficient and has lower latency than conventional systems. In addition, when a moving vehicle attempts to obtain information related to the vehicle using a publish / subscribe communication method, the problem of being unable to start receiving information promptly due to waiting times incurred for topic generation and subscribing operations is solved.

[0045] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0046] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0047] 101: camera, 102: relay device, 103: vehicle, 104: wireless base station, 105: camera, 106: traffic information server

Claims

1. A communication system that distributes messages generated by a distribution device to communication devices owned by mobile objects using a publish / subscribe communication method, an identification means for identifying the moving object and generating identification information for the moving object; a generation means for generating a topic based on the identification information; a registration means for subscribing and registering the communication device to the topic generated based on the identification information of the mobile device in response to receiving a subscribe registration request including information identifying the mobile device from the communication device; a distribution unit that distributes information generated by the distribution device regarding the topic to the communication device that has been registered as a subscriber to the topic by the registration unit, the identification unit generates the identification information based on detection of information capable of identifying the moving object in the image acquired by the distribution device; and The generating means generates the topic associated with the identification information based on the generation of the identification information. A communication system comprising:

2. 2. The communication system according to claim 1, wherein the identification unit detects information that can identify the moving object by analyzing an image captured by an imaging device, and generates the identification information.

3. 3. The communication system according to claim 2, wherein the moving object is a vehicle, and the identification means generates the identification information from an image of the license plate of the vehicle.

4. The communication system described in claim 2 or 3, further comprising a cancellation means for canceling the subscription registration when it is detected by analyzing an image captured by the imaging device that the moving object is no longer present within the imaging range.

5. The communication system according to any one of claims 1 to 4, characterized in that the information generated regarding the topic includes a message notifying an event related to the moving object detected from an image captured by an imaging device.

6. a storage unit for storing information generated about the topic if the information is obtained before the communication device is subscribed to the topic; The communication system according to any one of claims 1 to 5, characterized in that the distribution means distributes the information stored in the storage means to the communication device in response to the communication device being subscribed.

7. a relay device that functions as a broker in a publish / subscribe communication system, the relay device functioning as the generating means, the registering means, and the distributing means; 7. The communication system according to claim 1, wherein the relay device includes a notification unit that notifies the distribution device of the topic generated by the generation unit.

8. a distribution device other than the distribution device that functions as a publisher in a publish / subscribe communication system; 8. The communication system according to claim 7, wherein the notification means further notifies the other distribution devices of the topic.

9. a plurality of said identification means; 2. The communication system according to claim 1, wherein the generating unit generates the topic when the mobile object is identified by at least one of the plurality of identifying units.

10. a plurality of said identification means; 2. The communication system according to claim 1, wherein the generating unit generates the topic when the mobile object is identified by all of the plurality of identifying units.

11. The communication system described in claim 9 or 10, further comprising a cancellation means for canceling the subscription registration of the communication device by the registration means under either the condition that the mobile body can no longer be identified by at least one of the plurality of identification means, or the condition that the mobile body can no longer be identified by all of the plurality of identification means.

12. A communication device that functions as a publisher in a publish / subscribe communication system, an identification means for generating identification information for identifying a moving object in response to detection of the moving object; an acquisition means for acquiring a topic generated based on the identification information; generating means for generating information to be distributed regarding the topic; a transmitting means for transmitting the information generated by the generating means to a relay device that functions as a broker in the communication method, the identification means generates the identification information based on detection of information capable of identifying the moving object in the image acquired by the communication device; The acquisition means acquires the topic associated with the identification information, which is generated based on the generation of the identification information. A communication device comprising:

13. a notification unit configured to notify the relay device that the moving object has not been detected when the identifying unit has detected the moving object; 13. The communication device according to claim 12, wherein the generating means stops generating information about the topic when the moving object is no longer detected.

14. 14. The communication device according to claim 12, wherein the acquisition unit transmits the identification information to the relay device and receives a notification of the topic associated with the identification information from the relay device.

15. A communication device that functions as a broker in a publish / subscribe communication system, a generating means for generating a topic based on identification information of a mobile object received from a first other communication device that functions as a publisher in the communication method; notification means for notifying the first other communication device of the topic; receiving means for receiving a request for subscribe registration via a communication connection with a second other communication device owned by the mobile unit; a registration means for subscribing and registering the mobile entity to the topic in response to the information for identifying the mobile entity included in the request and the identification information indicating the same mobile entity; the identification information is generated based on detection of information capable of identifying the moving object in an image acquired by the first other communication device, The generating means generates the topic associated with the identification information based on the generation of the identification information. A communication device comprising:

16. A control method for a communication system that distributes a message generated by a distribution device to a communication device owned by a mobile object using a publish / subscribe communication method, comprising: an identification step of identifying the moving object and generating identification information of the moving object; a generation step of generating a topic based on the identification information; a registration step of subscribing the communication device to the topic generated based on the identification information of the mobile device in response to receiving a subscribe registration request including information identifying the mobile device from the communication device; a distribution step of distributing information generated by the distribution device regarding the topic to the communication device that has registered as a subscriber to the topic in the registration step, In the identifying step, the identification information is generated based on information that can identify the moving object being detected in the image acquired by the distribution device, and In the generating step, the topic associated with the identification information is generated based on the identification information being generated. A control method for a communication system comprising:

17. A method for controlling a communication device that functions as a publisher in a publish / subscribe communication system, comprising: an identification step of generating identification information for identifying the moving object in response to the detection of the moving object; an acquisition step of acquiring a topic generated based on the identification information; generating information for distribution regarding the topic; a transmitting step of transmitting the information generated by the generating step to a relay device that functions as a broker in the communication method, In the identification step, the identification information is generated based on the detection of information capable of identifying the moving object in the image acquired by the communication device, In the acquiring step, the topic associated with the identification information, which is generated based on the generation of the identification information, is acquired. A method for controlling a communication device.

18. A method for controlling a communication device that functions as a broker in a publish / subscribe communication system, comprising: a generating step of generating a topic based on identification information of a mobile object received from a first other communication device functioning as a publisher in the communication method; a notification step of notifying the first other communication device of the topic; a receiving step of receiving a request to subscribe via a communication connection with a second other communication device owned by the mobile unit; a registration step of subscribing the mobile entity to the topic in response to the information for identifying the mobile entity included in the request and the identification information indicating the same mobile entity; the identification information is generated based on detection of information capable of identifying the moving object in an image acquired by the first other communication device, In the generating step, the topic associated with the identification information is generated based on the identification information being generated. A method for controlling a communication device.

19. A program for causing a computer to function as the communication device according to any one of claims 12 to 15.

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