Communication device and remote instruction system

Abstract

To provide a communication device and a remote command system that make it possible to improve viewability of video data by a remote commander and reduce an amount of transmitted data.SOLUTION: A communication device is mounted to a vehicle that is capable of executing remote support corresponding to remote commands from a remote commander and transmits video data from the vehicle via a communication network. Transmission conditions including the desired value of a video data transmission frame rate and the desired value of a video data transmission resolution are set on the basis of a vehicle speed of the vehicle. Video data is transmitted on the basis of the transmission conditions so that the transmission resolution and the transmission frame rate equal the respective desired values. Determination is made as to whether to suppress transmitted image quality of video data including the transmission frame rate and the transmission resolution, on the basis of the vehicle speed of the vehicle and the communication quality information of the communication network. When it is determined to suppress the transmitted image quality, the desired value of the transmission resolution is reduced while maintaining the desired value of the transmission frame rate, with the transmitted image quality thereby suppressed.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a communication device and a remote instruction system. [Background technology]

[0002] A remote video output device is known that, when the communication delay from a vehicle via a network is a second delay time that is longer than a first delay time, cuts out a second range from the video that is narrower than the first range and outputs it (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 155159 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technical field of vehicle remote support, efforts have been made to reduce the amount of video data transmitted from vehicles over communication networks. However, the video data referenced by a remote commander must have a quality that allows the remote commander to visually recognize the information needed to issue remote instructions, so there is room for improvement in reducing the amount of data transmitted. [Means for solving the problem]

[0005] One aspect of the present invention is a communication device that is mounted on a vehicle capable of performing remote support in response to remote instructions from a remote commander and that transmits video data from the vehicle via a communication network, and includes a transmission condition setting unit that sets transmission conditions including a target value for the transmission frame rate of the video data and a target value for the transmission resolution of the video data based on the vehicle speed, and a transmission unit that transmits the video data based on the transmission conditions so that the transmission resolution and transmission frame rate reach their respective target values.The transmission condition setting unit determines whether to suppress the transmission image quality of the video data including the transmission frame rate and the transmission resolution based on the vehicle speed and communication quality information of the communication network, and if it is determined that the transmission image quality should be suppressed, the transmission image quality is suppressed by maintaining the target value of the transmission frame rate and reducing the target value of the transmission resolution.

[0006] According to one aspect of the present invention, a communication device determines whether to suppress the transmission image quality of video data, including the transmission frame rate and the transmission resolution, based on the vehicle speed and communication quality information of the communication network. If it is determined that the transmission image quality should be suppressed, the target value of the transmission frame rate is maintained and the target value of the transmission resolution is reduced. This reduces the amount of transmission data without lowering the transmission frame rate of the video data while taking into account both the vehicle speed and the communication quality information of the communication network, thereby preventing, for example, the transmission frame rate from being insufficient compared to the vehicle speed. This makes it possible to achieve both good visibility of the video data by the remote commander and a reduction in the amount of transmission data.

[0007] In one embodiment, the transmission condition setting unit may reduce or increase the target value of the transmission resolution so that the absolute value of the time rate of change of the target value of the transmission resolution does not exceed a predetermined upper limit rate of change. In this case, it is possible to suppress the impact of a sudden change in the transmission resolution on the visibility of the video data viewed by the remote commander.

[0008] In one embodiment, when the transmission condition setting unit determines that the transmission image quality should be reduced when the target value of the transmission resolution has reached a predetermined minimum transmission resolution, the transmission condition setting unit may maintain the target value of the transmission resolution and reduce the target value of the transmission frame rate. In this case, the amount of transmission data can be reduced so as not to lower the transmission resolution below the minimum transmission resolution.

[0009] Another aspect of the present invention is a remote instruction system including the above-mentioned communication device and a remote instruction device that receives video data transmitted from the above-mentioned communication device via a communication network, wherein the remote instruction device has an information receiving unit that acquires the received resolution of the video data and an information transmitting unit that transmits the received resolution to the communication device via the communication network, and wherein the transmission condition setting unit, when the received resolution is smaller than the target value of the transmission resolution of the video data, maintains the target value of the transmission frame rate and sets the target value of the transmission resolution based on the received resolution.

[0010] According to another aspect of the remote instruction system of the present invention, when the receiving resolution of the video data is lower than the target value of the transmitting resolution, the target value of the transmitting frame rate is maintained and the target value of the transmitting resolution is set based on the receiving resolution, thereby making it possible to efficiently reduce the amount of transmitting data by utilizing the information on the receiving resolution. [Effects of the Invention]

[0011] According to the present invention, it is possible to achieve both visibility of video data by a remote commander and a reduction in the amount of data transmitted. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating an example of an overall image of a remote instruction system according to an embodiment; [Figure 2] 1 is a block diagram illustrating an example of a configuration of a vehicle including a communication device according to an embodiment. [Figure 3] FIG. 2 is a block diagram showing an example of a hardware configuration of a remote instruction server. [Figure 4]2 is a block diagram showing an example of a configuration of a remote instruction device and a functional configuration of a remote instruction server. FIG. [Figure 5] 10A is a diagram illustrating an example of the relationship between vehicle speed and a target value of transmission resolution, and FIG. 10B is a diagram illustrating an example of the relationship between vehicle speed and a target value of transmission frame rate. [Figure 6] FIG. 10 is a sequence diagram illustrating an example of processing by the remote instruction system. [Figure 7] 10 is a flowchart illustrating an example of a transmission condition setting process. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, identical or corresponding elements will be designated by the same reference numerals, and redundant description will be omitted.

[0014] [Remote instruction system overview] FIG. 1 is a diagram illustrating an example of an overall view of a remote instruction system according to an embodiment. As shown in FIG. 1, the remote instruction system 100 includes a remote instruction device 1 to which a remote commander R inputs remote instructions, a vehicle 2, and a communication device 4. A remote instruction server 10 of the remote instruction device 1 is communicably connected to a plurality of vehicles 2 via a communication network N, for example. The communication network N is a wireless communication network. For example, the communication network N includes a network (communication network) operated by one or more communication carriers. Various types of information are sent to the remote instruction device 1 from the communication device 4 of the vehicle 2.

[0015] The remote instruction system 100 performs remote support of the vehicle 2 in response to remote instructions from the remote commander R. The remote instructions are instructions from the remote commander R regarding the remote support of the vehicle 2. The remote commander R is an operator who provides remote support to the vehicle 2. The remote commander R is deployed, for example, in a remote cockpit provided in a facility or the like away from the vehicle 2. The number of remote commanders R may be one or two or more.

[0016] The vehicle 2 is a vehicle configured to be able to perform remote support. The vehicle 2 may be configured to be able to perform automatic driving control. The number of vehicles 2 that can communicate with the remote instruction system 100 is not particularly limited.

[0017] Remote support includes remote monitoring in which the remote commander R monitors the situation around the vehicle and the situation of the driver, remote assistance in which the remote commander R provides information and instructions to the driver of the vehicle, and remote driving in which the remote commander R gives instructions related to the automatic driving of the vehicle. For example, instructions related to automatic driving include instructions to move vehicle 2 forward and instructions to stop vehicle 2. Instructions related to automatic driving may include instructions to change lanes for vehicle 2. Instructions related to automatic driving may include instructions to offset and avoid obstacles ahead, instructions to overtake a leading vehicle, instructions to make an emergency evacuation, etc.

[0018] In the remote instruction system 100, video data of a surrounding environment image is acquired from detection data of the surrounding environment detected by, for example, an external sensor 22 of the vehicle 2. The surrounding environment image is a captured image of the surrounding environment of the vehicle 2 detected by the external sensor 22. The video data of the surrounding environment image is transmitted from the vehicle 2 to the remote instruction server 10 of the remote instruction device 1 via the communication network N by the communication device 4 of the vehicle 2. The remote instruction server 10 displays an image representing the surrounding environment image to the remote commander R. The remote commander R inputs remote instructions to the commander interface 3 of the remote instruction device 1 while referring to the surrounding environment image. The remote instruction device 1 transmits the remote instructions to the vehicle 2 via the communication network N. The vehicle 2 performs remote support in accordance with the remote instructions.

[0019] [Vehicle configuration] First, an example of the configuration of the vehicle 2 will be described. FIG. 2 is a block diagram showing an example of the configuration of a vehicle including a communication device according to the embodiment. As shown in FIG. 2, the vehicle 2 has, as an example, a remote driving ECU 30. The remote driving ECU 30 is an electronic control unit having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The remote driving ECU 30, for example, loads a program recorded in the ROM into the RAM and executes the program loaded into the RAM by the CPU, thereby realizing various functions. The remote driving ECU 30 may be composed of multiple electronic units. The remote driving ECU 30 is also referred to as, for example, an RDK (Remote Driving Kit).

[0020] The remote driving ECU 30 is connected to a GPS (Global Positioning System) receiving unit 21, an external sensor 22, an internal sensor 23, a map database 24, an actuator 25, and a communication unit 26.

[0021] The GPS receiver 21 receives signals from three or more GPS satellites to measure the position of the vehicle 2 (for example, the latitude and longitude of the vehicle 2). The GPS receiver 21 transmits the measured position information of the vehicle 2 to the remote driving ECU 30.

[0022] The external sensor 22 is an in-vehicle sensor that detects the surrounding environment of the vehicle 2. The external sensor 22 transmits the detected data to the remote driving ECU 30.

[0023] The external sensor 22 includes at least a camera. The camera is an imaging device that captures images of the surrounding environment of the vehicle 2. The camera is provided, for example, behind the windshield of the vehicle 2, and captures images in front of the vehicle. The camera may also capture images of the sides and rear of the vehicle 2.

[0024] The external sensor 22 may include a radar sensor. A radar sensor is a detection device that uses radio waves (e.g., millimeter waves) or light to detect objects around the vehicle 2. The radar sensor includes, for example, radar (millimeter wave radar) or LiDAR (Light Detection and Ranging).

[0025] The internal sensor 23 is an in-vehicle sensor that detects the traveling state of the vehicle 2. The internal sensor 23 may include a vehicle speed sensor, an acceleration sensor, and a yaw rate sensor. Known sensors can be used as the vehicle speed sensor, the acceleration sensor, and the yaw rate sensor.

[0026] The map database 24 is a database that records map information. The map database 24 is formed, for example, in a recording device such as a hard disk drive (HDD) mounted on the vehicle 2. The map information includes road position information, road shape information (e.g., curvature information), and intersection and branch point position information.

[0027] The actuators 25 are devices used to control the driving of the vehicle 2, and operate in response to control signals from the remote driving ECU 30. The actuators 25 include at least a drive actuator, a brake actuator, and a steering actuator. The drive actuator is provided, for example, in an engine or a motor serving as a power source, and controls the driving force of the vehicle 2. The brake actuator is provided, for example, in a hydraulic brake system, and controls the braking force applied to the wheels of the vehicle 2. The steering actuator is, for example, an assist motor in an electric power steering system, and controls the steering torque of the vehicle 2.

[0028] The communication unit 26 is a communication device that controls wireless communication with the outside of the vehicle 2. The communication unit 26 transmits and receives various information to and from the remote instruction device 1 via, for example, a communication network N of a communication carrier.

[0029] Next, we will explain an example of the functional configuration of the remote driving ECU 30. The remote driving ECU 30 has a vehicle position acquisition unit 31, a surrounding environment recognition unit 32, a driving state recognition unit 33, a route generation unit 34, a remote driving control unit 35, a display information acquisition unit 36, a transmission condition setting unit 37, and a display information transmission unit (transmission unit) 38.

[0030] The vehicle position acquisition unit 31 acquires the position information (position on the map) of the vehicle 2 based on the position information of the GPS receiving unit 21 and the map information of the map database 24, or by using SLAM (Simultaneous Localization and Mapping) technology.

[0031] The surrounding environment recognition unit 32 recognizes the surrounding environment of the vehicle 2 based on the detection data of the external sensor 22. The surrounding environment may include information used for autonomous driving, such as the relative position, relative speed, and movement direction of surrounding objects with respect to the vehicle 2.

[0032] The running state recognition unit 33 recognizes the running state of the vehicle 2 based on the detection result of the internal sensor 23. The running state includes the speed of the vehicle 2, the acceleration of the vehicle 2, and the yaw rate of the vehicle 2 (the direction of the vehicle 2).

[0033] The trajectory generation unit 34 generates a trajectory to be used for the autonomous driving of the vehicle 2. The trajectory generation unit 34 generates a trajectory for autonomous driving based on a preset target route, map information, position information of the vehicle 2, the surrounding environment of the vehicle 2, and the driving state of the vehicle 2. The trajectory corresponds to a driving plan for autonomous driving. Well-known methods related to autonomous driving can be used to generate the trajectory in the trajectory generation unit 34. The same applies to the content of the trajectory.

[0034] The remote driving control unit 35 performs remote assistance, remote driving, or automatic driving of the vehicle 2. The remote driving control unit 35 may provide information and instructions to the driver of the vehicle 2 in response to a remote instruction from the remote commander R. The remote driving control unit 35 may perform automatic driving of the vehicle 2 based on the surrounding environment of the vehicle 2, the driving state of the vehicle 2, and the route generated by the route generation unit 34. The remote driving control unit 35 may issue instructions related to the automatic driving of the vehicle 2 in response to a remote instruction from the remote commander R. The remote driving control unit 35 can perform remote driving and automatic driving of the vehicle 2 by sending a control signal to the actuator 25.

[0035] The display information acquisition unit 36 ​​acquires display information to be displayed on the remote commander R based on the detection data of the external sensors 22 or the calculation results of the remote driving ECU 30. The display information may include information on the position of the vehicle 2, the destination, the route of the vehicle 2 generated by the route generation unit 34, and the driving state (e.g., vehicle speed). The display information may be information outside the operation design domain (ODD) of the autonomous driving system. The ODD is the range within which the autonomous driving system operates as designed.

[0036] The display information includes video data of the surrounding environment image that is transmitted to the remote commander R to display the surrounding environment image. The video data of the surrounding environment image may include, for example, an image of the scenery ahead of the vehicle 2, an overhead image of the vehicle 2, etc. The video data of the surrounding environment image may include detection data of an image of the side or rear of the vehicle 2 captured by a camera of the vehicle 2. The display information acquisition unit 36 ​​acquires the video data of the surrounding environment image based on an image captured by the camera of the external sensor 22.

[0037] The transmission condition setting unit 37 sets the transmission conditions based on the speed of the vehicle 2. The transmission conditions are conditions (settings) related to the transmission image quality of the surrounding environment image. The transmission image quality is the image quality when transmitting the video data of the surrounding environment image from the communication device 4 to the communication network N. The transmission image quality includes a target value for the transmission frame rate of the surrounding environment image (video data) and a target value for the transmission resolution of the surrounding environment image (video data).

[0038] The transmission condition setting unit 37 acquires communication quality information of the communication network N. The communication quality information is information relating to the communication quality of the communication network N, and includes, for example, the transmission frame rate and transmission resolution of the surrounding environment image (video data).

[0039] The transmission frame rate is the actual frame rate value of the video data of the surrounding environment image transmitted so as to be the target value of the transmission frame rate. The transmission frame rate is, for example, a performance value provided by the communication carrier of the communication network N. The transmission frame rate may also be an estimated value obtained based on information provided by the communication carrier of the communication network N.

[0040] The transmission resolution is the actual resolution value of the video data of the surrounding environment image transmitted so as to achieve the target transmission resolution. The transmission resolution is, for example, a performance value provided by a communication carrier of the communication network N. The transmission resolution may also be an estimated value obtained based on information provided by the communication carrier of the communication network N.

[0041] The transmission condition setting unit 37 may calculate, as other communication quality information, packet loss of video data of the surrounding environment image based on a measurement value of the amount of data transmitted and received during communication.

[0042] The transmission condition setting unit 37 determines whether to suppress the transmission image quality of the video data based on the speed of the vehicle 2 and communication quality information of the communication network N. "Suppressing the transmission image quality of the video data" includes reducing at least one of the transmission frame rate and the transmission resolution. The transmission condition setting unit 37 sets the transmission conditions for the video data of the surrounding environment image according to the speed of the vehicle 2 so that the remote commander R can obtain the minimum transmission image quality required to remotely support the vehicle 2.

[0043] The transmission condition setting unit 37 can adjust the transmission image quality of the surrounding environment image between a predetermined rated transmission image quality (e.g., 1080 bps and 30 FPS) and a transmission image quality that reduces the amount of transmission data compared to the rated transmission image quality. The transmission image quality of the surrounding environment image can be reduced in amount of transmission data compared to the rated transmission image quality, taking into consideration the visibility of the video data by the remote commander R. "Taking into consideration the visibility of the video data by the remote commander R" means that the remote commander R can recognize necessary information through the surrounding environment image. One example of "taking into consideration the visibility of the video data by the remote commander R" can be, for example, when the remote commander R recognizes a "Stop" sign in the surrounding environment image while remotely driving the vehicle 2 and stops the vehicle 2 at the stop line.

[0044] Specifically, for example, in a situation where a "Stop" sign is present ahead of the vehicle 2, the remote commander R issues a remote instruction to brake the vehicle 2 while referring to the surrounding environment image received by the remote instruction device 1, and remotely supports the vehicle 2 to stop at the stop line. The time lag (the time required for recognition, judgment, and operation) from when the remote commander R recognizes the stop sign in the surrounding environment image to when the remote commander R issues the remote instruction can be, for example, 500 ms to 1000 ms. The time required for communication of the remote instruction from the remote instruction device 1 to the vehicle 2 (G2G delay) can be, for example, 100 ms to 300 ms. The time required for the actuator 25 in the vehicle 2 to operate in response to the remote instruction (operation delay) can be, for example, 80 ms to 200 ms. The deceleration from when the actuator 25 operates until the vehicle 2 stops can be, for example, 0.2 G to 0.3 G. By performing calculations that satisfy the above requirements, the distance from the position of the stop sign to the front side in the traveling direction of vehicle 2 can be determined according to the vehicle speed. This distance corresponds to the timing at which the remote commander R should recognize the stop sign in the surrounding environment image, for example, under a deceleration that will prevent a vehicle following vehicle 2 from colliding with vehicle 2 from the rear. The transmission condition setting unit 37 sets the transmission frame rate and transmission resolution of the transmission image quality of the surrounding environment image so as to satisfy the above requirements.

[0045] FIG. 5(a) is a diagram illustrating the relationship between vehicle speed and the target value of transmission resolution. The horizontal axis of FIG. 5(a) represents vehicle speed, and the vertical axis represents the target value of transmission resolution. The dashed line L1 in FIG. 5(a) represents the minimum target value of the transmission resolution of the surrounding environment image determined to satisfy the above-mentioned requirements. The dashed line L1 in FIG. 5(a) represents the preset minimum transmission resolution. The solid line L2 in FIG. 5(a) represents the target value of the transmission resolution (e.g., 1080 bps) corresponding to a predetermined rated transmission image quality. The solid line L3 in FIG. 5(a) represents the target value of the transmission resolution corresponding to a transmission image quality with a reduced amount of transmission data compared to the predetermined rated transmission image quality. The target value of the solid line L3 partially overlaps with the minimum transmission resolution. All of the target values ​​of the solid line L3 may be greater than the minimum transmission resolution.

[0046] As shown in FIG. 5(a), the rated transmission image quality (solid line L2 and part of solid line L3) can be set to a constant value relative to vehicle speed, for example. The transmission resolution (dashed line L1), which corresponds to a transmission image quality with a reduced amount of transmission data compared to the rated transmission image quality, can be set to a higher resolution value, for example, as the vehicle speed increases. In other words, the minimum transmission resolution required to satisfy the above requirements is calculated to be a higher resolution value as the vehicle speed increases. This tendency corresponds to the fact that the higher the vehicle speed of the vehicle 2, the higher the resolution required for the video data referenced by the remote commander R in order to properly view the information used by the remote commander R to issue remote instructions. The transmission condition setting unit 37 can adjust the target value of the transmission resolution, for example, between the transmission image quality of the solid line L2, the transmission image quality of the solid line L3, and the transmission image quality of the dashed line L1 in FIG. 5(a).

[0047] FIG. 5(b) is a diagram illustrating the relationship between vehicle speed and the target value of the transmission frame rate. The horizontal axis of FIG. 5(b) represents vehicle speed, and the vertical axis represents the target value of the transmission frame rate. The dashed line L4 in FIG. 5(b) represents the minimum target value of the transmission frame rate of the surrounding environment image, which is preset in accordance with an increase or decrease in the vehicle speed of the vehicle 2 as a frame rate required for the remote commander R to recognize various objects in the surrounding environment image while remotely driving the vehicle 2. The dashed line L4 in FIG. 5(b) represents the preset minimum transmission frame rate. The solid line L5 in FIG. 5(b) represents the target value of the transmission frame rate corresponding to a predetermined rated transmission image quality (e.g., 30 FPS). The solid line L6 in FIG. 5(b) represents the target value of the transmission frame rate corresponding to a transmission image quality with a reduced amount of transmission data compared to the predetermined rated transmission image quality. The target value of the solid line L6 partially overlaps with the minimum transmission frame rate. All of the target values ​​of the solid line L6 may be greater than the minimum transmission frame rate.

[0048] As shown in FIG. 5(b), the rated transmission image quality (solid lines L5 and L6) can be constant with respect to vehicle speed, for example. The transmission frame rate (dashed line L4), which corresponds to a transmission image quality with a reduced amount of transmission data compared to the rated transmission image quality, can be set to a higher frame rate value, for example, as the vehicle speed increases. That is, the minimum transmission frame rate determined to satisfy the above requirements is calculated to be a higher frame rate value as the vehicle speed increases. This tendency corresponds to the fact that the higher the vehicle speed of the vehicle 2, the higher the transmission frame rate required for the video data referenced by the remote commander R in order to properly view the information used by the remote commander R to issue remote instructions. The transmission condition setting unit 37 can adjust the target value of the transmission frame rate, for example, between the transmission image quality of the solid line L5, the solid line L6, and the dashed line L4 in FIG. 5(b).

[0049] The transmission condition setting unit 37 determines whether or not to suppress the transmission image quality including the transmission frame rate and the transmission resolution based on, for example, the speed of the vehicle 2 and the communication quality information of the communication network N. When the transmission condition setting unit 37 determines to suppress the transmission image quality, it prioritizes reducing the target value of the transmission resolution over the target value of the transmission frame rate.

[0050] More specifically, the transmission condition setting unit 37 compares the transmission resolution and transmission frame rate of the video data of the surrounding environment image, which is transmitted so as to achieve the set target values ​​for transmission resolution and transmission frame rate, with the target values ​​based on the communication quality information of the communication network N. The transmission condition setting unit 37 may determine to suppress the transmission image quality, for example, when the actual value of the transmission resolution is smaller than the target value of the transmission resolution by a certain value or more. An estimated value of the transmission resolution may be used for the determination of the transmission resolution. Alternatively, the transmission condition setting unit 37 may determine to suppress the transmission image quality when the calculated packet loss of the video data of the surrounding environment image is equal to or greater than a certain value. The "certain value" used for the determination may be, for example, a predetermined positive constant value.

[0051] When the transmission condition setting unit 37 determines to suppress the transmission image quality, it maintains the target value of the transmission frame rate while reducing the target value of the transmission resolution, thereby suppressing the transmission image quality. In the example of FIG. 5(a), when the target value of the transmission resolution is set to the solid line L2 corresponding to the rated transmission image quality, the transmission condition setting unit 37 determines to suppress the transmission image quality when the actual value of the transmission resolution becomes smaller than the target value by a certain value or more, or when packet loss of the video data of the surrounding environment image becomes equal to or greater than a certain value. In this case, the transmission condition setting unit 37 switches the target value of the transmission resolution from the solid line L2 corresponding to the rated transmission image quality to the solid line L3. At this time, the transmission condition setting unit 37 maintains the target value of the transmission frame rate at the solid line L5 in FIG. 5(b), which corresponds to the predetermined rated transmission image quality.

[0052] Furthermore, in the example of FIG. 5(a), when the target value of transmission resolution is the solid line L3, if the actual value of transmission resolution becomes smaller than the target value of transmission resolution corresponding to the solid line L3 by a certain value or more, or if packet loss of the video data of the surrounding environment image becomes greater than a certain value, the transmission condition setting unit 37 determines to suppress the transmission image quality. In this case, the transmission condition setting unit 37 switches the target value of transmission resolution from the solid line L3 to the dashed line L1. At this time, the transmission condition setting unit 37 maintains the target value of the transmission frame rate as the solid line L5 in FIG. 5(b), which corresponds to the predetermined rated transmission image quality. Here, the target value of transmission resolution reaching the dashed line L1 indicates that the preset minimum transmission resolution has been reached.

[0053] When the transmission condition setting unit 37 determines to suppress the transmission image quality when the target value of the transmission resolution reaches a predetermined minimum transmission resolution, it may maintain the target value of the transmission resolution and reduce the target value of the transmission frame rate. For example, when the target value of the transmission resolution is the dashed line L1 in FIG. 5(a) and the target value of the transmission frame rate is the solid line L5 corresponding to the rated transmission image quality in FIG. 5(b), the transmission condition setting unit 37 may determine to suppress the transmission image quality when the actual value of the transmission frame rate is smaller than the target value by a certain value or when packet loss of the video data of the surrounding environment image exceeds a certain value. In this case, the transmission condition setting unit 37 switches the target value of the transmission frame rate from the solid line L5 corresponding to the rated transmission image quality to the solid line L6. At this time, the transmission condition setting unit 37 maintains the target value of the transmission resolution at the dashed line L1 in FIG. 5(a). Furthermore, in the example of FIG. 5(b), when the target value of the transmission frame rate is set to solid line L6, if the actual value of the transmission frame rate becomes smaller than the target value corresponding to solid line L6 by a certain value or more, or if packet loss of the video data of the surrounding environment image becomes greater than a certain value, the transmission condition setting unit 37 may determine to suppress the transmission image quality. In this case, the transmission condition setting unit 37 switches the target value of the transmission frame rate from solid line L6 to dashed line L4. At this time, the transmission condition setting unit 37 maintains the target value of the transmission resolution as shown by dashed line L1 in FIG. 5(a).

[0054] If the transmission condition setting unit 37 determines not to suppress the transmission image quality, it may increase the target value of the transmission resolution and also increase the target value of the transmission frame rate. Alternatively, if the transmission condition setting unit 37 determines not to suppress the transmission image quality, it may increase the target value of the transmission frame rate, giving priority over the target value of the transmission resolution. In this case, the transmission condition setting unit 37 may increase the target value of the transmission resolution when the target value of the transmission frame rate reaches the solid line L5 corresponding to the rated transmission image quality. If the transmission condition setting unit 37 determines not to suppress the transmission image quality, it may maintain the target value of the transmission resolution and also maintain the target value of the transmission frame rate.

[0055] The transmission condition setting unit 37 may reduce or increase the target value of the transmission resolution so that the absolute value of the time rate of change of the target value of the transmission resolution does not exceed a predetermined upper limit of the change rate. The upper limit of the change rate of the transmission resolution is the upper limit of the absolute value of the time rate of change of the target value of the transmission resolution. In the example of FIG. 5(a), for example, when switching the target value of the transmission resolution from the solid line L2 corresponding to the rated transmission image quality to the solid line L3, the transmission condition setting unit 37 may gradually decrease the target value of the transmission resolution while limiting the amount of change per predetermined unit time by the upper limit of the change rate of the transmission resolution, rather than changing the target value of the transmission resolution from the solid line L2 to the solid line L3 in one go. Conversely, when switching the target value of the transmission resolution from the dashed line L1 to the solid line L3, the transmission condition setting unit 37 may gradually increase the target value of the transmission resolution while limiting the amount of change per predetermined unit time by the upper limit of the change rate of the transmission resolution, rather than changing the target value of the transmission resolution from the dashed line L1 to the solid line L3 in one go.

[0056] Similarly, the transmission condition setting unit 37 may decrease or increase the target value of the transmission frame rate so that the absolute value of the time rate of change of the target value of the transmission frame rate does not exceed a predetermined upper limit of change rate. The upper limit of change rate of the transmission frame rate is the upper limit of the absolute value of the time rate of change of the target value of the transmission frame rate. In the example of FIG. 5(b), for example, when switching the target value of the transmission frame rate from solid line L5 corresponding to the rated transmission image quality to solid line L6, the transmission condition setting unit 37 may gradually decrease the target value of the transmission frame rate while limiting the amount of change per predetermined unit time by the upper limit of change rate of the transmission frame rate, rather than changing the target value of the transmission frame rate from solid line L5 to solid line L6 in one go. Conversely, when switching the target value of the transmission frame rate from dashed line L4 to solid line L6, the transmission condition setting unit 37 may gradually increase the target value of the transmission frame rate while limiting the amount of change per predetermined unit time by the upper limit of change rate of the transmission frame rate, rather than changing the target value of the transmission frame rate from dashed line L4 to solid line L6 in one go.

[0057] The transmission condition setting unit 37 may set a target value for the transmission resolution based on the reception resolution of the video data received by the remote instruction device 1. The reception resolution is the resolution value for the video data of the surrounding environment image received by the remote instruction device 1. The reception resolution will be described in detail later.

[0058] The transmission condition setting unit 37 receives, for example, the reception resolution transmitted from the remote instruction server 10 of the remote instruction device 1 via the communication network N. For example, the transmission condition setting unit 37 compares the target value of the transmission resolution of the video data of the surrounding environment image transmitted to the remote instruction device 1 with the reception resolution (actual value) received from the remote instruction device 1, and determines whether the reception resolution is lower than the target value of the transmission resolution of the video data. If the reception resolution is lower than the target value of the transmission resolution of the video data, the transmission condition setting unit 37 may maintain the target value of the transmission frame rate and set the target value of the transmission resolution based on the reception resolution. For example, if the reception resolution is lower than the target value of the transmission resolution of the video data and is equal to or higher than the minimum transmission resolution, the transmission condition setting unit 37 may set the resolution value of the reception resolution to the target value of the transmission resolution and maintain the target value of the transmission frame rate.

[0059] The display information transmitting unit 38 transmits the display information acquired by the display information acquiring unit 36 ​​to the remote instruction device 1. The display information transmitting unit 38 transmits the display information to the remote instruction device 1 via the communication network N using the communication unit 26. For video data of the surrounding environment image, the display information transmitting unit 38 transmits the video data based on the transmission conditions set by the transmission condition setting unit 37 so that the transmission resolution and transmission frame rate are their respective target values.

[0060] [Configuration of remote instruction device] The remote instruction device 1 receives video data transmitted from the communication device 4 of the vehicle 2 via the communication network N. The configuration of the remote instruction device 1 will be described with reference to the drawings. FIG. 3 is a block diagram showing an example of the hardware configuration of a remote instruction server. FIG. 4 is a block diagram showing an example of the configuration of the remote instruction device and the functional configuration of the remote instruction server. As shown in FIGS. 3 and 4, the remote instruction device 1 has a remote instruction server 10 and a commander interface 3.

[0061] First, we will explain the hardware configuration of the remote instruction server 10. The remote instruction server 10 is configured as a general computer equipped with, for example, a processor 10a, a storage unit 10b, a communication unit 10c, and a user interface 10d. The user of the user interface 10d refers to the user (administrator, etc.) of the remote instruction device 1.

[0062] The processor 10a runs various operating systems to control the remote instruction server 10. The processor 10a is a computing unit such as a CPU including a control device, an arithmetic unit, a register, etc. The processor 10a controls the storage unit 10b, the communication unit 10c, and the user interface 10d. The storage unit 10b is configured to include at least one of a memory and a storage. The memory is a recording medium such as a ROM or a RAM. The storage is a recording medium such as a HDD.

[0063] The communication unit 10c is a communication device for communicating via the communication network N. A network device, a network controller, a network card, etc. can be used for the communication unit 10c. The user interface 10d is an input / output unit of the remote instruction device 1 for a user such as an administrator. The user interface 10d includes output devices such as a display and a speaker, and an input device such as a touch panel. Note that the remote instruction device 1 does not necessarily have to be installed in a facility having a remote cockpit, but may be mounted on a mobile object such as a vehicle.

[0064] The commander interface 3 is an input / output section of the remote instruction device 1 for the remote commander R. The commander interface 3 has an output section 3a and an instruction input section 3b.

[0065] The output unit 3a is a device that outputs information used to remotely instruct the vehicle 2 to the remote commander R. The output unit 3a includes, for example, a plurality of displays that output images. The output unit 3a may also include a speaker that outputs sound. The speaker may be, for example, a headset speaker that is worn on the head of the remote commander R. The output unit 3a may also provide information to the remote commander R by vibration, for example, using a vibration actuator or the like provided on the seat.

[0066] The multiple displays display images of the surrounding environment for the remote commander R. As an example, the multiple displays display an image of the scenery in front of the vehicle 2 captured by a camera on the vehicle 2. The multiple displays may also display images of the side or rear of the vehicle 2 captured by a camera on the vehicle 2.

[0067] The instruction input unit 3b is a device to which remote instructions are input by the remote commander R. The instruction input unit 3b may have an operation device with a known configuration, such as an operation lever, an operation pedal, or an operation button.

[0068] Next, a description will be given of the functional configuration of the remote instruction server 10. As shown in Fig. 6, the remote instruction server 10 has an information receiving unit 11, a display image acquiring unit 12, a display control unit 13, and an information transmitting unit 14.

[0069] The information receiving unit 11 receives driving information for the remote commander R to remotely support the vehicle 2. The driving information includes video data of an image of the surrounding environment. The driving information may also include information related to the automatic driving of the vehicle 2, such as the route the vehicle 2 will take when driving automatically.

[0070] The information receiving unit 11 may acquire the reception resolution of the video data. The reception resolution is, for example, an actual value provided by a communication carrier of the communication network N. The reception resolution may also be an estimated value obtained based on information provided by the communication carrier of the communication network N. The information receiving unit 11 may also acquire the reception resolution based on a measurement value of the amount of transmission and reception of each piece of data involved in communication.

[0071] Based on the received driving information, the display image acquisition unit 12 acquires an image to be displayed for the remote commander R. The display image acquisition unit 12 acquires, for example, a surrounding environment image from the received video data as the image to be displayed for the remote commander R.

[0072] The display control unit 13 controls the display of images on multiple displays for the remote commander R. For example, the display control unit 13 causes a surrounding environment image acquired from video data to be displayed on multiple displays for the remote commander R. The display control unit 13 may also provide various types of information regarding remote support to the remote commander R.

[0073] The information transmitting unit 14 transmits various information and data related to remote instructions from the remote commander R to the communication device 4 of the vehicle 2. For example, when the remote commander R inputs a remote instruction to the instruction input unit 3b of the commander interface 3, the information transmitting unit 14 transmits the input remote instruction to the vehicle 2.

[0074] The information transmitting unit 14 may transmit the receiving resolution to the communication device 4 via the communication network N. The information transmitting unit 14 transmits, for example, the receiving resolution acquired by the information receiving unit 11 to the communication device 4 of the vehicle 2 via the communication network N.

[0075] [Communication equipment and remote control system processing] Next, an example of the processing of the communication device 4 and the remote instruction system 100 will be described with reference to Figs. 6 and 7. Fig. 6 is a sequence diagram showing an example of the processing of the remote instruction system. Fig. 7 is a flowchart showing an example of the processing for setting transmission conditions. The processing shown in Figs. 6 and 7 is executed, for example, while the vehicle 2 is being driven.

[0076] 6, in the remote instruction system 100, in S10, the remote driving ECU 30 of the vehicle 2 recognizes the surrounding environment of the vehicle 2 using the surrounding environment recognition unit 32. The surrounding environment recognition unit 32 recognizes the surrounding environment of the vehicle 2 based on, for example, detection data of the external sensor 22.

[0077] In S11, the remote driving ECU 30 of the vehicle 2 acquires video data of the surrounding environment image using the display information acquisition unit 36. The display information acquisition unit 36 ​​acquires the video data of the surrounding environment image based on an image captured by the camera of the external sensor 22.

[0078] The remote operation ECU 30 sets the transmission conditions in S12. As the processing of S12, the remote operation ECU 30 performs the processing of the flowchart in FIG.

[0079] 7, in S30, the remote driving ECU 30 acquires the vehicle speed using the driving condition recognition unit 33. The driving condition recognition unit 33 acquires the vehicle speed of the vehicle 2 as the driving condition of the vehicle 2 based on, for example, the detection result of the internal sensor 23.

[0080] In S31, the remote operation ECU 30 acquires communication quality information using the transmission condition setting unit 37. The transmission condition setting unit 37 acquires communication quality information, for example, based on information provided by a communication carrier of the communication network N. The transmission condition setting unit 37 may also acquire estimated values ​​of the transmission frame rate and estimated values ​​of the transmission resolution as communication quality information.

[0081] In S32, the remote driving ECU 30 determines whether or not to suppress the transmission image quality using the transmission condition setting unit 37. The transmission condition setting unit 37 determines whether or not to suppress the transmission image quality including the transmission frame rate and the transmission resolution based on, for example, the vehicle speed of the vehicle 2 and the communication quality information of the communication network N.

[0082] If the transmission condition setting unit 37 determines in S33 that the transmission image quality is to be suppressed (S33: YES), the remote operation ECU 30 proceeds to processing of S34. If the transmission condition setting unit 37 determines in S33 that the transmission image quality is not to be suppressed (S33: NO), the remote operation ECU 30 proceeds to processing of S37.

[0083] In S34, the remote operation ECU 30 determines whether the target value of the transmission resolution has reached the minimum transmission resolution using the transmission condition setting unit 37. If the remote operation ECU 30 determines in S34 that the target value of the transmission resolution has reached the minimum transmission resolution (S34: YES), the remote operation ECU 30 proceeds to processing of S36. If the remote operation ECU 30 determines in S34 that the target value of the transmission resolution has not reached the minimum transmission resolution (S34: NO), the remote operation ECU 30 proceeds to processing of S35.

[0084] In S35, the remote driving ECU 30 causes the transmission condition setting unit 37 to maintain the target value of the transmission frame rate while reducing the target value of the transmission resolution. The transmission condition setting unit 37 maintains the target value of the transmission frame rate while reducing the target value of the transmission resolution, for example, by switching the target value of the transmission resolution shown in FIG. 5(a) while not switching the target value of the transmission frame rate shown in FIG. 5(b). The transmission condition setting unit 37 may reduce the target value of the transmission resolution so that the absolute value of the time rate of change of the target value of the transmission resolution does not exceed a predetermined upper limit rate of change. Thereafter, the remote driving ECU 30 ends the processing of FIG. 7 and returns to the processing of FIG. 6.

[0085] In S36, the remote driving ECU 30 causes the transmission condition setting unit 37 to maintain the target value of the transmission resolution while reducing the target value of the transmission frame rate. The transmission condition setting unit 37 maintains the target value of the transmission resolution while reducing the target value of the transmission frame rate, for example, by not switching the target value of the transmission resolution shown in FIG. 5(a) and switching the target value of the transmission frame rate shown in FIG. 5(b). The transmission condition setting unit 37 may reduce the target value of the transmission frame rate so that the absolute value of the time rate of change of the target value of the transmission frame rate does not exceed a predetermined upper limit rate of change. Thereafter, the remote driving ECU 30 ends the processing of FIG. 7 and returns to the processing of FIG. 6.

[0086] In S37, the remote driving ECU 30 increases the target value of the transmission frame rate and increases the target value of the transmission resolution using the transmission condition setting unit 37. The transmission condition setting unit 37 increases the target value of the transmission resolution and increases the target value of the transmission frame rate, for example, by switching the target value of the transmission resolution shown in FIG. 5(a) and switching the target value of the transmission frame rate shown in FIG. 5(b). Thereafter, the remote driving ECU 30 ends the processing of FIG. 7 and returns to the processing of FIG. 6.

[0087] 6, in S13, the remote driving ECU 30 of the vehicle 2 transmits the video data via the display information transmission unit 38. The display information transmission unit 38 transmits the video data of the surrounding environment image to the remote instruction device 1 via the communication network N using, for example, the communication unit 26.

[0088] At S20, the remote instruction server 10 of the remote instruction device 1 receives the video data via the information receiving unit 11. The information receiving unit 11 receives, for example, video data of a surrounding environment image transmitted from the communication device 4 of the vehicle 2 via the communication network N.

[0089] In S21, the remote instruction server 10 acquires the reception resolution using the information receiving unit 11. The remote instruction server 10 acquires, as the reception resolution, a resolution value for the received video data of the surrounding environment image based on, for example, a performance value provided by a communication carrier of the communication network N.

[0090] In S22, the remote instruction server 10 transmits the reception resolution via the information transmission unit 14. The information transmission unit 14 transmits the acquired reception resolution to the communication device 4 of the vehicle 2 via the communication network N, for example.

[0091] In S14, the remote driving ECU 30 of the vehicle 2 receives the reception resolution using the transmission condition setting unit 37. The transmission condition setting unit 37 receives the reception resolution transmitted from the remote instruction server 10 of the remote instruction device 1 via the communication network N, for example.

[0092] In S15, the remote driving ECU 30 determines whether the reception resolution is lower than the target value of the transmission resolution of the video data using the transmission condition setting unit 37. The transmission condition setting unit 37, for example, compares the target value of the transmission resolution of the video data of the surrounding environment image transmitted to the remote instruction device 1 in S13 with the reception resolution (actual value) received from the remote instruction device 1 in S14, to determine whether the reception resolution is lower than the target value of the transmission resolution of the video data.

[0093] If the transmission condition setting unit 37 determines in S15 that the reception resolution is lower than the target value of the transmission resolution of the video data (S15: YES), the remote driving ECU 30 proceeds to the processing of S16. If the transmission condition setting unit 37 determines in S15 that the reception resolution is equal to or higher than the target value of the transmission resolution of the video data (S15: NO), the remote driving ECU 30 ends the processing of Fig. 6. The remote driving ECU 30 may restart the processing of Fig. 6 after a predetermined time has elapsed.

[0094] In S16, the remote driving ECU 30 maintains the target value of the transmission frame rate and sets the target value of the transmission resolution based on the reception resolution using the transmission condition setting unit 37. For example, if the reception resolution is equal to or higher than the minimum transmission resolution indicated by the dashed line L1 in FIG. 5(a), the transmission condition setting unit 37 may set the resolution value of the reception resolution to the target value of the transmission resolution and maintain the target value of the transmission frame rate shown in FIG. 5(b). In this case, as the transmission condition setting process, the processes of S12 and S16 are performed each time the process of FIG. 6 is executed. Note that, for example, if the reception resolution is lower than the minimum transmission resolution indicated by the dashed line L1 in FIG. 5(a), the transmission condition setting unit 37 may not perform the process of S16. Thereafter, the remote driving ECU 30 ends the process of FIG. 6. The remote driving ECU 30 may restart the process of FIG. 6 after a predetermined time has elapsed.

[0095] As described above, the communication device 4 determines whether to suppress the transmission image quality of the video data, including the transmission frame rate and the transmission resolution, based on the vehicle speed of the vehicle 2 and the communication quality information of the communication network N. If it is determined that the transmission image quality should be suppressed, the target value of the transmission frame rate is maintained and the target value of the transmission resolution is reduced. This reduces the amount of transmission data without lowering the transmission frame rate of the video data, while taking into account both the vehicle speed of the vehicle 2 and the communication quality information of the communication network N, thereby preventing, for example, the transmission frame rate from being insufficient compared to the vehicle speed. This makes it possible to achieve both good visibility of the video data by the remote commander R and a reduction in the amount of transmission data.

[0096] The transmission condition setting unit 37 reduces or increases the target value of the transmission resolution so that the absolute value of the time rate of change of the target value of the transmission resolution does not exceed a predetermined upper limit. This makes it possible to suppress the impact of a sudden change in the transmission resolution or transmission frame rate on the visibility of the video data displayed by the remote commander R. Specifically, if a decision is made not to suppress the transmission image quality after suppressing the transmission image quality and the target value of the transmission resolution or the transmission frame rate suddenly increases, the target value will be too high compared to the communication quality information, which may actually cause the image of the surrounding environment to freeze due to packet loss of the video data. Therefore, by suppressing a sudden change in the transmission resolution or the transmission frame rate, it is possible to suppress the impact on the visibility of the video data displayed by the remote commander R. Note that image freeze refers to, for example, a state in which the image is not updated (i.e., the last displayed image remains displayed) continuing for a predetermined period of time (e.g., one second).

[0097] When the transmission condition setting unit 37 determines that the transmission image quality should be reduced if the target value of the transmission resolution has reached a preset minimum transmission resolution, it maintains the target value of the transmission resolution and reduces the target value of the transmission frame rate, thereby reducing the amount of transmission data without causing the transmission resolution to fall below the minimum transmission resolution.

[0098] When the receiving resolution of the video data is lower than the target value of the transmitting resolution, the remote instruction system 100 maintains the target value of the transmitting frame rate and sets the target value of the transmitting resolution based on the receiving resolution. This makes it possible to efficiently reduce the amount of data to be transmitted by utilizing the information on the receiving resolution.

[0099] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

[0100] In the above embodiment, the transmission condition setting unit 37 reduces or increases the target value of the transmission resolution so that the absolute value of the time rate of change of the target value of the transmission resolution does not exceed a predetermined upper limit of the change rate, but this is not limiting. For example, if the target value is unlikely to be high relative to the communication quality information, such as when a temporary deterioration in communication quality is resolved, the transmission condition setting unit 37 may reduce or increase the target value of the transmission resolution so that it exceeds the upper limit of the change rate.

[0101] In the above embodiment, when the transmission condition setting unit 37 determines that the transmission image quality should be suppressed because the target value of the transmission resolution has reached the minimum transmission resolution, the transmission condition setting unit 37 maintains the target value of the transmission resolution and reduces the target value of the transmission frame rate, but this is not limiting. For example, when the transmission condition setting unit 37 determines that the transmission image quality should be suppressed because the target value of the transmission resolution has reached the minimum transmission resolution, the transmission condition setting unit 37 may limit the image capture range of the vehicle 2 included in the video data by a known method, thereby reducing the volume of the video data.

[0102] In the above embodiment, when the reception resolution is lower than the target transmission resolution of the video data and the reception resolution is equal to or greater than the minimum transmission resolution indicated by the dashed line L1 in FIG. 5A, the transmission condition setting unit 37 maintains the target transmission frame rate and sets the target transmission resolution based on the reception resolution. However, this is not limiting. The transmission condition setting unit 37 may set the target transmission resolution based on the reception resolution even if the reception resolution is lower than the minimum transmission resolution indicated by the dashed line L1 in FIG. 5A. Alternatively, the transmission condition setting unit 37 may not have the function of using the reception resolution as the target transmission resolution. For example, in the process of FIG. 6, steps S13, S14, S20, S21, and S22 may be omitted. That is, in the example of FIG. 6, the communication device 4 may perform steps S10 to S13. In this case, step S12 is performed as the transmission condition setting process each time the process of FIG. 6 is executed.

[0103] In the above embodiment, the vehicle 2 having an automatic driving function is exemplified as a vehicle capable of performing remote support, but the automatic driving function is not essential. The vehicle may have a driving assistance function instead of the automatic driving function, or may have only a manual driving function. In short, the vehicle only needs to be configured to be able to perform remote support in response to remote instructions from a remote commander.

[0104] In the above embodiment, for example, a cloud server may be interposed between the vehicle 2 and the remote instruction device 1. The cloud server, for example, relays various information and data transmitted from the vehicle 2 so that the information and data is transmitted to the remote instruction device 1. The cloud server, for example, relays various information and data transmitted from the remote instruction device 1 so that the information and data is transmitted to the vehicle 2.

[0105] The function of the remote driving ECU 30 may be realized, for example, by controlling the actuator 25 of the vehicle 2 in response to a vehicle control request from an ADK (Autonomous Driving Kit) connected to the vehicle 2 via a communication interface. [Explanation of symbols]

[0106] 1...remote instruction device, 2...vehicle, 4...communication device, 11...information receiving unit, 14...information transmitting unit, 37...transmission condition setting unit, 38...display information transmitting unit (transmitting unit), 100...remote instruction system, N...communication network, R...remote commander

Claims

1. A communication device that is mounted on a vehicle capable of performing remote support in response to a remote instruction from a remote commander, and that transmits video data from the vehicle via a communication network, a transmission condition setting unit that sets transmission conditions including a target value of a transmission frame rate of the video data and a target value of a transmission resolution of the video data based on a speed of the vehicle; a transmitting unit that transmits the video data based on the transmission conditions so that the transmission resolution and the transmission frame rate reach the respective target values, The transmission condition setting unit determining whether to suppress the transmission image quality of the video data, including the transmission frame rate and the transmission resolution, based on the vehicle speed of the vehicle and communication quality information of the communication network; When it is determined that the transmission image quality is to be suppressed, the communication device suppresses the transmission image quality by maintaining the target value of the transmission frame rate and reducing the target value of the transmission resolution.

2. The communication device according to claim 1 , wherein the transmission condition setting unit reduces or increases the target value of the transmission resolution so that an absolute value of a time rate of change of the target value of the transmission resolution does not exceed a predetermined upper limit rate of change.

3. 3. The communication device according to claim 1, wherein when the transmission condition setting unit determines that the transmission image quality should be suppressed if the target value of the transmission resolution has reached a predetermined minimum transmission resolution, the transmission condition setting unit maintains the target value of the transmission resolution and reduces the target value of the transmission frame rate.

4. 3. A remote instruction system including the communication device according to claim 1 or 2 and a remote instruction device that receives the video data transmitted from the communication device via a communication network, The remote instruction device an information receiving unit that acquires a reception resolution of the video data; an information transmitting unit that transmits the reception resolution to the communication device via the communication network; A remote instruction system in which, when the receiving resolution is smaller than the target value of the transmission resolution of the video data, the transmission condition setting unit maintains the target value of the transmission frame rate and sets the target value of the transmission resolution based on the receiving resolution.

Images