Control device

Abstract

This control device comprises: a quality management unit that acquires transmission quality in a transmission path between an operation target and a remote operation device that remotely operates the operation target, and determines whether or not the acquired transmission quality satisfies a quality requirement; and a transmission control unit that, when the transmission quality does not satisfy the quality requirement, performs notification at least to the remote operation device, or control on the operation target.　

Description

Control device

[0001] The present invention relates to a control device.

[0002] Conventionally, a remote control system has been proposed that includes an operation target and a remote control device, and that operates the operation target using the remote control device (see, for example, Patent Document 1). Fig. 6 is a diagram showing an example of the configuration of a conventional remote control system S. The remote control system S includes an operation target 1 and a remote control device 2. The operation target 1 is, for example, a vehicle, and transmits image data captured by a central camera provided on the vehicle to the remote control device 2.

[0003] If the delay time in receiving image data exceeds a predetermined time, the remote control device 2 can issue a warning to the operator and adjust the data capacity of the buffer. The mechanism by which the remote control device 2 issues a warning to the operator is measured by the amount of image data buffered in the remote control device 2.

[0004] JP 2018-180771 A

[0005] However, with conventional technology, when a constant delay occurs, it is not possible to issue a warning to the operator even if the delay time in receiving image data becomes long. In such cases, the update of the image displayed to the operator becomes unstable. As a result, there is a problem that it becomes difficult to remotely control the operation target. This problem is not limited to image data, but occurs in all delays that occur in communication between the operation target and the remote control device via a transmission path.

[0006] In view of the above circumstances, an object of the present invention is to provide a technique that can reduce the influence of remote control on an object to be controlled.

[0007] One aspect of the present invention is a control device that includes a quality management unit that acquires transmission quality in a transmission path between an object to be operated and a remote control device that remotely operates the object to be operated, and determines whether the acquired transmission quality satisfies quality requirements, and a transmission control unit that, if the transmission quality does not satisfy the quality requirements, notifies at least the remote control device or controls the object to be operated.

[0008] According to the present invention, it is possible to reduce the influence of remote control on an object to be controlled.

[0009] FIG. 1 is a diagram for explaining an overview of a remote control system according to the present invention. FIG. 2 is a diagram showing an example of the configuration of a remote control system according to a first embodiment. FIG. 3 is a diagram showing an example of the configuration of a remote control system according to a second embodiment. FIG. 4 is a diagram showing an example of the configuration of a remote control system according to a third embodiment. FIG. 5 is a diagram showing an example of the configuration of a remote control system according to a fourth embodiment. FIG. 6 is a diagram showing an example of the configuration of a conventional remote control system.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (Overall Configuration and Overview) First, before explaining with a specific example, an overview of the remote control system 100 of the present invention will be described with reference to Fig. 1. Fig. 1 is a diagram for explaining the overview of the remote control system 100 of the present invention. The remote control system 100 is a system for remotely operating equipment, etc. located at a different point from one point. The remote control system 100 is not particularly limited as long as it is used for tasks such as remote arm operation, remote surgery, remote construction, remote inspection, etc., as long as it remotely operates equipment to be operated.

[0012] The remote control system 100 includes a remote control device 10, an operation target 20, a quality control unit 30, a transmission control unit 40, and a processing device 50. The remote control device 10, the operation target 20, the quality control unit 30, the transmission control unit 40, and the processing device 50 are connected via a transmission network NW. The transmission network NW may be a network of any configuration, such as the Internet. Note that the transmission network NW may also be a wireless network. Furthermore, the number of remote control devices 10, operation targets 20, quality control units 30, transmission control units 40, and processing devices 50 is not particularly limited.

[0013] The quality control unit 30 and the transmission control unit 40 are provided in one or more housings and function as a control device. This also applies to the following embodiments. The control device includes a CPU (Central Processing Unit), memory, auxiliary storage device, etc., connected via a bus, and executes a program. By executing the program, the control device functions as a device including the quality control unit 30 and the transmission control unit 40. Note that all or part of the functions of the control device may be realized using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The program may also be recorded on a computer-readable recording medium. Examples of computer-readable recording media include portable media such as a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), and a CD-ROM, and storage devices such as a hard disk built into a computer system. The program may also be transmitted and received via a telecommunications line.

[0014] The remote control device 10 is a device for controlling an operation target 20 installed at a different location. The remote control device 10 includes, for example, an output device 11 and an operation input device 12. The output device 11 is a device that outputs information obtained from the operation target 20 and management results obtained by the quality control unit 30. The output device 11 is a device that can output information that affects the five senses (e.g., images, sounds, smells, etc.) such as a monitor or speaker. The operation input device 12 is a device for inputting instructions to the operation target 20. The operation input device 12 is an operation device such as a controller, mouse, or keyboard.

[0015] The operation target 20 is remotely operated by the remote control device 10. The operation target 20 includes, for example, an information collection device 21 and a drive device 22. The information collection device 21 is a device that collects information in response to instructions from the remote control device 10. The information collection device 21 is not particularly limited as long as it is a device that can collect the state of the operation target, such as image data, sound information, haptic information, taste information, or database information, and express it on the remote control device 10 side.

[0016] The driving device 22 is a device that is driven in response to an instruction from the remote control device 10. The driving device 22 may be, for example, a robot, a drone, a car, a server that does not physically move, or an electrical appliance, as long as it can be remotely controlled.

[0017] The quality management unit 30 collects the transmission quality between the remote operation device 10 and the operation target 20. In the example shown in Fig. 1 , the sections managed by the quality management unit 30 are, for example, the following sections: (Section 1) Section between the information collection device 21 and the output device 11 (Section 2) Section combining the section between the information collection device 21 and the processing device 50 and the section between the processing device 50 and the output device 11 (information collection device 21 <- processing device 50 <- output device 11) (Section 3) Section combining the section between the operation input device 12 and the processing device 50 and the section between the processing device 50 and the drive device 22 (operation input device 12 <- processing device 50 <- drive device 22)

[0018] In addition, in a section including the processing device 50, the quality control unit 30 collects transmission quality taking into account the processing time of the processing device 50. Information collected by the quality control unit 30 includes, for example, delay information, information indicating usage status such as an overload state or a congestion state, and availability information such as a failure. When collecting transmission time, Ping or the like may be used, or information within packets of transmitted information may be used. The method of collecting the processing time of the processing device 50 may be a method of collecting it directly from the processing device 50, or a method of obtaining it using an external time measurement device.

[0019] The quality control unit 30 uses quality requirements from a separately held operation system to determine whether the transmission quality obtained based on each collected information satisfies the quality requirements. The transmission quality is, for example, any of the transmission time, transmission time fluctuation, power in the optical transmission section, and data error rate.

[0020] For example, suppose the quality requirement is a condition related to transmission time, and that the time between the information collecting device 21 and the output device 11 must be within 100 ms. If the results collected by the quality management unit 30 show that the transmission time between the information collecting device 21 and the processing device 50 is 40 ms, the processing time by the processing device 50 is 40 ms, and the transmission time between the processing device 50 and the output device 11 is 40 ms, the total transmission time will be 120 ms. In this case, the quality management unit 30 determines that the quality requirement is not met and that the quality is degraded. Similarly, the load state of the processing device 50, the packet transmission success rate (error rate), and the fluctuation in transmission time may also be quality requirements.

[0021] For example, if the quality management unit 30 determines that the quality requirements are not satisfied, it notifies the transmission control unit 40 of a quality judgment result indicating that the quality is degraded. For example, if the quality management unit 30 determines that the quality requirements are satisfied, it notifies the transmission control unit 40 of a quality judgment result indicating that the quality is good. Note that if the quality requirements are satisfied, the network environment is not particularly bad, so the quality management unit 30 does not need to notify the quality judgment result.

[0022] The transmission control unit 40 receives the quality assessment result notified from the quality management unit 30 as an input. Based on the received quality assessment result, the transmission control unit 40 reflects the information included in the quality assessment result. For example, the transmission control unit 40 may reflect the information from the information collection device 21 to the output device 11, or may reflect the information from the operation input device 12 to the drive device 22.

[0023] The method of reflecting the information may be that the transmission control unit 40 individually notifies the output device 11 or drive device 22 that is the target of the notification, or if the information passes through the processing device 50 when being transmitted, the information may be added by the processing device 50.

[0024] For example, when the transmission control unit 40 determines that the quality is degraded, it displays "degraded quality" on the display image of the output device 11. Furthermore, when the transmission control unit 40 determines that the quality is good, it displays "good quality" on the display image of the output device 11.

[0025] Furthermore, for example, when the quality determination result indicates that the quality requirements are not satisfied while the remote control device 10 is controlling the drive device 22, the transmission control unit 40 performs control to lower the operating state of the drive device 22. The control to lower the operating state of the drive device 22 may be, for example, an emergency stop of the drive device 22 or a slowing down of the operation speed.

[0026] For example, when the quality determination result indicates that the quality requirements are satisfied while the remote control device 10 is controlling the drive device 22, the transmission control unit 40 performs control to increase the operating state of the drive device 22. Control to increase the operating state of the drive device 22 may be, for example, increasing the operating speed of the drive device 22. The processing by the transmission control unit 40 may be performed by the processing device 50 to directly affect the operation, or notification and control may be performed using a separate means. Note that the transmission control unit 40 performs at least either notification or control (including both notification and control).

[0027] The processing device 50 performs processing to improve operability when notifying the remote control device 10 of information (e.g., image, audio / haptic information, etc.) acquired from the operation target 20. Here, the processing to improve operability performed on the information acquired from the operation target 20 may be, for example, processing to process an image to display operation procedure instructions or image judgment results, processing to convert information into other communication means to display or notify, or processing to predict an action and notify early.

[0028] The processing device 50 performs processing to improve operability on information collected by the information collection device 21, for example, and displays the processed information on the output device 11. For example, if the information collected by the information collection device 21 is visual information such as video, the processing device 50 performs image processing on video captured by a camera to improve operability and displays the processed video on the output device 11. When performing image processing to improve operability on visual information, the image processing may include adding a display to the video that identifies the object to be operated, adding information instructing the next operation, or displaying supplemental information necessary for operation by referring to a database. Note that the processing to improve operability on the information collected by the information collection device 21 in the processing device 50 does not have to be performed.

[0029] Furthermore, the processing device 50 performs processing to improve operability when notifying the operation target 20 (for example, control of a moving part such as a robot arm) of operation information from the remote control device 10. Here, the processing to improve operability when notifying the operation target 20 of operation information from the remote control device 10 may be, for example, processing to convert the operation information into motor operation information, or processing to predict an operation and notify it early.

[0030] The processing device 50 performs processing to improve operability on information input from the operation input device 12, for example, and transmits the processed operation information to the drive device 22 for control. Processing to improve operability on information input from the operation input device 12 may include emergency stops for safety considerations and speed control to improve operability (such as multiplying or dividing the amount of movement for the same input, or adjusting acceleration from stop to movement or movement to stop). Furthermore, input information from multiple operation input devices 12 may be integrated, or control may be based on information from other external factors. Operability control may not be performed. Note that processing to improve operability on information input from the operation input device 12 in the processing device 50 may not be performed. The processing device 50 may be the same device as the operation target 20, may be the same device as the remote control device 10, or may be independent.

[0031] In the remote control system 100 of the present invention, the above configuration allows accurate understanding of network delays and processing times, and when quality requirements are not met, it is possible to notify the operator and control the operation target. Note that the configuration shown in Figure 1 is an example, and the above effects can be achieved even if some of the components are not included in the remote control system 100. Specific embodiments will be described below.

[0032] 2 is a diagram showing an example of the configuration of a remote control system 100a according to the first embodiment. The remote control system 100a includes a remote control device 10, an operation target 20, a quality management unit 30, and a transmission control unit 40. The remote control device 10, the operation target 20, the quality management unit 30, and the transmission control unit 40 are connected via a transmission network NW. The numbers of the remote control devices 10, the operation target 20, the quality management unit 30, and the transmission control unit 40 are not particularly limited.

[0033] 2, the remote operation system 100a does not include a processing device 50. In the remote operation system 100a, a case where the driving device 22 is controlled will be described. As a specific example, the output device 11 included in the remote operation device 10 is a monitor, and the operation input device 12 is a controller. As another specific example, the information collection device 21 included in the operation target 20 is a camera, and the driving device 22 is a robot. Therefore, in the remote operation system 100a, a robot will be described as an example.

[0034] The operation input device 12 receives input of instructions for the drive device 22, which is the operation target 20. The operation input device 12 transmits the input operation information to the drive device 22 via the transmission network NW.

[0035] The robot, which is the driving device 22 , performs an action according to the operation information transmitted from the operation input device 12 .

[0036] Five patterns of processing by the quality control unit 30 and the transmission control unit 40 under such circumstances will be described.

[0037] [Pattern 1] - Measure the transmission time, and if quality degradation occurs, display a message indicating that the quality has deteriorated on the monitor screen. In pattern 1, the quality control unit 30 measures the transmission time between the operation input device 12 and the drive device 22. The quality control unit 30 compares the acquired transmission time with the value indicated by the quality requirement to determine whether the acquired transmission time satisfies the quality requirement. If the acquired transmission time is less than the value indicated by the quality requirement, the quality control unit 30 determines that the transmission time satisfies the quality requirement. On the other hand, if the acquired transmission time is equal to or greater than the value indicated by the quality requirement, the quality control unit 30 determines that the transmission time does not satisfy the quality requirement.

[0038] If the quality control unit 30 determines that the acquired transmission time satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the transmission time satisfies the quality requirements.

[0039] On the other hand, if the quality control unit 30 determines that the acquired transmission time does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the transmission time does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 displays on the screen of the output device 11, which is a monitor, that the state is in a "quality degradation state."

[0040] The quality control unit 30 may measure the transmission time at any timing while an instruction is being issued from the operation input device 12 to the drive device 22. Furthermore, the quality control unit 30 may measure the transmission delay not only once, but also continuously every time a predetermined time has elapsed.

[0041] [Pattern 2] - The transmission time is measured, and if the quality deteriorates, the operation of the moving parts (such as arms and rollers) is stopped or the speed of the moving parts is slowed. In Pattern 2, the processing is basically the same as in Pattern 1. If the quality control unit 30 determines that the acquired transmission time does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the transmission time does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 may stop the operation of the drive unit 22, or stop the operation of moving parts such as arms and rollers provided on the drive unit 22, which is a robot, or slow down the speed of the moving parts. Note that the transmission control unit 40 may gradually slow down the speed of the moving parts each time a quality judgment result indicating that the transmission time does not satisfy the quality requirements is obtained.

[0042] [Pattern 3] - Combination of Pattern 1 and Pattern 2 In Pattern 3, the same processing as in Pattern 1 is basically performed. If the quality control unit 30 determines that the acquired transmission time does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the transmission time does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 displays a "quality degradation state" on the screen of the output device 11, which is a monitor, as in Pattern 1, and then performs an emergency stop on the operation of the drive device 22, or stops the operation of moving parts such as arms and rollers provided in the drive device 22, which is a robot, or slows down the operation speed, as in Pattern 2.

[0043] The processing device 50 may control the screen display on the output device 11 and control the operation of the drive device 22 at different timings or at the same timing.

[0044] [Pattern 4] - When the information acquired in Patterns 1 to 3 is transmission time fluctuation Here, the case of Pattern 1 will be described as an example. In Pattern 4, the quality control unit 30 measures the transmission time fluctuation between the operation input device 12 and the drive device 22. The quality control unit 30 determines whether the measured transmission time fluctuation satisfies the quality requirements. If the measured transmission time fluctuation is less than the value indicated by the quality requirements, the quality control unit 30 determines that the transmission time fluctuation satisfies the quality requirements. On the other hand, if the measured transmission time fluctuation is equal to or greater than the value indicated by the quality requirements, the quality control unit 30 determines that the transmission time fluctuation does not satisfy the quality requirements.

[0045] If the quality control unit 30 determines that the measured transmission time fluctuation satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the transmission time fluctuation satisfies the quality requirements.

[0046] On the other hand, if the quality control unit 30 determines that the measured transmission time fluctuation does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the transmission time fluctuation does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 displays on the screen of the output device 11, which is a monitor, that the state is in a "quality degradation state."

[0047] [Pattern 5] - When the information acquired in Patterns 1 to 3 is the power of an optical transmission line section or the error rate of packets or signals. Here, Pattern 1 will be described as an example. When acquiring the power of an optical transmission line section, it is assumed that the operation input device 12 and the drive device 22 are connected via an optical transmission line. In Pattern 5, the quality control unit 30 measures the power of the optical transmission line section between the operation input device 12 and the drive device 22. The quality control unit 30 determines whether the acquired power of the optical transmission line section satisfies the quality requirements. If the power of the optical transmission line section is equal to or greater than the value indicated by the quality requirements, the quality control unit 30 determines that the power of the optical transmission line section satisfies the quality requirements. On the other hand, if the acquired power of the optical transmission line section is less than the value indicated by the quality requirements, the quality control unit 30 determines that the power of the optical transmission line section does not satisfy the quality requirements.

[0048] If the quality control unit 30 determines that the power of the acquired optical transmission line section satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the power of the optical transmission line section satisfies the quality requirements.

[0049] On the other hand, if the quality control unit 30 determines that the acquired power of the optical transmission line section does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the power of the optical transmission line section does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified from the quality control unit 30. For example, the transmission control unit 40 causes the output device 11, which is a monitor, to display on its screen that the state is in a "quality degradation state."

[0050] Similarly, in pattern 5, the quality control unit 30 measures the error rate (packet loss) of packets or signals between the operation input device 12 and the drive device 22. The quality control unit 30 determines whether the acquired packet or signal error rate satisfies the quality requirements. If the packet or signal error rate is less than the value indicated by the quality requirements, the quality control unit 30 determines that the packet or signal error rate satisfies the quality requirements. On the other hand, if the acquired packet or signal error rate is equal to or greater than the value indicated by the quality requirements, the quality control unit 30 determines that the packet or signal error rate does not satisfy the quality requirements.

[0051] If the quality control unit 30 determines that the error rate of the acquired packet or signal meets the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the error rate of the packet or signal meets the quality requirements.

[0052] On the other hand, if the quality control unit 30 determines that the error rate of the acquired packets or signals does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the error rate of the packets or signals does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 displays on the screen of the output device 11, which is a monitor, that the state is in a "quality degradation state."

[0053] According to the remote control system 100a configured as described above, the control device includes a quality management unit 30 that acquires the transmission quality of the transmission path between the remote control device 10 and the operation target 20 and determines whether the acquired transmission quality satisfies the quality requirements, and a transmission control unit 40 that notifies at least the operation target 20 or controls the remote control device 10 if the transmission quality does not satisfy the quality requirements.

[0054] This allows accurate understanding of the transmission quality (e.g., network delay) of the transmission path between the remote control device 10 and the operation target 20, and if the quality requirements stipulated in the remote control system 100 are not met, at least one of notifying the operator and controlling the operation target 20 can be performed so that an operation that satisfies safety, immediacy, and accuracy can be achieved. In this way, it becomes possible to reduce the impact of remote control on the operation target.

[0055] Furthermore, in the remote operation system 100a, the quality management unit 30 acquires, as transmission quality, any of the transmission time, transmission time fluctuation, power in the optical transmission section, or data error rate in the section between the remote operation device 10 and the operation target 20, and compares the acquired transmission quality with the quality requirements. This makes it possible to more accurately grasp delays occurring in communication between the remote operation device 10 and the operation target 20 via the transmission network NW. As a result, if the quality requirements specified in the remote operation system 100 are not met, it becomes possible to notify the operator and control the operation target 20 so that safe, immediate, and accurate operations can be achieved.

[0056] Furthermore, in the remote operation system 100a, when the transmission quality does not satisfy the quality requirements, the transmission control unit 40 notifies the remote operation device 10 of information indicating that the transmission quality does not satisfy the quality requirements. This allows the user operating the remote operation device 10 to be notified in real time that the transmission quality is poor. This allows the user to respond immediately, and reduces the impact of the remote operation on the operation target.

[0057] Furthermore, in the remote operation system 100a, when the transmission quality does not satisfy the quality requirements, the transmission control unit 40 performs control to lower the operating state of the operation target 20. For example, the control to lower the operating state of the operation target 20 is performed by performing an emergency stop or slowing down the speed of the operation of the moving part. Therefore, it is possible to reduce the influence of the remote operation on the operation target.

[0058] (Variation 1 of the First Embodiment) In the above-described Pattern 5, the quality control unit 30 may be configured to determine whether or not a quality requirement is satisfied by combining a plurality of transmission qualities. For example, the quality control unit 30 may determine whether or not a quality requirement is satisfied based on two transmission qualities, namely, the power of the optical transmission line section and the error rate of packets or signals. In such a configuration, when the quality requirement is satisfied for each of the two transmission qualities, namely, the power of the optical transmission line section and the error rate of packets or signals, the quality control unit 30 may or may not notify the transmission control unit 40 of a quality determination result indicating that the quality requirement is satisfied.

[0059] On the other hand, if the quality requirements are not met for two transmission qualities, the power of the optical transmission line section and the error rate of packets or signals, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are not met. For example, taking the two transmission qualities, the power of the optical transmission line section and the error rate of packets or signals, as an example, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are met if the total value of the power satisfies the quality requirements and the total value of the error rates of packets or signals satisfies the quality requirements. On the other hand, in other cases, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are not met. This configuration makes it possible to deal with situations where one transmission quality satisfies the quality requirements but the network environment does not satisfy the quality requirements for another reason.

[0060] (Modification 2 of the First Embodiment) The quality control unit 30 may be configured to determine whether or not the quality requirements are satisfied by combining any of the above-described patterns 1 to 5. A specific method is as shown in Modification 1 of the second embodiment.

[0061] Second Embodiment In the first embodiment, a configuration in which the remote control system does not include a processing device is described. In contrast, in the second embodiment, a configuration in which the remote control system includes a processing device is described. In the case where the remote control system includes a processing device, whether or not the quality requirements are satisfied is determined taking into account the processing time of the processing device.

[0062] 3 is a diagram showing an example of the configuration of a remote control system 100b according to the second embodiment. The remote control system 100b includes a remote control device 10, an operation target 20, a quality control unit 30, a transmission control unit 40, and a processing device 50. The remote control device 10, the operation target 20, the quality control unit 30, the transmission control unit 40, and the processing device 50 are connected via a transmission network NW. The numbers of the remote control devices 10, the operation target 20, the quality control unit 30, the transmission control unit 40, and the processing device 50 are not particularly limited.

[0063] As shown in Fig. 3, the remote operation system 100b includes a processing device 50. In the remote operation system 100b, a case where the driving device 22 is controlled will be described. As a specific example, the output device 11 included in the remote operation device 10 is a monitor, and the operation input device 12 is a controller. As another specific example, the information collection device 21 included in the operation target 20 is a camera, and the driving device 22 is a robot. As another specific example, the processing device 50 is a server. Therefore, in the remote operation system 100b, a robot will be described as an example.

[0064] The operation input device 12 receives input of instructions for the drive device 22, which is the operation target 20. The operation input device 12 transmits the input operation information to the processing device 50 via the transmission network NW.

[0065] The processing device 50 receives operation information transmitted from the operation input device 12. The processing device 50 processes the input operation information to improve operability. The processing device 50 then transmits the processed operation information to the drive device 22.

[0066] The robot, which is the driving device 22, performs an operation in accordance with the processed operation information transmitted from the processing device 50.

[0067] Five patterns of processing by the quality control unit 30 and the transmission control unit 40 under such circumstances will be described.

[0068] [Pattern 1] - Measure the transmission time and processing time, and display a quality degradation status on the monitor screen when quality degradation occurs. In pattern 1, the quality control unit 30 measures the transmission time between the operation input device 12 and the processing device 50, and the transmission time between the processing device 50 and the drive device 22. Furthermore, the quality control unit 30 measures the processing time by the processing device 50. The quality control unit 30 then calculates the total time of each measured time. The quality control unit 30 compares the calculated total time with the value indicated by the quality requirement to determine whether the calculated total time satisfies the quality requirement. If the calculated total time is less than the value indicated by the quality requirement, the quality control unit 30 determines that the total time satisfies the quality requirement. On the other hand, if the calculated total time is equal to or greater than the value indicated by the quality requirement, the quality control unit 30 determines that the total time does not satisfy the quality requirement.

[0069] If the quality control unit 30 determines that the calculated total time satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the total time satisfies the quality requirements.

[0070] On the other hand, if the quality control unit 30 determines that the calculated total time does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the total time does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 causes the output device 11, which is a monitor, to display on its screen that the "quality degradation state" is occurring.

[0071] The quality control unit 30 may measure the transmission time and the processing time at any timing while an instruction is being issued from the operation input device 12 to the drive device 22. Furthermore, the quality control unit 30 may measure the transmission time and the processing time not only once, but also continuously every time a predetermined time has elapsed.

[0072] [Pattern 2] - The transmission time and processing time are measured, and if quality deteriorates, the operation of the moving parts (such as arms and rollers) is stopped or the speed of the moving parts is slowed. In Pattern 2, the processing is basically the same as in Pattern 1. If the quality control unit 30 determines that the calculated total time does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the total time does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 may stop the operation of the drive unit 22, or stop the operation of moving parts such as arms and rollers provided on the drive unit 22, which is a robot, or slow down the speed of the moving parts. Note that the transmission control unit 40 may gradually slow down the speed of the moving parts each time a quality judgment result indicating that the total time does not satisfy the quality requirements is obtained.

[0073] [Pattern 3] - Combination of Pattern 1 and Pattern 2 In Pattern 3, the same processing as in Pattern 1 is basically performed. If the quality control unit 30 determines that the calculated total time does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the total time does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 displays a "quality degradation state" on the screen of the output device 11, which is a monitor, as in Pattern 1, and then performs an emergency stop on the operation of the drive device 22, or stops the operation of moving parts such as arms and rollers provided in the drive device 22, which is a robot, or slows down the operation speed, as in Pattern 2.

[0074] The processing device 50 may control the screen display on the output device 11 and control the operation of the drive device 22 at different timings or at the same timing.

[0075] [Pattern 4] - When the information acquired in Patterns 1 to 3 is the fluctuation between transmission time and processing time. Here, Pattern 1 will be described as an example. In Pattern 4, the quality control unit 30 measures the transmission time fluctuation between the operation input device 12 and the processing device 50 and the transmission time fluctuation between the processing device 50 and the drive device 22. Furthermore, the quality control unit 30 measures the fluctuation of the processing time by the processing device 50. Then, the quality control unit 30 calculates the sum of the fluctuations for each measured time. The quality control unit 30 compares the calculated sum of the fluctuations with the value indicated by the quality requirement to determine whether the calculated sum of the fluctuations satisfies the quality requirement. If the calculated sum of the fluctuations is less than the value indicated by the quality requirement, the quality control unit 30 determines that the sum of the fluctuations satisfies the quality requirement. On the other hand, if the calculated sum of the fluctuations is equal to or greater than the value indicated by the quality requirement, the quality control unit 30 determines that the sum of the fluctuations does not satisfy the quality requirement.

[0076] If the quality control unit 30 determines that the calculated total value of fluctuations satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the total value of fluctuations satisfies the quality requirements.

[0077] On the other hand, if the quality control unit 30 determines that the calculated total value of fluctuations does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the total value of fluctuations does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 causes the output device 11, which is a monitor, to display on the screen that the state is in a "quality degradation state."

[0078] [Pattern 5] - When the information acquired in Patterns 1 to 3 is the power of an optical transmission line section, the packet or signal error rate, or the processing load of the processing device 50. Here, Pattern 1 will be described as an example. When acquiring the power of an optical transmission line section, it is assumed that the operation input device 12 and the processing device 50, and the processing device 50 and the driving device 22 are connected by optical transmission lines. In Pattern 5, the quality control unit 30 measures the power of the optical transmission line section between the operation input device 12 and the processing device 50 and the power of the optical transmission line section between the processing device 50 and the driving device 22. Then, the quality control unit 30 calculates the sum of the measured power values ​​for each section. The quality control unit 30 compares the calculated power sum with the value indicated by the quality requirement to determine whether the calculated power sum satisfies the quality requirement.

[0079] If the calculated total power value is less than the value indicated by the quality requirement, the quality control unit 30 determines that the calculated total power value satisfies the quality requirement. On the other hand, if the calculated total power value is equal to or greater than the value indicated by the quality requirement, the quality control unit 30 determines that the calculated total power value does not satisfy the quality requirement.

[0080] If the quality control unit 30 determines that the calculated total power value satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the total power value satisfies the quality requirements.

[0081] On the other hand, if the quality control unit 30 determines that the calculated total power value does not satisfy the quality requirement, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the total power value does not satisfy the quality requirement. The transmission control unit 40 performs control based on the quality judgment result notified from the quality control unit 30. For example, the transmission control unit 40 causes the output device 11, which is a monitor, to display on its screen that the state is in a "quality degradation state."

[0082] Similarly, in pattern 5, the quality control unit 30 measures the packet or signal error rate (packet loss) between the operation input device 12 and the processing device 50, and the packet or signal error rate (packet loss) between the processing device 50 and the drive device 22. The quality control unit 30 then calculates the total value of the measured packet or signal error rates for each section. The quality control unit 30 compares the calculated total value of the packet or signal error rates with the value indicated by the quality requirement, thereby determining whether the calculated total value of the packet or signal error rates satisfies the quality requirement.

[0083] If the calculated total value of the packet or signal error rates is less than the value indicated by the quality requirement, the quality control unit 30 determines that the calculated total value of the packet or signal error rates satisfies the quality requirement. On the other hand, if the calculated total value of the packet or signal error rates is equal to or greater than the value indicated by the quality requirement, the quality control unit 30 determines that the calculated total value of the packet or signal error rates does not satisfy the quality requirement.

[0084] If the quality control unit 30 determines that the calculated total value of the packet or signal error rate satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the total value of the packet or signal error rate satisfies the quality requirements.

[0085] On the other hand, if the quality control unit 30 determines that the calculated total value of the packet or signal error rates does not satisfy the quality requirements, the quality control unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the total value of the packet or signal error rates does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality control unit 30. For example, the transmission control unit 40 displays on the screen of the output device 11, which is a monitor, that the state is in a "quality degradation state."

[0086] Similarly, in pattern 5, the quality control unit 30 acquires the processing load in the processing device 50. The quality control unit 30 determines whether the acquired processing load satisfies the quality requirements. If the acquired processing load is less than the value indicated by the quality requirements, the quality control unit 30 determines that the processing load satisfies the quality requirements. On the other hand, if the acquired processing load is equal to or greater than the value indicated by the quality requirements, the quality control unit 30 determines that the processing load does not satisfy the quality requirements.

[0087] If the quality control unit 30 determines that the acquired processing load satisfies the quality requirements, the quality control unit 30 may or may not notify the transmission control unit 40 of the quality judgment result indicating that the processing load satisfies the quality requirements.

[0088] On the other hand, if the quality management unit 30 determines that the acquired processing load does not satisfy the quality requirements, the quality management unit 30 notifies the transmission control unit 40 of the quality judgment result indicating that the processing load does not satisfy the quality requirements. The transmission control unit 40 performs control based on the quality judgment result notified by the quality management unit 30. For example, the transmission control unit 40 causes the output device 11, which is a monitor, to display on its screen that the processing load is in a "quality degradation state."

[0089] According to the remote operation system 100b configured as described above, when the processing device 50 is provided, the sum of the transmission time between the remote operation device 10 and the processing device 50, the transmission time between the operation target 20 and the processing device 50, and the processing time by the processing device 50 is used as the transmission quality. This makes it possible to acquire the transmission quality by taking into account the processing time for information transmitted from the remote operation device 10 to the operation target 20 or information transmitted from the operation target 20 to the remote operation device 10. Then, when the quality requirements stipulated in the remote operation system 100a are not satisfied, it becomes possible to notify the operator and control the operation target 20 so as to realize an operation that satisfies safety, immediacy, and accuracy.

[0090] (Variation 1 of the Second Embodiment) In the above-described Pattern 5, the quality control unit 30 may be configured to determine whether a quality requirement is satisfied by combining multiple transmission qualities. For example, the quality control unit 30 may select two or more transmission qualities from among the power of the optical transmission line section, the error rate of packets or signals, and the processing load of the processing device 50, and determine whether the quality requirement is satisfied by the selected two or more transmission qualities. In such a configuration, when the quality requirement is satisfied by each of the selected two or more transmission qualities, the quality control unit 30 may or may not notify the transmission control unit 40 of a quality determination result indicating that the quality requirement is satisfied.

[0091] On the other hand, if the quality requirements are not met for any of the two or more selected transmission qualities, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are not met. For example, taking two transmission qualities, the power of the optical transmission line section and the error rate of packets or signals, as an example, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are met if the total value of the power satisfies the quality requirements and the total value of the error rates of packets or signals satisfies the quality requirements. On the other hand, in other cases, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are not met. This configuration makes it possible to deal with situations where one transmission quality satisfies the quality requirements but the network environment does not satisfy the quality requirements for another reason.

[0092] (Modification 2 of the Second Embodiment) The quality control unit 30 may be configured to determine whether or not the quality requirements are satisfied by combining any of the above-described patterns 1 to 5. A specific method is as shown in Modification 1 of the second embodiment.

[0093] Third Embodiment In a third embodiment, a configuration in which a processing device is provided on the remote control device side will be described.

[0094] 4 is a diagram showing an example of the configuration of a remote operation system 100c according to the third embodiment. The remote operation system 100c includes a remote operation device 10, an operation target 20, a quality management unit 30, and a transmission control unit 40. The remote operation device 10, the operation target 20, the quality management unit 30, and the transmission control unit 40 are connected via a transmission network NW. The numbers of the remote operation devices 10, the operation target 20, the quality management unit 30, and the transmission control unit 40 are not particularly limited.

[0095] 4, the remote control system 100c includes processing devices in both the remote control device 10 and the operation target 20. As a specific example, the output device 11 included in the remote control device 10 is a monitor, the operation input device 12 is a controller, and the processing device 13 is a server. As another specific example, the processing device 23 included in the operation target 20 is a server. The remote control system 100c covers all inter-server communication between networks, such as cloud processing, server access, or browsing.

[0096] The processing device 13 communicates with the processing device 23 via the transmission network NW in response to a user operation. The processing device 13 requests the processing device 23 to perform processing or provide information. The processing device 13 may display information obtained from the processing device 23 on a monitor.

[0097] The processing device 23 communicates with the processing device 13 via the transmission network NW in response to a user operation. The processing device 23 performs processing in response to a request from the processing device 13.

[0098] The processing of the quality control unit 30 and the transmission control unit 40 under such circumstances is basically the same as that of patterns 1, 4, and 5 shown in the second embodiment. The following mainly describes the differences from the second embodiment.

[0099] [Pattern 1] - Measure the transmission time and processing time, and if quality deteriorates, display a message indicating that the quality has deteriorated on the monitor screen. In pattern 1, the quality control unit 30 measures the transmission time between the processing device 13 and the processing device 23. Furthermore, the quality control unit 30 measures the processing time by the processing device 23. The quality control unit 30 then calculates the total time of each measured time. The quality control unit 30 compares the calculated total time with the value indicated by the quality requirement to determine whether the calculated total time satisfies the quality requirement. Subsequent processing is the same as in the second embodiment.

[0100] [Pattern 4] When the information acquired in Pattern 1 is the fluctuation between transmission time and processing time In Pattern 4, the quality control unit 30 measures the fluctuation in transmission time between the processing device 13 and the processing device 23. Furthermore, the quality control unit 30 measures the fluctuation in the processing time by the processing device 23. Then, the quality control unit 30 calculates the sum of the fluctuations for each measured time. The quality control unit 30 compares the calculated sum of the fluctuations with the value indicated by the quality requirement to determine whether the calculated sum of the fluctuations satisfies the quality requirement. The subsequent processing is the same as in the second embodiment.

[0101] [Pattern 5] When the information acquired in Pattern 1 is the power of the optical transmission line section, the error rate of packets or signals, or the processing load of the processing device 50 When acquiring the power of the optical transmission line section, it is assumed that the processing device 13 and the processing device 23 are connected by an optical transmission line. In Pattern 5, the quality control unit 30 measures the power of the optical transmission line section between the processing device 13 and the processing device 23. The subsequent processing is the same as in the second embodiment.

[0102] Similarly, in pattern 5, the quality control unit 30 measures the error rate (packet loss) of packets or signals between the processing device 13 and the processing device 23. The quality control unit 30 determines whether the error rate of the acquired packets or signals satisfies the quality requirements. The subsequent processing is the same as in the second embodiment.

[0103] Similarly, in pattern 5, the quality control unit 30 acquires the processing load of the processing device 23. The quality control unit 30 determines whether the acquired processing load satisfies the quality requirements. The subsequent processing is the same as in the second embodiment.

[0104] According to the remote control system 100c configured as above, it is possible to obtain the same effects as those of the first embodiment even in an environment in which communication is performed between servers.

[0105] In the fourth embodiment, a configuration in which a plurality of remote control devices are provided will be described.

[0106] 5 is a diagram showing an example of the configuration of a remote operation system 100d according to the fourth embodiment. The remote operation system 100d includes remote operation devices 10-1 to 10-2, an operation target 20, a quality management unit 30, and a transmission control unit 40. The remote operation devices 10-1 to 10-2, the operation target 20, the quality management unit 30, and the transmission control unit 40 are connected via a transmission network NW. The numbers of the remote operation devices 10-1 to 10-2, the operation target 20, the quality management unit 30, and the transmission control unit 40 are not particularly limited.

[0107] As shown in FIG. 5, the remote operation system 100d includes multiple remote operation devices 10-1 to 10-2. For example, the remote operation devices 10-1 and 10-2 may be installed at different geographical locations, or may be installed within the same base. As a specific example, the output device 11-1 included in the remote operation device 10-1 is a monitor, and the operation input device 12-1 is a controller. As another specific example, the output device 11-2 included in the remote operation device 10-2 is a monitor, and the operation input device 12-2 is a controller. As another specific example, the processing device 23 included in the operation target 20 is a server. The remote operation system 100d covers all uses in which a server and multiple remote operation devices 10 are connected across a network, such as online games, collaborative work, remote conferences, and webinars.

[0108] The processing of the quality control unit 30 and the transmission control unit 40 under such circumstances is basically the same as that of patterns 1, 4, and 5 shown in the second embodiment. The following mainly describes the differences from the second embodiment.

[0109] [Pattern 1] - Measure the transmission time and processing time, and if quality deteriorates, display a message indicating that the quality has deteriorated on the monitor screen. In pattern 1, the quality control unit 30 measures the transmission time between the remote control device 10-1 and the processing device 23, and the transmission time between the remote control device 10-2 and the processing device 23. Furthermore, the quality control unit 30 measures the processing time by the processing device 23. Thereafter, the quality control unit 30 calculates the total time of each measured time. The quality control unit 30 compares the calculated total time with the value indicated by the quality requirement to determine whether the calculated total time satisfies the quality requirement. Subsequent processing is the same as in the second embodiment.

[0110] [Pattern 4] When the information acquired in Pattern 1 is the fluctuation in transmission time and processing time In Pattern 4, the quality control unit 30 measures the transmission time fluctuation between the remote control device 10-1 and the processing device 23, and the transmission time fluctuation between the remote control device 10-2 and the processing device 23. Furthermore, the quality control unit 30 measures the fluctuation in the processing time by the processing device 23. Thereafter, the quality control unit 30 calculates the sum of the fluctuations for each measured time. The quality control unit 30 compares the calculated sum of fluctuations with the value indicated by the quality requirement, and determines whether the calculated sum of fluctuations satisfies the quality requirement. The subsequent processing is the same as in the second embodiment.

[0111] [Pattern 5] When the information acquired in Pattern 1 is the power of an optical transmission line section, the packet or signal error rate, or the processing load of the processing device 50. When acquiring the power of an optical transmission line section, it is assumed that the remote control device 10-1 and the processing device 23, and the remote control device 10-2 and the processing device 23 are connected by optical transmission lines. In Pattern 5, the quality control unit 30 measures the power of the optical transmission line section between the remote control device 10-1 and the processing device 23, and the power of the optical transmission line section between the remote control device 10-2 and the processing device 23. The quality control unit 30 then calculates the sum of the measured power of each optical transmission line section. The quality control unit 30 compares the calculated sum of the power of each optical transmission line section with the value indicated by the quality requirement to determine whether the calculated sum of the power of each optical transmission line section satisfies the quality requirement. The subsequent processing is the same as in the second embodiment.

[0112] Similarly, in pattern 5, the quality control unit 30 measures the error rate (packet loss) of packets or signals between the processing device 13 and the processing device 23. The quality control unit 30 determines whether the error rate of the acquired packets or signals satisfies the quality requirements. The subsequent processing is the same as in the second embodiment.

[0113] Similarly, in pattern 5, the quality control unit 30 acquires the processing load of the processing device 23. The quality control unit 30 determines whether the acquired processing load satisfies the quality requirements. The subsequent processing is the same as in the second embodiment.

[0114] According to the remote control system 100d configured as above, it is possible to obtain the same effects as those of the first embodiment even in an environment where a plurality of remote control devices 10 exist.

[0115] (Variation 1 common to the third and fourth embodiments) In the above-described pattern 5, the quality control unit 30 may be configured to determine whether a quality requirement is satisfied by combining multiple transmission qualities. For example, the quality control unit 30 may select two or more transmission qualities from among the power of the optical transmission line section, the error rate of packets or signals, and the processing load of the processing device 50, and determine whether the quality requirement is satisfied by the selected two or more transmission qualities. When configured in this manner, if the quality requirement is satisfied by each of the selected two or more transmission qualities, the quality control unit 30 may or may not notify the transmission control unit 40 of a quality determination result indicating that the quality requirement is satisfied.

[0116] On the other hand, if the quality requirements are not met for any of the two or more selected transmission qualities, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are not met. For example, taking two transmission qualities, the power of the optical transmission line section and the error rate of packets or signals, as an example, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are met if the total value of the power satisfies the quality requirements and the total value of the error rates of packets or signals satisfies the quality requirements. On the other hand, in other cases, the quality management unit 30 notifies the transmission control unit 40 of a quality judgment result indicating that the quality requirements are not met. This configuration makes it possible to deal with situations where one transmission quality satisfies the quality requirements but the network environment does not satisfy the quality requirements for another reason.

[0117] (Modification 2 common to the third and fourth embodiments) The quality control unit 30 may be configured to determine whether or not the quality requirements are satisfied by combining any of the above-described patterns 1, 4, and 5. A specific method is as shown in Modification 1 common to the third and fourth embodiments.

[0118] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0119] The present invention is applicable to systems that operate remotely.

[0120] 10... remote control device, 20... operation target, 30... quality control unit, 40... transmission control unit, 50... processing device, 11, 11-1 to 11-2... output device, 12, 12-1 to 12-2... operation input device, 13... processing device, 21... information collection device, 22... drive device, 23... processing device, 100, 100a, 100b, 100c, 100d... remote control system

Claims

1. A control device comprising: a quality management unit that acquires the transmission quality of a transmission path between an object to be operated and a remote control device that remotely operates the object to be operated, and determines whether the acquired transmission quality satisfies quality requirements; and a transmission control unit that, if the transmission quality does not satisfy the quality requirements, notifies at least the remote control device or controls the object to be operated.

2. The control device according to claim 1, wherein the quality management unit acquires as the transmission quality one of the transmission time, transmission time fluctuation, power in the optical transmission section, or data error rate in the section between the operation target and the remote control device, and compares the acquired transmission quality with the quality requirements.

3. The control device according to claim 1, wherein, when a processing device is provided between the object to be operated and the remote control device, the processing device performs processing to improve operability for at least one of information collected by the object to be operated and operation information by the remote control device, the quality management unit determines whether the transmission quality satisfies the quality requirements, taking into account the processing time by the processing device.

4. The control device according to claim 3, wherein the quality management unit acquires a first transmission time in the section between the operation target and the processing device, a second transmission time in the section between the remote control device and the processing device, and the processing time, and compares the sum of the acquired first transmission time, second transmission time, and processing time as the transmission quality with the quality requirements.

5. The control device according to any one of claims 1 to 4, wherein, when the transmission quality does not satisfy the quality requirement, the transmission control unit notifies the remote control device of information indicating that the transmission quality does not satisfy the quality requirement.

6. The control device according to any one of claims 1 to 4, wherein the transmission control unit performs control to lower the operating state of the operation target when the transmission quality does not satisfy a quality requirement.

7. The control device according to claim 1 or 2, wherein the remote control device includes an information processing device that communicates with the information processing device included in the operation target, and the quality management unit acquires transmission quality between the information processing devices.

8. The control device according to claim 1 or 2, wherein the remote control device includes a plurality of information processing devices that communicate with the information processing devices included in the operation target, and the quality management unit acquires the transmission quality between each of the plurality of information processing devices and the information processing devices included in the operation target.

Images