Systems and programs

Abstract

To provide a technology relating to recording of information for identifying a time of data recording.SOLUTION: A system includes an internal clock, and includes a function of acquiring a correct time T4' during recording of a video, and a function of, when the correct time has been acquired during recording of the data, determining a difference ΔT between the time and a time T4 of the internal clock to record it without performing time adjustment of the internal clock. Even if the correct time has been acquired, time adjustment is not performed, and thus the internal clock continuously advances with T3, T4, T5, T6, .... When the recording is stopped, time adjustment is performed (Tn→Tn'). The time based on the internal clock and the difference are recorded in association with a video file, and thus a correct recording time can be determined from the time information and the difference.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to, for example, a system and a program. [Background technology]

[0002] An example of a system for correcting the time of an internal clock in a drive recorder is the invention disclosed in Patent Document 1. In this Patent Document 1, with regard to an invention relating to a vehicle video recording device such as a drive recorder and an in-vehicle system including the vehicle video recording device (paragraph

[0001] , etc.), paragraph

[0054] states that "the drive recorder 1 further includes an internal clock 33 and a control unit 36 ​​within the main body 10," and paragraph

[0065] states that "the control unit 36, which acquires reference date and time data sent from the navigation device 2 at a predetermined timing, corrects and calibrates the internal clock 33." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5704425 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, modifying information that identifies the recording time of already recorded data after the fact can be considered a type of tampering with the recording time, and may be undesirable in some cases. On the other hand, if the time is not synchronized, the recording time will be recorded based on an incorrect clock, which may cause problems as it will be impossible to correctly identify the time at which the location in the captured video was passed. For this reason, technology related to the recording of information that can identify the time at which data was recorded is desired.

[0005] The above-mentioned problems are stated as independent, and the present invention does not necessarily solve all of the problems stated. The purpose of the present invention is not limited to these, and the applicant intends to obtain rights for configurations that aim to achieve the effects achieved by parts of the configuration disclosed in the specification and drawings, etc., through divisional applications, amendments, etc. For example, this specification discloses a problem in which the phrase "can be" is read as "the problem is...". The problems are stated as independent, and the applicant intends to obtain rights for configurations that solve these problems separately through divisional applications, amendments, etc. Even if the problem is implicitly understood from the description in the specification, the applicant intends to claim part of the configuration described in this specification through amendments or divisional applications. Problems that combine these independent problems are also disclosed. [Means for solving the problem]

[0006] (1) A system having a recording device for recording data is provided, the system comprising: a function for acquiring, from a clock unit, a first time for identifying the time when the data was recorded; a function for acquiring information for adjusting the time of the clock unit to a second time; and a function for, if the information is acquired while the data is being recorded, not adjusting the time but instead recording the difference between the first time and the second time in association with the data. In this way, since the time of the clock unit is not adjusted while the data is being recorded, the continuity of the time indicated by the clock unit is ensured, and time jumps can be prevented. For example, when control such as data recording is performed based on the clock unit, if time adjustment is performed during that control, the time used as the reference for control would jump discontinuously, but this can be prevented from occurring.

[0007] (2) The control function may record the first time in addition to the difference in association with the data, and may keep the first time recorded before the time adjustment stored even after the time adjustment. In this way, the time when the data was recorded can be determined based on the difference. Furthermore, since the recorded first time is stored as is, the data is not altered, and the actual time when the data was recorded can be identified.

[0008] (3) It is preferable to have a function of determining a third time indicating the time when the data was recorded based on the first time and the difference recorded in association with the data, and outputting the data based on the determined third time. In this way, even if the time on the clock unit is out of sync, the time when the data was recorded can be identified based on the first time and the difference, and the data can be output.

[0009] (4) The data may include an image and may have a function for displaying the third time together with the image, thereby allowing a viewer of the image to visually understand the time when the image was recorded.

[0010] (5) The display function may include a function for selectively displaying the third time and the first time together with the video, thereby allowing a viewer of the video to visually understand the time measured by the clock unit and the time calculated from the difference and the time used for time adjustment, with respect to the time when the video was recorded.

[0011] (6) The display function may be configured to display the time so as to indicate whether the displayed time is the third time or the first time. This allows a person viewing the video to visually understand whether the displayed time is the time measured by the clock unit or the time calculated from the difference and the time used for time adjustment, with respect to the time when the video was recorded.

[0012] (7) It is advisable to obtain the information for synchronizing the time in a manner that does not require access by unspecified parties. This increases the security of the system's communications and minimizes the risk of information leaks, for example.

[0013] (8) If the control function acquires information for adjusting the time while the data is being recorded, the time adjustment may be performed after the data recording has stopped. In this way, even if the time for adjusting the time is acquired while the data is being recorded, discontinuity in the information identifying the time of data recording can be prevented. Furthermore, after the data recording has stopped and the subsequent data recording has started, the recording is preferably performed based on the time with high accuracy after the time adjustment.

[0014] (9) The information for time adjustment can be acquired from multiple different sources, and when the control function acquires the information for time adjustment while the data is being recorded, it is preferable to preferentially adopt the information for time adjustment from a predetermined source with a high priority. In this way, by making it possible to acquire information for time adjustment from multiple different sources and prioritizing the source with a high priority, it is possible to more easily ensure the accuracy of the time measured by the clock unit. For example, it is possible to acquire a time closer to the correct time.

[0015] (10) The recording device operates by receiving power from the vehicle, and the control function preferably performs the time adjustment when the vehicle engine is stopped and the data recording stops. In this way, by adjusting the time when the engine is stopped, the time is corrected to the time after the time adjustment when the engine is next started, which is advantageous. Although it is possible to adjust the time when the engine is next started, it is sometimes desirable to start recording data as quickly as possible when starting, so it is preferable to adjust the time when the engine is stopped and there is ample time.

[0016] (11) The recording devices may include a first recording device and a second recording device, and when the first recording device acquires the information for setting the time, it may transmit information for setting the time to a fourth time calculated based on the acquired information to the second recording device, and the second recording device may record the difference between the fourth time and the first time acquired by itself based on the information for setting the time acquired from the first recording device. In this way, the first recording device that acquires the time for setting the time can transmit it to the second recording device.

[0017] (12) The recording device may include a third recording device, and the second recording device may transmit information for setting the time to the fifth time based on information for setting the time to the fourth time to the third recording device, and the third recording device may record the difference between the fifth time and the first time acquired by itself based on the information for setting the time acquired from the second recording device. In this way, the third recording device sets its time using the time acquired from the second recording device, so that multiple recording devices can transmit the time for setting their time one after another as if they were in a chain.

[0018] (13) The first recording device may record video of the vehicle's surroundings and have a GPS receiver, and the second recording device may record video of the vehicle's interior, and the first recording device may calculate the fourth time based on the second time acquired based on a signal received by the GPS receiver. In this way, even if the second recording device does not have a GPS receiver or cannot use a GPS receiver, it can record information identifying the time of data recording based on the time for time adjustment calculated based on the GPS receiver of the first recording device. For example, it is possible to identify and display video recorded at the same time on multiple recording devices based on the correct time.

[0019] (14) The first recording device may generate information for adjusting the time to the fourth time by taking into account the elapsed time since acquiring the information for adjusting the time to the second time. In this way, the time for time adjustment can be transmitted to recording devices that cannot obtain the time for time adjustment themselves, such as those that use a GPS receiver, or to recording devices that cannot directly access the source of the time for time adjustment. The process of generating the time taking into account the elapsed time may, for example, measure the elapsed time since reception and add it to the time for time adjustment received by the device itself. Alternatively, the time for time adjustment may be generated without measuring the elapsed time, for example, from the difference between the time at the time of reception and the time at the time of transmission, since the time at which the clock unit receives the time has advanced by that time.

[0020] (15) The recording devices may include a fourth recording device and a fifth recording device, and the fourth recording device may be capable of communicating with an external device. The fourth recording device may forward a data transmission request received from the external device to the fifth recording device. The fifth recording device may transmit the recorded data corresponding to the data transmission request obtained from the fourth recording device to the fourth recording device, and the fourth recording device may forward the data obtained from the fifth recording device to the external device. In this manner, data recorded by the fifth recording device can be transmitted to the external device via the fourth recording device without the fifth recording device communicating with the external device. The transmission request may, for example, specify the time of recording, and the correct time data may be transmitted using a difference. For security reasons, communication with the external device may be performed using, for example, closed communication.

[0021] (16) A data recording system is provided that has a control function for recording, when recording data, the difference between a first time measured by a clock unit for identifying the time when the data was recorded and a second time that is more accurate than the first time, in association with the data. In this way, a technology for recording information for identifying the time when the data was recorded can be provided.

[0022] (17) It is preferable to provide a program for causing a computer to realize the functions of any one of the systems (1) to (16).

[0023] The above-described system may be configured from one device or multiple devices.

[0024] The inventions (1) to (16) above can be combined in any way. For example, it is possible to combine all or part of the configuration of the invention shown in (1) with at least part of the configuration of at least one invention from (2) onwards. In particular, it is preferable to combine the invention shown in (1) with at least part of the configuration of at least one invention from (2) onwards. The applicant intends to obtain patent rights, design rights, etc. for those including these configurations by filing amendments, divisional applications, or applications for conversion to design registration applications, etc. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a technology for recording information for identifying the time when data was recorded. Furthermore, for example, at least one of the following effects can be achieved. In a system where recording is controlled based on a clock unit, the time on which control is based can be maintained without discontinuous jumps during recording, ensuring continuity. Furthermore, by adjusting the time at an appropriate timing, the system will subsequently operate based on the adjusted time. This is advantageous because the time when data was recorded is not altered.

[0026] The effects of the present invention are not limited to these, and effects achieved by the components disclosed in the present specification and drawings, etc., are also disclosed, and the applicant intends to obtain rights to the components that achieve these effects through divisional applications, amendments, etc. For example, in this specification, statements such as "can..." clearly state the effects that are achieved, and there are also parts that demonstrate the effects even without the statement "can...". Furthermore, there are effects that can be understood from the components even without such statements. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a block diagram showing a preferred embodiment of a system according to the present invention; [Figure 2] 10 is a flowchart showing a time correction process. [Figure 3] FIG. 10 is a diagram illustrating the operation of setting the time. [Figure 4] FIG. 10 is a diagram showing an example of a display of a captured video. [Figure 5] FIG. [Figure 6] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings. These drawings are used to explain technical features that may be adopted by the present invention. The configurations and shapes of the described devices are merely illustrative examples, and the present invention should not be construed as being limited thereto. Various changes, modifications, and improvements may be made based on the knowledge of those skilled in the art without departing from the scope of the present invention. In the following description, labeling using numbers such as 1 (first), 2 (second), etc. is intended to identify each element and does not define the number of elements.

[0029] [Background to the concept of the present invention] The inventor has discovered a new problem with regard to alteration of video files recorded based on an internal clock with a time adjustment function, such as in a drive recorder, and the resulting problem of admissibility as evidence. For example, if the time is adjusted during recording, the recording time will change discontinuously, resulting in loss of continuity of the recording time. For example, if the recording time is recorded in each frame that makes up the recorded data, the recording time will jump before and after the time adjustment, resulting in discontinuity. Furthermore, altering the recording time midway through the recording process constitutes a form of falsification, which may, for example, reduce the admissibility of the recorded data as evidence.

[0030] On the other hand, if the time is not synchronized, the recording time will be recorded based on an incorrect clock, and it will be impossible to correctly determine the hour, minute, and second at which the person passed through the location in the footage. This may reduce the admissibility of footage taken before the time was synchronized.

[0031] In addition to the above-mentioned problems, there may be other cases where it is undesirable to subsequently modify information that identifies the recording time of data in an already recorded file. The following embodiment is an example of an embodiment for solving such problems.

[0032] [Basic configuration of one embodiment of the system] 1 shows a preferred embodiment of the system. The system 1 of this embodiment includes a drive recorder 2, which is a type of recording device, and a device 3 that can communicate with the drive recorder 2 and provide the time.

[0033] Communication between the drive recorder 2 and the device 3 may be performed, for example, via wireless communication, wired communication, or a combination of these, and wireless communication is particularly preferred. In the case of wireless communication, it is preferable to perform the communication in an environment connected to, for example, a wireless LAN or LTE. The drive recorder 2 and the device 3 are preferably used in a limited, closed space such as a vehicle, an office, or a business, and preferably in an environment connected to a relatively secure line. In this embodiment, the secure line is preferably a line that allows communication in a more secure environment than a public line such as the Internet. In this embodiment, the secure line is preferably a communication line that restricts the parties that can communicate with each other using virtual (logical) or physical means. The secure line may be a line that restricts the parties that can communicate using authentication information such as an ID or password. Examples of such a line include Wi-Fi (e.g., Wi-Fi with a password) and other wireless LANs (Local Area Networks). Such wireless LANs may not require pay-per-use charges based on the amount of communication, or may be cheaper than public lines. The secure line may be, for example, a VPN (Virtual Private Network), which is a virtual network established via a telecommunications carrier's public line (e.g., a Long Term Evolution (LTE) line). The secure line may also be a dedicated line (e.g., a wired communication path) or a network (a closed network) that is physically isolated from the public line. In this way, it is desirable for the drive recorder 2 to communicate with the device 3 using a method that does not use an environment accessible to unspecified persons (e.g., communication devices). This is desirable from the perspective of communication security, as it can prevent third parties from accessing the drive recorder 2.

[0034] The device 3 has a function to provide the drive recorder 2 with a time (an example of a second time) that defines the time after time adjustment as information for time adjustment. Time adjustment is a process of correcting the time measured by a clock. Time adjustment reduces (ideally, reduces to zero) the time discrepancy between the time measured by the clock. In this embodiment, time adjustment is a process of correcting the time measured by the clock by regarding an externally provided time as the correct time. In this embodiment, the time provided by the device 3 is treated as correct time information in the system 1. If the time provided by the device 3 indicates a standard time such as Japan Standard Time in Japan, the accuracy of the time measured by the drive recorder 2 after time adjustment is improved. The device 3 may have a clock that measures the current time, such as a PC APP, a smartphone APP, a server APP, or a mobile communication base station, and may have a function to provide the time obtained from that clock to the drive recorder 2, for example, by superimposing the time on a command. The server APP may be a server other than an NTP server that is accessible to the general public. When a communication device connects to an NTP server, it must connect to the public Internet line, which may cause security problems. Using a server app other than an NTP server is preferable from the perspective of communication security. Device 3 may also be, for example, a drive recorder or other in-vehicle device.

[0035] In this embodiment, the drive recorder 2 is a device that is later installed in a vehicle. Vehicles include, for example, private automobiles and commercial automobiles, and vehicle types include passenger cars, buses, trucks, special vehicles such as forklifts, etc. Vehicles are not limited to automobiles, and include various types of vehicles such as public transportation vehicles such as trains, monorails, and linear motor cars. Vehicles other than automobiles may also be used, such as ships and airplanes.

[0036] The drive recorder 2 includes a camera 11, a microphone 12, an abnormality detection sensor 13, a GPS module 14, operation buttons 15, a control unit 16, a temporary storage memory 17, a monitor 18, a speaker 19, a memory card slot 20, a first internal clock 22, a power supply unit 23, a first communication unit 24, and the like. The camera 11 captures an image of a predetermined area, such as the front of the vehicle. The microphone 12 collects, for example, ambient sounds. The microphone 12 collects, for example, the voices of passengers inside the vehicle and other sounds generated inside the vehicle, as well as impact sounds when an object collides with the vehicle. The abnormality detection sensor 13 is, for example, an acceleration sensor or a six-axis sensor (integrated with three-axis acceleration and three-axis angular velocity) and detects vehicle conditions such as an impact applied to the vehicle, the vehicle's acceleration, and inclination. The control unit 16 infers that an accident (collision) has occurred when the detection value of the abnormality detection sensor 13 exceeds a threshold value or shows a predetermined temporal change indicating, for example, the occurrence of an impact. In addition to the occurrence of an accident, the control unit 16 may also be used to detect driving conditions such as sudden braking, sudden steering, sudden acceleration, and sudden braking, and to record the history of such conditions.

[0037] The GPS module 14 receives a GPS signal based on the positioning. The control unit 16 determines the current position from the received GPS signal and sends the position information (longitude, latitude) of the determined current position to the control unit 16. The GPS module 14 also obtains date and time information based on the received GPS signal and sends it to the control unit 16. The date and time information obtainable from the GPS signal includes the current time, so the control unit 16 can use this information to set the time of the first internal clock 22.

[0038] The operation button 15 is a button that issues various instructions to the control unit 16, and has a function to issue an instruction to start recording, for example. When the operation button 15 is pressed, the control unit 16 may perform event recording, which starts recording the video captured by the camera 11 and the sound collected by the microphone 12. The operation button 15 may also have a function to issue an instruction to stop recording. The instruction to start recording and the instruction to stop recording may be issued by different buttons, for example, but it is also preferable to issue them by different operations on the same button. This is advantageous because it reduces the number of buttons installed and allows the drive recorder 2 to be made smaller.

[0039] The temporary storage memory 17 is, for example, a RAM that temporarily stores video data captured by the camera 11. The control unit 16 constantly stores video data captured at least a certain amount of time in the past. Since the storage capacity is limited, the control unit 16 deletes old video data according to a certain criterion. The certain criterion may be, for example, video data stored a certain amount of time ago or when the storage memory capacity exceeds a certain amount. In this embodiment, the temporary storage memory 17 may be, for example, a ring buffer.

[0040] The monitor 18 is a display unit that displays images. The control unit 16 displays, for example, video data captured by the camera 11 on the monitor 18 in real time. The speaker 19 outputs sound. The control unit 16 outputs predetermined sounds from the speaker 19 during predetermined recording, alarm, operation, etc. The control unit 16 uses the speaker 19 to notify, for example, the operation sounds of the operation buttons 15 and various messages (guides, alarms, etc.).

[0041] The memory card slot 20 allows, for example, a microSD card 21 to be attached and detached. When the microSD card 21 is attached, the control unit 16 reads and writes data from and to the microSD card 21. The microSD card 21 is a storage medium on which data such as video is recorded by the drive recorder 2. The microSD card 21 is an external storage means that is attachable and detachable to the memory card slot 20, but instead of or in combination with this, an internal storage means of the drive recorder 2 (for example, a hard disk or an EEPROM) or other storage means may be used. However, in order to protect the data stored in the storage means, it is desirable for the drive recorder 2 to be able to access a system that can record data without using an environment that is accessible to the general public (for example, a cloud computing environment).

[0042] The first internal clock 22 is a clock unit that provides a time (an example of a first time) that serves as a reference for control operations in the drive recorder 2. The first internal clock 22 measures a time (current time) for specifying the time when data was recorded in the drive recorder 2. In this embodiment, the time measured by the first internal clock 22 includes date and time information. In this embodiment, the first internal clock 22 is a real-time clock driven by a crystal oscillator.

[0043] The power supply unit 23 supplies power to each component of the drive recorder 2. The power supply unit 23 is connected to the vehicle (vehicle battery) and receives power from the vehicle while the vehicle is operating, for example, after the engine is turned on. The power supply unit 23 steps down the power to a predetermined voltage, for example, and supplies the power supply voltage to devices and the like provided in the drive recorder 2, thereby supplying operating power to each component. The power supply unit 23 also has a power storage means, such as a secondary battery, and has a function of charging the power storage means during operation and supplying power for keeping the drive recorder 2 in an ON state for a predetermined period of time even after the engine is turned off. Instead of or in addition to the secondary battery of the power supply unit 23, a power storage means such as a supercapacitor or a capacitor may be used as a power storage means capable of storing an electric charge internally. An environment may also be created in which the drive recorder 2 can operate for a certain period of time by receiving power from an external source.

[0044] The control unit 16 is a microcomputer equipped with a CPU, ROM, RAM, non-volatile memory, I / O, etc., and executes predetermined processing based on information input from the various input devices (camera 11, microphone 12, abnormality detection sensor 13, GPS module 14, operation buttons 15, temporary storage memory 17, memory card slot 20, etc.) and outputs predetermined information using output devices (temporary storage memory 17, monitor 18, speaker 19, memory card slot 20, etc.). The functions of the drive recorder 2 are stored in the EEPROM of the control unit 16 as programs executed by a computer included in the control unit 16, and are realized by the computer executing these programs. Functions realized by the computer using the programs stored in the control unit 16 include various controls of the drive recorder 2. The control unit 16 has, for example, a function to record data such as video (recording function), a function to output data, a function to display images (video), and a time setting function to set the time on the first internal clock 22.

[0045] The control unit 16 is a circuit for implementing the basic functions of the drive recorder 2. It stores video data captured by the camera 11 as a video file in the temporary storage memory 17, and stores the captured video file in a non-volatile memory based on a detection signal from the abnormality detection sensor 13 or a press of the operation button 15. In this embodiment, a microSD card 21 inserted in the memory card slot 20 is used as the non-volatile memory. By removing the microSD card 21 and inserting it into a memory card reader or the like connected to a PC, data can be imported into the PC and the video file can be played back using a viewer installed on the PC. Recorded video and other data can be transmitted via wired or wireless communication, rather than being retrieved externally by removing and inserting the microSD card 21 as described above. For wired communication, the drive recorder 2 may be provided with a connector, USB, or the like for connecting a communication cable.

[0046] The function of recording this video data (recording function) will now be described in more detail. The camera 11, for example, constantly captures images of the surroundings of the vehicle. The control unit 16 stores the video data captured by the camera 11 in a temporary storage memory 17 such as a ring buffer. The video stored in this temporary storage memory 17 is successively updated to the latest video, and past video data is held for a set period of time.

[0047] When the output value of the abnormality detection sensor 13, which may be due to an impact such as an accident, sudden braking, or sudden steering, exceeds a threshold or shows a predetermined temporal change, the control unit 16 reads video data from the temporary storage memory 17 for a certain period before the impact was detected and stores it in a nonvolatile memory, such as the microSD card 21. After the threshold is exceeded, the control unit 16 records the video captured by the camera 11 on the microSD card 21 directly or via the temporary storage memory 17. This allows video footage spanning a predetermined period before and after the impact to be stored in the microSD card 21, which is a nonvolatile memory. At this time, the control unit 16 also records the surrounding sounds collected by the microphone 12 in association with the video data. The control unit 16 also temporarily stores this recording in the temporary storage memory 17, and when storing the video data on the microSD card 21, it also stores the recorded audio data on the microSD card 21.

[0048] The control unit 16 creates and records one file for each predetermined unit time as the video data to be recorded. Therefore, one file contains multiple frames acquired at a predetermined frame rate. The frames are managed in chronological order in the order they were recorded, and are output and played back in that order. Audio data collected at the same time is also stored in this file.

[0049] Furthermore, when storing data such as video data in the temporary storage memory 17 or the microSD card 21, the control unit 16 associates and stores the data with a time (an example of a first time) obtained from the first internal clock 22 and indicating the time at which the data was recorded. The time indicating the time at which the data was recorded may be associated with each frame, for example, or the recording time may be recorded for the entire file. Furthermore, the control unit 16 may record, as the associated data, not only the time based on the first internal clock 22 but also, for example, the time based on a GPS signal detected and output by the GPS module 14. In the drive recorder 2, if a GPS signal cannot be received, for example, immediately after power-on or while in a tunnel, the time based on the GPS signal cannot be obtained. In such cases, the control unit 16 may leave the storage area for the time based on the GPS signal blank or record information indicating that the signal cannot be received. Furthermore, the information that the control unit 16 associates and stores with the video data may include, but is not limited to, time, as described above, but may also include, for example, GPS-based location information, a sensor output value, and the time at which the sensor output value exceeded a threshold value. The sensor output value may be recorded if it exceeds a threshold value, for example, and not recorded if it does not exceed the threshold value.

[0050] Storing data in the microSD card 21 in the drive recorder 2 is not limited to being triggered by the detection signal from the anomaly detection sensor 13 as described above. The control unit 16 may have a function to trigger this trigger, for example, by pressing the operation button 15. This allows video recording when a situation occurs that the user desires to record. Furthermore, recording to the microSD card 21 is not limited to an event recording mode, which is performed when a recording start condition is met, such as when an accident occurs based on the output of the anomaly detection sensor 13 or when the operation button 15 is pressed. For example, a continuous recording mode, in which recording is performed on the microSD card 21 from when the drive recorder 2 is powered on until it is powered off, may be provided. When the continuous recording mode is provided, the control unit 16 may record video data output from the camera 11 and audio data output from the microphone 12 directly to the microSD card 21 rather than to the temporary storage memory 17. By directly recording to the microSD card 21 in this manner, the process of writing data to the temporary storage memory 17 once is unnecessary. Furthermore, when video data and the like are written directly to the microSD card 21 and the device has both a continuous recording mode and an event recording mode, when the event recording start condition is met, the control unit 16 may use the data recorded as continuous recording for the past section from the time the condition was met.The control unit 16 may then record the event recording as, for example, a file separate from the file for continuous recording.

[0051] For example, if the operation button 15 is operated to stop recording while the camera is operating in the continuous recording mode, the control unit 16 stops recording to the microSD card 21. Also, if the operation button 15 is operated to stop recording while the camera is operating in the event recording mode, the control unit 16 stops recording to the temporary storage memory 17, etc. Even if the continuous recording mode is not operating and only the event recording mode is operating, the control unit 16 performs a process of constantly recording a certain amount of video, etc., in the temporary storage memory 17, etc., in an overwrite manner, etc., in order to record video before the event occurred. If the operation button 15 is operated to stop recording, the control unit 16 stops recording as described above, since it does not need to store a certain amount of video, etc., in order to record video before the event occurred. This stopping of recording is performed, for example, when the microSD card is inserted or removed, mode setting is performed, or when the user decides not to record.

[0052] The first communication unit 24 is for communicating with devices. The first communication unit 24 has a function for communicating using a predetermined communication method such as wireless LAN or LTE. The first communication unit 24 connects to the second communication unit 34 according to a predetermined procedure and transmits and receives data and commands.

[0053] In this embodiment, the device 3 includes a control unit 31, a second internal clock 32, a power supply unit 33, a second communication unit 34, and the like. The second communication unit 34 establishes communication upon receiving access from the first communication unit 24 and exchanges data and commands with the first communication unit 24. The second internal clock 32 has higher accuracy than the first internal clock 22 of the drive recorder 2, and provides time calculated, for example, based on a GPS reception function. High accuracy means that the second internal clock 32 has a smaller time deviation from the original time (standard time in this embodiment) than the first internal clock 22. Although not shown, the device 3 may also have a function to acquire time using a GPS module or the like and adjust the time based on the acquired time. The power supply unit 33 receives power from, for example, a commercial power source, reduces the voltage to a predetermined value, and supplies the power supply voltage to operate the device 3. In this way, the device 3 operates continuously, receiving power from the commercial power source.

[0054] [Time adjustment function] The time calculated based on the GPS signal acquired by the GPS module 14 is accurate. However, the GPS module 14 may not be able to receive the GPS signal immediately after startup or in a location where radio waves cannot reach, such as a tunnel. In such cases, the accurate time cannot be obtained based on the GPS signal. For example, when the GPS module 14 operates in continuous recording mode, it may not be able to receive the GPS signal at the start of recording. In such cases, control cannot be performed based on the time obtained using the GPS signal. In such cases, the control unit 16 obtains the time from the first internal clock 22 and performs control based on that time.

[0055] A drive recorder may be installed inside the vehicle's cabin. The temperature inside the vehicle can become high, for example, when parked in the hot summer sun, and low, similar to the temperature outside the vehicle, when parked in winter. The air conditioner adjusts the temperature to a comfortable level for the driver while inside the vehicle, so the temperature can fluctuate greatly even within a day. Furthermore, if the drive recorder 2 is installed in a forklift, the temperature range can be expected to increase and the time lag can become significant when the forklift enters and exits a freezer, for example. For example, if the drive recorder 2 enters a freezer at -30 degrees and then returns to the outdoors in midsummer (above 30 degrees), the temperature difference can exceed 60 degrees. This can also lead to time lags on the vehicle's internal clock.

[0056] In this embodiment, the first internal clock 22 is driven by a crystal oscillator, and the accuracy of crystal oscillators may decrease due to temperature changes, causing the clock to deviate from the correct time over time. Therefore, it is preferable for the drive recorder 2 to synchronize the time of the first internal clock 22, which serves as the control reference, at appropriate times to correct the time. As described above, the video file is recorded in association with the recording time based on the time of the first internal clock 22. For example, it is preferable to synchronize the time of the first internal clock 22 in order to improve the evidential value of the video, such as identifying the hour, minute, and second at which the video was taken.

[0057] Therefore, in this embodiment, the control unit 16 of the drive recorder 2 has a function of adjusting the time based on the time of the second internal clock 32 provided from the device 3. As shown in Fig. 2, the control unit 16 acquires the time of the second internal clock 32 from the device 3 with which communication has been established (S1). This time acquisition may be performed, for example, by establishing communication with the device 3 at an appropriate timing when the drive recorder 2 is powered on, and the control unit 16 of the drive recorder 2 sending a request to the control unit 31 of the device 3 to send the time of the second internal clock 32, and in response, the control unit 31 superimposing the time of the second internal clock 32 on a command and transmitting it. The control unit 16 acquires the time from the received command.

[0058] The control unit 16 determines whether or not recording is in progress (S2). If video data or the like is being recorded to the temporary storage memory 17 and / or the micro SD card 21 (Yes in S2), the control unit 16 compares the time acquired from the device 3 with the time of the first internal clock 22, and determines the difference between the times (S3).

[0059] The control unit 16 records the calculated difference in association with the data being recorded (S4). The difference may be stored, for example, in a frame or in the history of the video file. While the control unit 16 records the calculated difference in this manner, it does not synchronize the time of the first internal clock 22. Furthermore, the drive recorder 2 creates and records video files in short time units, such as one minute or several minutes. Therefore, the control unit 16 also records the calculated difference in association with the data being recorded in video files created thereafter. As will be described later, the control unit 16 synchronizes the time of the first internal clock 22 at an appropriate timing. Therefore, the control unit 16 also records the difference in association with the data being recorded in video files created thereafter, as described above, until the time synchronization is performed.

[0060] During recording, the control unit 16 associates the difference with each video file that is created one after another and stores it. Therefore, the difference calculated in processing step S3 may be stored by the control unit 16, and the stored difference may be associated with and stored in association with data to be recorded thereafter.

[0061] On the other hand, when the time is acquired from the device 3, if video data etc. is not being recorded in the temporary storage memory 17 and / or the micro SD card 21 (No in S2), the control unit 16 adjusts the time of the first internal clock 22 based on the acquired time (S5).

[0062] The control unit 16 records video data, etc., in units of time. Therefore, if, as shown in Figure 3(b), time T4' is acquired during a recording operation when the time on the first internal clock 22 is T4, and the time on the first internal clock 22 is corrected to T4' and then switched so that the time on the first internal clock 22 counts up from the corrected T4' to T5', T6', ..., the recorded time will be discontinuous.

[0063] 3(a), even if the control unit 16 acquires time T4' (an example of the first time) during recording, it simply records the obtained difference Δt without adjusting the time of the first internal clock 22, and advances the time in the same time increments as T4, T5, T6, .... This ensures the continuity of the times recorded in association with the video data, such as T4, T5, T6, ....

[0064] The control unit 16 may preferably have the difference as a fixed value. The difference may preferably indicate the difference between the most recently acquired time and the time measured by the first internal clock 22 at that time. The control unit 16 also counts up the time of the first internal clock 22 as time passes. Therefore, the time after a predetermined time has passed can be found by adding / subtracting the difference to / from the counted-up time.

[0065] Furthermore, when the control unit 16 acquires the time from the device 3 after recording starts and adjusts the time of the first internal clock 22, there may be a discontinuity between the time immediately before the time adjustment and the time after the time adjustment. For example, when the control unit 16 records the recording time in each frame constituting the recorded data, the recording time jumps before and after the time adjustment, resulting in discontinuity. In this case, the time adjustment causes data rewriting. This constitutes a form of falsification, which may reduce the evidentiary value of the recorded data. For example, the evidentiary value of the vehicle's travel route and the date and time it was at each location based on the recorded file may be reduced.

[0066] *Time adjustment based on the difference Δt The control unit 16 adjusts the time of the first internal clock 22 when the drive recorder 2 is powered off. When the power supply from the vehicle battery to the drive recorder 2 is stopped, for example, when the vehicle engine is turned off (ACC OFF), the control unit 16 performs a predetermined termination process and then turns off the power of the main unit. As described above, the power supply unit 23 includes a power storage means such as a secondary battery, so that it can continue to supply power voltage to internal devices for a predetermined period of time even when the power supply from the external power source is cut off. Therefore, the control unit 16 performs various termination processes, such as recording various data to the micro SD card 21, while the power supply is continued. At this time, after the recording process is stopped due to the power-off process, the control unit 16 adjusts the time by correcting the current time Tn (an example of the first time) of the first internal clock 22 to the correct time Tn′ (= Tn − Δt) based on the difference Δt.

[0067] In this way, when the power supply of the drive recorder 2 is turned off when no recording is being performed, the time of the first internal clock 22 is adjusted, so that the next time the power supply of the drive recorder 2 is turned on, recording processing and various other controls are performed based on the correct time after the time adjustment.

[0068] Furthermore, in this embodiment, the control unit 16 synchronizes the time of the first internal clock 22, but leaves already recorded data as it is without correcting the time indicating when that data was recorded. Because the time recorded in the video file is not corrected in this way, the data is not altered, potentially increasing the admissibility of the data as evidence. Furthermore, because the video file records the difference associated with the data, even if the time of the first internal clock 22 is incorrect, the correct time indicating when the data was recorded can be determined later. Then, when the time of the first internal clock 22 is synchronized, the difference is set to zero.

[0069] As described above, the time is adjusted when the power is turned off. However, if the control unit 16 cannot change the time when the power is turned off, it may correct the time when the power is next turned on. For example, the control unit 16 adjusts the time of the first internal clock 22 based on the stored difference at an appropriate timing when the startup process is performed when the power is turned on. Because recording is performed at least after this startup process is complete, it is also possible to adjust the time based on the difference and the time measured by the first internal clock 22 at startup, even before recording begins. Therefore, the recording time of a video file performed after the power is turned on will be recorded based on the time after the time has been adjusted, and various controls also operate based on the time after the time has been adjusted.

[0070] The difference used when adjusting the time when the power is turned on may be recorded, for example, in association with a video file and the difference may be read from there, or the difference may be stored in a non-volatile memory such as a microSD card 21 and read from there for use.

[0071] Furthermore, the time setting of the first internal clock 22 is not limited to when the drive recorder 2 is turned off or started up as described above. For example, the control unit 16 may have a function to set the time of the first internal clock 22 when recording is not being performed, even while the drive recorder 2 is powered on. For example, the control unit 16 may set the time when recording is stopped while the drive recorder 2 is powered on. Recording may be stopped, for example, by a user operation or by a decision made by the control unit 16. An instruction to stop recording may be issued, for example, when the microSD card 21 is replaced. The control unit 16 may set the time when the microSD card 21 is removed from the drive recorder 2. If a recording period is set by a timer, the control unit 16 may stop recording and set the time when the recording period ends. In this way, the time can be set to the correct time while the drive recorder 2 is powered on, so that subsequent recordings can be recorded at the correct recording time. Since recording is stopped, there is no problem with the continuity of the recorded video file.

[0072] The control unit 16 keeps the difference associated with the video file before the time adjustment and does not correct the recorded time. Then, since the time of the first internal clock 22 becomes correct after the time adjustment, it is preferable to invalidate the difference before the time adjustment for the video file after the time adjustment. To invalidate the difference, the control unit 16 may, for example, clear (delete) the difference, associate an invalidation flag with the difference (set an invalid flag), or set the difference to zero. By invalidating the difference, it is possible to determine which differences are not necessary for future time adjustment.

[0073] [Getting the time to synchronize the time] In the above-described embodiment, the drive recorder 2 communicates with the device 3 and acquires the time of the second internal clock 32 of the device 3. However, for example, the drive recorder 2 may receive a GPS signal via the GPS module 14 and use the time obtained from the GPS signal. GPS signals are also highly secure and are not susceptible to eavesdropping. This eliminates the need for communication with the device 3, making time adjustment easier and more preferable from a security perspective.

[0074] The GPS module 14 starts positioning a predetermined time or more after the power of the drive recorder 2 is turned on. However, the drive recorder 2 often starts recording before this positioning is performed. Therefore, when the GPS module 14 determines the position and acquires the time after recording starts, the control unit 16 may calculate the difference between the time acquired and the time of the first internal clock 22 based on the acquired time, and record the calculated difference in association with the video file.

[0075] The time for time adjustment may also be a time manually input by the user into the drive recorder 2. This time can be input at any time while the drive recorder 2 is powered on. In the system 1, this manually input time is also treated as correct time information. For example, the user may register the current time in the drive recorder 2 while checking the correct time using a GPS clock or other device. The control unit 16 compares the input time for time adjustment with the time of the first internal clock 22 to determine the difference. When a time for time adjustment is manually registered, it is common to immediately adjust the first internal clock 22. However, in this embodiment, the control unit 16 does not immediately adjust the time, but instead determines and records the difference between the time of the first internal clock 22 at that time and the input time for time adjustment.

[0076] The drive recorder 2 can obtain the time for time adjustment from different sources. When the time is acquired during recording, the difference is calculated and recorded from the time source (GPS, LTE, server, manual user input, etc.). If multiple correct times are acquired during recording, the control unit 16 may use the difference calculated based on the source with the highest predetermined priority, rather than the first received time. The priority may be determined based on accuracy, for example. By assigning a higher priority to a source that provides a time that is more consistent or more likely to match standard time, the accuracy of the time after time adjustment can be improved. The priority may be determined before shipping the drive recorder 2 or after shipping by user setting or other method.

[0077] The timing for acquiring the time for time adjustment may be any timing while the drive recorder 2 is powered on. For example, it may be performed each time the power is turned on. For example, when the power is turned on and the system starts up, the system communicates with the device 3 to acquire the time held by the second internal clock 32, or acquires the correct time information obtained through positioning by the GPS module 14, and stores and retains the difference between the time held by the first internal clock 22. The first internal clock 22 may then be adjusted when recording ends, such as when the power is turned off. The control unit 16 may acquire the time for time adjustment, for example, at predetermined intervals. The timing for acquiring the time is determined before shipping the drive recorder 2, taking into account, for example, the magnitude of the time discrepancy that occurs in the first internal clock 22.

[0078] [Video file playback function] As described above, the video files stored on the microSD card 21 can be played back by the drive recorder 2 or an external playback device. The playback device is, for example, a personal computer (PC). In this case, the video files are recorded on the PC and can be played back, for example, by a viewer installed on the PC. The drive recorder 2 or the external playback device (hereinafter referred to as the "playback device, etc.") has a function to play back video based on the recorded video file and simultaneously display the time indicating when the video was recorded. The time may be displayed, for example, on a time display section 51 superimposed on an image 50 of a captured frame, as shown in FIG. 4.

[0079] The playback device or the like may have a function of selecting and displaying on the time display unit 51 the time based on an internal clock (for example, the first internal clock 22 or the internal clock of the playback device) and the time based on a GPS signal. The selection may be made by a user instruction, but the playback device or the like may be configured so that if the time based on the GPS signal is stored in association with the time based on the GPS signal, the time based on the GPS signal is given priority and displayed on the time display unit 51.

[0080] When a playback device or the like has the function of displaying multiple types of time, it is preferable that the playback device or the like has a function that allows the user to see which type of time is currently being displayed. This display can be made clear by various methods, such as changing the display color or by closely arranging type-indicating information 52, such as icons, marks, or characters. While type-indicating information 52 should preferably display a corresponding type for each type, the playback device or the like may display only one type, so that the other type can be understood when it is not displayed. Furthermore, if the time is recorded based on the first internal clock 22 and the time is continuous, the playback device or the like can also correct and display times that are past the time when the time for time adjustment was determined. Note that when displaying the time after time adjustment, it is not necessary to display the time in a way that makes it clear that it is the time after time adjustment.

[0081] The time based on the internal clock may be the time of the internal clock, or may be a time calculated based on the recorded time of the first internal clock 22 and the difference Δt (an example of a third time). In this way, even when the playback device or the like cannot receive a GPS signal, the correct time can be displayed, and the user can know the correct time from the display. The playback device or the like should display the time so that it is clear which of these two times is being displayed. The clear display may be the same as the method described above.

[0082] [Other forms of record systems] The recording system is not limited to a drive recorder 2 installed in a vehicle, but may be, for example, a system that records the operating status of a vehicle for operational management, a monitoring system that records the operating status of machinery in a factory, or a monitoring system that records images captured by monitoring cameras installed in various locations.

[0083] In the above-described embodiment, the data to be recorded is an example of application to a drive recorder, and therefore an example of recording video files captured by a camera, etc. has been described, but the present invention is not limited to this, and may be applied to a recording device for various time-series data, such as the location history of a vehicle or device, changes in the location and acceleration of a vehicle or device, the operating state of a vehicle or device (for example, driving state), and sensor values ​​detected by a sensor that indicate the state of a vehicle or device.

[0084] Furthermore, the number of recording devices such as the drive recorder 2 that record data is not limited to one, and a system may be provided with multiple devices. In such a system with multiple devices, each recording device may be connected to the device 3 and acquire the time from the device 3, but it is also preferable to send and receive the time between the recording devices to synchronize the time.

[0085] *A form of system with multiple recording devices When multiple drive recorders are installed, it is preferable to use drive recorders mounted at appropriate positions on the vehicle, such as front and rear cameras. For example, a system may be provided with a first drive recorder 2a equipped with a camera 11 that captures the view ahead of the vehicle, a second drive recorder 2b equipped with a camera 11 that captures the view behind the vehicle, and a third drive recorder 2c equipped with a camera 11 that captures the view inside the vehicle cabin. The first drive recorder 2a is attached to the windshield of the vehicle 60, for example, the second drive recorder 2b is attached to the rear window of the vehicle, for example, and the third drive recorder 2c is attached to the ceiling of the vehicle cabin, for example, and each record video of a predetermined shooting area and record the video on a microSD card 21. Each drive recorder is also equipped with a first internal clock 22, and the time of the first internal clock 22 of the drive recorder is recorded in association with the video file.

[0086] For example, the third drive recorder 2c installed in the vehicle cabin may have a harder time receiving GPS signals than other drive recorders. Furthermore, the third drive recorder 2c may not have a GPS module. In a system with such a configuration, the first drive recorder 2a and / or the second drive recorder 2b may be the time source for synchronizing the time of the third drive recorder 2c.

[0087] For example, the first drive recorder 2a and the second drive recorder 2b (an example of a first recording device) are connected to a communication unit 24 of a third drive recorder 2c (an example of a second recording device) via their respective communication units 24, enabling wireless communication. The control unit 16 of the third drive recorder 2c establishes communication with the first drive recorder 2a or the second drive recorder 2b at an appropriate timing and transmits a time transmission request for time adjustment to the drive recorder with which communication has been established. The control unit of the drive recorder that receives the transmission request transmits the time, for example, by superimposing a time acquired by its own GPS module 14 as information for time adjustment and a time (an example of a fourth time) that specifies the time after time adjustment on a command and transmitting the command to the control unit 16 of the third drive recorder 2c. The control unit 16 of the third drive recorder 2c then calculates the difference between this time and the time measured by the first internal clock 22 of its own device based on the acquired time for time adjustment, and records the difference in association with the video file. The control unit 16 then adjusts the time of the first internal clock 22 at an appropriate timing, such as when the power is turned off.

[0088] Furthermore, the control units 16 of the first drive recorder 2a and the second drive recorder 2b may adjust the time of the first internal clock 22 based on the time acquired by the GPS module 14 of the drive recorder itself, using the method already described.

[0089] In the above example, the first drive recorder 2a and the second drive recorder 2b transmit the time based on the GPS signal received by the GPS module 14 to the third drive recorder 2c, but for example, by storing and holding a difference as described above, the first drive recorder 2a and the second drive recorder 2b may obtain a time (an example of the fourth time) using the difference stored in the first drive recorder 2a and the time of the first internal clock 22 of the first drive recorder 2b, and transmit the obtained time to the third drive recorder 2c. In this way, the time can be transmitted even in a situation where the GPS module 14 cannot perform positioning when a transmission request is received from the third drive recorder 2c and the time based on the GPS signal cannot be obtained.

[0090] According to this embodiment, the three drive recorders are synchronized based on the time of the GPS signal, so even if there is a time discrepancy in each internal clock, video files recorded at the same time in each drive recorder can be associated based on differential data.

[0091] In the embodiment described above, both the first drive recorder 2a and the second drive recorder 2b are equipped with a GPS module, but it is also possible to configure the second drive recorder 2b to be of a type that does not have a GPS module, and to set the time of the second drive recorder 2b based on the time acquired from the first drive recorder 2a. In this way, the times of the three drive recorders are corrected based on the time acquired by the same GPS module, which makes it easier to synchronize them.

[0092] *Another form of system with multiple recording devices (recording system implemented on trains) As shown in FIG. 6, a recording system may include various types of surveillance camera devices installed at predetermined locations on trains. The surveillance cameras include, for example, a first surveillance camera device 61 installed outside the lead car, and multiple second surveillance camera devices 62 installed at the entrances and exits of the trains, near fluorescent lights on the ceilings of the trains, near couplings, etc. The first surveillance camera device 61 and the second surveillance camera device 62 each have a control unit 65 that operates based on the time of an internal clock 66 (an example of a clock for identifying the time of data recording) and records video files captured by their own cameras 63 on a recording medium such as an SD card 64. The video data is formed into a single video file at predetermined time intervals and is continuously recorded while the train is in operation. Furthermore, the first surveillance camera device 61 and the second surveillance camera device 62 each have a communication unit 67, enabling communication between the surveillance camera devices via a predetermined communication method such as Wi-Fi. Furthermore, in this embodiment, the first surveillance camera device 61 has a built-in GPS module 68 that can acquire location information and time information from received GPS signals.

[0093] The SD card 64 is located at the back of the device body, which is covered with multiple layers, and can be removed by removing the multiple covers using a screwdriver or key. Furthermore, the communication unit 67 communicates via a secure line. This increases security and minimizes the risk of recorded video or other data leaking to the outside.

[0094] As in the above-described embodiments, the control unit 65 of the first surveillance camera device 61 calculates the difference between the time acquired by the GPS module 68 and the time on the internal clock 66, stores the difference in association with the video file, and adjusts the internal clock 66 while recording is stopped or at other appropriate times. In other words, while the train is running, changing the time on the internal clock would disrupt the continuity of the recorded video file. Therefore, for example, it is recommended to record continuously from the starting station to the final station without adjusting the time on the internal clock 66, and more preferably, not adjust the time until the train leaves the depot and returns. While the internal clock 66 is not adjusted during this period, recording the difference allows the correct recording time of the recorded video file to be determined. The time may be acquired once during a series of recordings, for example, immediately after startup.

[0095] Since it is difficult to receive GPS signals inside a vehicle, in this embodiment, the time is set based on the time obtained from the GPS signal acquired by the first monitoring camera device 61. For this reason, the second monitoring camera device 62 does not need to be equipped with a GPS module.

[0096] The first monitoring camera device 61 may transmit the time acquired by the first monitoring camera device 61 to each of the multiple second monitoring camera devices 62. However, in this embodiment, the first monitoring camera device 61 (an example of a first recording device) transmits a time (an example of a fifth time) specifying the time after time adjustment to one or some of the second monitoring camera devices 62 (an example of a second recording device) as information for time adjustment, and the other second monitoring camera devices 62 (an example of a third recording device) acquire the time from the second monitoring camera device 62 that received the time. This configuration is advantageous in that, for example, an increase in the communication load on the first monitoring camera device 61 can be suppressed when the number of installed second monitoring camera devices 62 increases. Furthermore, the first monitoring camera device 61 is installed outside the lead car and away from the second monitoring camera device 62, whereas the multiple second monitoring camera devices 62 may be installed in a relatively limited, narrow space, such as within the same car. In such a case, the first surveillance camera device 61 may transmit the time to another specified second surveillance camera device 62 using, for example, LTE as a first communication method, and the time may be transmitted between the second surveillance camera devices 62 in a sequential chain-like manner using, for example, Wi-Fi as a second communication method.

[0097] Furthermore, for example, some surveillance cameras installed on fluorescent lights are equipped with LTE communication capabilities, so the second surveillance camera device 62 installed on the fluorescent light can obtain the time from the first surveillance camera device 61, and the second surveillance camera device 62 installed on the fluorescent light can transmit the time to the second surveillance camera device 62 that does not have LTE communication capabilities as a first communication method using Wi-Fi as a second communication method.

[0098] The second surveillance camera device 62 that receives the time calculates and records the difference, and when transmitting the time to another second surveillance camera device 62, it adds the elapsed time from reception to transmission to calculate a time for time adjustment (an example of a fourth time) and transmits it. In this embodiment, the time of the internal clock 66 is not adjusted immediately after reception, so the time for time adjustment does not need to be immediately transmitted to another surveillance camera device. In such a case, instead of adding the elapsed time, it is preferable to add or subtract the difference to the current time of the internal clock 66 to calculate the time and transmit it as the time for time adjustment. In this way, the internal clocks of multiple surveillance camera devices can be synchronized. The time transmission method is not limited to Wi-Fi, and any method that can transmit time electrically, radio waves, or visually, such as LTE, GPS, wired communication LAN, UART, or video analysis, can be used.

[0099] In this embodiment, based on the time acquired by the first surveillance camera device 61, the multiple second surveillance camera devices 62 perform time correction processing such as calculating and recording the difference and adjusting the time, so that when playing back footage captured by multiple surveillance camera devices, it is possible to synchronize the time by outputting or identifying footage captured at the same time.

[0100] Furthermore, the first monitoring camera device 61 (an example of a fourth recording device) and the second monitoring camera device 62 (an example of a fifth recording device) may preferably have a function for transmitting video (an example of data) at a predetermined time in response to an instruction to acquire the video at that time. In this way, even while the train is running, the recorded video can be transmitted to the outside in response to a request from outside the recording system, for example, and the recorded video can be checked. In such a case, the video corresponding to the predetermined time may be read and transmitted by taking into account the difference in the recording time based on the internal clock 66 recorded on the SD card. In this way, video at the correct time can be transmitted.

[0101] Furthermore, since the instruction to acquire the video at the specified time may be sent from a remote location, a surveillance camera device equipped with, for example, an LTE communication function as a first communication method receives the acquisition instruction and transfers the video at the corresponding time. Furthermore, the surveillance camera device equipped with the LTE communication function may be equipped with a function to send a transfer request to another surveillance camera device not equipped with the function to transmit video at the same time, and the other surveillance camera device may transmit the video at the requested time to the surveillance camera device equipped with the LTE communication function. The surveillance camera device that has acquired the video may transfer the video at the specified time using LTE communication. LTE communication may be replaced with other communication methods (e.g., 4G, 5G).

[0102] Furthermore, the instruction to acquire video at a specified time can be issued to all surveillance camera devices or to a specific surveillance camera device, and a surveillance camera device that has, for example, an LTE communication function as a first communication method and that receives an acquisition instruction for a specific surveillance camera device can send a request to the specific surveillance camera to transmit video at the same time using, for example, Wi-Fi as a second communication method, and can forward the received video if a response is received.

[0103] The information for time adjustment is not limited to a time that defines the time after time adjustment (for example, a time obtained from the device 3 or input by a user), but may also indicate a correction amount for time adjustment. For example, the device 3 calculates a correction amount from the difference between the time measured by the first internal clock 22 of the drive recorder 2 and the time measured by the second internal clock 32, and provides this to the drive recorder 2. The control unit 16 of the drive recorder 2 applies this correction amount to the time measured by the first internal clock 22 (for example, by adding or subtracting) to adjust the time of the first internal clock 22.

[0104] The device 3 that provides correct time information is not limited to the above, and can be applied to various devices, such as base stations for mobile communications such as mobile phones. Such base stations have the function of receiving GPS signals and storing accurate current time information based on the GPS signals. A communication module (e.g., an LTE module) that communicates with a base station has the function of acquiring correct time information based on the GPS held by the base station when connected to the base station. When the drive recorder 2 enters an area where communication with a base station is possible, it connects to the base station (more specifically, connects wirelessly). This connection is usually achieved automatically without any explicit human instruction, such as an operation to instruct the connection. In addition, the communication module has the function of allowing the time information acquired by the communication module to be accessed and referenced from outside.

[0105] Therefore, a communication module that communicates with a base station is installed in a recording device such as a drive recorder or a surveillance camera. The control unit of the recording device can then perform the time correction process described above using the time information acquired when the communication module connects to the base station. The communication module installed in the recording device can be installed inside the main body case of the recording device, for example, or it can be a separate type that is provided separately from the main body case.

[0106] When a recording device or the like is mounted on a moving object such as a vehicle, the base station to which the communication module connects changes as the vehicle or the like moves. After powering on, the communication module acquires correct time information when it first connects to a base station and establishes communication. Thereafter, it does not acquire new time information even if the connected base station changes until the power is turned off. Therefore, even if the connected base station changes as the vehicle moves, it does not acquire time information each time. The control unit 16 performs processing such as calculating and storing differential data based on the correct time information acquired after powering on. Then, once this processing is performed after powering on, it is not performed again until powering off. This is based on the knowledge that it is sufficient to perform correction processing when powering on and connecting to a base station for the first time, but correction processing may also be performed by connecting to a base station at another time while power is on. Furthermore, while the above-mentioned variant describes the device 3 as a base station, for example, the communication module may also be considered the device 3.

[0107] The scope of the present invention is not limited to the structures explicitly described in the specification, but also includes combinations of various aspects of the present invention disclosed herein. The structures of the present invention that are sought to be patented are specified in the appended claims, but it is the intention of the present inventors to claim structures disclosed in this specification in the future, even if they are not currently specified in the claims.

[0108] The present invention is not limited to the configurations described in the above-described embodiments. The components of each of the above-described embodiments and variations may be arbitrarily selected and combined. Furthermore, any component of each embodiment or variation may be arbitrarily combined with any component described in the Summary of the Invention or any component embodying any component described in the Summary of the Invention. The present invention also intends to obtain rights to these configurations through amendments or divisional applications of the present application. Even if a description is made of "in the case of..." or "when...," it is not intended to describe a configuration limited to that case or time. Configurations that are not limited to those cases or times are also disclosed, and the present invention intends to obtain rights to them. Furthermore, any descriptions that specify an order are not limited to this order. Configurations in which some parts are deleted or the order is changed are also disclosed, and the present invention intends to obtain rights to them.

[0109] Furthermore, we intend to obtain rights to the overall design or partial design by converting the application to a design registration. The drawings depict the entire device in solid lines, but they also include partial designs claimed for parts of the device. For example, a partial design can be a partial design for a part of the device, or a part of that part. A partial design can be a part of the device, or a part of that part. We intend to obtain rights not only for the overall design, but also for partial designs in which any part of the solid line portion of the drawing is drawn as a broken line. Furthermore, all of the modules, components, and parts inside the device's casing, shown in the drawings, are subject to independent commerce, and we intend to similarly obtain rights by converting the application to a design registration. [Explanation of symbols]

[0110] 1: System 2: Drive recorder 2a: First drive recorder 2b: Second drive recorder 2c: Third drive recorder 3:Equipment 11: Camera 14: GPS module 15: Operation buttons 16: Control section 17: Temporary memory 18: Monitor 19: Speaker 20: Memory card slot 21: Micro SD card 22: First internal clock 23: Power supply section 24: First Communications Department 31: Control unit 32: Second internal clock 33: Power supply section 33: Internal clock 34: Second Communications Department 36: Control section 41: GPS receiver 42: Internal clock 50: Image 51: Time display section 60: Vehicle 61: First surveillance camera device 62: Second surveillance camera device 63: Camera 64: SD card 65: Control section 66: Internal clock 67: Communications Department 68: GPS module

Claims

1. A function that associates the recording time with the video data of continuous recording based on the time of the internal clock, a function of stopping recording of the video data when a recording stop command is received during continuous recording; It has the function to acquire the time from other devices. The device has a function of, when the time is acquired from the other device while the video data is being recorded, recording the difference between the time acquired from the other device and the time of the internal clock in association with the video data being recorded, without adjusting the time of the internal clock, and adjusting the time of the internal clock based on the stored difference at an appropriate timing when a startup process accompanying power-on is performed and before recording starts after the power is turned on, and a function of, when the time is acquired from the other device while the video data is not being recorded, adjusting the time of the internal clock based on the time acquired from the other device. A drive recorder that features the following.

2. The difference used when adjusting the time when the power is turned on is read out from a difference recorded in association with a video file, or is stored in a non-volatile memory and read out from there for use. The drive recorder according to claim 1 .

3. A program for causing a computer to realize the functions of the drive recorder according to claim 1 or 2.

Images