System, program and the like

Abstract

To provide a system that is superior to the conventional system such as the system and the like capable of identifying a time without requiring a manual input of information by users, under a situation where information cannot be directly acquired from any of a time server and a reception unit of a satellite positioning system in the system using a time.SOLUTION: A system 901 comprises: a drive recorder 1 that is mounted to each of a plurality of vehicles; a time recorder 2 that transmits time information to the drive recorder 1; a time server 3 that transmits the time information to the time recorder 2; and a data server 4 that stores variety of information such as attendance information and the like the drive recorder 2 generates. The drive recorder 1 is configured to receive time information indicative of a current time from the time recorder 2 by wireless communication, for example, every time a prescribed tim goes by. The drive recorder 1 includes an internal time piece, and is configured to calibrate a time the internal time piece counts, using the time information received from the time recorder 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] For example, the present invention relates to a technology for identifying time. [Background technology]

[0002] For example, see Patent Document 1. Patent Document 1 describes a system that includes a drive recorder and a car navigation device (hereinafter referred to as "car navigation") that are connected by a connection cable. The drive recorder acquires reference date and time data from the car navigation system, and records date and time data set based on the acquired reference date and time data in association with the captured image data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-257849 A Summary of the Invention [Problem to be solved by the invention]

[0004] Most systems that use time are equipped with an internal clock, such as an RTC (Real Time Clock), and use the time kept by the internal clock. Most internal clocks keep time based on a signal that is periodically emitted by a relatively inexpensive quartz crystal oscillator, but the period of the signal emitted by the quartz crystal oscillator does not necessarily match the design value, and there is a problem in that the time kept by the internal clock deviates from the correct time over time.

[0005] Furthermore, if the battery that supplies power to the internal clock runs out of charge during a period when the system that uses the time is not supplied with external power, the internal clock will stop operating, and when the external power supply to the system is resumed, the internal clock will not be able to keep the correct time.

[0006] As a method for solving the above-mentioned inconvenience, first, a user interface such as an operation button is provided in the system that uses time, and the user operates the user interface to manually input information indicating the time (hereinafter referred to as "time information"). In this case, the system that uses time can identify and use the time using the time information manually input by the user. However, it is troublesome for the user to manually input the time information.

[0007] As a method that does not require the user to manually input information, for example, a system that uses time may directly acquire time information from a time server that distributes time information. Time servers include those that transmit time information in packets according to communication protocols such as NTP (Network Time Protocol) and PTP (Precision Time Protocol, IEEE 1588), and those that transmit time information modulated into radio waves assuming reception by a radio-controlled clock. In this case, the system that uses time can specify and use the time using the time information acquired from the time server. It is also possible that the system that uses time may directly acquire time information from a receiver of a satellite positioning system (hereinafter referred to as a "GNSS (Global Navigation Satellite System) unit"). In this case, the system that uses time can acquire time information received by the GNSS unit from the GNSS unit from the artificial satellite, and specify and use the acquired time information.

[0008] However, there are cases where a system that uses time cannot directly obtain time information from either a time server or a GNSS unit due to, for example, physical or financial reasons. For example, if a system that uses time does not have a communication function, or if it has a communication function but cannot connect to a network that belongs to a time server, the system that uses time cannot directly obtain time information from a time server. Also, if a system that uses time does not have a GNSS unit, or if it has a GNSS unit but cannot receive radio waves from artificial satellites due to the influence of obstacles, the system that uses time cannot directly obtain time information from the GNSS unit.

[0009] The object of the present invention is to provide a system that is superior to conventional systems, such as a system that uses time and can determine the time without the user having to manually input information in a situation where information cannot be obtained directly from either a time server or a receiver of a satellite positioning system.

[0010] The purpose of the present invention is not limited to this, and the applicant intends to obtain rights for configurations that aim to obtain effects from parts of the configurations disclosed in this specification and drawings, etc., by filing a divisional application, amendment, etc. For example, this specification discloses a problem in which the part described as "can be" in this specification is read as "the problem is to be". The problems are described as being independent, and the applicant intends to obtain rights for the configurations for solving each problem separately by filing a divisional application, amendment, etc. Even if the problems are implicitly understood from the description in the specification, the applicant intends to include part of the configurations described in this specification in the scope of the patent claim by amendment or divisional application. In addition, the applicant has disclosed a configuration that solves a problem that combines these independent problems, and intends to obtain rights for it. [Means for solving the problem]

[0011] (1) It is preferable that the system be provided with an identification means having a function of acquiring information for identifying the time without acquiring information directly from either a time server or a receiving unit of a satellite positioning system and without requiring a user to manually input information, and a function of identifying the time using the acquired information for identifying the time.

[0012] According to the above system, even in a situation where information cannot be obtained directly from either a time server or a receiving unit of a satellite positioning system, the time can be determined without requiring the user to manually input information.

[0013] The time server may be, for example, a server on the Internet, and may particularly be, for example, an NTP (Network Time Protocol) server. The receiver of the satellite positioning system may be, for example, a GPS (Global Positioning System) receiver module. The system directly acquiring information from the time server or the receiver of the satellite positioning system may mean that the system receives information transmitted or output by the time server or the receiver of the satellite positioning system to the system. The manual input of information by the user may be, for example, that the user inputs information by operating a physical operator such as a button or a virtual operator such as an icon displayed on a display.

[0014] The information for specifying the time may be information indicating the time itself. However, it is particularly preferable that the information for specifying the time is information that does not indicate the time itself. Information that does not indicate the time itself may be, for example, information that represents an image of a landscape with a clock, or information that indicates the elapsed time of a 1PPS (Pulse Per Second) signal output by a receiving unit of a satellite positioning system. Specifying the time may be, for example, information such as the hour and minute.

[0015] (2) The function of acquiring information for identifying the time that the identification means has should preferably be a system having a communication function for receiving information for identifying the time from an external system without acquiring information directly from either a time server or a receiving unit of a satellite positioning system, and without requiring a user to manually input information.

[0016] According to the above system, by using the communication function possessed by the above system, the time can be determined without the user having to manually input information, even in situations where information cannot be obtained directly from either the time server or the receiver of the satellite positioning system.

[0017] The external system may be, for example, a system that directly acquires information for identifying the time from a time server, and the above system may indirectly acquire information for identifying the time from the time server via the external system. Also, the external system may be, for example, a system that includes a receiver of a satellite positioning system, and the above system may indirectly acquire information for identifying the time from the receiver of the satellite positioning system via the external system.

[0018] It is particularly preferable that the external system has a function of recording time. The function of recording time may be, for example, a function of recording the time when a specific event occurs. The specific event may be, for example, a person being in a specific place, and particularly, a specific person being in a specific place. The specific event may be, for example, a passerby passing through a ticket gate at a station. The specific event may be, for example, a worker arriving at work or leaving work. The external system may have, for example, a time recorder that records the worker's arrival time and leaving time. The system may have, for example, a function of storing information generated by a process performed in the system and the worker's arrival time and leaving time recorded by the time recorder in association with each other. The information generated by a process performed in the system may be, for example, information representing a captured image.

[0019] It is particularly preferable that the external system has an internal clock and a function for correcting the time kept by the internal clock. The function for correcting the time kept by the internal clock may be, for example, a function for correcting the time using information indicating the time that the external system directly obtains from a time server. Also, the function for correcting the time kept by the internal clock may be, for example, a function for correcting the time using information for identifying the time that the external system directly obtains from a receiving unit of a satellite positioning system. Also, the function for correcting the time kept by the internal clock may be, for example, a function for correcting the time using information for identifying the time manually input by a user. For example, the system may obtain information indicating the corrected time from an external system having an internal clock and a function for correcting the time kept by the internal clock.

[0020] It is particularly preferable that the external system is a mobile system. The external system may be, for example, a mobile terminal of a user. The system may acquire information for identifying the time from the user's mobile terminal when the user approaches the system to a distance where wireless communication is possible. For example, when the user approaches the system, the user's mobile terminal and the system may establish a communication connection according to a wireless communication standard such as Bluetooth (registered trademark), and the system may receive information for identifying the time from the user's mobile terminal via the communication connection. For example, there may be a plurality of the systems, and each of the plurality of the systems may acquire information for identifying the time from the same mobile terminal of the approaching user. In this case, the times identified by the plurality of the systems are synchronized with each other.

[0021] The external system may be, for example, an in-vehicle device. The system may obtain information for identifying the time from an in-vehicle device mounted on a vehicle when the vehicle approaches the system. For example, there may be a plurality of the systems, and each of the plurality of systems may obtain information for identifying the time from the same in-vehicle device mounted on a vehicle traveling nearby. In this case, the times identified by each of the plurality of systems are synchronized with each other.

[0022] (3) The function of acquiring information for identifying the time that the identification means has should be a system having a function of receiving information that is not intended to notify of the time and is sent from the external system on the network via the communication function, and acquiring information for identifying the time from information accompanying the received information.

[0023] According to the above system, by using the communication function of the above system to connect to a network through which information that is not intended to notify the time is communicated, the time can be determined without the user having to manually input information even in situations where information cannot be obtained directly from either the time server or the receiver of the satellite positioning system.

[0024] The information that is not intended to notify the time may be, for example, the message body sent from a Web server by HTTP communication. The above system may receive the message body from the Web server by HTTP communication, and obtain information for identifying the time from the HTTP header accompanying the message body. In this case, the above system can identify the time by accessing the Web server.

[0025] Also, the information for identifying the time acquired from the information accompanying the information not intended to notify the time may be, for example, the sending time of the data not intended to notify the time. The above system may, for example, receive a message body from a Web server by communication using HTTP, and acquire the sending time of the message body from the HTTP header accompanying the message body as information for identifying the time. The above system may, for example, receive an email from a mail server by communication using SMTP, and acquire the sending time of the email from the received email as information for identifying the time. The above system may, for example, receive an email from a mail server by communication using SMTP, and acquire information for identifying the time from the message body included in the received email, but it is particularly preferable to acquire, for example, the sending time of the email as information for identifying the time from the SMTP header accompanying the message body of the received email, since this makes it easier to search for information for identifying the time.

[0026] However, the protocol is not limited to HTTP or SMTP, and various protocols may be used. In particular, it is preferable to obtain information for identifying the time from a header added to the message body in the application layer.

[0027] (4) The function of acquiring information for identifying the time that the identification means has should preferably be a system having a function of receiving information that is not addressed to the local system and is communicated over a network by the communication function, and acquiring information for identifying the time from the information that is not addressed to the local system.

[0028] According to the above system, by using the communication function of the above system to connect to a network through which information not addressed to the system is communicated, the time can be determined without the user having to manually input information even in situations where information cannot be obtained directly from either the time server or the receiver of the satellite positioning system.

[0029] The system may, for example, receive information communicated between a plurality of external systems and obtain information for identifying the time from the information. The system may, for example, include a relay device that relays information communicated between a plurality of external systems and obtain information for identifying the time from the information received by the relay device.

[0030] The above system may receive information that is not addressed to the system itself and is communicated over a network, and obtain information for identifying the time from the message body of the information, but it is particularly advantageous to obtain information for identifying the time from a header accompanying the message body, as this makes it easier to search for information for identifying the time.

[0031] (5) The function of acquiring information for identifying the time that the identification means has should preferably be a system having a function of acquiring information representing a captured image and acquiring information for identifying the time from the image.

[0032] According to the above system, by using the function of acquiring information representing an image possessed by the above system, the time can be determined without the user having to manually input information, even in situations where information cannot be acquired directly from either the time server or the receiver of the satellite positioning system.

[0033] The system may, for example, recognize an image and obtain information for identifying the time. The system may, for example, recognize a clock from the image and recognize the time indicated by the recognized clock. The system may, for example, determine whether the image includes information for identifying the time, and obtain information for identifying the time from the image when it is determined that the image includes information for identifying the time. The system may, for example, include a utilization means for utilizing information representing the acquired image for a purpose other than identifying the time, and obtain information for identifying the time from the information representing the image used by the utilization means. The utilization means for utilizing information representing the acquired image for a purpose other than identifying the time may, for example, be a recording device for recording information representing the acquired image, a video distribution device for distributing information representing the acquired image, or the like.

[0034] The system may, for example, include an image capturing means, and may obtain information representing an image captured by the image capturing means as information for identifying the time. The system may, for example, include a drive recorder, and may capture the scenery around the vehicle using the image capturing means included in the drive recorder, recognize the captured image, determine whether or not a clock is included in the image, and if it is determined that a clock is included in the image, recognize the time indicated by the clock to identify the time. The system may, for example, identify the time from an image captured when a vehicle equipped with the drive recorder is traveling near a clock.

[0035] The system may acquire information representing one image or multiple images as information for identifying the time. For example, the system may identify the time from one image showing a clock, or from multiple images showing the same clock taken consecutively in chronological order.

[0036] The system may acquire information representing a plurality of images of visible light that changes over time according to a visible light communication standard in a time series as information for identifying the time, and identify the time from the plurality of images. For example, when a user's mobile terminal emits visible light indicating the time according to a visible light communication standard, the system may acquire information representing a plurality of images of the visible light emitted by the user's mobile terminal in a time series, and identify the time from the plurality of images. The system may acquire information representing a plurality of images of infrared light that changes over time according to an infrared communication standard in a time series, and identify the time from the plurality of images. The system may acquire information representing a plurality of images of infrared light emitted from an infrared remote control in a time series in response to a user's input operation of a numerical value indicating the time, and identify the time from the plurality of images. The system may not include a dedicated light receiving means for visible light communication or infrared communication, but may include a photographing means, and may photograph visible light or infrared light emitted from an external system according to a visible light communication or infrared communication standard by the photographing means, and may identify the time based on the photographed images.

[0037] (6) The function of acquiring information for identifying the time that is provided in the identification means should be a system having a function of acquiring information representing a picked-up sound and acquiring information for identifying the time from the sound.

[0038] According to the above system, by using the function of the above system to acquire information representing sound, the time can be determined without the user having to manually input information, even in situations where information cannot be acquired directly from either the time server or the receiver of the satellite positioning system.

[0039] The system may, for example, obtain information representing a voice uttered by a person and recognize information for identifying the time from the voice. In this case, for example, when a user utters a time, the system identifies the time. The system may also, for example, include a sound collection means and obtain information for identifying the time from the sound picked up by the sound collection means.

[0040] (7) The function of acquiring information for identifying the time provided by the identification means should be a system having a function of acquiring information for identifying the time in a format that can be recognized by an apparatus with greater accuracy than a human can recognize.

[0041] According to the above system, even in a situation where information cannot be obtained directly from either the time server or the receiver of the satellite positioning system, the time can be determined with high accuracy without the user having to manually input information, compared to a case where the system obtains information in a format that is easily recognizable by humans, such as an image of a clock, an image showing letters, or a voice uttering the time, as information for determining the time.

[0042] The system may, for example, obtain information representing a barcode and decode the barcode to obtain information for identifying the time. The system may also, for example, obtain information representing a sound modulated according to an acoustic coupler standard and demodulate the sound to obtain information for identifying the time.

[0043] (8) The function of acquiring information for identifying the time that the identification means has should be a system having a function of acquiring the information for identifying the time accompanied by information for error detection and correction, and if an error is detected in the information for identifying the time using the information for error detection and correction, correcting the error using the information for error detection and correction.

[0044] According to the above system, even in a situation where information cannot be obtained directly from either a time server or the receiving unit of a satellite positioning system, and information obtained to identify the time may contain errors, the time can be determined with high accuracy without the user having to manually input information.

[0045] The above system may, for example, acquire an image of a two-dimensional code, such as a QR code (registered trademark), that includes information for error detection and correction as information for determining the time, and determine the time using information obtained by decoding the two-dimensional code.

[0046] (9) The function of the identification means for acquiring information for identifying the time may have a function for acquiring information for identifying a plurality of times which vary, and the function of the identification means for identifying the time may have a function for identifying the time using information for identifying a plurality of times which vary.

[0047] According to the above system, even if there is variation in the information for identifying each time acquired by the system, a probable time can be identified by using a plurality of pieces of information.

[0048] The system may, for example, identify a statistical value of information for identifying a plurality of times with variation, and identify the time using the statistical value. The statistical value may, for example, be an average value. The statistical value may also be a mode. Furthermore, the system may, for example, remove outliers from the information for identifying a plurality of times with variation, identify a statistical value of information for identifying a plurality of times with variation that does not include outliers, and identify the time using the statistical value.

[0049] Furthermore, the system may, for example, acquire information representing a number of images, each of which depicts a different clock, as information for identifying the time, recognize the time from each of the multiple images, and identify the time as a statistical value of the multiple recognized times.

[0050] (10) A system may be provided having an oscillator that emits a signal at a predetermined period and an internal clock that keeps time based on the signal emitted by the oscillator, wherein the function of the determination means to acquire information for identifying the time has a function of acquiring information indicating a difference between the predetermined period and a reference period as information for identifying the time, and the determination means has a function of correcting the time kept by the internal clock using the information indicating the difference.

[0051] According to the above system, even in a situation where information cannot be obtained directly from either the time server or the receiver of the satellite positioning system, and a difference occurs between the period of the signal actually emitted by the oscillator of the internal clock and the reference period, the time can be determined with high accuracy based on the time kept by the internal clock, without the user having to manually input information.

[0052] The internal clock may be, for example, an RTC (Real-Time Clock). The information indicating the period may be, for example, information determined using a 1PPS signal emitted by a receiver of a satellite positioning system at a period of 1 second. The function of acquiring the information for identifying the time may include a function of acquiring the information indicating the period stored in a storage means such as a memory by reading it from the storage means as the information for identifying the time.

[0053] For example, if the reference frequency of the signal emitted by an oscillator in an internal clock is X (kHz) and the frequency of the signal actually emitted by the oscillator, determined using a 1PPS signal, is Y (kHz), the function of acquiring information for identifying the time of the system may acquire information indicating the value of X / Y as information for identifying the time, and the system may have a function of correcting the time kept by the internal clock using the value of X / Y.

[0054] (11) The system may include a measuring means for measuring a physical quantity that affects the period at which the oscillator emits a signal, and the function of acquiring information for identifying the time may include a function of acquiring information indicating the period at which the oscillator emits a signal, which corresponds to the physical quantity measured by the measuring means, as information for identifying the time.

[0055] According to the above system, even in a situation where information cannot be obtained directly from either a time server or the receiver of the satellite positioning system, and a difference occurs between the period of the signal actually emitted by the oscillator of the internal clock and the reference period, and this difference is affected by changes in the physical quantities of the environment in which the oscillator is placed, the time can be determined with high accuracy based on the time kept by the internal clock, without the user having to manually input information.

[0056] The physical quantity that affects the period at which the oscillator emits a signal may be, for example, temperature. The above system may, for example, include a thermometer that measures the current temperature, obtains information indicating the period at which the oscillator emits a signal according to the measured temperature, and corrects the time kept by the internal clock using the period.

[0057] (12) The function of acquiring information for identifying the time may be a first acquiring function, and the identification means may have one or more of a function of acquiring information for identifying the time directly from a time server, a function of acquiring information for identifying the time directly from a receiving unit of a satellite positioning system, and a function of acquiring information for identifying a time manually entered by a user as a second acquiring function, and the function of correcting the time kept by the internal clock may be a function of correcting the time kept by the internal clock using the information acquired by the second acquiring function.

[0058] According to the above system, the second acquisition function determines the time with high accuracy based on the time measured by an internal clock corrected using information for identifying the time obtained directly from either a time server or a receiver of a satellite positioning system, or information for identifying the time manually input by the user, even in a situation where the second acquisition function is not available.

[0059] The second acquiring function may, for example, be a function of acquiring information indicating the current time manually input by a user, and the function of correcting the time kept by the internal clock may, for example, be a function of correcting the time kept by the internal clock using the information indicating the current time. The second acquiring function may, for example, be a function of acquiring a 1PPS signal emitted by a receiving unit of a satellite positioning system, and the first acquiring function may, for example, be acquiring information indicating a period at which an oscillator emits a signal by using the 1PPS signal to generate information for specifying the time, and the function of correcting the time kept by the internal clock may, for example, be a function of correcting the time kept by the internal clock using the period.

[0060] (13) The system may include a transmitting means for transmitting at least one of the information for identifying the time and information indicating a time identified using the information for identifying the time to an external system as information for identifying the time.

[0061] According to the above system, time synchronization is performed between the above system and an external system.

[0062] For example, the external system may be a system having a similar configuration to the above-mentioned system. Alternatively, the external system may be a plurality of systems having a similar configuration to the above-mentioned system. In this case, time synchronization is performed between the above-mentioned system and the plurality of systems having a similar configuration to the above-mentioned system.

[0063] For example, when the system is an in-vehicle device and multiple vehicles equipped with the system are parked in a parking lot or the like, the system installed in a first vehicle obtains information for determining the time from an external system, determines the time using the information, and transmits information indicating the determined time to the system installed in a second vehicle as information for determining the time, and the system installed in the second vehicle determines the time using the information for determining the time received from the system installed in the first vehicle, and transmits information indicating the determined time to the system installed in a third vehicle as information for determining the time. In this manner, by sequentially communicating information for determining the time between the multiple systems, the multiple systems can determine a synchronized time.

[0064] (14) The above system may be a first system, and a second system may be provided that includes a plurality of first systems, each of which obtains information for identifying time from the same information source.

[0065] According to the second system, time synchronization is performed among a plurality of first systems.

[0066] Each of the multiple first systems included in the second system may, for example, acquire information for identifying the time from the same information source within a predetermined period. In addition, the spatial reach of the information emitted from the information source may be limited, and the multiple first systems present within the reach may acquire information for identifying the time from the same information source. For example, the multiple first systems may be multiple in-vehicle devices (e.g., drive recorders) mounted on the same vehicle, the information source may be a passenger of the vehicle or a mobile terminal (e.g., smartphone) of the passenger, and the multiple first systems (e.g., drive recorders) may pick up a voice indicating the time uttered by the passenger in the vehicle or a sound indicating the time uttered by the mobile terminal (e.g., smartphone) of the passenger in the vehicle, and each of the multiple first systems (e.g., drive recorders) may identify the time from the voice or sound picked up by the multiple first systems (e.g., drive recorders). Also, for example, the multiple first systems may be multiple network cameras placed in the same room, the information source may be a clock placed in the room (for example, the time display unit of a time recorder), and the time may be determined from an image captured by each of the multiple first systems (network cameras) of the same clock.

[0067] (15) The above system may be a first system, and a third system may be provided which includes an output means for outputting information for identifying the time acquired by the first system in a format that can be recognized by an apparatus with greater accuracy than human recognition.

[0068] According to the third system, the time can be determined with high accuracy in the first system, compared to when, for example, information for determining the time is output in a format that is easily recognizable by humans, such as an image of a clock, an image showing letters, or a voice stating the time.

[0069] For example, the first system may be a drive recorder, and the third system may be a user's mobile terminal. For example, the user's mobile terminal, which is the third system, may display a QR code indicating the time, and the drive recorder, which is the first system, may take a picture of the QR code displayed on the user's mobile terminal, obtain the taken image as information for identifying the time, and decode the QR code to identify the time. For example, the user's mobile terminal, which is the third system, may produce a sound indicating the time according to a pitch, and the drive recorder, which is the first system, may pick up the sound produced by the user's mobile terminal with a built-in microphone, obtain information representing the picked-up sound as information for identifying the time, and identify the time from the pitch of the sound.

[0070] (16) It is preferable that the fourth system comprises the first system and the third system.

[0071] According to the fourth system, even in a situation in which information cannot be obtained directly from either the time server or the receiver of the satellite positioning system in the first system, the time can be determined with high accuracy without the user having to manually input information, compared to a case in which information in a format that is easily recognizable by humans, such as an image of a clock, an image showing letters, or a voice uttering the time, is used as information for determining the time.

[0072] (17) The above system may be a first system, and a third system may be provided that includes an output means for outputting the information for identifying the time acquired by the first system as information accompanied by information for error detection and correction.

[0073] According to the third system, for example, even in a situation where there is a possibility of an error in information occurring along the information transmission path from the third system to the first system, the first system can determine the time with high accuracy.

[0074] (18) It is preferable that the fourth system comprises the first system and the third system.

[0075] According to the fourth system, in the first system, even in a situation where information cannot be obtained directly from either the time server or the receiving unit of the satellite positioning system and there is a possibility of an error in the information transmission path for determining the time, the time can be determined with high accuracy without the user having to manually input information.

[0076] (19) It is preferable to program a computer to function as the identification means provided in the above system.

[0077] According to the above program, a system is realized that uses a computer to determine the time without requiring the user to manually input information, even in situations where information cannot be obtained directly from either a time server or the receiver of a satellite positioning system.

[0078] (20) It is preferable that the program causes a computer to function as the output means provided in the third system.

[0079] According to the above program, a third system is realized that enables the first system to determine the time with high accuracy without requiring the user to manually input information, even in a situation where the first system is unable to directly obtain information from either a time server or a receiving unit of a satellite positioning system, using a computer.

[0080] The inventions shown in (1) to (20) above can be arbitrarily combined. For example, at least a part of the configuration of at least one of the inventions after (2) may be added to all or a part of the configuration of the invention shown in (1). In particular, at least a part of the configuration of at least one of the inventions after (2) may be added to the invention shown in (1). In addition, any configuration may be extracted from the inventions shown in (1) to (20) and the extracted configurations may be combined. The applicant of this application intends to obtain rights to the inventions including these configurations. In addition, even if there is a description such as "in the case of" or "when", it is not intended to describe the configuration as being limited to that case or time. These are examples of better configurations, and the applicant intends to obtain rights to configurations other than these cases or times. In addition, the parts described in order are not limited to this order. Configurations in which some parts have been deleted or the order has been changed are also disclosed, and the applicant intends to obtain rights. Effect of the Invention

[0081] The user does not have to manually input information to allow the system to determine the time in situations where the information cannot be obtained directly from either a time server or a satellite positioning system receiver.

[0082] The effects of the invention of this application are not limited to this, and effects obtained from the configuration disclosed in the specification and drawings, etc. are also disclosed, and the intention is to obtain rights to the configuration that achieves the effects by divisional applications, amendments, etc. For example, in this specification, the phrase "can" is a description that clearly indicates the effect that is achieved, and there are also parts that show the effect even without the phrase "can." Also, there are effects that can be understood from the configuration even without such a description. [Brief description of the drawings]

[0083] [Figure 1] FIG. 1 is a diagram showing an overall configuration of a system according to an embodiment. [Diagram 2] FIG. 1 is a diagram showing an external appearance of a drive recorder according to an embodiment. [Diagram 3] FIG. 1 is a diagram showing an internal structure of a drive recorder according to an embodiment. [Figure 4] FIG. 1 is a diagram showing an internal structure of a time recorder according to an embodiment. [Diagram 5] 13 is an example of a video playback screen displayed on a display device connected to a terminal device according to an embodiment. [Figure 6] 13 shows an example of a playback screen in a system according to a modified example of an embodiment. [Figure 7] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 8] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 9] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 10] FIG. 13 is a diagram showing an example of a sequence of processes performed by a drive recorder and a tablet PC according to a modified example of an embodiment. [Figure 11] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 12] FIG. 1 is a diagram showing an overall configuration of a system according to an embodiment. [Figure 13] 13 is an example of response information received from an HTTP server by a drive recorder according to an embodiment. [Figure 14] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 15] 13 illustrates an example of information received by a time recorder according to a modified example of an embodiment. [Figure 16] FIG. 1 is a diagram showing an overall configuration of a system according to an embodiment. [Figure 17] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 18] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 19] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 20] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 21] FIG. 13 is a diagram for explaining a mechanism by which a tablet PC transmits time information in a system according to a modified example of an embodiment. [Figure 22] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 23] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 24] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Diagram 25] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 26] FIG. 13 is a diagram showing a state in which a drive recorder according to a modified example of an embodiment is mounted on a vehicle and used. [Figure 27] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Figure 28] FIG. 13 is a diagram showing a state in which a drive recorder according to a modified example of an embodiment is mounted on a vehicle and used. [Figure 29] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. [Diagram 30] FIG. 1 is a diagram showing an overall configuration of a system according to an embodiment. [Diagram 31] FIG. 13 is a diagram showing an overall configuration of a system according to a modified example of an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0084] [First embodiment] 1 is a diagram showing the overall configuration of a system 901 including a drive recorder 1 which is a system according to a first embodiment of the present invention. The system 901 includes the drive recorder 1 mounted on each of a plurality of vehicles under the management of a vehicle operating company (e.g., a taxi company, a bus company, etc.), a time recorder 2 (an example of the same information source) which is a device that transmits information for identifying time (hereinafter referred to as "time information") to each of the drive recorders 1, a time server 3 which is a device that transmits the time information to the time recorder 2, and a data server 4 which stores various information such as attendance information generated by the time recorder 2.

[0085] FIG. 1 shows, as an example, two drive recorders 1 installed in a vehicle identified by a vehicle ID (Identifier) ​​"0001" and a vehicle identified by a vehicle ID "0002", but the number of drive recorders 1 constituting the system 901 varies depending on the number of vehicles using the system 901.

[0086] The drive recorder 1 and the time recorder 2 communicate wirelessly according to a communication protocol such as WiFi (registered trademark) or Bluetooth (registered trademark). For example, when the vehicle is turned on, the drive recorder 1 receives power from the vehicle battery and starts operating. The drive recorder 1 attempts to establish a communication connection with the time recorder 2 at the start of operation and every time a predetermined time (for example, 10 seconds) has elapsed during operation, and when the communication connection is established, it receives time information indicating the current time from the time recorder 2. The drive recorder 1 has an internal clock, and calibrates the time kept by the internal clock using the time information received from the time recorder 2, and specifies the calibrated time as the current time. Therefore, when the driver of the vehicle turns on the power of the vehicle parked in an office, or drives the vehicle from outside the office to move into the office, the drive recorder 1 receives time information from the time recorder 2 and calibrates the time kept by the internal clock without requiring a user operation.

[0087] The time recorder 2 and the time server 3 can communicate with each other via a wired connection (e.g., Ethernet (registered trademark)) or wirelessly (e.g., WiFi). The time server 3 is installed, for example, outside the office of a vehicle operating company, and communicates with the time recorder 2 via a WAN such as the Internet. The time server 3, for example, includes a receiving unit for a Global Navigation Satellite System (GNSS), wirelessly receives time information indicating the current time kept by an atomic clock mounted on the satellite from the satellite, and transmits the received time information to an external device. The time server 3 transmits the time information to an external device using, for example, the Network Time Protocol (NTP).

[0088] The time recorder 2 and the data server 4 can communicate with each other by wire or wirelessly. The data server 4 is installed, for example, in the office of a vehicle operating company, and communicates with the time recorder 2 via a LAN.

[0089] FIG. 2 is a diagram showing the appearance of the drive recorder 1. The drive recorder 1 includes a cylindrical main body 11, and a mounting bracket 12 is attached to one axial end of the main body 11. The main body 11 is constructed by butting together a first case 111 and a second case 112, which are divided into two halves, front and rear. One end 1111 of the first case 111 and one end 1121 of the second case 112 are formed to have slightly smaller outer dimensions, and male threads are formed on the outer peripheral surfaces of the tips. Furthermore, a step surface is formed between the one end 1111, the one end 1121, and the central portion of the main body 11 in the axial direction, based on the difference in outer diameter.

[0090] The mounting bracket 12 includes a ring portion 121 having an inner diameter that is approximately equal to (slightly larger than) the outer diameters of one end portion 1111 of the first case 111 and one end portion 1121 of the second case 112, a mounting plate 122, and a connecting column portion that connects the two. The mounting plate 122 is disposed so as to be inclined at a predetermined angle with respect to the diameter direction of the ring portion 121. An adhesive member such as double-sided adhesive tape is attached to a mounting surface 1221 of the mounting plate 122, and the mounting plate is fixed to the windshield of the vehicle via the adhesive member.

[0091] With the ring portion 121 attached to one end 1111 and one end 1121 of the main body 11, the nut member 13 is attached to the male thread portion formed on the outer circumferential surface of the one end 1111 and one end 1121. The nut member 13 is in the form of a flat disk-shaped cap, and a female thread portion that matches the male thread portion is formed on its inner circumferential surface. By fastening the nut member 13, both axial surfaces of the ring portion 121 are sandwiched and fixed between the nut member 13 and the above-mentioned step surface of the main body 11. As a result, when the ring portion 121 is attached to one end 1111 of the first case 111 and one end 1121 of the second case 112, before being firmly fastened by the nut member 13, the ring portion 121 can rotate forward and backward relative to the one end 1111 of the first case 111 and one end 1121 of the second case 112 about its central axis as a rotation center. Then, when the relative angular position of the two is desired, the nut member 13 is tightened, thereby fixing the mounting bracket 12 at any relative angular position. If triangular wave-shaped (saw-tooth) teeth are provided on the step surface of the main body 11 and on the side surface of the ring portion 121 facing it, the teeth can be meshed with each other to fix firmly.

[0092] As described above, the drive recorder 1 is attached and fixed to the windshield of the vehicle using a double-sided tape (not shown) or other adhesive member attached to the upper surface of the mounting plate 122. Therefore, the drive recorder 1 of this embodiment can be adjusted to fit various windshield angles (25 to 75 degrees). That is, the mounting plate 122 is parallel to the angle of the windshield, but as described above, the relative angle of the main body 11 to the mounting plate 122 (mounting bracket 12) can be adjusted, so that the basic up-down direction of the main body 11 can be made parallel to, for example, a vertical plane (with respect to the ground) regardless of the angle of the mounting plate 122 (windshield). Of course, the angle between the basic up-down direction of the main body 11 and the vertical plane with respect to the ground can also be set to an appropriate angle. Therefore, one drive recorder 1 can be mounted on different types of vehicles.

[0093] Further, a circular through hole 131 is formed in the center of the nut member 13. The tip surfaces of one end 1111 of the first case 111 and one end 1121 of the second case 112 are exposed to the outside from this through hole 131, and objects to be operated by the user, such as the volume dial 14 and the DC jack 15, are provided on the exposed parts of the tip surfaces. By adopting such a configuration, it is possible to place the objects to be operated in the limited space of the main body 11, and as a result of attracting the user's attention during operation, it is possible to easily check whether the nut member 13 is loose.

[0094] By attaching a DC plug (not shown) attached to one end of a power cable connected to a cigarette lighter socket, for example, to the DC jack 15, the drive recorder 1 of this embodiment can receive power from the vehicle battery. Since the power cable is pulled out from the side of the main body 11 in this way, the drive recorder can be mounted next to or near the rearview mirror, making it possible to hide the power cable in the rearview mirror and making it look beautiful. Furthermore, by receiving power from the vehicle side via the DC jack 15, the drive recorder 1 can be used alone.

[0095] A CCD camera 16 is installed in an exposed state in the first case 111. The CCD camera 16 captures images of the area ahead of the vehicle. Although not shown, a microphone may be built into the main body 11. The microphone can pick up surrounding sounds.

[0096] Furthermore, the other end of the main body 11 is provided with an interface for connecting a connection cable for transmitting and receiving information to and from an external device, and a slot for an SD memory card.

[0097] 3 is a diagram showing the internal structure of the drive recorder 1. The drive recorder 1 further includes an accident detection sensor 101, a temporary storage memory 102, an internal clock 103, a speaker 104, a switch 105, a microphone 106, a control unit 107, and an interface 108 within a main body 11. The accident detection sensor 101 is realized by an impact detection sensor such as an acceleration sensor. When a certain impact (acceleration) is detected, it is determined that an accident (crash) has occurred. In addition, by appropriately setting a threshold value for the certain impact, it is also possible to output a detection signal not only when an accident occurs, but also when sudden braking or steering is performed.

[0098] The temporary storage memory 102 is, for example, a RAM that temporarily stores image data captured by the CCD camera 16, and is configured to constantly store image data captured at least a certain amount of time in the past. However, since the storage capacity is limited, old image data is deleted according to a certain criterion. The certain criterion may be, for example, image data stored a certain amount of time ago, or when the memory capacity for storage reaches a certain amount. In this embodiment, the temporary storage memory 102 is configured by a ring buffer.

[0099] The speaker 104 outputs, for example, operation sounds of a switch 105 and various messages (guides, warnings, etc.). The volume dial 14 adjusts the output level of the speaker 104.

[0100] The control unit 107 is a microcomputer equipped with a CPU, a ROM, a RAM, a non-volatile memory, an I / O, etc., and executes a predetermined process based on information input from the above-mentioned various input devices, and outputs predetermined information using an output device. The functions of the drive recorder 1 are stored in the EEPROM of the control unit 107 as a program executed by the computer included in the control unit 107, and are realized by the computer included in the control unit 107 executing the program.

[0101] Functions that are realized by the computer through the programs contained in the control unit 107 include an image recording function, an image output function, and an internal clock calibration function.

[0102] The control unit 107 is a circuit for realizing the basic functions of the drive recorder, and stores the image (image data) captured by the CCD camera 16 as an image file in the temporary storage memory 102, and stores the captured image data (image file) in a non-volatile memory based on a detection signal from the accident detection sensor 101. In this embodiment, a memory card 17 (e.g., an SD memory card) inserted in a card slot 109 (e.g., a slot for an SD memory card) is used as the non-volatile memory. By removing this memory card 17 and inserting it into a memory card reader or the like connected to a personal computer, data can be imported into the personal computer. In addition, the recorded images and the like can be transmitted not only by removing the memory card 17 (recording medium) as described above and taking them out, but also by wired or wireless communication (data transmission). In order to perform wired communication, it is preferable to provide the main body with a connector, USB, or the like for connecting a communication cable.

[0103] To explain the image recording function of recording this image data in more detail, the CCD camera 16 constantly captures images of the vehicle and the surroundings from the driver's viewpoint (field of vision), and the captured image data is stored in a temporary storage memory 102 such as a ring buffer. The images stored in this temporary storage memory 102 are updated to the latest ones one after another, and past image data is held for a set period of time.

[0104] When the accident detection sensor 101 detects an impact that occurs during an accident or sudden braking / steep steering (the output value of the sensor exceeds a threshold), image data (video) for a certain period before the threshold is exceeded (the impact is detected) is read from the temporary storage memory 102 and stored in a non-volatile memory (memory card 17), and after the threshold is exceeded, the video captured by the CCD camera 16 is recorded on the memory card 17 directly or via the temporary storage memory 102, so that the video for a certain period before and after the impact is stored in the non-volatile memory, the memory card 17. At this time, if a microphone 106 is built in, the surrounding sound picked up by the microphone 106 is also recorded in association with the image data. This sound is also temporarily stored in the temporary storage memory 102, and when the image data is stored in the memory card 17, the recorded audio data is also stored in the memory card 17. It is preferable to add audio along with the video, as this increases the sense of realism.

[0105] The internal clock 103 has, for example, an RTC and continuously keeps track of the current time. The interface 108 is an interface for communicating with an external device. In this embodiment, the drive recorder 1 communicates with the time recorder 2 via the interface 108.

[0106] 4 is a diagram showing the internal structure of the time recorder 2. The time recorder 2 is equipped with a display unit 21, operation buttons 22, a reading unit 23, a printing unit 24, an internal clock 25, an interface 26, and a control unit 27. The main body of the time recorder 2 is also provided with a slit through which a user can insert a time card into the time recorder 2 when punching the time card.

[0107] The display unit 21 is, for example, a liquid crystal display, and displays information such as the current time. The operation button 22 is a button that accepts user operations. The operation button 22 may be a physical button or a virtual button displayed on a touch screen. When punching a time card, the user operates the operation button 22 to input to the time recorder 2 whether the punch corresponds to clocking in, clocking out, etc.

[0108] The reading unit 23 is, for example, an optical scanner, and reads a driver ID (for example, an employee number) that identifies the driver and is printed on the time card in advance. The driver ID printed on the time card may be characters that are recognizable by humans, or an image such as a barcode that is easily read by the reading unit 23.

[0109] The printing unit 24 is, for example, a thermal transfer printer, and prints (stamps) the current time kept by the internal clock 25 on a time card inserted in the time recorder 2. The internal clock 25 has, for example, an RTC, and continuously keeps track of the current time.

[0110] The interface 26 is an interface for communicating with an external device. In this embodiment, the time recorder 2 communicates with each of the drive recorders 1, the time server 3, and the data server 4 via the interface 26.

[0111] The control unit 27 is a computer equipped with a processor and a memory, and the processor processes data according to a program stored in the memory, thereby controlling the operation of each component of the time recorder 2 and realizing various functions of the time recorder 2. The functions realized by the control unit 27 include a function of calibrating the current time kept by the internal clock 25 using time information received from the time server 3, a function of displaying the current time kept by the internal clock 103 on the display unit 21, a function of printing the current time kept by the internal clock 25 on a predetermined position (a position determined according to the current date and whether the user has specified the time of arrival / leave work by operating the operation button 22) on a time card inserted into the time recorder 2 by the printing unit 24, and a function of transmitting attendance information for each driver identified by punching the time card to the data server 4 via the interface 26.

[0112] The data server 4 stores, for example, a vehicle-drive recorder correspondence table that stores information indicating the correspondence between vehicles and drive recorders 1, a vehicle allocation database that stores information indicating the allocation of vehicles to drivers, and an attendance database that stores the attendance information of drivers.

[0113] The information stored in the vehicle / drive recorder correspondence table indicates which vehicle is equipped with which drive recorder 1. The vehicle / drive recorder correspondence table stores a record for each vehicle, and each record stores, for example, a vehicle ID (e.g., a vehicle number, etc.) that identifies the vehicle, and a drive recorder ID (e.g., a serial number of the drive recorder 1, etc.) that identifies the drive recorder 1 installed in the vehicle. The information stored in the vehicle / drive recorder correspondence table is, for example, inputted into a terminal device by an administrator of a vehicle operating company, and transmitted from the terminal device to the data server 4.

[0114] The information stored in the vehicle allocation database indicates which driver each vehicle is assigned to during which time period. The vehicle allocation database is a collection of allocation tables for each vehicle identified by, for example, a vehicle ID, and the allocation table stores records for each time period, such as "XX year XX month XX day XX hour XX minute to XX year XX month XX day XX hour XX minute," and each record stores, for example, information indicating the time period and a driver ID (e.g., employee number) that identifies the driver to whom the vehicle is assigned during that time period. The information stored in the vehicle allocation database is, for example, input into a terminal device by an administrator of a vehicle operating company and transmitted from the terminal device to the data server 4.

[0115] The information stored in the attendance database indicates what time period each driver worked. The attendance database is a collection of attendance tables for each driver identified by, for example, a driver ID, and the attendance tables store records for each time, for example, "xx year xx month xx day xx hour xx minute," and each record stores, for example, information indicating the time and information indicating what state the driver's attendance status changed to at that time (for example, arriving at work, leaving work, etc.). The information stored in the attendance database is the accumulated information sent from the time recorder 2 to the data server 4 every time the driver inserts a time card into the time recorder 2.

[0116] As described above, each of the drive recorders 1 stores information (hereinafter referred to as sound-attached video information) in which the video (video) captured by the CCD camera 16 of the drive recorder itself is associated with the sound picked up by the microphone 106. The sound-attached video information includes still image information representing still images captured at a predetermined period (e.g., 1 / 30 seconds) as information representing a video. When storing the still image information, the drive recorder 1 stores time information indicating the current time clocked by the internal clock 103 at the time when the still image was captured by the CCD camera 16 and work status information indicating the work status (on duty, off duty, etc.) of the driver assigned to the vehicle at that time, in association with the still image information. Hereinafter, the drive recorder 1 stores the time information and the work status information in a form including the sound-attached video information, but at least one of the time information and the work status information may be stored as information separate from the sound-attached video information.

[0117] As described above, for example, when a vehicle driver turns on the power of a vehicle parked in an office, or drives the vehicle from outside the office into the office, the drive recorder 1 and time recorder 2 installed in the vehicle establish a wireless communication connection.

[0118] When the drive recorder 1 establishes a communication connection with the time recorder 2, the drive recorder 1 transmits to the time recorder 2 a drive recorder ID for identifying the drive recorder itself.

[0119] When the time recorder 2 receives the drive recorder ID from the drive recorder 1, it first refers to the vehicle-drive recorder correspondence table and identifies the vehicle ID that identifies the vehicle in which the drive recorder 1 identified by the received drive recorder ID is installed. Then, the time recorder 2 refers to the vehicle allocation database and identifies the driver ID that identifies the driver to whom the vehicle identified by the identified vehicle ID is currently assigned. Then, the time recorder 2 reads out the latest attendance information of the driver identified by the identified driver ID from the attendance database. Then, the time recorder 2 transmits to the drive recorder 1 the identified vehicle ID, the driver ID, work status information indicating the current work status (e.g., on duty, off duty, etc.) of the driver indicated by the attendance information read from the attendance database, and time information indicating the current time clocked by the internal clock 25 at that time.

[0120] The drive recorder 1 stores the vehicle ID, the driver ID, and the work status information received from the time recorder 2 in the memory of the control unit 107. The drive recorder 1 also calibrates the time kept by the internal clock 103 of the drive recorder 1 using the time information received from the time recorder 2. For example, the drive recorder 1 calculates the time difference between the current time indicated by the time information received from the time recorder 2 and the current time kept by the internal clock 103 at a time point a predetermined time before the time information was received, which is required for generating and transmitting and receiving the time information, and keeps the current time after calibration by adding (if the internal clock 103 is behind the internal clock 25) or subtracting (if the internal clock 103 is ahead of the internal clock 25) the time difference to the current time kept by the internal clock 103. That is, the drive recorder 1 includes a determination means for determining the current time using the time information.

[0121] The drive recorder 1 then generates video information representing a video by associating and accumulating still image information representing a still image captured by the CCD camera 16 with time information indicating the current time after calibration clocked by the internal clock 103 and the latest vehicle ID, driver ID, and work status information stored in the memory of the control unit 107. The drive recorder 1 generates sound-accompanied video information by associating sound information representing a sound picked up by the microphone 106 with the video information thus generated so as to be synchronized on the time axis. The time information indicating the current time after calibration may be stored, for example, in the memory card 17 as information separate from the sound-accompanied video information, or may be stored in any one of the frames, headers (or footers), and management areas (for example, setting files, log files, etc.) of the sound-accompanied video information.

[0122] The manager of the vehicle operating company removes the memory card 17 of the drive recorder 1 installed in a vehicle parked in the company's parking lot from the card slot 109, inserts the memory card 17 into a card reader built into or externally connected to a terminal device such as a personal computer, and moves the audio-accompanying video information stored in the memory card 17 to the memory of the terminal device. After that, the manager of the vehicle operating company returns the memory card 17 to the card slot 109 of the drive recorder 1.

[0123] The terminal device has a function of displaying the video represented by the sound-accompanied video information moved to its own memory, for example, on a display device (e.g., a liquid crystal display) built into or externally connected to the terminal device. FIG. 5 is an example of a video playback screen displayed on a display device connected to a terminal device used by an administrator of a vehicle operating company. As shown in FIG. 5, the playback screen plays and displays a video captured by a CCD camera 16. The playback screen also displays the vehicle ID of the vehicle from which the currently displayed image was captured, the time when the image was captured (captured time), the driver ID (e.g., employee number) of the driver who was driving the vehicle at the capture time, and the driver's work status.

[0124] The shooting time displayed on the playback screen is the current time measured by the internal clock 103 of the drive recorder 1, and the current time measured by the internal clock 103 is the current time calibrated using the time information transmitted from the time recorder 2. Therefore, the current time measured by the internal clock 103 of the drive recorder 1 and the current time measured by the internal clock 25 of the time recorder 2 are substantially synchronized. Therefore, according to the system 901, there is no inconvenience that an incorrect shooting time, driver ID, or work status is displayed on the playback screen due to a discrepancy between the current times measured by the internal clocks of the drive recorder 1 and the time recorder 2.

[0125] (Modification of the first embodiment) (1-1) In the above-described system 901, the time information stored by the drive recorder 1 in association with the still image information included in the sound-accompanied video information indicates the current time measured by the internal clock 103, calibrated using the time information received from the time recorder 2. In addition to the current time measured and calibrated by the internal clock 103, the drive recorder 1 may also store time information indicating the current time before calibration in association with the still image information included in the sound-accompanied video information.

[0126] Fig. 6 is an example of a playback screen in the system 901 according to this modified example. In this modified example, as shown in Fig. 6, two shooting times, "shooting time (standard)" and "shooting time (time recorder)", are displayed on the playback screen. The shooting time (standard) is the current time before calibration clocked by the internal clock 103 at the time when the still image is shot, and the shooting time (time recorder) is the current time after correction by adding or subtracting the time difference between the times clocked by the internal clock 103 and the internal clock 25 to the current time before calibration clocked by the internal clock 103 at the time when the still image is shot.

[0127] According to this modified example, for example, a manager of a vehicle operating company can easily confirm that the shooting time included in the sound-accompanying video information has not been changed arbitrarily.

[0128] (1-2) In the above-mentioned system 901, the drive recorder 1 receives the driver ID and the work status information from the time recorder 2, and stores them in association with the still image information included in the sound-accompanied video information. The time recorder 2 does not need to transmit the driver ID and the work status information to the drive recorder 1, and the drive recorder 1 does not need to store the driver ID and the work status information in association with the still image information included in the sound-accompanied video information.

[0129] In this modification, the drive recorder 1 includes the drive recorder ID of the device that captured the image in the header information of the sound-accompanied video information, for example. Then, when displaying a playback screen, the terminal device used by the manager of the vehicle operating company transmits the drive recorder ID included in the header information of the sound-accompanied video information to be played back and time information indicating the shooting time associated with the still image to be displayed to the data server 4, and receives, in response, the vehicle ID of the vehicle that captured the still image, the driver ID of the driver of the vehicle at the time the image was captured, and information indicating the working status of the driver from the data server 4. The terminal device used by the manager of the vehicle operating company displays the vehicle ID, driver ID, and working status indicated by the information received from the data server 4 on the playback screen (see FIG. 5).

[0130] According to this modification, the data format of the sound-accompanying video information generated and stored by the drive recorder 1 does not need to be a data format capable of storing the vehicle ID, the driver ID, and the work status information.

[0131] (1-3) In the above-mentioned system 901, the type of device that acquires time information indicating the current time as information for identifying the time from the time recorder 2 and calibrates the current time measured by the internal clock using the acquired time information is a drive recorder. The type of device that acquires time information from the time recorder 2 is not limited to a drive recorder.

[0132] FIG. 7 is a diagram showing the overall configuration of a system 902 according to an example of this modified example. The system 902 includes multiple surveillance cameras 5 instead of the multiple drive recorders 1 included in the system 901. The time recorder 2, data server 4, and surveillance camera 5 of the system 902 are installed in a factory. The time recorder 2 is used for attendance management of employees working in the factory. The multiple surveillance cameras 5 are installed at different positions in the factory, and continuously capture images of the inside of the factory at different angles of view, and store the captured images as videos. The surveillance camera 5 includes a camera such as a CCD camera, a microphone, a memory, an internal clock that continuously keeps track of the current time, an interface that exchanges information with an external device, and a control unit that is a computer that controls each component of the surveillance camera 5.

[0133] The time recorder 2 wirelessly transmits time information indicating the current time measured by the internal clock 25 at that time to the surveillance camera 5 every time a predetermined time (e.g., 30 minutes) has elapsed. The surveillance camera 5 calibrates the time continuously measured by its own internal clock using the time information received from the time recorder 2, and identifies the calibrated time as the current time. Therefore, the current time determined by each of the multiple surveillance cameras 5 substantially matches the current time determined by the time recorder 2.

[0134] The surveillance camera 5 generates video information including still image information representing a plurality of still images captured by the camera at a predetermined cycle. The surveillance camera 5 associates each of the plurality of still image information included in the video information with time information indicating the current time measured by an internal clock at the time the still image information is generated. Thus, the video information includes time information indicating the capture time of each still image represented by the still image information. The surveillance camera 5 generates video information with sound by associating the video information with sound information representing sound picked up by a microphone, and temporarily stores the generated video information with sound in memory.

[0135] The surveillance camera 5 sequentially transmits the sound-accompanied video information temporarily stored in its memory to the time recorder 2. The surveillance camera 5 sequentially deletes the sound-accompanied video information transmitted to the time recorder 2 from its memory. The time recorder 2 temporarily stores the sound-accompanied video information received from the surveillance camera 5 in the memory of the control unit 27, and sequentially transmits the stored sound-accompanied video information to the data server 4. The time recorder 2 sequentially deletes the sound-accompanied video information transmitted to the data server 4 from its memory.

[0136] A manager of a factory or the like uses a terminal device such as a personal computer to play back the video and sound represented by the video with sound information stored in the data server 4. At that time, still images constituting the video and the shooting times of the still images are displayed in sequence on a display device connected to the terminal device. According to the system 902, the shooting times displayed on the display device do not substantially deviate from the current time kept by the internal clock 25 of the time recorder 2. Therefore, a manager of a factory or the like can correctly confirm, for example, whether an on-duty employee indicated by the attendance information is working in the factory, and whether an off-duty employee indicated by the attendance information is not working in the factory.

[0137] (1-4) In the above-described system 901, the type of device that transmits the time information used by the drive recorder 1 to calibrate the time measured by the internal clock 103 is a time recorder. The type of device that transmits the time information acquired by the drive recorder 1 is not limited to a time recorder.

[0138] 8 is a diagram showing the overall configuration of a system 903 according to one example of this modification. The system 903 includes a car navigation system 6 and a plurality of artificial satellites 7, instead of the time recorder 2, the time server 3, and the data server 4 included in the system 901.

[0139] The car navigation system 6 and the multiple drive recorders 1 of the system 903 are mounted on the same vehicle. One of the multiple drive recorders 1, for example, captures the front from inside the windshield of the vehicle, and another captures the rear from inside the rear window of the vehicle, for example. In this way, the multiple drive recorders 1 are installed in different locations of the same vehicle and capture images in different directions from inside the vehicle.

[0140] The car navigation system 6 includes a GNSS unit which is a receiving unit of the satellite positioning system, a memory, a touch screen, a speaker, an interface for wirelessly transmitting and receiving information to and from external devices, an internal clock, and a control unit which is a computer that controls each component of the car navigation system 6. The car navigation system 6 stores map information representing a map in its memory.

[0141] The GNSS unit included in the car navigation system 6 receives information transmitted from each of multiple artificial satellites 7, and identifies the position of the device on the earth (e.g., latitude and longitude) using the received information. The information received by the GNSS unit from the artificial satellite 7 includes time information indicating the current time kept by an atomic clock mounted on the artificial satellite 7. The car navigation system 6 calibrates the time kept by its own internal clock using the time information acquired from the artificial satellite 7 by the GNSS unit, and identifies the calibrated time as the current time.

[0142] While the vehicle is traveling, the car navigation system 6 continuously identifies its own position using the GNSS unit, and displays a map on the touch screen with the identified position as its approximate center. When a destination to which the vehicle is to be moved is input by a user's touch operation on the touch screen, the car navigation system 6 identifies a travel route from the current position of the vehicle identified by the GNSS unit to the destination, and displays a line indicating the identified travel route on the touch screen, superimposed on the map. The driver of the vehicle can easily reach the destination by driving the vehicle according to the travel route indicated by the line displayed on the map by the car navigation system 6.

[0143] The car navigation system 6 operates by receiving power from the vehicle's battery. When the driver of the vehicle turns on the vehicle and power supply from the battery to the car navigation system 6 begins, the car navigation system 6 starts up and attempts to acquire information from the artificial satellite 7 using the GNSS unit. If the car navigation system 6 succeeds in acquiring information from the artificial satellite 7, it calibrates the time kept by its own internal clock using the time information included in the information acquired from the artificial satellite 7, and specifies the calibrated time as the current time.

[0144] When the car navigation system 6 first succeeds in acquiring information from the artificial satellite 7 after startup, calibrates the time kept by its own internal clock using the time information included in the information acquired from the artificial satellite 7, and identifies the calibrated time as the current time, it wirelessly transmits time information indicating the identified current time to each of the multiple drive recorders 1. After that, the car navigation system 6 wirelessly transmits time information indicating the current time kept by the internal clock 25 at that time to each of the multiple drive recorders 1 every time a predetermined time (e.g., every 30 minutes) has elapsed.

[0145] The drive recorder 1 calibrates the time continuously measured by the internal clock 103 using the time information received from the car navigation system 6, and specifies the calibrated time as the current time. Therefore, the current time specified by each of the multiple drive recorders 1 substantially matches the current time specified by the car navigation system 6. According to the system 903, there is no discrepancy between the shooting times included in the video information generated by multiple drive recorders 1 mounted on the same vehicle.

[0146] It should be noted that there are cases where the internal clock 103 cannot be calibrated while the drive recorder 1 is capturing images. In such cases, it is advisable to calibrate the internal clock 103 while the drive recorder 1 is not capturing images.

[0147] (1-5) In the above-described system 903, the type of device that transmits the time information used to calibrate the time measured by the internal clock 103 of each of the multiple drive recorders 1 mounted on the same vehicle is a car navigation system. The type of device that transmits the time information acquired by the multiple drive recorders 1 mounted on the same vehicle is not limited to a car navigation system.

[0148] FIG. 9 is a diagram showing the overall configuration of a system 904 according to one example of this modified example. The system 904 includes a tablet PC 8 and a time server 3 instead of the car navigation system 6 and the artificial satellite 7 included in the system 903. The tablet PC 8 is a device carried by any of the passengers (including the driver) of the vehicle, and is a slate-type personal computer including a processor, a memory, an internal clock, a touch screen (an example of an output means), and a communication interface. The tablet PC 8 may be a smartphone including a mobile phone function. The time server 3 included in the system 904 has a configuration similar to that of the time server 3 included in the system 901.

[0149] The communication interface of the tablet PC 8 includes a communication unit that connects to a mobile communication network according to a communication standard such as 3G, 4G, or LTE, and a communication unit that performs short-range wireless communication according to a communication protocol such as Bluetooth. The tablet PC 8 connects to the Internet via the mobile communication network, and receives time information from the time server 3 via the Internet. The tablet PC 8 calibrates the time kept by its own internal clock using the time information received from the time server 3, and specifies the calibrated time as the current time.

[0150] When the tablet PC 8 establishes a short-distance wireless communication connection with the drive recorder 1 while a program prepared for the system 904 (hereinafter referred to as a "dedicated application") is running in the background, the tablet PC 8 transmits time information indicating the current time clocked by its own internal clock at that time to the drive recorder 1. The drive recorder 1 calibrates the time clocked by the internal clock 103 using the time information received from the tablet PC 8, and specifies the calibrated time as the current time.

[0151] 10 is a diagram showing an example of a sequence of processes performed by the drive recorder 1 and the tablet PC 8. The drive recorder 1 mounted on the vehicle creates a UUID (Universally Unique Identifier) ​​dedicated to time adjustment to prompt clock adjustment, and transmits a beacon (e.g., Bluetooth Beacon) according to a short-range wireless communication protocol (e.g., Bluetooth) every time a predetermined time (e.g., one minute) has elapsed.

[0152] Examples of triggers for the drive recorder 1 to start and end periodic beacon transmission include a configuration in which the transmission starts when the vehicle's ACC is turned OFF and ends when the ACC is turned ON, a configuration in which no beacons are transmitted while ACC is OFF and beacon transmission starts when the ACC is turned ON and beacon transmission ends if there is no connection from the tablet PC 8 within a specified time (e.g., a few seconds), a configuration in which beacons are always transmitted at long, specified intervals while the drive recorder 1 is operating, etc.

[0153] When a passenger carrying a tablet PC 8 with a dedicated app running in the background gets into a vehicle, the tablet PC 8 detects the beacon transmitted by the drive recorder 1. In response to the detection of the beacon, the tablet PC 8 establishes a communication connection according to Bluetooth with the drive recorder 1 that transmitted the beacon.

[0154] When the tablet PC 8 establishes a communication connection with the drive recorder 1, it transmits a clock setting request to the drive recorder 1. This clock setting request includes time information indicating the current time measured by the tablet PC 8 using its own internal clock (time calibrated using time information acquired from the time server 3). The drive recorder 1 uses the time information included in the clock setting request received from the tablet PC 8 to update clock data indicating the reference time used by the internal clock 103 for time measurement. This calibrates the time measured by the internal clock 103. Next, the drive recorder 1 transmits a clock setting response to the tablet PC 8 notifying that the update of the clock data has been completed.

[0155] When the tablet PC 8 receives the clock setting response from the drive recorder 1, for example, it disconnects the communication connection established with the drive recorder 1. However, after receiving the clock setting response from the drive recorder 1, the tablet PC 8 may hold the communication connection established with the drive recorder 1 and, for example, every time a predetermined time (for example, 30 minutes) elapses, transmit a clock setting request including time information indicating the current time identified at that time to the drive recorder 1 using the held communication connection. In this case, the drive recorder 1 updates clock data indicating the reference time used by the internal clock 103 for timekeeping, using the time information included in the clock setting request received from the tablet PC 8, every time a predetermined time (for example, 30 minutes) elapses.

[0156] The process according to the above-mentioned sequence is performed between each of the multiple drive recorders 1 mounted on the same vehicle and the tablet PC 8.

[0157] According to the system 904, when a vehicle occupant gets into the vehicle, the time of the internal clock 103 of the drive recorder 1 is adjusted without the occupant having to perform any operation on the drive recorder 1 to adjust the time.

[0158] Furthermore, the current time specified by each of the multiple drive recorders 1 mounted on the same vehicle substantially coincides with the current time specified by the tablet PC 8. Therefore, according to the system 904, there is no discrepancy between the shooting times included in the video information generated by the multiple drive recorders 1 mounted on the same vehicle.

[0159] In the above-mentioned system 904, the tablet PC 8 obtains time information from the time server 3. Alternatively, for example, the tablet PC 8 may be equipped with a GNSS unit and use the time information indicated by radio waves received from an artificial satellite to calibrate the time kept by its own internal clock, and identify the calibrated time as the current time.

[0160] (1-6) In the above-mentioned system 903, the devices that calibrate the time kept by the internal clock using the time information obtained from the car navigation system 6 are multiple drive recorders mounted in the same vehicle as the car navigation system 6. Alternatively, the devices that calibrate the time kept by the internal clock using the time information obtained from the car navigation system 6 may be devices installed at each of multiple locations through which the vehicle passes.

[0161] Fig. 11 is a diagram showing the overall configuration of a system 905 according to one example of this modification. The system 905 includes a plurality of artificial satellites 7, a car navigation system 6 mounted on a vehicle, and a time recorder 2A and a time recorder 2B installed in each of a plurality of facilities (facility A and facility B exemplified in Fig. 11).

[0162] While the vehicle is traveling outdoors, the car navigation system 6 receives information transmitted from an artificial satellite 7 via a GNSS unit, and uses the time information contained in the received information to calibrate the time kept by the internal clock, and identifies the calibrated time as the current time.

[0163] Thereafter, when the vehicle moves into facility A, the car navigation system 6 establishes a communication connection with the time recorder 2A in facility A according to a short-range wireless communication protocol such as Bluetooth, and transmits time information indicating the current time kept by its own internal clock to the time recorder 2A. The time recorder 2A calibrates the time kept by its internal clock 25 using the time information received from the car navigation system 6, and specifies the calibrated time as the current time.

[0164] Thereafter, when the vehicle moves into facility B, the car navigation system 6 establishes a communication connection with the time recorder 2B in facility B in accordance with a short-range wireless communication protocol such as Bluetooth, and transmits time information indicating the current time kept by its own internal clock to the time recorder 2B. The time recorder 2 calibrates the time kept by its internal clock 25 using the time information received from the car navigation system 6, and specifies the calibrated time as the current time.

[0165] As described above, when the vehicle passes through a plurality of facilities, the current time specified by the time recorder 2 installed in each of the plurality of facilities substantially coincides with the current time specified by the car navigation system 6. According to the system 905, every time the vehicle equipped with the car navigation system 6 passes through a plurality of facilities, the discrepancy between the current times specified by the time recorder 2 installed in each of the plurality of facilities is eliminated.

[0166] (1-7) In the above-described system 901, the time recorder 2 receives time information from the time server 3 via a network. Alternatively, for example, the time recorder 2 may be equipped with a radio-controlled clock module, and the radio-controlled clock module may receive and use radio waves indicating the time information transmitted from a transmitting station that keeps time using an atomic clock.

[0167] [Second embodiment] FIG. 12 is a diagram showing the overall configuration of a system 906 according to an embodiment of the present invention. The system 906 includes an HTTP (Hypertext Transfer Protocol) server 9 arranged in a company office and a drive recorder 1 mounted on a vehicle. The HTTP server 9 is a device that transmits various information to a requesting device in response to a request from an external device according to HTTP. In this embodiment, the HTTP server 9 is connected to an intranet managed by the company. The HTTP server 9 is a computer equipped with a processor, a memory, and a communication interface, and transmits and receives information to and from an external device by wire and wirelessly via the communication interface. The wireless communication performed by the HTTP server 9 through the communication interface is, for example, short-distance wireless communication according to a communication protocol such as WiFi or Bluetooth.

[0168] The drive recorder 1 included in the system 906 has the same configuration as the drive recorder 1 included in the system 901. However, the drive recorder 1 included in the system 906 has a Web browser function.

[0169] In the system 906, the drive recorder 1 performs wireless communication with the HTTP server 9 via the interface 108. Note that, although it is assumed in Fig. 12 that the drive recorder 1 and the HTTP server 9 perform one-to-one communication (for example, communication by WiFi Direct, etc.), the HTTP server 9 may perform communication with a plurality of devices including the drive recorder 1 via a relay device (for example, a wireless LAN bridge, etc.). In this case, the drive recorder 1 communicates with the HTTP server 9 via the relay device.

[0170] When a vehicle moves toward, for example, a parking lot near a company office and a wireless communication connection is successfully established between the drive recorder 1 mounted on the vehicle and the HTTP server 9 installed in the office, the drive recorder 1 uses a Web browser function to make an access request to the HTTP server 9 using a URL or IP address of the HTTP server 9 that is registered in advance in the drive recorder 1. In response to the access request, the HTTP server 9 transmits response information to the drive recorder 1.

[0171] FIG. 13 is an example of response information that the drive recorder 1 receives from the HTTP server 9. In the response information shown in FIG. 13, the following portion is the message body, and the previous portion is the HTTP header. The HTTP header included in the response information contains time information indicating the time the response information was sent (e.g., time information indicating GMT (Greenwich Mean Time)). In FIG. 13, the portion surrounded by a dashed line is the time information. The drive recorder 1 calibrates the time kept by the internal clock 103 using the time information included in the response information, and identifies the calibrated time as the current time.

[0172] According to the system 906, when the vehicle equipped with the drive recorder 1 moves to the vicinity of the office, the time kept by the internal clock 103 of the drive recorder 1 is calibrated without the need for a user operation on the drive recorder 1.

[0173] In addition, the drive recorder 1 may connect to a network (such as an intranet) using WiFi or the like near the office and transmit sound-accompanied video information and the like recorded on the memory card 17 to the data server via the network. In addition, the drive recorder 1 may be unable to access the HTTP server 9 while transmitting sound-accompanied video information and the like. In such a case, the drive recorder 1 may access the HTTP server 9 and calibrate the internal clock 103, for example, before starting or after completing transmission of information to the data server. In addition, the drive recorder 1 may temporarily stop transmitting information to the data server, access the HTTP server 9 to complete the calibration of the internal clock 103, and then access the data server again to transmit unsent information.

[0174] (Modification of the second embodiment) (2-1) In the above-mentioned system 906, the drive recorder 1, which is a system that receives time information, receives information addressed to the drive recorder 1, which is its own system, from the HTTP server 9, which is a system that transmits time information, and acquires the time information contained in the received information. The type of the system that receives the time information is not limited to the drive recorder, and the type of the system that transmits the time information is not limited to the HTTP server. In addition, the system that receives the time information may receive information that is not addressed to the own system and is communicated on the network, and acquire the time information from the received information.

[0175] 14 is a diagram showing the overall configuration of a system 907 according to one example of this modified example. The system 907 includes a groupware server 71, which is a system that transmits information including time information, a time recorder 2 and multiple terminal devices 72, which are systems that receive information including time information, and a relay device 73. The relay device 73 is connected wirelessly or by wire to each of the groupware server 71, the time recorder 2, and the multiple terminal devices 72, and relays communications between these systems. The groupware server 71, the time recorder 2, the multiple terminal devices 72, and the relay device 73 included in the system 907 are installed, for example, in a company office, and form an intranet.

[0176] For example, in response to a request from the terminal device 72, the groupware server 71 transmits information to the requesting terminal device 72 in accordance with HTTP. Information transmitted by the groupware server 71 to the terminal device 72 is received by all systems on the intranet, but the system receiving the information normally uses the information addressed to its own system and discards information not addressed to its own system. In the system 907, the time recorder 2 monitors the information transmitted by the groupware server 71 to the terminal device 72, and if the information contains time information, acquires and uses the time information.

[0177] Specifically, when the time recorder 2 receives information sent by the groupware server 71 with the terminal device 72 as its destination, before discarding the information that is not addressed to its own system, the time recorder 2 acquires the time information contained in the HTTP header of the information, calibrates the time kept by the internal clock 25 using the acquired time information, and acquires the calibrated time as the current time.

[0178] Figure 15 is a diagram showing an example of information received by time recorder 2. In Figure 15, the portion surrounded by a dashed line is time information indicating the transmission time of this information. The information shown in Figure 15 is information transmitted from groupware server 71 to any of terminal devices 72, and is not addressed to time recorder 2, but time recorder 2 uses the time information included in this information to calibrate the time kept by internal clock 25.

[0179] According to the system 907, the time kept by the internal clock 25 of the time recorder 2 is calibrated without the need for user operation on the time recorder 2.

[0180] (2-2) In the above-mentioned system 906, communication between the HTTP server 9 and the drive recorder 1 is performed according to HTTP. In the above-mentioned system 907, communication between the groupware server 71 and the terminal device 72 is performed according to HTTP. In the system according to the present invention, communication between these systems may be performed according to a communication protocol other than HTTP (for example, RTSP, etc.).

[0181] (2-3) In the above-mentioned system 906, the drive recorder 1 acquires time information contained in the header of information received from the HTTP server 9. Also, in the above-mentioned system 907, the time recorder 2 acquires time information contained in the header of information received from the groupware server 71. In the system according to the present invention, the system that acquires time information may acquire time information not from the header but from the message body. For example, in the system 907, the groupware server 71 may send an e-mail addressed to the terminal device 72, and the time recorder 2 may acquire information indicating the sending time contained in the message body of the e-mail as time information for calibrating the time kept by the internal clock 25.

[0182] (2-4) In the above-described system 907, the information received by the time recorder 2 is information transmitted and received on an intranet, but the time recorder 2 may receive information transmitted and received via the Internet. For example, the system 907 may include a plurality of HTTP servers connected to the Internet instead of the groupware server 71, and the time recorder 2 may receive information transmitted from each of the plurality of HTTP servers in response to a request from any of the terminal devices 72, with the information addressed to the requesting terminal device 72, and the time information included in the received information may be used to calibrate the time kept by the internal clock 25.

[0183] In this modified example, the devices from which the information received by the time recorder 2 is sent are an unspecified number of HTTP servers, so the current time kept by the internal clocks of these HTTP servers is not necessarily correct. Therefore, when the time recorder 2 receives information from an HTTP server that is not addressed to its own system, it determines whether the time information included in the information is an abnormal value or not, and does not use the time information determined to be an abnormal value. For example, if the internal clock of the HTTP server that is the source of the information is broken, the HTTP server may use a default value (for example, 00:00:00 on January 1, 1970, which is the start time of UNIX (registered trademark) time) as the transmission time of the information. If the time indicated by the time information included in the received information indicates the default value, the time recorder 2 determines that the time is an abnormal value and does not use it.

[0184] Also, there are cases where the time kept by the internal clock of the HTTP server is significantly different from the correct time. In order to determine that the time indicated by the time information included in the HTTP header of the information sent from such an HTTP server is an abnormal value, the time recorder 2 compares the current time kept by the internal clock 25 with the sending time indicated by the time information included in the information received from the HTTP server, and if the time difference between them is equal to or greater than a predetermined threshold, it determines that the time indicated by the time information included in the information received from the HTTP server is an abnormal value and does not use it.

[0185] The method by which the time recorder 2 judges whether the time indicated by the time information included in the information received from the HTTP server is an abnormal value is not limited to the above. For example, when the time recorder 2 receives information from the HTTP server, it stores time difference information indicating the time difference between the time indicated by the time information included in the received information plus a predetermined time and the time measured by the internal clock 25 at that time. This predetermined time is, for example, a time that is preset as an average time required from the time when the HTTP server acquires the transmission time when transmitting information until the information transmitted from the HTTP server is received by the time recorder 2. The time recorder 2 stores the above time difference information for each piece of information received from various HTTP servers, and judges, for example, every time a predetermined time has passed or every time a predetermined number of pieces of time difference information are stored, a time difference indicating, for example, a value outside a predetermined confidence interval among the time differences indicated by the stored time difference information to be an abnormal value.

[0186] The time recorder 2 excludes the abnormal values ​​determined as described above, and identifies a likely time difference from among the time differences determined not to be abnormal. As a method for identifying a likely time difference, for example, if there are two or more time differences of the same value, it can be considered to identify the time difference as a likely time difference. As a method for identifying a likely time difference, it can be considered to calculate a statistical value of the time differences determined not to be abnormal. Examples of statistical values ​​calculated by the time recorder 2 include an average value, a median value, and a mode value. The time recorder 2 calibrates the time measured by the internal clock 25 using the identified likely time difference.

[0187] According to this modification, even if there is variation in the time indicated by the time information that the time recorder 2 acquires from each of a plurality of HTTP servers, the time recorder 2 can calibrate the time kept by the internal clock 25.

[0188] [Third embodiment] 16 is a diagram showing the overall configuration of a system 908 according to an embodiment of the present invention. The system 908 includes a drive recorder 1 mounted on a vehicle, and a tablet PC 8 carried by a passenger (including the driver) of the vehicle.

[0189] The drive recorder 1 included in the system 908 has the same configuration as the drive recorder 1 included in the system 901. However, the drive recorder 1 included in the system 908 has a function of decoding a barcode (for example, a two-dimensional barcode such as a QR code) included in an image captured by the CCD camera 16.

[0190] The tablet PC 8 included in the system 908 has the same configuration as the tablet PC 8 included in the system 904. However, the tablet PC 8 included in the system 908 has a function of displaying a two-dimensional barcode indicating the current time measured by the internal clock of the device on the touch screen by executing a program (hereinafter referred to as a "time code display application") prepared for the system 908. The tablet PC 8 running the time code display application updates and displays a two-dimensional barcode indicating the current time, for example, in units of seconds, on the touch screen every second.

[0191] When the vehicle is turned on and the drive recorder 1 is operating with power supplied from the vehicle's battery, the vehicle occupant holds the touch screen of the tablet PC 8 running a time code display application over the shooting direction of the CCD camera 16 of the drive recorder 1. The drive recorder 1 determines, for example, every second, whether or not a two-dimensional barcode is included in a still image captured by the CCD camera 16, and if it determines that a two-dimensional barcode is included, it decodes the two-dimensional barcode and obtains time information.

[0192] The drive recorder 1 calibrates the time kept by the internal clock 103 using the time information acquired as described above, and specifies the calibrated time as the current time. When the drive recorder 1 completes the process of calibrating the time kept by the internal clock 103 using the time information acquired from the two-dimensional barcode, it issues a voice message such as "Time adjustment is complete" through the speaker 104. Upon hearing this voice message, the vehicle occupant stops holding the tablet PC 8 in the shooting direction of the CCD camera 16.

[0193] In addition, in order to avoid unnecessarily repeating the process of calibrating the time measured by the internal clock 103 while the tablet PC 8 is held in the direction of the CCD camera 16, when the drive recorder 1 acquires time information from the two-dimensional barcode, it does not thereafter determine whether or not a two-dimensional barcode is included in the still image captured by the CCD camera 16 for a predetermined period of time (e.g., five minutes).

[0194] In the system 908, the still images used by the drive recorder 1 to obtain time information are still images originally captured to record the situation while the vehicle is traveling. Therefore, according to the system 908, the vehicle occupant does not need to perform an operation to switch from the normal mode to the time adjustment mode, for example, and can have the drive recorder 1 calibrate the time of the internal clock 103 simply by holding the tablet PC 8 running a time code display application over the CCD camera 16.

[0195] In the system 908, the tablet PC 8 displays the time information by a two-dimensional barcode. A two-dimensional barcode is an example of a display format of information that can be recognized by a device with higher accuracy than a human can recognize. Therefore, compared with a case where the tablet PC 8 displays the time information by a numerical value or the like, the drive recorder 1 can recognize the time information with higher accuracy.

[0196] Furthermore, it is more preferable that the tablet PC 8 displays a two-dimensional barcode indicating the time information accompanied by information for error detection and correction. For example, the information indicated by the QR code includes information for error detection and correction. Therefore, the tablet PC 8 may display the time information by the QR code. In this case, when the drive recorder 1 decodes the QR code included in the captured still image, the drive recorder 1 checks whether there is an error such as a missing part in the time information indicated by the QR code using the information for error detection and correction included in the QR code, and if there is an error such as a missing part, corrects the error in the time information using the information for error detection and correction included in the QR code, and uses the time indicated by the corrected time information to calibrate the time measured by the internal clock 103.

[0197] (Modification of the third embodiment) (3-1) In the above-mentioned system 908, the time indicated by the time information acquired by the drive recorder 1 by decoding the two-dimensional barcode is a time earlier than the current time at the time of acquisition. This is because the drive recorder 1 provided in the above-mentioned system 908 does not take into consideration the time required for the tablet PC 8 to generate a two-dimensional barcode indicating the time and start displaying it on the touch screen after the tablet PC 8 measures the time using its internal clock, and the time required for the drive recorder 1 to photograph the two-dimensional barcode using the CCD camera 16 after the two-dimensional barcode is displayed on the touch screen of the tablet PC 8 and complete decoding of the two-dimensional barcode included in the photographed image. In addition, the timing at which the time measured in seconds by the tablet PC 8 using its internal clock changes does not necessarily coincide with the timing at which the drive recorder 1 determines whether or not a two-dimensional barcode is included in a still image photographed by the CCD camera 16. Therefore, there is a maximum lag of one second between these timings. Therefore, if the time indicated by the time information obtained by the drive recorder 1 by decoding the two-dimensional barcode is regarded as the current time at that point in time and the time measured by the internal clock 103 is calibrated, the calibrated time will be slightly off from the correct current time.

[0198] In order to alleviate the above inconvenience, the drive recorder 1 may perform the following process. In the following description, it is assumed, as an example, that the CCD camera 16 captures images every 1 / 30 seconds.

[0199] First, the drive recorder 1 judges whether or not a two-dimensional barcode is included in a still image captured by the CCD camera 16 every 1 / 30 seconds. If the drive recorder 1 judges that a two-dimensional barcode is included in a still image, the drive recorder 1 decodes the two-dimensional barcode to obtain time information, and temporarily stores the obtained time information. In this modification, even after obtaining time information from the two-dimensional barcode once, the drive recorder 1 repeatedly judges whether or not each of the subsequent still images includes a two-dimensional barcode, decodes the two-dimensional barcode included in the still image, and stores the time information obtained by decoding.

[0200] When the drive recorder 1 acquires new time information, it compares the time information acquired last and stored with the newly acquired time information, and if they are different, it specifies the time obtained by adding a predetermined time to the time indicated by the newly acquired time information as the current time, and uses the specified current time to calibrate the time measured by the internal clock 103. Here, the predetermined time is the sum of the time required for the tablet PC 8 to generate a two-dimensional barcode indicating the time after the tablet PC 8 measures the time using its internal clock and start displaying it on the touch screen (hereinafter referred to as "the time required to display the two-dimensional barcode"), and the time required for the drive recorder 1 to photograph the two-dimensional barcode using the CCD camera 16 and complete decoding of the two-dimensional barcode included in the photographed image after the two-dimensional barcode is displayed on the touch screen of the tablet PC 8 (hereinafter referred to as "the time required to read the two-dimensional barcode"), and is a time that is specified in advance by performing measurements using a tablet PC with a general processing speed.

[0201] In addition, when considering the processing speed that differs for each tablet PC, for example, the tablet PC 8 may display a two-dimensional barcode indicating the time measured by the internal clock plus the time required to display the two-dimensional barcode (the time reflecting the processing speed of the tablet PC 8) instead of displaying a two-dimensional barcode indicating the time itself measured by the internal clock. In this case, the drive recorder 1 specifies, at the timing when the time information acquired from the two-dimensional barcode changes, the time obtained by adding the time required to read the two-dimensional barcode to the time indicated by the changed time information, as the current time. The drive recorder 1 calibrates the time measured by the internal clock 103 using the current time specified in this way. In this case, the drive recorder 1 can calibrate the time measured by the internal clock 103 with an accuracy higher than one second.

[0202] (3-2) In the above-described system 908, the drive recorder 1 recognizes a two-dimensional barcode from a still image captured by the CCD camera 16. Alternatively, the drive recorder 1 may recognize a clock from a still image captured by the CCD camera 16 and identify the time indicated by the recognized clock.

[0203] 17 is a diagram showing the overall configuration of a system 909 according to one example of this modification. The system 909 includes a drive recorder 1 mounted on a vehicle. The drive recorder 1 included in the system 909 is different from the drive recorder 1 included in the system 908 in that the drive recorder 1 recognizes a clock (either an analog clock or a digital clock) instead of a two-dimensional barcode from a still image captured by a CCD camera 16.

[0204] When a vehicle occupant holds a watch 74, for example, worn on the driver's wrist, in the direction of the CCD camera 16 of the operating drive recorder 1, the drive recorder 1 recognizes the watch 74 from a still image captured by the CCD camera 16, and identifies the time indicated by the watch 74 based on the position of the hands of the watch 74 if the recognized watch 74 is an analog watch, or based on the numerical value of the watch 74 if the recognized watch 74 is a digital watch. The drive recorder 1 calibrates the time kept by the internal clock 103 using the time information indicating the identified time.

[0205] When the drive recorder 1 recognizes an analog clock without a dial, it may recognize, for example, the arm on which the analog clock is worn and the thumb of the hand connected to the arm from a still image in order to specify the orientation of the analog clock. In this case, the drive recorder 1 specifies the direction perpendicular to the direction in which the arm is extended, toward the little finger, as the 12 o'clock direction of the analog clock. The drive recorder 1 may also recognize the band of the analog clock instead of the arm, and specify the direction in which the band extends, toward the little finger, as the 12 o'clock direction of the analog clock.

[0206] According to the system 909 , a vehicle occupant can have the drive recorder 1 calibrate the time kept by the internal clock 103 by holding the watch over the CCD camera 16 of the drive recorder 1 .

[0207] In the system 909, the drive recorder 1 may constantly monitor whether or not a clock is included in the image captured by the CCD camera 16 during operation, but may also issue a notification such as "Please hold up your watch" immediately after the power is turned on and the drive recorder 1 is started up, or after the user performs an operation to adjust the time on the drive recorder 1, and monitor whether or not a clock is included in the image captured by the CCD camera 16 only for a predetermined period of time thereafter. Also, after the previous time adjustment, it may monitor whether or not a clock is included in the image captured by the CCD camera 16 only for a predetermined period of time from the point in time when a predetermined time has elapsed.

[0208] Furthermore, in the system 909, when the drive recorder 1 calibrates the time kept by the internal clock 103, a notification may be issued to the user urging the user to make a confirmation such as pressing a predetermined button.

[0209] In the above-mentioned system 909, the drive recorder 1 identifies the time from an image of the wristwatch of the vehicle occupant captured by the CCD camera 16, but the clock captured by the CCD camera 16 is not limited to the wristwatch of the vehicle occupant. For example, if the instrument panel of the vehicle is included in the capturing range of the CCD camera 16, the drive recorder 1 may identify the time indicated by the clock included in the instrument panel from the image captured by the CCD camera 16.

[0210] Also, the accuracy of the time on the clock 74 worn by the vehicle passenger may not be high. Therefore, instead of the drive recorder 1 calibrating the time kept by the internal clock 103 based on the time shown in the image of the clock 74 captured by the CCD camera 16, for example, when there is a discrepancy of a predetermined threshold or more between the time kept by the internal clock 103 and the time identified from the image of the clock 74, the drive recorder 1 may notify the user of the need to adjust the time, for example, by saying "The time setting is significantly off. Please adjust the time."

[0211] (3-3) In the above-mentioned systems 908 and 909, the type of device that acquires time information from a still image captured by a camera is a drive recorder, but the type of device is not limited to a drive recorder. Fig. 18 is a diagram showing the overall configuration of a system 910 according to one example of this modification. The system 910 includes a time recorder 2 and a surveillance camera 75. The time recorder 2 and the surveillance camera 75 are arranged indoors, for example, in a factory. The configuration of the time recorder 2 included in the system 910 is similar to the configuration of the time recorder 2 included in the system 901. The surveillance camera 75 differs from the surveillance camera 5 included in the system 902 in that it includes a semi-spherical camera, but otherwise has the same configuration as the surveillance camera 5.

[0212] The surveillance camera 75 is installed, for example, on the ceiling of a factory, and simultaneously captures an area covering the space from the ceiling down in all directions. The time recorder 2 is positioned so that the display unit 21 can be seen from the position of the surveillance camera 75. Therefore, the still image captured by the surveillance camera 75 includes the numerical value indicating the time displayed on the time recorder 2.

[0213] The surveillance camera 75 recognizes the time displayed on the time recorder 2 from the captured still image, for example, every time a predetermined period of time (e.g., 30 minutes) has elapsed, and uses the recognized time to calibrate the time kept by the internal clock of the surveillance camera 75.

[0214] According to the system 910, the current time kept by the internal clock of the surveillance camera 75 and the current time kept by the internal clock 25 of the time recorder 2 are substantially the same. Therefore, there is no inconsistency caused by the difference between the times kept by the internal clocks of the surveillance camera 75 and the time used to generate attendance information by the time recorder 2, between the shooting time indicated by the time information included in the video information generated and stored by the surveillance camera 75.

[0215] If the shooting range of the surveillance camera 75 and the position of the time recorder 2 do not change, the position of the area in which the time recorder 2 displays the time in the image captured by the surveillance camera 75 does not change. Therefore, for example, the user may specify the area of ​​the clock in the image captured by the surveillance camera 75 by encircling it, and the surveillance camera 75 may recognize the clock from the area specified by the user. In this case, for example, the user may connect a terminal device such as a laptop computer to the surveillance camera 75 and use a mouse or the like to specify the area of ​​the clock in the image captured by the surveillance camera 75 and displayed on the terminal device.

[0216] Furthermore, if the time display on the time recorder 2 is an analog clock-style display, the user may specify a reference direction, such as the 12 o'clock direction, on the image displayed on the terminal device.

[0217] (3-4) In the above-described system 909, the drive recorder 1 identifies a clock held up by a vehicle occupant from a still image captured by the CCD camera 16. Alternatively, the drive recorder 1 may identify a clock placed outside the vehicle from a still image captured by the CCD camera 16, and use the time indicated by the identified clock to calibrate the time kept by the internal clock 103.

[0218] 19 is a diagram showing the overall configuration of a system 911 according to one example of this modified example. The system 911 includes a drive recorder 1 and a car navigation system 6 mounted on a vehicle. The car navigation system 6 included in the system 911 wirelessly transmits to the drive recorder 1, for example, via a communication protocol such as Bluetooth, vehicle position information indicating the position (e.g., latitude and longitude) of the vehicle measured by the car navigation system 6 itself, and driving direction information indicating the driving direction of the vehicle identified by a change over time in the position indicated by the vehicle position information.

[0219] The drive recorder 1 stores a clock position table that stores clock position information indicating the position (e.g., latitude and longitude) of each of various clocks placed in positions visible from the road outdoors. The drive recorder 1 extracts a position that falls within the angle of view of the CCD camera 16 from among the clock positions indicated by any of the clock position information stored in the clock position table, based on vehicle position information and driving direction information continuously received from the car navigation system 6, for example, every time a predetermined time period (e.g., every 10 seconds) has elapsed. Hereinafter, a period during which one or more clock positions falling within the angle of view of the CCD camera 16 are extracted from the clock positions indicated by the clock position information stored in the clock position table is referred to as a "clock capture period." The drive recorder 1 stores the start time and end time of the clock capture period.

[0220] When the drive recorder 1 stores the end time of a certain clock photographing period, it attempts to recognize a clock from each of the still images photographed by the CCD camera 16 during the clock photographing period, identifies the recognized clock, selects the image with the clearest image from among those judged to be the same clock, and specifies the time indicated by the clock shown in the selected image.

[0221] If the clock shown in the image is a digital clock, the drive recorder 1 identifies the time by OCR. If the clock shown in the image is an analog clock, the drive recorder 1 identifies, for example, the direction of the up and down lines of the building shown in the image as the vertical direction, and identifies the time based on the positions of the hour and minute hands with the identified vertical direction being the 12 o'clock-6 o'clock direction. The drive recorder 1 stores time difference information indicating the time difference between the identified time and the time the image was captured (time measured by the internal clock 103).

[0222] While the vehicle is traveling, the drive recorder 1 stores the above-mentioned time difference information for each of the multiple clocks placed near the vehicle's travel route. When the number of stored time difference information reaches a predetermined number, the drive recorder 1 selects, from among the time differences indicated by the stored time difference information, those within a confidence interval of 95%, for example, and calculates a statistical value (for example, an average value, etc.) of the selected time difference.

[0223] The drive recorder 1 calibrates the time kept by the internal clock 103 using the statistical value of the time difference calculated as described above.

[0224] According to the system 911, a vehicle occupant can cause the drive recorder 1 to calibrate the time kept by the internal clock 103 by driving the vehicle without performing any operation on the drive recorder 1.

[0225] In the above system 911, the drive recorder 1 recognizes the clock from the image and identifies the time when the drive recorder 1 approaches the position indicated by the clock position information. Alternatively, the drive recorder 1 may constantly recognize the clock from the image and identify the time during a period when the vehicle's traveling speed is slower than a predetermined threshold, for example.

[0226] (3-5) In the above-described system 908, the tablet PC 8 displays a two-dimensional barcode, and the drive recorder 1 acquires time information by reading and decoding the two-dimensional barcode displayed by the tablet PC 8. Alternatively, the tablet PC 8 may display colors that change according to a visible light communication standard on a touch screen, and the drive recorder 1 may capture an image of the touch screen of the tablet PC 8 with the CCD camera 16, and acquire time information indicated by the change in color shown in the captured image.

[0227] Fig. 20 is a diagram showing the overall configuration of a system 912 according to one example of this modified example. The system 912 includes a drive recorder 1 mounted on a vehicle, and a tablet PC 8 carried by a passenger (including the driver) of the vehicle. In the system 912, the tablet PC 8 has a function of displaying visible light (color) that changes over time and indicates the current time measured by its own internal clock on the touch screen by executing a program (hereinafter referred to as a "time color display application") prepared for the system 912. The tablet PC 8, while executing the time color display application, displays a changing color on the touch screen as a background color, which indicates, for example, the current time in minutes in accordance with the visible light communication standard.

[0228] 21 is a diagram for explaining a mechanism for transmitting time information by changing the color displayed as the background color on the touch screen by the tablet PC 8 in the system 912. For example, in the visible light communication standard used in the system 912, purple (e.g., electromagnetic waves with a wavelength in the range of 380-450 nm) indicates a series of color divisions (stop bits) indicating one piece of information, red (e.g., electromagnetic waves with a wavelength in the range of 620-750 nm) indicates binary "0," and green (e.g., electromagnetic waves with a wavelength in the range of 495-570 nm) indicates binary "1." The tablet PC 8 displays an image of background colors that change, for example, from purple → red → green → red → red → green →... in a cycle of 1 / 30 seconds on the touch screen.

[0229] The drive recorder 1 attempts to recognize the image of the tablet PC 8 from the captured still image every time it captures an image with the CCD camera 16. If the drive recorder 1 succeeds in recognizing the image of the tablet PC 8 from the still image captured by the CCD camera 16, it then identifies the background color contained in the recognized image of the tablet PC 8. For example, if the ratio of the area of ​​a uniform color area to the area of ​​the entire touch screen in the recognized image of the tablet PC 8 is equal to or greater than a predetermined value (e.g., 70%), the drive recorder 1 identifies that color as the background color.

[0230] The drive recorder 1 stores color information indicating the background color identified as above. When the drive recorder 1 first recognizes purple as the background color and then recognizes purple again, it identifies time information indicated by the bit string indicated by the color information stored during that time. The drive recorder 1 calibrates the time kept by the internal clock 103 using the time information thus identified, and identifies the calibrated time as the current time. When the drive recorder 1 completes the process of calibrating the time kept by the internal clock 103, it issues a voice message such as "Time adjustment has been completed" through the speaker 104. The vehicle occupant hears this voice message and stops holding the tablet PC 8 in the shooting direction of the CCD camera 16.

[0231] According to the system 912, a vehicle occupant can calibrate the time measured by the internal clock 103 of the drive recorder 1 by holding a tablet PC 8 running a time color display app over the CCD camera 16 of the drive recorder 1 without performing any operation on the drive recorder 1.

[0232] (3-6) In the above-described system 912, the drive recorder 1 captures visible light displayed on the touch screen of the tablet PC 8 and obtains time information indicated by the color of the captured visible light. The drive recorder 1 may capture infrared light emitted from an infrared remote control instead of the light displayed on the touch screen of the tablet PC 8 and obtain time information indicated by the captured infrared light.

[0233] 22 is a diagram showing the overall configuration of a system 913 according to one example of this modified example. The system 913 includes a drive recorder 1 mounted on a vehicle, and an infrared remote control 76 operated by a passenger (including the driver) of the vehicle. The infrared remote control 76 has a plurality of buttons that accept user operations, and when the user presses any of the buttons, an infrared signal indicating a numerical value or the like corresponding to the pressed button is emitted from a light-emitting unit. As a method of indicating a numerical value or the like by infrared rays, for example, a method of indicating a bit value by a combination of the length of an infrared transmission time and a non-transmission time can be given.

[0234] Each time the drive recorder 1 captures an image using the CCD camera 16, it determines whether or not infrared light is captured in the captured still image, and if so, stores the capture time of the still image. When a vehicle occupant aims the light-emitting part of the infrared remote control 76 at the CCD camera 16 of the drive recorder 1, presses buttons corresponding to the numerical values ​​indicating the current time (for example, "13:15:30" for "13:15:30") in sequence, and then presses the "OK" button, the drive recorder 1 stores all capture times within the period during which infrared light was emitted from the infrared remote control 76 (infrared light transmission period). Based on the infrared light transmission period indicated by the stored capture time and the length of the period between these transmission periods (infrared light non-transmission period), the drive recorder 1 identifies the bit string indicated by the signal emitted from the infrared remote control 76, and identifies the time indicated by the identified bit string.

[0235] When the drive recorder 1 specifies the time as described above, it uses the specified time to calibrate the time measured by the internal clock 103. When the drive recorder 1 completes the process of calibrating the time measured by the internal clock 103, it issues a voice message through the speaker 104, such as "Time adjustment has been completed."

[0236] According to the system 913, a vehicle occupant can have the drive recorder 1 calibrate the time kept by the internal clock 103 by inputting the time into the infrared remote control 76 while pointing the infrared remote control 76 at the drive recorder 1.

[0237] (3-7) In the above-mentioned system 908, the tablet PC 8 displays an image indicating the current time, and the drive recorder 1 captures the image and identifies the current time indicated by the captured image. Alternatively, the tablet PC 8 may emit a sound indicating the current time, and the drive recorder 1 may pick up the sound and identify the current time indicated by the picked up sound.

[0238] 23 is a diagram showing an overall configuration of a system 914 according to one example of this modification. The system 914 includes a drive recorder 1 mounted on a vehicle and a tablet PC 8 carried by a passenger (including the driver) of the vehicle. In the system 914, the tablet PC 8 includes a speaker and has a function of emitting a sound indicating the current time measured by the internal clock of the device from the speaker by executing a program (hereinafter referred to as a "time sound transmission application") prepared for the system 914. Examples of a method for indicating the current time by sound include DTMF (Dual-Tone Multi-Frequency), amplitude modulation, frequency modulation, phase modulation, and combinations thereof.

[0239] The drive recorder 1 continuously determines whether the sound picked up by the microphone 106 includes a sound indicating the current time (e.g., a modulated sound), and if so, identifies the current time indicated by the sound. When a vehicle occupant causes the tablet PC 8 to execute a time sound transmission application inside the vehicle, the tablet PC 8 emits a sound indicating the current time, and the drive recorder 1 identifies the current time indicated by the sound.

[0240] When the drive recorder 1 identifies the current time as described above, it uses the identified current time to calibrate the time measured by the internal clock 103. When the drive recorder 1 completes the process of calibrating the time measured by the internal clock 103, it issues a voice message through the speaker 104, such as "Time adjustment has been completed."

[0241] According to the system 914, a vehicle occupant can cause the tablet PC 8 inside the vehicle to execute a time sound transmission application, thereby causing the drive recorder 1 to calibrate the time kept by the internal clock 103.

[0242] (3-8) In the above-described system 914, the drive recorder 1 acquires time information from a sound emitted by the tablet PC 8. Alternatively, the drive recorder 1 may acquire time information from a voice emitted by a passenger (including the driver) of the vehicle.

[0243] 24 is a diagram showing an overall configuration of a system 915 according to one example of this modification. The system 915 includes a drive recorder 1 mounted on a vehicle.

[0244] The drive recorder 1 continuously performs a process of recognizing voice from the sound picked up by the microphone 106. Then, when the drive recorder 1 recognizes a predetermined word (e.g., "What time is it now?") from the sound picked up by the microphone 106, it issues a voice message (e.g., "It is xx:xx minutes" etc.) notifying the current time measured by the internal clock 103 from the speaker 104. The vehicle occupant compares the current time notified by this voice message with, for example, the current time indicated by a watch carried by the vehicle occupant, and if the two do not substantially match, it issues a voice notifying the current time indicated by the watch carried by the vehicle occupant (e.g., "It is xx:xx minutes" etc.).

[0245] The drive recorder 1 recognizes the voice spoken by the vehicle occupant and acquires time information contained in the recognized voice. The drive recorder 1 calibrates the time measured by the internal clock 103 using the time information acquired from the voice. When the drive recorder 1 completes the process of calibrating the time measured by the internal clock 103, it issues a voice message from the speaker 104, such as "The time has been adjusted. The current time is XX:XX." The vehicle occupant confirms from this voice message that the time measured by the drive recorder 1 has been correctly calibrated.

[0246] According to the system 915, a vehicle occupant can have the drive recorder 1 calibrate the time kept by the internal clock 103 by interacting with the drive recorder 1.

[0247] [Fourth embodiment] FIG. 25 is a diagram showing the overall configuration of a system 916 according to an embodiment of the present invention. The internal clock 103 of the drive recorder 1 includes an oscillator 1031 (for example, a crystal oscillator such as a temperature compensated crystal oscillator (TCXO)) that periodically emits a signal, and a clock unit 1032 that counts the number of signals emitted by the oscillator 1031 after a reference time to measure the current time. The period at which the oscillator 1031 emits a signal is determined by the oscillation frequency of the oscillator of the oscillator 1031, but the oscillation frequency may deviate from the design value due to an error during processing of the oscillator. When the oscillation frequency of the oscillator deviates from the design value, the time measured by the internal clock 103 deviates from the correct time over time. The system 916 uses a pulse signal called a 1PPS (Pulse Per Second) signal output by a GNSS unit to solve the above-mentioned problems.

[0248] The system 916 includes a GNSS unit 77, a correction multiplier calculation device 78, and a drive recorder 1. The GNSS unit 77, the correction multiplier calculation device 78, and the drive recorder 1 shown in Fig. 25 are arranged in a factory where the drive recorder 1 is manufactured. The drive recorder 1 included in the system 916 includes a non-volatile memory 110 in addition to the same configuration as the drive recorder 1 included in the system 901.

[0249] The GNSS unit 77 is a device that receives information transmitted from the artificial satellite 7 and measures its own position (e.g., latitude and longitude). The information that the GNSS unit 77 receives from the artificial satellite 7 includes time information that the GNSS unit 77 uses to measure its own position. This time information is time information generated by an atomic clock mounted on the artificial satellite 7, and is more accurate than the time information indicating the time kept by the internal clock 103. The GNSS unit 77 has a 1PPS signal output unit 771 that outputs a 1PPS signal every second based on the time information received from the artificial satellite 7.

[0250] The correction multiplier calculation device 78 has an operator 781, a correction multiplier calculation unit 782, and a correction multiplier output unit 783. The operator 781 is an operation button or the like that accepts an operation by an operator to the correction multiplier calculation device 78. The correction multiplier calculation unit 782 receives a 1PPS signal every second from the 1PPS signal output unit 771 of the GNSS unit 77, triggered by a predetermined operation being performed on the operator 781, and receives a signal at a constant cycle (an example of a predetermined cycle) from the oscillator 1031 of the internal clock 103 of the drive recorder 1, and counts the number of signals received from the oscillator 1031 in a predetermined time T (for example, one minute, etc.) specified by the reception timing of the 1PPS signal. Hereinafter, the number of signals counted by the correction multiplier calculation device 78 will be referred to as the number of measured signals Cm.

[0251] The correction multiplier calculation unit 782 calculates the number of signals (hereinafter, this number is called the design signal number Cd) output in a predetermined time T (for example, one minute) when the oscillator 1031 outputs signals at a designed period (an example of a reference period) divided by the measured signal number Cm as a correction multiplier M (an example of information indicating the difference between the predetermined period and the reference period). That is, M=Cd / Cm.

[0252] The correction multiplier output unit 783 outputs the correction multiplier M calculated by the correction multiplier calculation unit 782 to the drive recorder 1. The drive recorder 1 stores the correction multiplier M received from the correction multiplier output unit 783 of the correction multiplier calculation device 78 in the non-volatile memory 110.

[0253] As described above, when the drive recorder 1 is shipped and installed in a vehicle for use, the correction multiplier M stored in the nonvolatile memory 110 is used when the timer unit 1032 measures the current time based on the signal received from the oscillator 1031. Fig. 26 is a diagram showing a state in which the drive recorder 1 provided in the system 916 is installed in a vehicle for use.

[0254] After the reference time, the timer unit 1032 continuously counts the number of signals received from the oscillator 1031. Hereinafter, the number of signals currently counted by the timer unit 1032 is referred to as the measured signal number Dm. The timer unit 1032 calculates the elapsed time P (seconds) from the reference time to the present time according to the following formula, where F is the design value of the oscillation frequency (Hz) of the resonator of the oscillator 1031. P = (Dm × M) / F

[0255] For example, if the design value F of the oscillation frequency of the resonator of the oscillator 1031 is 32.768 kHz, and the predetermined time T is one minute, then the design signal number Cd is 1,966,080. For example, if the measurement signal number Cm is 1,966,078, then the oscillation frequency of this resonator is lower than the design value (the period in which the signal is output is long). In this case, the correction multiplier M is 1,966,080 / 1,966,078.

[0256] If the actual oscillation frequency of the resonator of oscillator 1031 coincides with design value F, the elapsed time P from the reference time is Dm / F. However, in the above example, the elapsed time calculated by Dm / F is shorter than the actual elapsed time P. Therefore, in this case, the current time kept by internal clock 103 lags behind the actual current time as time passes. If a value obtained by multiplying the number of measurement signals Dm by a correction multiplier M (in this case, M>1) is used instead of the number of measurement signals Dm, no difference occurs between the current time kept by internal clock 103 and the actual current time.

[0257] According to system 916, even if the period during which oscillator 1031 of internal clock 103 outputs a signal does not match the designed value due to an error during processing of the vibrator or the like, the current time kept by internal clock 103 will not deviate from the actual current time due to this.

[0258] (Modification of the fourth embodiment) (4-1) The period at which the oscillator of the internal clock emits a signal may change depending on external environmental parameters (physical quantities). For example, if the oscillator of the internal clock is a quartz oscillator that uses a quartz crystal as an oscillator, the period at which the oscillator emits a signal is affected by temperature. In the above-mentioned system 916, the influence of these environmental parameters on the current time kept by the internal clock 103 is not taken into account, but the influence of these environmental parameters may be taken into account.

[0259] 27 is a diagram showing the configuration of a system 917 according to one example of this modification. The drive recorder 1 included in the system 917 includes a thermometer 1000 (an example of a measuring means) in addition to the components included in the drive recorder 1 included in the system 916.

[0260] The correction multiplier calculation unit 782 of the correction multiplier calculation device 78 included in the system 917 calculates a correction multiplier M when a predetermined operation is performed on the operation button 781, and receives temperature information indicating the temperature measured by the thermometer 1000 from the drive recorder 1, and passes the received temperature information together with the calculated correction multiplier M to the correction multiplier output unit 783. The correction multiplier output unit 783 outputs the correction multiplier M and the temperature information received from the correction multiplier calculation unit 782 to the drive recorder 1. The drive recorder 1 stores the correction multiplier M and the temperature information received from the correction multiplier calculation device 78 in the non-volatile memory 110 in association with each other.

[0261] For example, an operator places the drive recorder 1 in a container equipped with a heater and a cooler in a factory, changes the temperature around the drive recorder 1, for example, by 1 degree at a time within a range that can be changed in the environment in which the drive recorder 1 is placed during use, and performs a predetermined operation on the operator 781 to cause the correction multiplier calculation device 78 to calculate the correction multiplier M at that temperature. The correction multiplier M calculated by the correction multiplier calculation device 78 is stored in the non-volatile memory 110 in association with temperature information indicating the temperature of the environment in which the drive recorder 1 was placed at the time of calculation.

[0262] When the drive recorder 1 is used, the timer 1032 of the internal clock 103 receives temperature information indicating the temperature at that time from the thermometer 1000, for example, every time a predetermined time (for example, 10 seconds) has elapsed, reads the correction multiplier M stored in association with the received temperature information from the nonvolatile memory 110, and uses the read correction multiplier M to time the current time. Fig. 28 is a diagram showing how the timer 1032 receives temperature information from the thermometer 1000, reads the correction multiplier M from the nonvolatile memory 110, and receives a signal from the oscillator 1031 when the drive recorder 1 provided in the system 917 is used.

[0263] In the above explanation, an example was given in which temperature is used as an external environmental parameter (physical quantity) that affects the period at which oscillator 1031 emits a signal, but other types of physical quantities may be used in addition to or instead of temperature.

[0264] According to the system 917, even if the period at which the oscillator 1031 of the internal clock 103 emits a signal changes depending on an external environmental parameter (physical quantity), the deviation of the current time measured by the internal clock 103 from the actual current time caused by the change in the environmental parameter is reduced.

[0265] (4-2) In the above-described systems 916 and 917, the correction multiplier M is calculated at a factory before the drive recorder 1 is shipped. Alternatively, the correction multiplier M may be calculated during the use of the drive recorder 1 mounted on the vehicle.

[0266] 29 is a diagram showing a configuration of a system 918 according to one example of this modification. The system 918 includes a car navigation system 6 and a drive recorder 1 mounted on a vehicle. The car navigation system 6 included in the system 918 includes a GNSS unit 77 having a 1PPS signal output unit 771. The drive recorder 1 included in the system 918 includes a correction multiplier calculation unit 782 that is included in the correction multiplier calculation device 78 in the system 917.

[0267] In the system 918, immediately after starting operation, the drive recorder 1 calculates the correction multiplier M by the correction multiplier calculation unit 782 and stores the calculated correction multiplier M in the nonvolatile memory 110. Thereafter, during operation, the drive recorder 1 calculates a new correction multiplier M by the correction multiplier calculation unit 782, for example, every time a predetermined time (for example, 10 minutes) has elapsed, and overwrites the correction multiplier M stored in the nonvolatile memory 110 with the newly calculated correction multiplier M. Every time the correction multiplier M stored in the nonvolatile memory 110 is updated, the internal clock 103 reads the updated correction multiplier M from the nonvolatile memory 110 and uses it to measure the current time.

[0268] According to the system 918, even if the period at which the oscillator 1031 in the internal clock 103 emits a signal deviates from the design value, the deviation of the current time kept by the internal clock 103 from the actual current time, which is caused by the deviation, is reduced.

[0269] (4-3) In the above-described systems 916 and 917, a 1PPS signal is used to correct the internal clock 103. Instead of the 1PPS signal, other types of signals output at predetermined time intervals may be used. For example, when the car navigation system 6 and the drive recorder 1 are equipped with a module called USART (Enhanced Universal Synchronous Asynchronous Receiver Transmitter) or UART (Universal Asynchronous Receiver Transmitter) and transmit and receive data via a wired connection, a signal called Start Bit is transmitted and received at a predetermined time interval. The drive recorder 1 may calculate the correction multiplier M by counting the Start Bit transmitted from the car navigation system 6.

[0270] [Fifth embodiment] 30 is a diagram showing the overall configuration of a system 919 according to an embodiment of the present invention. The system 919 includes a car navigation system 6 mounted on a vehicle, one drive recorder 1A, and one or more drive recorders 1B. The car navigation system 6 has a configuration similar to that of the car navigation system 6 included in the system 903. The drive recorders 1A and 1B have a configuration similar to that of the drive recorder 1 included in the system 901. The drive recorder 1A communicates with the car navigation system 6 according to a communication protocol such as Bluetooth, and the drive recorder 1B communicates with the drive recorder 1A according to a communication protocol such as Bluetooth.

[0271] Like the drive recorder 1 in the system 903, the drive recorder 1A receives time information from the car navigation system 6 and calibrates the time kept by its own internal clock 103 using the received time information. The drive recorder 1A also transmits time information indicating the time kept by its own internal clock 103 (the time after calibration using the time information received from the car navigation system 6) to the drive recorder 1B. The drive recorder 1B calibrates the time kept by its own internal clock 103 using the time information received from the drive recorder 1A.

[0272] According to the system 919, the drive recorder 1A and the drive recorder 1B keep the correct time without requiring an operation for adjusting the time by the occupant of the vehicle.

[0273] (Modification of the fifth embodiment) In the above-described system 919, time information is transmitted and received between a plurality of drive recorders mounted on the same vehicle. Alternatively, time information may be transmitted and received between a plurality of drive recorders mounted on different vehicles.

[0274] FIG. 31 is a diagram showing a configuration of a system 900 according to an example of this modification. The system 900 includes, for example, a drive recorder 1 (not shown) mounted on each of a plurality of vehicles traveling on a road, and a tablet PC 8 carried by a passenger of any of the vehicles. The tablet PC 8 of the system 900 includes a configuration similar to that of the tablet PC 8 of the system 904. The drive recorder 1 of the system 900 includes a configuration similar to that of the drive recorder 1 of the system 901. Hereinafter, the drive recorders 1 mounted on each of the vehicles a to n shown in FIG. 31 are referred to as drive recorders 1a to 1n. Each of the drive recorders 1a to 1n constructs a mesh network according to, for example, the Bluetooth Mesh standard, which is an extension of BLE (Bluetooth Low Energy).

[0275] For example, when a passenger of vehicle i carrying a tablet PC 8 gets into vehicle i and then the vehicle i is turned on, the drive recorder 1i receives time information from the tablet PC 8 and calibrates the time measured by the internal clock 103 of the drive recorder 1i using the received time information. After that, the drive recorder 1i attempts to establish a communication connection with a drive recorder 1 mounted in any vehicle traveling near the vehicle i until a predetermined time (e.g., 10 minutes) has elapsed.

[0276] When the drive recorder 1i succeeds in establishing a communication connection with any one of the drive recorders 1, it transmits the time information received from the tablet PC 8 (hereinafter referred to as time information X) and the time information indicating the current time measured by the internal clock 103 of its own device (hereinafter referred to as time information Y) to the drive recorder 1 of the other party of the communication connection. The arrows in Fig. 31 indicate that the drive recorder 1i succeeds in establishing a communication connection with each of the drive recorders 1f and 1j and transmits the time information X and the time information Y to those drive recorders 1.

[0277] It is not necessary for the drive recorder 1i to simultaneously establish a communication connection with each of the drive recorder 1f and the drive recorder 1j. For example, the drive recorder 1i establishes a communication connection with the drive recorder 1f, transmits the time information X and the time information Y indicating the current time clocked by the internal clock 103 at that time to the drive recorder 1f, and then releases the communication connection with the drive recorder 1f, and then establishes a communication connection with the drive recorder 1j, transmits the time information X and the time information Y indicating the current time clocked by the internal clock 103 at that time to the drive recorder 1j, and then releases the communication connection with the drive recorder 1j.

[0278] Also, each of the drive recorders 1 may store a drive recorder ID that identifies the drive recorder 1 with which the drive recorder 1 has once established a communication connection and transmitted and received the time information X and the time information Y until a predetermined time (e.g., one hour) has elapsed, and may not establish a communication connection with the drive recorder 1 identified by the stored drive recorder ID. In this way, the drive recorder 1 does not wastefully transmit and receive the time information X and the time information Y to and from the same party repeatedly.

[0279] As described above, the drive recorder 1f and the drive recorder 1j that have received the time information X and the time information Y from the drive recorder 13I calibrate the time measured by the internal clock 103 of the drive recorder 1f and the drive recorder 1j using the received time information Y. Then, the drive recorder 1f attempts to establish a communication connection with the drive recorder 1 mounted on any vehicle traveling near the vehicle f until a predetermined time (e.g., 10 minutes) has elapsed from the time indicated by the time information X, and when the communication connection is successfully established, the drive recorder 1f transmits the time information X received from the drive recorder 1i and the time information Y indicating the current time measured by the internal clock 103 of the drive recorder 1f and the drive recorder 1g to the other drive recorder 1 with which the communication connection is established. The arrows in FIG. 31 indicate that the drive recorder 1f has successfully established a communication connection with the drive recorder 1g and transmitted the time information X and the time information Y to the drive recorder 1g.

[0280] Like the drive recorder 1f, the drive recorder 1j also attempts to establish a communication connection with a drive recorder 1 mounted on any vehicle traveling near the vehicle j until a predetermined time (e.g., 10 minutes) has elapsed from the time indicated by the time information X, and when the communication connection is successfully established, the drive recorder 1j transmits the time information X received from the drive recorder 1i and the time information Y indicating the current time clocked by the internal clock 103 of the drive recorder 1j to the drive recorder 1k of the communication connection partner. The arrows in FIG. 31 indicate that the drive recorder 1j has successfully established a communication connection with the drive recorder 1k and transmitted the time information X and the time information Y to the drive recorder 1k.

[0281] As described above, a drive recorder 1 that receives time information from a nearby drive recorder 1 transmits the time information to another nearby drive recorder 1, thereby calibrating the time kept by the internal clock 103 in multiple drive recorders 1. At that time, passengers of the vehicles in which those drive recorders 1 are installed are not required to perform any operation to adjust the time on the drive recorder 1.

[0282] In the example of FIG. 31, the drive recorder 1h receives time information from both the drive recorder 1g and the drive recorder 1l. In this case, the drive recorder 1h selects one of the time information Y according to a predetermined rule, such as using the later time information Y only when the time indicated by the time information X associated with the later time information Y is newer than the time indicated by the time information X associated with the earlier time information Y, and calibrates the time kept by the internal clock 103 using the selected time information Y.

[0283] [Variations] In the above-described embodiment, the time information for calibrating the time kept by the internal clock 103 of the drive recorder 1 may be generated by a GNSS unit, a time server, a tablet PC, or an image of a clock. Two or more of these may be used. In this case, the type of time information used by the drive recorder 1 to calibrate the internal clock 103 may be recorded, and, for example, when playing back an image, the type of time information used to calibrate the image capture time may be displayed, for example, by an icon, together with the image capture time of the image.

[0284] In addition, the drive recorder 1 may record location information indicating the location where the time information was calibrated, and, for example, when playing back an image, may display the location where the calibration of the shooting time was performed together with the shooting time of the image.

[0285] In addition, it is preferable to write the time information used by the drive recorder 1 to calibrate the internal clock 103, its type, and time information indicating the current time measured by the internal clock 103 (the current time before calibration and the current time after calibration) into the blockchain. In this case, the time information may be written into the blockchain in real time, for example, by LPWA (Low Power Wide Area), or may be written into the blockchain when the data is imported into a PC viewer. In this case, tampering with the time information is prevented. [Explanation of symbols]

[0286] 1...Drive recorder, 2...Time recorder, 3...Time server, 4...Data server, 5...Surveillance camera, 6...Car navigation system, 7...Satellite, 8...Tablet PC, 9...HTTP server, 11...Main body, 12...Mounting bracket, 13...Nut member, 14...Volume dial, 15...DC jack, 16...CCD camera, 17...Memory card, 21...Display unit, 22...Operation button, 23...Reading unit, 24...Printing unit, 25...Internal clock, 26...Interface, 27...Control unit, 71...Groupware server, 72...Terminal device, 73...Relay device, 74...Clock, 75...Surveillance camera, 76...Infrared remote control, 77...GNSS unit, 7 8...correction multiplier calculation device, 101...accident detection sensor, 102...temporary storage memory, 103...internal clock, 104...speaker, 105...switch, 106...microphone, 107...control unit, 108...interface, 109...card slot, 110...non-volatile memory, 111...first case, 112...second case, 121...ring portion, 122...mounting plate, 131...through hole, 771...1PPS signal output portion, 781...operator, 782...correction multiplier calculation portion, 783...correction multiplier output portion, 900~919...system, 1000...thermometer, 1031...oscillator, 1032...timekeeping portion, 1111...one end portion, 1121...one end portion, 1221...mounting surface.

Claims

1. A system comprising a drive recorder installed in the vehicle and an external device for managing the driver's attendance information, The aforementioned drive recorder is When a communication connection is established with the external device, the device has a function to transmit a drive recorder ID that identifies itself to the external device, The external device has a function to receive work status information indicating the driver's current work status and time information indicating the current time. The device has a function to calibrate the time measured by its internal clock using the time information received from the external device, A function to store, in the video information that represents a video, time information indicating the current time after calibration measured by the internal clock and work status information, in the video information. Equipped with, The external device is, Based on the drive recorder ID received from the drive recorder, a vehicle ID is identified to identify the vehicle on which the drive recorder is installed; based on the identified vehicle ID, a driver ID is identified to identify the driver to whom the vehicle is currently assigned; and based on the identified driver ID, the work status information is acquired. A system characterized by the following:

2. The external device refers to a vehicle-drive recorder correspondence table and identifies the vehicle ID that identifies the vehicle on which the drive recorder is installed, as identified by the received drive recorder ID. The system according to claim 1, characterized by the following:

3. The external device refers to the vehicle assignment database and identifies the driver ID that identifies the driver to whom the vehicle identified by the identified vehicle ID is currently assigned. The system according to claim 1 or 2, characterized by the above.

4. The external device reads the latest attendance information of the driver identified by the specified driver ID from the attendance database, and obtains the work status information indicating the driver's current work status as shown by the read attendance information. A system according to any one of claims 1 to 3, characterized by the following:

5. The aforementioned work status includes both during and outside of work hours. A system according to any one of claims 1 to 4, characterized by the above.

6. The external device transmits the identified vehicle ID, the driver ID, the work status information, and time information indicating the current time to the drive recorder. A system according to any one of claims 1 to 5, characterized by the above.

7. The drive recorder stores the vehicle ID, driver ID, and work status information received from the external device in the memory of the control unit. The system according to claim 6, characterized by the following:

8. The drive recorder, when generating the video information, stores the following information in the video information: time information indicating the current time after calibration measured by the internal clock, the vehicle ID, the driver ID, and the work status information. The system according to claim 7, characterized by the following:

9. The aforementioned drive recorder generates video information with sound by associating the video information with sound information representing sounds picked up by the microphone in a time-synchronized manner. A system according to any one of claims 1 to 8, characterized by the following:

10. The drive recorder stores time information indicating the current time before calibration, in addition to the current time measured and calibrated by the internal clock, in association with the time information indicating the current time after calibration when generating the video information. A system according to any one of claims 1 to 9, characterized by the following:

11. The aforementioned system includes a mobile terminal, The aforementioned mobile terminal has a function to calibrate the time measured by its internal clock using time information received from a time server, and to identify the calibrated time as the current time. The aforementioned drive recorder has a function to create a UUID specifically for time adjustment to prompt clock adjustment, and to transmit a beacon according to a short-range wireless communication protocol at predetermined intervals. When the mobile terminal detects the beacon while the dedicated application is running in the background, it establishes a communication connection with the drive recorder, which is the source of the beacon. The system according to any one of claims 1 to 10, characterized by the following:

12. The aforementioned short-range wireless communication protocol is Bluetooth. The beacon in question is a Bluetooth Beacon. The system according to claim 11, characterized by the following:

13. When the mobile terminal establishes a communication connection with the drive recorder, it sends a clock setting request to the drive recorder. The aforementioned clock setting request includes time information indicating the current time measured by the mobile terminal's internal clock. The system according to claim 11 or 12, characterized by the above.

14. The drive recorder updates the clock data indicating the reference time used by the internal clock for timing, using the time information included in the clock setting request received from the mobile terminal. The system according to claim 13, characterized by the following:

15. The drive recorder sends a clock setting response to the mobile terminal to notify it that the clock data update is complete. When the mobile terminal receives the clock setting response from the drive recorder, it disconnects the communication connection established between itself and the drive recorder. The system according to claim 14, characterized by the following:

16. The system includes a mobile terminal that runs a time code display application, The aforementioned mobile terminal has a function to display a two-dimensional barcode on its touchscreen that indicates the current time, measured by the device's internal clock. The aforementioned drive recorder determines whether or not a two-dimensional barcode is included in the captured still image, and if it determines that a two-dimensional barcode is included, it decodes the two-dimensional barcode and obtains the time information. The system according to any one of claims 1 to 10, characterized by the following:

17. The aforementioned mobile terminal displays a two-dimensional barcode on its touchscreen that shows the current time in seconds, updating every second. The system according to claim 16, characterized by the following:

18. The aforementioned drive recorder is The system determines whether a captured still image contains a two-dimensional barcode. If it determines that the still image contains a two-dimensional barcode, it decodes the barcode to obtain time information, and temporarily stores the obtained time information. When new time information is acquired, the system compares the newly acquired time information with the last acquired and stored time information. If they differ, it identifies the time indicated by the newly acquired time information plus a predetermined amount of time as the current time, and uses this identified current time to calibrate the time measured by the internal clock. The system according to claim 16 or 17, characterized by the above.

19. Computers, Functions of a drive recorder in the system according to any one of claims 1 to 18 A program designed to function as such.

20. Computers, Functions of a mobile terminal provided by the system according to any one of claims 11 to 18 A program designed to function as such.

Images