JP2012169754A - Information recording apparatus for moving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely store important information acquired on a mobile body without a need of a preliminary power supply even when power supply is cut off.SOLUTION: An information recording apparatus for the moving body includes a non-volatile recording medium 100 securing a recording destination region A1; a data writing control section 111 which sequentially writes acquired information in the recording destination region, overwrites a region in which old data is written with new data when a free region does not exist and repetitively uses the same region; a condition data holding section 12a holding data showing a protection condition for deciding an overwriting suppression region allocated in the recording destination region; and an overwriting suppression control section 113 grasping a present situation, comparing the protection condition of the condition data holding section with the present situation and allocating automatically the overwriting suppression region near a present data writing position on the recording destination region when the protection condition is satisfied.

Description

  The present invention relates to a moving body information recording apparatus that continuously or intermittently acquires information that changes over time on a moving body such as a vehicle and stores the information as necessary.

  2. Description of the Related Art Conventionally, an on-vehicle device such as a drive recorder or a digital tachograph has been used as an information recording apparatus for a moving body mounted on a vehicle such as an automobile.

  In general, a drive recorder uses an in-vehicle camera fixed on a vehicle to continuously photograph a subject viewed from a window in front of or behind the vehicle in the traveling direction and a vehicle interior situation, and sequentially obtain the obtained image data. On the recording medium. In addition, this type of drive recorder includes a constant recording type in which image data is always recorded and a trigger recording type in which an image is recorded only in a special situation such as a traffic accident. In the case of a trigger recording type drive recorder, this is regarded as a recording start trigger when a specific condition is met, as in the case of detecting an abnormally large acceleration, and an image is recorded for a predetermined time before and after the trigger generation timing.

  In addition, digital tachographs installed on commercial vehicles, etc., regularly display information indicating the actual operation status of vehicles equipped with them, specifically vehicle position information, vehicle speed, brake status, turn signal status, etc. Thus, time series data including these are sequentially recorded on a predetermined recording medium. The drive recorder described above can be connected to a digital tachograph, and the function of the drive recorder can be built in the digital tachograph.

  Further, as conventional techniques related to the present invention, for example, techniques disclosed in Patent Documents 1 to 3 are known.

  In Patent Document 1, in a vehicle event recorder, a long time moving image and a detailed image before and after the accident are reliably recorded, the capacity of the storage device is saved, and the cause of the accident can be easily analyzed. Techniques for doing so are disclosed. Specifically, a high-speed recording area and a low-speed storage area are provided on the storage device, information obtained by compressing video captured by the imaging device is recorded endlessly in the high-speed recording area, and the oldest information recorded in the high-speed recording area is recorded. Information read from the portion is thinned out at a constant rate and recorded endlessly in the low-speed storage area.

  Patent Document 2 discloses a mobile phone with a drive recorder function. In Patent Document 2, moving images are continuously shot, the captured images are recorded in a recording memory endlessly, and moving image data of a predetermined recording size is stored in a file on an auxiliary storage medium by detecting an impact. It also discloses that a retention period is set for the retention file to be erased and protected, and a file whose retention period has expired is automatically erased.

  Patent Document 3 discloses a technique for storing an optimum traveling state without causing a shortage of a capacity of a recording medium that stores a traveling state of a moving body. Further, paragraph [0078] of Patent Document 3 discloses that when a trigger is detected, an overwritten recording image for a drive recorder is stored in a recording medium such as a magnetic disk or an optical disk. Furthermore, as the drive recorder image, it is possible to save the image at the detection time point when the trigger is detected and a certain time before and after that, or to extend the save time when a specific behavior is detected again within a certain time from the detection time point. A point is suggested.

JP 2006-67172 A JP 2006-245836 A JP 2007-122515 A

  By the way, in a general mobile information recording apparatus such as a drive recorder or a digital tachograph, information that changes over time, for example, information such as images and vehicle speeds is acquired continuously or intermittently. The information is always recorded on the buffer memory according to the order of the time when the information is acquired. In addition, a storage area of a certain capacity is secured on the buffer memory, and information is recorded endlessly in this storage area. That is, since the capacity of this storage area is limited, when there is no free area in the storage area, new data is overwritten in the area where old data is written. As a result, information acquired from a predetermined time before the current time determined by the capacity of the storage area to the present can always be retained in the buffer memory, and data that is older in time is automatically deleted.

  Further, when a specific situation occurs as in the case where a large acceleration is detected, data storage is started using this as a trigger. In this case, important time information is lost by extracting necessary time zone information from the information stored in the buffer memory within a predetermined time and transferring it to a non-volatile recording medium such as a memory card. Do not save.

  However, if the supply of power to the vehicle-mounted device is stopped for some reason, the information stored in the buffer memory will disappear, so information that has not been transferred to the nonvolatile recording medium It will disappear. For example, even when important information representing the situation is to be saved as in the case of a traffic accident, the information cannot be saved when the supply of power is stopped.

  To ensure that necessary information is saved even when the supply of power to the OBE is stopped, a system that detects when the power is turned off or when the power from the vehicle to the OBE is cut off A spare power supply must be added to supply the necessary power to the instrument. Therefore, a significant increase in device cost is inevitable, leading to an increase in the size of the device.

  For example, when data is recorded intermittently, the capacity of the data to be recorded can be reduced, so that information on the buffer memory can be periodically transferred to, for example, a non-volatile recording medium regardless of the occurrence of a trigger. It is also possible to transfer and save it above. In this case, even if the supply of power to the vehicle-mounted device is stopped, the information that has been transferred before that remains on the nonvolatile recording medium, so the supply of power is stopped by analyzing this information. It is possible to investigate the previous situation. However, since the data stored in this case is only intermittent information, there is a high possibility that a part of information necessary for analysis is missing.

  The present invention has been made in view of the above-described circumstances, and its purpose is to obtain important information acquired on a mobile body without requiring a spare power source even when the power supply is cut off. It is an object to provide an information recording apparatus for a moving body that can securely store the information.

In order to achieve the above-mentioned object, the mobile information recording apparatus according to the present invention is characterized by the following (1) to (8).
(1) A moving body information recording device that continuously or intermittently acquires information that changes over time on a moving body such as a vehicle and stores the information as necessary.
At least one nonvolatile recording medium in which one or more recording destination areas are secured;
The information acquired on the moving body is sequentially written in the recording destination area, and when there is no free area in the recording destination area, the area where the old data is written is overwritten with new data, and the same area is overwritten. A data write control unit to be used repeatedly;
A condition data holding unit for holding data representing a protection condition for determining an overwrite suppression area allocated in the recording destination area;
While grasping the current situation on the mobile body and comparing the protection condition of the condition data holding unit with the current situation, if the protection condition is satisfied, the current data write position on the recording destination area And an overwrite suppression control unit that automatically assigns an overwrite suppression area in the vicinity.
(2) The mobile information recording apparatus according to (1) above,
A first recording destination area and a second recording destination area are secured as a plurality of recording destination areas on the nonvolatile recording medium,
The condition data holding unit has an area for holding at least recording condition information for designating a data recording period for each of the first recording destination area and the second recording destination area,
The data write control unit writes the common information acquired on the moving body to each of the first recording destination area and the second recording destination area in accordance with the recording condition information at an independent data recording cycle. .
(3) The mobile information recording apparatus according to (2) above,
The condition data holding unit has an area for holding data representing a plurality of independent protection conditions associated with each of the first recording destination area and the second recording destination area.
(4) The mobile information recording apparatus according to (1) above,
The condition data holding unit has areas for holding data of a plurality of types of protection conditions,
The overwriting suppression control unit compares each of the plurality of protection conditions of the condition data holding unit with the current situation, and if any one of the protection conditions is satisfied, the current data write position on the recording destination area An overwrite suppression area is automatically assigned in the vicinity of.
(5) The mobile information recording apparatus according to (1) above,
When the total number of the overwrite suppression areas allocated on the recording destination area or the capacity thereof exceeds a predetermined threshold, the overwrite suppression control unit, among a plurality of overwrite suppression areas allocated so far The area that holds the oldest data in time is switched to an overwritable state.
(6) The mobile information recording apparatus according to (1) above,
When the specified protection condition is satisfied, the overwrite suppression control unit assigns a range of a predetermined length as the overwrite suppression area in the vicinity of the current data writing position on the recording destination area, and is designated. If the specified protection condition is satisfied again after a predetermined time has elapsed since the state in which the protection condition is satisfied, the continuous length of the overwrite suppression area allocated immediately before is automatically set. Extend.
(7) The mobile information recording apparatus according to (6) above,
The overwriting suppression control unit determines the number of consecutive times or the length of the overwritten suppression area after extension when a state that satisfies the specified protection condition continuously occurs before a predetermined time elapses. Limit the extension operation so that the limit value is not exceeded.
(8) The mobile information recording apparatus according to (4) above,
The data write control unit, when satisfying any one of a plurality of protection conditions held in the condition data holding unit, at least the event information that can identify the type of the corresponding protection condition, the corresponding overwrite suppression area Automatically record in association with.

According to the mobile information recording apparatus having the configuration (1), even when the supply of power is interrupted, the information acquired immediately before can be reliably stored. That is, since the recording destination area is allocated on the non-volatile recording medium, the information written in the recording destination area is held as it is even when the supply of power is stopped. In addition, old information written in the recording destination area is overwritten and disappears when there is no free area, but important information that satisfies the specified protection conditions is suppressed, so that it is retained as it is old. The
According to the mobile information recording apparatus having the configuration (2), it is possible to write common information in the first recording destination area and the second recording destination area at different recording cycles. Therefore, for example, continuously recorded information and intermittently recorded information can be recorded and stored simultaneously.
According to the mobile information recording apparatus having the configuration (3), the protection condition for the first recording destination area and the protection condition for the second recording destination area can be designated independently.
According to the mobile information recording apparatus having the configuration (4), it is possible to protect the information written in correspondence with each of a plurality of different types of events. Therefore, it is possible to protect and store information recorded for various types of events as well as events representing vehicle behavior such as detection of large accelerations.
According to the mobile information recording apparatus configured as described in (5) above, a new empty area (overwriteable area) can be secured when the overwrite suppression area allocated on the recording destination area increases excessively. It is possible to prevent a shortage of capacity in the recording destination area.
According to the mobile information recording apparatus having the configuration of (6) above, when events corresponding to the designated protection condition repeatedly occur in a short time period, the information corresponding to them is collected in one area Can be managed with.
According to the mobile information recording apparatus having the configuration (7), the length of the overwritten suppression area after extension can be limited. Therefore, it is possible to prevent the length of information stored for one event from becoming excessive.
According to the mobile information recording apparatus configured as described above in (8), it is possible to grasp what type of event the stored information is recorded for each type of event occurrence.

  According to the mobile information recording apparatus of the present invention, important information acquired on a mobile object can be reliably stored without requiring a spare power source even when the power supply is interrupted. That is, since the recording destination area is allocated on the non-volatile recording medium, the information written in the recording destination area is held as it is even when the supply of power is stopped. In addition, old information written in the recording destination area is overwritten and disappears when there is no free area, but important information that satisfies the specified protection conditions is suppressed, so that it is retained as it is old. The

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

It is a block diagram which shows the structural example of the hardware of the information recording device for moving bodies. It is a block diagram which shows the structure of the principal part on the function regarding the onboard equipment shown in FIG. It is a flowchart showing the content of the main processes which the microcomputer of FIG. 1 performs. It is a flowchart which shows the detailed operation | movement equivalent to S12 of FIG. FIG. 4 is a schematic diagram illustrating a specific example of contents of a recording control table illustrated in FIG. 3. It is a block diagram which shows the specific example (1) of allocation of a recording destination area | region. It is a block diagram which shows the specific example (2) of allocation of a recording destination area | region. It is a block diagram which shows the specific example (3) of allocation of a recording destination area | region. It is a time chart which shows the example of the data writing operation with respect to each position in each recording destination area | region. It is a flowchart which shows the outline | summary of the recording operation in a modification. It is a time chart which shows the example of the recording operation in a modification.

  Specific embodiments relating to the mobile information recording apparatus of the present invention will be described below with reference to the drawings.

  An example of the hardware configuration of the mobile information recording apparatus in this embodiment is shown in FIG. Moreover, the structure of the principal part on the function regarding the onboard equipment shown in FIG. 1 is shown by FIG. As a specific example, the mobile information recording apparatus shown in FIGS. 1 and 2 is assumed to be mounted on a mobile body such as a passenger car or various business vehicles and used as a drive recorder or a digital tachograph.

  In the configuration example shown in FIG. 1, a microcomputer 11, a nonvolatile memory 12, an interface 13, a video signal processing unit 14, a power supply voltage monitoring unit 15, a clock circuit 16, and interfaces 17 and 18 are provided inside the vehicle-mounted device 10. Yes. In addition, an in-vehicle camera 22, a vehicle speed sensor 23, an acceleration sensor 24, a temperature sensor 25, a GPS receiver 26, and a memory card (nonvolatile recording medium) 100 are connected to the in-vehicle device 10.

  The in-vehicle camera 22 is used, for example, to acquire necessary video information by photographing the scenery outside the vehicle seen through the front or rear windshield glass from the inside of the vehicle, the state of the vehicle interior, and the like. The in-vehicle camera 22 can repeatedly capture images at a constant frame period (for example, 20 frames / second) and output an obtained video signal.

  The vehicle speed sensor 23 is attached to the output shaft of the vehicle transmission, and outputs vehicle speed pulses as the vehicle moves. By monitoring this vehicle speed pulse, it becomes possible to grasp the vehicle speed and the amount of movement of the vehicle.

  The acceleration sensor 24 can detect the magnitude of acceleration applied to the vehicle. For example, in the case of a general drive recorder, when an abnormally large acceleration is detected in a traffic accident or the like, a recording start trigger is generated and data such as an image is stored.

  The temperature sensor 25 is used for detecting, for example, the temperature inside the refrigerator, the temperature inside the vehicle compartment, the temperature inside the engine room, and the like.

  The GPS receiver 26 receives radio waves from each of a plurality of GPS (Global Positioning System) satellites, and can calculate the current position (latitude / longitude) of the vehicle based on the arrival times of these radio waves.

  The memory card 100 is a recording medium composed of a non-volatile memory in which data can be written and read, and has a relatively large capacity so that data such as images can be stored for a predetermined time. That is, this memory card 100 is used for storing data acquired by a drive recorder or a digital tachograph. In the present embodiment, as will be described later, a recording destination area for recording the latest data is secured on the memory card 100.

  The microcomputer 11 controls the vehicle-mounted device 10 by executing a program prepared inside in advance. For example, each function shown in FIGS. 2 to 4 is also realized by a program executed by the microcomputer 11.

  The nonvolatile memory 12 can freely write and read data, and is used to hold the recording control table TBL shown in FIGS. 3 and 5 and other constant data. The contents of the recording control table TBL can be rewritten by a predetermined administrator or user using an external device (such as a personal computer). The external device can be connected to the interface 18 of the vehicle-mounted device 10.

  The interface 13 is used for connecting the memory card 100 to the vehicle-mounted device 10. The microcomputer 11 can access the memory card 100 via the interface 13 and write and read data.

  The video signal processing unit 14 processes the video signal output from the in-vehicle camera 22 and sequentially generates image data of each frame. The generated image data is input to the microcomputer 11.

  The power supply voltage monitoring unit 15 monitors a voltage appearing on a predetermined power supply line (typically, the voltage of the vehicle battery), and detects an abnormal voltage drop. For example, this can be detected when the power supply line on the supply side is disconnected and power is not supplied to the vehicle-mounted device 10. Even when the supply of power is stopped, the operation of the vehicle-mounted device 10 can be continued for a while using the energy stored in the capacitor of the power circuit inside the vehicle-mounted device 10 immediately after that. .

  The clock circuit 16 is an integrated circuit having a clock function, and can output information representing the current date and time by constantly counting stable clock pulses having a constant cycle. Therefore, the microcomputer 11 can always grasp the current date and time.

  The interface 17 converts signals output from the vehicle speed sensor 23, the acceleration sensor 24, the temperature sensor 25, and the GPS receiver 26 into signals suitable for the microcomputer 11 to handle. Therefore, the microcomputer 11 can input and grasp the current vehicle speed, acceleration, temperature, and vehicle position information from the interface 17.

  Specific examples of allocation of recording destination areas on the memory card 100 are shown in FIGS. As shown in FIG. 6, in this embodiment, a plurality of independent areas A1 and A2 can be allocated on the memory card 100 as data recording destination areas.

  When there are a plurality of memory cards 100A and 100B, one recording destination area A2 can be divided and arranged on the two memory cards 100A and 100B as shown in FIG. As shown in FIG. 2, the two recording destination areas A1 and A2 can be divided and arranged on the two memory cards 100A and 100B.

  The microcomputer 11 of the vehicle-mounted device 10 writes information to be recorded, for example, image data of a video obtained by photographing by the vehicle-mounted camera 22 continuously or intermittently in the recording destination areas A1 and A2 on the memory card 100. it can. However, since the capacities of the recording destination areas A1 and A2 are limited, it is not possible to store all data having a large data size such as images over a long period of time. Therefore, when there is no free space, in order to secure a new write destination area, the old data is erased in time or the same area is repeatedly used in a state where the data can be overwritten. Also, important data that needs to be stored for a long period of time is automatically protected from being erased or overwritten.

  Data representing various conditions for controlling the recording operation of the vehicle-mounted device 10 is held in the recording control table TBL on the nonvolatile memory 12. In the example shown in FIG. 5, “recording start condition”, “recording period”, “protection condition A”, “protection range A”, “protection condition B”, “protection range B” are recorded for each of the recording destination areas A1 and A2. An area for holding data representing "is secured on the recording control table TBL.

  The data C11 shown in FIG. 5 means that the recording operation for the recording destination area A1 is started when the ignition is on (IGN ON). Data C12 means that data to be recorded (image data) is continuously recorded in the recording destination area A1. The data C13A means that when the condition “temperature change is 5 degrees or more” is satisfied, the corresponding recording data area is protected (overwriting is prohibited). The data C14A means that the length of the range protected by the condition of the data C13A is 10 seconds before and after the timing that satisfies the condition. The data C13B means that a recording data area corresponding to a specific behavior (when a large acceleration is detected) is protected.

  In the example of the recording control table TBL shown in FIG. 5, a plurality of types of protection conditions (protection condition A and protection condition B) can be specified simultaneously. As protection conditions that can be specified by the contents of the recording control table TBL, for example, various types of conditions as shown below can be considered.

Temperature: When the change in the refrigerator interior temperature exceeds the threshold or the interior temperature reaches the specified temperature.
Power supply: When a problem occurs in the power supply and an abnormal drop in voltage is detected.
Vehicle position: When a vehicle exists at the specified position.
Time: When the specified time comes.
Vehicle position + time: When the state where the vehicle position does not change continues for the specified time.

  By controlling the recording operation according to the contents of the recording control table TBL, for example, an operation as shown in FIG. 9 is realized. In the example shown in FIG. 9, data (image or the like) is continuously written in the recording destination area A1, and at the same time, the same data is intermittently written in the recording destination area A2. In addition, when a specific behavior occurs, when a specific temperature is reached, when a predetermined time is reached, or when power-off is detected, the corresponding location of the recording destination area A1 is the specified length. Protected.

  In the example of FIG. 9, since recording is intermittently performed in the recording destination area A2, data can be recorded over a relatively long time without overwriting old data. Therefore, protection for the recording destination area A2 is not specified. However, if the contents of the recording control table TBL are rewritten, the protection operation can be performed on the recording destination area A2. In addition to “ignition on”, a condition such as “within 30 minutes after ignition off” can be designated as a condition for starting recording.

  As shown in FIG. 2, the in-vehicle device 10 includes data write control units 111 and 112 and overwrite suppression control units 113 and 114 as basic functions implemented by the processing of the microcomputer 11. The data write control unit 111 and the overwrite suppression control unit 113 control the first recording destination area A1, and the data write control unit 112 and the overwrite suppression control unit 114 control the second recording destination area A2.

  The data write controllers 111 and 112 sequentially write information (image data and the like) acquired on the vehicle to the recording destination areas A1 and A2, and old data is stored when there is no free area in the recording destination area. Overwrite the written area with new data and use the same area repeatedly.

  The overwrite suppression control units 113 and 114 grasp the current situation on the vehicle and compare the protection conditions of the condition data holding units 12a and 12b with the current situation. An overwrite suppression area, that is, a protection area is automatically assigned in the vicinity of the current data write position on A1 and A2.

  The condition data holding units 12a and 12b correspond to the above-described recording control table TBL, and hold data representing protection conditions for determining at least an overwrite suppression area (protection area) to be assigned.

  The contents of main processes executed by the microcomputer of FIG. 1 are shown in FIG. A detailed operation corresponding to step S12 in FIG. 3 is shown in FIG. The operations illustrated in FIGS. 3 and 4 correspond to the data write control unit 111 and the overwrite suppression control unit 113 illustrated in FIG. The operations of the data write control unit 112 and the overwrite suppression control unit 114 are the same as those in FIGS. 3 and 4, and only the data referred to on the recording control table TBL is different.

  For example, when the ignition of a vehicle equipped with the vehicle-mounted device 10 is turned on, the recording start condition C11 shown in FIG. 5 is satisfied, and the processing of the microcomputer 11 proceeds from step S11 to step S12 in FIG. Although not shown in FIG. 1, the microcomputer 11 can identify whether the ignition of the vehicle is on or off.

  In step S12, the microcomputer 11 performs a recording operation (data writing of an image or the like) on the above-described recording destination area A1 at the recording period specified by the recording period data C12 on the recording control table TBL. When the recording cycle data C12 is “continuous”, the image data is continuously recorded, for example, at 20 fps (frame / second). Further, when the recording cycle data C12 is “intermittent”, the image data is intermittently recorded at 1 fps, for example.

  In step S13, the microcomputer 11 updates the vehicle speed and acceleration calculated based on the latest information representing various states, that is, the power supply status output by the power supply voltage monitoring unit 15, the date and time output by the clock circuit 16, and the output of the vehicle speed sensor 23. Information such as the acceleration detected by the sensor 24, the temperature detected by the temperature sensor 25, and the vehicle position output from the GPS receiver 26 is acquired.

  In step S14, the microcomputer 11 grasps the current situation based on the information acquired in step S13, and compares this situation with the protection condition of C13A on the recording control table TBL. If the C13A protection condition is satisfied, the process proceeds to step S15. If not satisfied, the process proceeds to S16.

  Similarly, in step S16, the microcomputer 11 grasps the current situation based on the information acquired in step S13, and compares this situation with the protection condition of C13B on the recording control table TBL. If the C13B protection condition is satisfied, the process proceeds to step S17. If not satisfied, the process proceeds to S11.

  In step S15, the microcomputer 11 assigns the range of the length designated by C14A on the recording control table TBL as the current protection area with reference to the current writing position on the recording destination area A1. In other words, since there is a high possibility that important data to be stored is recorded in the current situation, the data is protected from being erased or overwritten. For example, since “10 seconds before and after” is designated in C14A shown in FIG. 5, an area in a range corresponding to 10 seconds before and after the current writing position is designated as a protection target under this condition.

  Similarly, in step S17, the microcomputer 11 assigns the range of the length designated by C14B on the recording control table TBL as the current protection area with reference to the current writing position on the recording destination area A1.

The detailed operation of step S12 will be described with reference to FIG.
When a write request for the recording destination area A1 occurs, the processing of the microcomputer 11 proceeds from step S20 to S21 in FIG.

  In step S21, the microcomputer 11 identifies whether or not the capacity of the data written so far in the recording destination area A1 has reached the capacity allocated in advance to the recording destination area A1 (capacity over). For example, the capacity of 300 seconds of continuously recorded image data is defined as the limit value, and the data is recorded so as not to exceed the limit value. If the capacity is not over, the process proceeds to step S29. If the capacity is over, the process proceeds to step S22.

  In step S22, the microcomputer 11 compares the number of protected areas allocated so far in the recording destination area A1 with a predetermined limit value (for example, 10). If the number of allocated protection areas is less than the limit value, the process proceeds to step S23, and if not, the process proceeds to step S26.

  In step S23, the microcomputer 11 identifies whether there is a sufficient area (for example, an area capable of recording for 60 seconds) other than the location assigned as the protection area in the recording destination area A1. When it exists, it progresses to step S24, and when it does not exist, it progresses to step S25.

  In step S24, the microcomputer 11 can erase the data in the area where the oldest data is written or overwrite the area other than the portion allocated as the protection area in the recording destination area A1. A new area is secured in the state.

  In step S25, the microcomputer 11 erases the protection area data in which the oldest data is written or cancels the protection of the area among the areas allocated as the protection area in the recording destination area A1. Then, a new area is secured by making it overwritable.

  In step S26, the microcomputer 11 records the recording status in the area other than the recording destination area A1 assigned as the main writing destination in this processing (corresponding to the data writing control unit 111), that is, in this case, the recording destination area A2. refer. Then, it is identified whether or not the capacity of data written to the recording destination area A2 so far has reached the capacity allocated to the recording destination area A2 in advance (capacity over). If the capacity is not over, the process proceeds to step S27. If the capacity is over, the process proceeds to step S28.

  In step S27, the microcomputer 11 secures a currently vacant area (an area in which data has not yet been written) in the recording destination area A2 as the next writing destination of this processing.

  In step S28, the microcomputer 11 erases or deletes the data in the area in which the oldest data is written, other than the portion allocated as the protection area in the other recording destination area A2. An overwritable state is set, and this is secured as the next write destination area.

  In step S29, the microcomputer 11 stores the acquired information such as image data in the contents of the recording control table TBL in the recording destination area A1 that is the main writing destination or in the recording destination area A2 that is assigned elsewhere. Write in order according to.

  Therefore, for example, a write operation as shown in FIG. 9 is performed. That is, since the data writing control unit 111 and the overwrite suppression control unit 113 perform the processes of FIGS. 3 and 4 according to the contents of C11 to C14B of the recording control table TBL, information such as image data is continuously recorded in the recording destination area A1. Written in. Further, since the data writing control unit 112 and the overwrite suppression control unit 114 perform the same processing as in FIGS. 3 and 4 according to the contents of C21 to C24B of the recording control table TBL, information such as image data is recorded on the recording destination area A2. Is written intermittently.

  Further, if the writing operation is performed for a long time, there is no free area in the recording destination areas A1 and A2, so that data in the area where the old data is written is erased or overwriting of the area is permitted and a new area is created. Is secured. That is, the same area on the recording destination areas A1 and A2 is cyclically used repeatedly. Also, in the area where overwriting is permitted, since the next overwriting is not performed until a predetermined time elapses after writing, data written during the most recent predetermined time (for example, 60 seconds) is recorded. The contents of the previous areas A1 and A2 are always held.

  When the protection condition registered in the recording control table TBL is satisfied, for example, when the specific behavior in FIG. 9 occurs, at a specific temperature, at a predetermined time, or when the power is shut off, the recording destination area A1 The corresponding area in the upper area is assigned as a protection area, and subsequent overwriting is suppressed. In other words, data acquired at the occurrence of a specific behavior, at a specific temperature, at a predetermined time, or when the power is turned off is stored on the memory card 100 as it is without being overwritten even after a long period of time. The

  When it is detected that the protection conditions specified in steps S14 and S16 in FIG. 3 are satisfied, an event indicating the type of the corresponding state (classification of behavior occurrence, temperature abnormality, power shutoff, vehicle position, time, etc.) Information may be written on the memory card 100 in association with the corresponding protection area.

  When the supply of power to the vehicle-mounted device 10 is interrupted, data such as images acquired between the present and a predetermined time (for example, 60 seconds) before is written on the recording destination areas A1 and A2, It remains intact without being overwritten. Since the recording destination areas A1 and A2 are on the memory card 100 and are non-volatile, they do not disappear even when the power supply is cut off. Therefore, the data acquired immediately before the supply of power is cut off is automatically saved.

  Next, a modified example of the mobile information recording apparatus shown in FIGS. An outline of the recording operation in this modification is shown in FIGS.

  Also in this modification, as shown in FIG. 11, data is written in parallel on the two recording destination areas A1 and A2. Further, it is assumed that data is written continuously (at 20 fps) to the recording destination area A1, and the same data is intermittently written to the recording destination area A2.

  As in the case of the mobile information recording apparatus described above, the data written in the recording destination area A1 is overwritten and disappears when it becomes old. Further, when the protection condition registered in the recording control table TBL is satisfied, that is, when a specific event occurs, a range for holding data recorded in a corresponding time zone is designated as a protection area, and this data is Saved without being overwritten.

  By the way, like the times t1, t2, and t3 shown in FIG. 11, the same type of event may repeatedly occur during a short time. In such a case, there is a possibility that the data length of each area to be stored becomes irregular, the data is interrupted in the middle, or a lot of event information is recorded in a short time.

  In order to solve such a problem, a special process is performed in the modification shown in FIG. That is, when the same type of event repeatedly occurs in a short time, such as at times t1, t2, and t3 in FIG. 11, the length of one area to be protected is automatically extended, and a plurality of events are Save them together in one area. Note that the writing of data to the recording destination area A2 is intermittent and data can be recorded for a long time, so that special protection against overwriting is not performed.

  In step S31 of FIG. 10, the acquired image data is continuously written in the recording destination area A1 at 20 fps. Further, only the area in which data exceeding 60 seconds is written is made overwritable so that new data written between the present and 60 seconds before remains. Of course, overwriting is also prohibited for the protection area allocated so far.

  In step S32, whether or not an event has occurred is identified as in steps S14 and S16 of FIG. When the occurrence of an event is detected, the process proceeds to step S34, and when not detected, the process proceeds to step S33.

  In step S33, in the recording destination area A1, unprotected data other than the area in which the latest 60-second data is written are set in a state where it can be deleted or overwritten.

  In step S34, in order to identify whether or not an event has occurred continuously a plurality of times, it is identified whether or not the current event occurrence time is within 10 seconds from the previous event occurrence time. If it is within 10 seconds, the process proceeds to step S40, and if it exceeds 10 seconds, the process proceeds to step S35.

  In step S35, a recording destination area A1 in which data within a certain time period (10 seconds in the case of FIG. 10 is assumed) from the event occurrence timing is allocated as a protection area, and this data is stored. In addition, a trigger signal indicating that an event has occurred is output to the outside of the vehicle-mounted device 10.

  In step S36, the recording destination area A1 is set in a state in which data other than the area for 10 seconds before and after the event assigned as the protection area and the area in which the latest 60-second data is written can be deleted or overwritten.

  In step S37, data representing the type of event that has occurred and data representing the length are recorded on the memory card 100 in association with the corresponding protection area.

  In step S38, a predetermined upper limit value is set for the entire recording capacity of each protection area on the recording destination area A1 in which data at the time of event occurrence is stored (corresponding to a length of 300 seconds in continuous recording in this example). If the data above the upper limit value has already been recorded, the process proceeds to step S39.

  In step S39, an area holding the data of the oldest event in time is selected from the protected areas allocated on the recording destination area A1, and the data in this area can be deleted or overwritten. Thus, a new writable area is secured on the recording destination area A1.

In step S40, in order to prevent the length of the area to be recorded for one event from becoming too long, whether to limit is identified by comparison of the following equation. The contents of the following expression can be changed as necessary.
(Current event time)-(Start time of continuous event) + 20 seconds ≥ (maximum time of one event)
If this condition is satisfied, the process proceeds to step S43. If the condition is not satisfied, the process proceeds to step S41.

  In step S41, the data storage for the event that occurred immediately before the current event is interrupted. As a result, after 10 seconds of data has been saved from the time of the event that occurred immediately before, the process proceeds to the next step S42.

  In step S42, data for 10 seconds from the time of the current event is stored. As a result, the length of the protection area for storing data recorded for the previous event is automatically extended to 10 seconds or more.

  In step S43, in order to regulate the length of the protection area for storing data for one event, data storage for the previous event is interrupted when the maximum time of one event is reached.

  As described above, the moving body information recording apparatus of the present invention can be mounted on a moving body such as a passenger car or various commercial vehicles, and can be used in the same manner as a conventional drive recorder or digital tachograph. By using this mobile information recording apparatus, it is possible to obtain continuously recorded data necessary for analyzing the state at that time even when the supply of power is cut off. In other words, the latest data has already been written to the non-volatile recording area even before special processing (allocation of protection area) is performed to save the data when various events occur. The latest data can be retained without being affected by blocking.

DESCRIPTION OF SYMBOLS 10 Onboard equipment 11 Microcomputer 12 Non-volatile memory 12a, 12b Condition data holding | maintenance part 13 Interface 14 Image | video signal processing part 15 Power supply voltage monitoring part 16 Clock circuit 17, 18 Interface 22 Car-mounted camera 23 Vehicle speed sensor 24 Acceleration sensor 25 Temperature sensor 26 GPS Receiver 100 Memory card 111, 112 Data write control unit 113, 114 Overwrite suppression control unit A1 First recording destination area A2 Second recording destination area TBL Recording control table

Claims (5)

A moving body information recording device that continuously or intermittently acquires information that changes with the passage of time on a moving body such as a vehicle and stores the information as necessary.
At least one nonvolatile recording medium in which one or more recording destination areas are secured;
The information acquired on the moving body is sequentially written in the recording destination area, and when there is no free area in the recording destination area, the area where the old data is written is overwritten with new data, and the same area is overwritten. A data write control unit to be used repeatedly;
A condition data holding unit for holding data representing a protection condition for determining an overwrite suppression area allocated in the recording destination area;
While grasping the current situation on the mobile body and comparing the protection condition of the condition data holding unit with the current situation, if the protection condition is satisfied, the current data write position on the recording destination area An overwriting suppression control unit that automatically allocates an overwriting suppression area in the vicinity of the mobile information recording apparatus. A first recording destination area and a second recording destination area are secured as a plurality of recording destination areas on the nonvolatile recording medium,
The condition data holding unit has an area for holding at least recording condition information for designating a data recording period for each of the first recording destination area and the second recording destination area,
The data write control unit writes the common information acquired on the moving body to each of the first recording destination area and the second recording destination area in accordance with the recording condition information at an independent data recording cycle. The moving body information recording apparatus according to claim 1. The condition data holding unit has areas for holding data of a plurality of types of protection conditions,
The overwriting suppression control unit compares each of the plurality of protection conditions of the condition data holding unit with the current situation, and if any one of the protection conditions is satisfied, the current data write position on the recording destination area The overwriting suppression area is automatically assigned in the vicinity of the mobile information recording apparatus according to claim 1. When the total number of the overwrite suppression areas allocated on the recording destination area or the capacity thereof exceeds a predetermined threshold, the overwrite suppression control unit, among a plurality of overwrite suppression areas allocated so far The mobile information recording apparatus according to claim 1, wherein an area holding the oldest data in time is switched to an overwritable state. When the specified protection condition is satisfied, the overwrite suppression control unit assigns a range of a predetermined length as the overwrite suppression area in the vicinity of the current data writing position on the recording destination area, and is designated. If the specified protection condition is satisfied again after a predetermined time has elapsed since the state in which the protection condition is satisfied, the continuous length of the overwrite suppression area allocated immediately before is automatically set. The mobile information recording apparatus according to claim 1, wherein the mobile information recording apparatus is extended.

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