JP5108312B2 - Drive recorder, drive recorder program, falsification analysis program, data analysis system, and image falsification detection method - Google Patents

Description

  The present invention relates to a vehicle-mounted drive recorder that captures and records an image for performing fact analysis relating to driving conditions such as vehicle behavior, ambient conditions, and operating conditions, and whether the images recorded by the drive recorder have been tampered with. The present invention relates to a falsification analysis program to be analyzed, a data analysis system, and a falsification detection method for images recorded by the drive recorder.

  2. Description of the Related Art In recent years, image recording type drive recorders that record images of the moment of an accident or a near-miss or before and after that have been provided.

Specifically, this type of drive recorder records, for example, compressed image information obtained by compressing an image captured by a CCD camera and information on each sensor such as an acceleration sensor in a random access memory at the same time, and a collision sensor is activated when an accident occurs. Then, write prohibition is instructed to the random access memory, the recording of each information is stopped, and the latest recorded information immediately before the stop is transferred from the random access memory to the flash memory. If the compressed image information recorded in the flash memory is decompressed and the image immediately before the accident is reproduced together with the sensor information, a fact analysis such as an accident can be performed (Patent Document 1).
JP 2000-6854 A

  However, the above-described conventional apparatus has a problem that, when the image itself becomes evidence, if the image is falsified, the ability as evidence is lost. For example, with recent image processing software, it is easy to make it difficult to know that an image has been tampered with without requiring advanced manipulation techniques. It is necessary to be able to easily and reliably determine whether or not the file has been tampered with.

  Accordingly, the present invention has been made to solve the above problems, and a drive recorder that can easily and reliably determine whether or not an image has been tampered so that the photographed image itself can be used as evidence. Is the main intended issue.

That is, the drive recorder according to the present invention includes a photographing unit attached to a vehicle, a state detecting unit for detecting a state related to the behavior of the vehicle, a surrounding situation, or an operation state, and an irreversible compression of an image photographed by the photographing unit. Recording means for recording the compressed image data and a protection code for detecting falsification of the compressed image data as data in association with each other, and a part of the compressed image data, A code of a predetermined size or more read from a predetermined address is used as an inspection code, and at least a part of the state data indicating the state output by the state detection unit is used as a state code . The protection code is used .

  Here, the inspection code has a predetermined size (for example, about 8 bytes) or more that can be handled as a “unique code”. The inspection code may be read from consecutive addresses of the compressed image data or may be read from discontinuous addresses.

  In this case, it is possible to determine whether or not the JPEG file to be verified has been tampered with based on the presence or absence of the protect code.

  Specifically, if there is no protect code in the compressed data for verification (for example, a JPEG file), it can be determined that there has been tampering. This is because if the original data to which the protection code is assigned is altered, the protection code is deleted at the time of saving.

  Further, when an original compressed data (also referred to as original data) is irreversibly compressed to reproduce an image, and the reproduced image is tampered with and then irreversibly compressed again, compressed data different from the original data (also referred to as falsified data). Therefore, it is possible to determine whether or not the compressed data to be verified has been tampered with from the inspection code that can be handled as a unique code.

  Specifically, even if the tamper has re-applied the protection code recorded in the original data after tampering, the compressed image data of the compressed data is irreversible compression data. The inspection code obtained from the compressed data is compared with the inspection code obtained by, for example, reverse operation from the protection code, and if they match, the compressed data for verification is not altered from the original data. If they do not match, it can be determined that there has been tampering.

  Further, since the state data indicating the state of the vehicle behavior, the surrounding situation, the operation situation, etc. is further used as a parameter for generating the protection code, particularly in a driving recorder for recording the situation such as an accident or a near miss, It becomes possible to detect tampering of important data other than images.

  In this way, whether or not the compressed data for verification has been tampered with can be easily and reliably determined by the presence or absence of the protection code and the comparison of the inspection code, and if it can be determined that there has been no tampering with the original data The photographed data itself can be used as evidence.

  If the file size of the compressed image data is included as a parameter for generating the protect code, tampering detection is performed by using the fact that the file size fluctuates when the replayed image is irreversibly compressed and recorded on the recording means. Accuracy can be increased.

As a desirable aspect of the drive recorder program of the present invention, the drive recorder program generates a compressed image data obtained by irreversibly compressing an image taken by a computer with a photographing means attached to a vehicle, and A part of the compressed image data , which is a code having a predetermined size or more read from a predetermined address of the compressed image data is used as an inspection code, and a state relating to the behavior of the vehicle, the surrounding situation, or the operating situation. A protection code that uses at least a part of the status data indicating the status output by the status detection means for detection as a status code , and uses the inspection code and the status code as a protection code for detecting falsification of the compressed image data A generator, the compressed image data, and the protect code, A data storage unit for recording the data with communication include those which is adapted to function as a.

As a desirable mode of the analysis program of the present invention, this analysis program is a compressed image data obtained by irreversibly compressing an image captured by a computer with a photographing means attached to a vehicle, and a part of the compressed image data. In addition, a code having a predetermined size or more read from a predetermined address of the compressed image data is used as an inspection code, and a state detection unit for detecting a state related to the behavior of the vehicle, the surrounding state, or the operation state is output. Read at least a part of the state data as a state code , and read out the protection code from the storage means for storing the inspection code and the protection code for detecting falsification of the compressed image data as the state code as data. A data reading unit for reading data and a processor that can be read by the data reading unit. If Tokodo absence, a tamper state determining unit which performs judgment that falsification is present in the compressed image data, and the like that so as to function as a.

  In this case, for example, if there is no protect code in the compressed data to be verified, it can be determined that there has been tampering. This is because if the original data to which the protection code is assigned is altered, the protection code is deleted at the time of saving.

Further, as another desirable aspect of the analysis program of the present invention, the analysis program irreversibly compresses an image photographed by a photographing means attached to a vehicle and one of the compressed image data and the compressed image data. A state detection unit for detecting a state related to the behavior of the vehicle, the surrounding state, or the operation state while using a code of a predetermined size or more read from a predetermined address of the compressed image data as an inspection code at least a portion of the state data means outputs a status code, the a check code and status code, from at least associated with storage means for storing the data and a protection code to detect tampering of the compressed image data, Data read unit for reading out the protection code and read by the data read unit When the inspection code comparison unit that compares the inspection code calculated backward from the protect code and the inspection code obtained from the compressed image data for verification and the inspection code comparison unit do not match, For example, the compressed image data may function as a falsification presence / absence determination unit that determines that falsification has occurred.

  If this is the case, the compressed image data of the compressed data is irreversibly compressed data even if the tamper has re-assigned the protection code recorded in the original data after the alteration. For the compressed data, the inspection code obtained from the compressed data is compared with the inspection code obtained by, for example, reverse operation from the protection code, and if they match, the compressed data for verification is the original data It can be determined that there has been no tampering from, and if they do not match, it can be determined that there has been tampering.

As a desirable mode of the data analysis system of the present invention, the data analysis system is a data analysis system including a drive recorder attached to a vehicle and an analysis device for analyzing data recorded by the drive recorder. The drive recorder has an irreversible compression of a photographing unit attached to a vehicle, a state detecting unit for detecting a state related to the behavior of the vehicle, a surrounding situation or an operation state, and an image photographed by the photographing unit. Recording means for recording at least associating compressed image data and a protection code for detecting falsification of the compressed image data as data, and a part of the compressed image data, wherein Tomo When read from the address and check code of a predetermined size or more code comprising , A state code at least part of the state data indicating the state of said state detecting means outputs, the test code and status code, the is intended to protect the code, the analyzer, from the storage means, A data reading unit for reading the protection code;
And a tampering presence / absence determining unit that determines that the compressed image data has been tampered with when there is no protect code that can be read by the data reading unit.

As another desirable mode of the data analysis system of the present invention, the data analysis system comprises a drive recorder used by being attached to a vehicle, and an analysis device for analyzing the data recorded by the drive recorder. The drive recorder includes a photographing unit attached to a vehicle, a state detecting unit for detecting a state related to the behavior of the vehicle, a surrounding situation or an operation state, and an irreversible compression of an image photographed by the photographing unit. Recording means for recording at least associating the compressed image data and the protection code for detecting falsification of the compressed image data as data, the compressed image data being a part of the compressed image data When read from the predetermined address and check code of a predetermined size or more code comprising Moni, a state encoding at least a portion of the state data indicating the state of said state detecting means outputs, the test code and status code is intended to be the protection code, the analyzing apparatus, the storage means A data reading unit for reading out the protection code, an inspection code that is calculated back from the protection code read out by the data reading unit, and an inspection code comparison unit that compares the inspection code obtained from the compressed image data to be verified; The inspection code comparison unit includes a falsification presence / absence determination unit that determines that the compressed image data is falsified when the inspection codes do not match.

  According to the present invention configured as described above, whether or not the compressed data for verification is falsified can be easily and reliably determined from the protection code, and based on the result, the photographed image itself can be used as evidence. become able to.

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

  As shown in FIGS. 1, 2, and 3, the drive recorder 1 according to the present embodiment is a vehicle-mounted type that records the behavior of the vehicle V, the surrounding situation, and the like during a certain period before and after an accident or near-miss. In a single casing 2 having a generally oval overall shape, basic components, that is, detection means 3, notification means 4, input means 5, communication means 6, detachable recording means 7, and information processing The unit 8 and the like are integrated. The drive recorder 1 has a mounting adapter AP (a device-side mounting portion AP1 (see FIG. 3) fixed to the casing 2) and a windshield V1 fixed to the windshield V1 and slide-engaged with the device-side mounting portion AP1. A portion AP2 (not shown) is used to be detachably attached to the windshield V1. Hereinafter, each part is demonstrated concretely.

  The detection means 3 senses a state relating to the behavior, the surrounding situation, the operation situation, etc. of the vehicle V, and senses state data indicating the state of the photographing means 31 for photographing the situation outside the vehicle and outputting image data indicating the image. Output state detecting means. In this embodiment, at least an acceleration sensor 32 and a position sensor 33 that output acceleration data and position data, which are state data, are used as the state detection means.

  The photographing means 31 is, for example, a CCD camera as shown in FIG.

  The acceleration sensor 32 is not shown in the figure because it is built in the casing 2, but is configured using, for example, a piezoresistive effect. , Right and left, up and down) is sensed, and state data (acceleration data) indicating the acceleration is output.

  The position sensor 33 is a GPS receiver that, for example, catches radio waves from a plurality of satellites, senses the position of the vehicle V, and outputs state data (position data) indicating the position, as shown in FIG. The status data includes vehicle speed data transmitted from the vehicle speed sensor of the automobile V, door opening / closing data indicating opening / closing of the door, and the like, which are received via the connector CN. The connector CN is also used for a power source.

  As shown in FIG. 2, the notification unit 4 includes an LED 41 that is a light emitter exposed on the surface of the casing 2, an audio output body (not shown) such as a buzzer or a speaker built in the casing 2, and the like.

  The input means 5 is a button switch provided on the surface of the casing 2 here, as shown in FIG.

  Although the communication means 6 is built in the casing 2 and is not shown, it is hardware for wireless communication that transmits and receives radio waves with a base station or the like.

  Here, the detachable recording means 7 is a CF memory card (not shown) removably attached to a slot 2S that opens to the side of the casing 2.

  As shown in FIG. 4, the information processing means 8 is a so-called computer circuit having a CPU 81, an internal memory 82 (for example, a non-volatile memory), an I / O buffer circuit (which may include an AD converter or the like) 83, and the like. Yes, it is built in the casing 2. Then, when the CPU 81 operates in accordance with the drive recorder program stored in a predetermined area of the internal memory 82, the information processing means 8 has a data fetch unit 8a1, a data compression unit 8a2, a protect unit, as shown in FIG. The code generation unit 8a3, the temporary data storage unit 8b, the data writing unit 8c, the data transmission unit 8d, the data management unit 8e, and the like are configured to exhibit their functions. Hereinafter, each part will be described in detail.

  The data capturing unit 8a1 records the status data and the image data in the temporary data storage unit 8b in a proper format one after another. Specifically, various state data such as driving, that is, acceleration data, GPS position data, speed data, brake data, time, blinker left / right lighting data, door switch data indicating door open / closed state, taxi If this is the case, data such as actual vehicle / empty vehicle data that understands the behavior of the vehicle, the surrounding situation, and the operation state, image data from the photographing means 31, and the like are captured at an appropriate sampling interval and recorded in the temporary data storage unit 8b.

  The data compressing unit 8a2 is for irreversibly compressing the image data captured by the data capturing unit 8a1 to generate compressed image data. In this embodiment, the JPEG method is adopted as the lossy compression method.

  The protect code generation unit 8a3 generates a protect code for detecting falsification of the JPEG file (corresponding to “compressed data” of the present invention) using at least the inspection code and the status code as parameters. Specifically, as shown in FIG. 6, the protection code is generated by performing some logical operation on the inspection code, the status code, and the key code.

The inspection code has a predetermined size or more that constitutes a part of the compressed image data. In the present embodiment, among the data recorded in the temporary data storage unit 8b as compressed image data, an 8-byte (64-bit) code string recorded at a specified predetermined address is used as the inspection code.

Status code, in this embodiment, is intended to include acceleration data indicating the acceleration acting on the motor vehicle V. More specifically, the status code includes not only the X-direction component (16 bits), Y-direction components (16 bits) and Z-direction components (16 bits) of acceleration data , but also the file size (16 bits) of compressed image data. These are included in a predetermined order.

  The key code is for preventing the protection code from being altered by a third party or the like. In this embodiment, this key code is, for example, one that has been distributed in advance to an analysis center that performs subsequent analysis (that is, one that is not known to a third party). With this key code, it is possible to handle the inspection code and the status code obtained by performing the reverse operation of the protection code as those without falsification at the time of falsification verification of the JPEG file to be verified. The code length of the key code is the same as the code length of the inspection code or the status code, but the code length of each code can be appropriately changed according to the embodiment.

  The temporary data storage unit 8 b stores at least temporarily the data acquired by the data acquisition unit 8 a 1 and is formed in a predetermined area in the internal memory 82.

  Further, the compressed image data generated by the data compression unit 8a2 and the protection code generated by the protection code generation unit 8a3 are associated with each other and stored as a JPEG file. Specifically, the protect code is stored in a comment segment at the end of the JPEG file (not shown).

  In this comment segment, state data (acceleration data, etc.) is further stored. That is, the JPEG file is a single file including not only image data but also status data. As described above, the protect code includes a part of the status data as the status code, and by comparing this with the status data stored in the comment segment, not only the alteration of the image data, It is possible to detect even the alteration of the status data included in the JPEG file.

  The data writing unit 8c, when an event indicating an impact of an accident or occurrence of an abnormality occurs, triggers the event data from the temporary data storage unit 8b to the detachable recording unit 7 over a certain period of time. It is transferred and recorded.

  In addition, “when an event indicating an impact of an accident or occurrence of an abnormality occurs” means that the acceleration (deceleration) indicated by the acceleration data exceeds a predetermined reference value, or if the time continues for a certain time or more, Corresponds to the case where the vehicle V is turned off or the like.

  In this embodiment, depending on the event that occurred, it is triggered only when the vehicle speed is higher than the upper limit speed, when the vehicle speed is lower than the acceleration / deceleration, or when some other conditions such as the presence or absence of a brake are met. As described above, data recording is performed to save data to be recorded.

  The detachable recording means 7 that records the state data in this way is extracted from the slot 2S and carried to, for example, an analysis center and used for subsequent analysis.

  The data transmission unit 8d reads, for example, the state data stored in the temporary data storage unit 8b and transmits it to, for example, an analysis center (not shown). In addition, as shown by a broken line in FIG. 5, the data stored in the removable recording means 7 can be read and transmitted.

  The data management unit 8e weights the data recorded in the temporary data storage unit 8b from the situation when the data is recorded, and classifies the data according to the importance to be recorded. Then, when the memory capacity becomes full or the like, management is performed such that new status data is recorded after being deleted from the less important ones. Moreover, you may delete in order from an old thing. Note that, as indicated by a one-dot broken line in FIG. 5, the status data recorded in the detachable recording means 7 can be classified in the same manner.

  In the drive recorder 1 configured as described above, an operation of generating a protection code from image data and status data and recording it as a JPEG file in the internal memory 82 will be described with reference to FIG.

  First, when the data capture unit 8a1 captures image data from the photographing unit 31 at a predetermined sampling timing (step S101), the data compression unit 8a2 converts the image data captured by the data capture unit 8a1 into the JPEG format. The lossy compression is performed to generate compressed image data (step S102).

  Next, the protect code generation unit 8a3 generates a protect code by performing a predetermined logical operation on the inspection code read from the compressed image data, the status code, and the key code (step S103).

  The generated protect code is associated with the compressed image data generated by the data compression unit 8a2, and these are recorded in the temporary data storage unit 8b as an original JPEG file (step S104).

  According to the drive recorder 1 according to the present embodiment configured as described above, it is possible to determine whether or not the verified JPEG file has been tampered with based on the presence or absence of the protection code.

  Specifically, if there is no protect code in the JPEG file to be verified, it can be determined that tampering has occurred. This is because if the original data to which the protection code is assigned is altered, the protection code is deleted at the time of saving.

  Such a determination can be made, for example, by the analysis device P provided in the analysis center that constitutes the data analysis system together with the drive recorder 1.

  Specifically, as shown in FIG. 8, the analysis device P includes a CPU 101, an internal memory 102, an external storage device 103 such as an HDD, an input interface 104 such as a mouse or a keyboard, a display device 105 such as a liquid crystal display, an Internet INT. A computer including a communication interface 106 for connecting to a communication network such as the above is used. Then, the analysis device P operates the CPU 101 and peripheral devices in accordance with a falsification analysis program stored in the internal memory 102, and as shown in FIG. 9, as a data reading unit P1, a falsification presence / absence determination unit P2, etc. So that the function of. Hereinafter, each means will be described.

  The data reading unit P1 is for reading the protect code from the detachable recording means 7. It should be noted that the data stored in the internal memory 82 of the drive recorder 1 is not prevented from being read using the data transmission unit 8d.

  The tampering presence / absence judging unit P2 judges that there is no tampering in the JPEG file to be verified when there is no protect code that can be read by the data reading unit P1, and judges that there is no tampering if there is any. Is. The determination result can be output by an appropriate method such as screen output or print output.

  Further, since the byte array of the inspection code has a size that can be handled as a unique code, it can be determined from this inspection code and the status code whether the JPEG file to be verified has been tampered with. become.

  Specifically, even if the tamper has re-assigned the protection code recorded in the original data after tampering, the compressed image data of the JPEG file is irreversible compression data, so the JPEG file for verification is The inspection code obtained from the JPEG file is compared with the inspection code obtained by, for example, reverse operation from the protection code, and if they match, the JPEG file to be verified has not been altered from the original data. If they do not match, it can be determined that there has been tampering.

  Such a determination is made by the analysis device P operating the CPU 101 and peripheral devices in accordance with another falsification analysis program stored in the internal memory 102, as shown in FIG. The functions of the code comparison unit P3, the alteration presence / absence determination unit P4, and the like may be exhibited. Hereinafter, the inspection code comparison unit P3 and the alteration presence / absence determination unit P4 will be described.

  The inspection code comparison unit P3 compares the inspection code calculated backward from the protect code read by the data reading unit P1 and the inspection code obtained from the compressed image data to be verified.

  The tampering determination unit P4 determines that the JPEG file for verification has been tampered with when the inspection code comparison unit P3 does not match, and if they match, there is no tampering. It is a judgment. The determination result can be output by an appropriate method such as screen output or print output.

  In this way, whether or not the image has been tampered with can be easily and reliably determined by the presence or absence of the protection code and the comparison of the inspection code, and if it can be determined that there is no tampering from the original data, the captured image itself is Can be used as evidence.

  Similarly, the acceleration data and file size to be verified stored as other state data, and the state code (X, Y and Z direction components of acceleration data, file size obtained by reverse operation of the protection code) ) Can be determined whether or not the acceleration data for verification and the file size have been tampered with. This makes it possible to detect the presence / absence of alteration not only in image alteration but also in status data such as acceleration data that is likely to be altered as evidence of an accident.

  The present invention is not limited to the above embodiment.

  For example, as the status code, in addition to the acceleration data and the file size, for example, latitude / longitude information that affects the fact analysis result such as an accident can be used.

  If the data that affects the fact analysis results such as accidents (also referred to as impact data) is stored in the storage means when tampered with, the protection code includes the impact data, so that when the fact analysis is performed, The influence data for verification stored in the storage means is compared with the influence data obtained from the protect code, and based on the result, it can be determined whether or not the influence data for verification is falsified. become.

  Further, the lossy compression method is not limited to the JPEG method.

  In addition, a type that is not attached to the vehicle can be used as the photographing means. In this case, the image can be used as an image recording apparatus that can use the image itself as evidence.

  Other configurations can be variously modified without departing from the spirit of the present invention.

The typical front view which shows the case where the drive recorder of this invention is attached to a motor vehicle. The perspective view at the time of seeing from the vehicle inside of the drive recorder in the embodiment. The perspective view at the time of seeing from the vehicle outer side of the drive recorder in the embodiment. The equipment block diagram of the drive recorder in the embodiment. The function block diagram of the information processing means in the embodiment. The figure for demonstrating the production | generation method of the protection code in the same embodiment. The flowchart which shows the operation | movement regarding recording from the image capture of the drive recorder in the embodiment. The equipment block diagram of the analyzer in the embodiment. The function block diagram of the analyzer in the embodiment. The other functional block diagram of the analyzer in the embodiment.

DESCRIPTION OF SYMBOLS 1 ... Drive recorder 8a2 ... Data compression part 8a3 ... Protect code production | generation part 8b ... Data storage part (temporary data storage part)
31... Shooting means 82... Recording means (internal memory)
V ... Vehicle (car)
P... Analyzing device P1... Data reading unit P2... Tampering presence / absence judgment unit P3... Inspection code comparison unit P4.

Claims (8)

Photographing means attached to the vehicle, and state detection means for detecting a state related to the behavior, surroundings or operation state of the vehicle;
Recording means for recording as compressed data at least associating compressed image data obtained by irreversibly compressing an image photographed by the photographing means and a protection code for detecting falsification of the compressed image data;
State data indicating a part of the compressed image data and having a code of a predetermined size or more read from a predetermined address of the compressed image data as an inspection code and indicating the state output by the state detection unit At least a portion and status encoding, the drive recorder the check code and status code to the protected code. The state data, the drive recorder according to claim 1, wherein the acceleration data indicating the acceleration acting on the vehicle. Computer
A data compression unit that generates compressed image data obtained by irreversibly compressing an image captured by an imaging unit attached to a vehicle;
A part of the compressed image data , which is a code having a predetermined size or more read from a predetermined address of the compressed image data is used as an inspection code, and a state relating to the behavior of the vehicle, the surrounding situation, or the operating situation. A protection code that uses at least a part of the status data indicating the status output by the status detection means for detection as a status code , and uses the inspection code and the status code as a protection code for detecting falsification of the compressed image data A generator,
A drive recorder program for functioning as a data storage unit that records at least the compressed image data and the protect code in association with each other. Computer
An image photographed by a photographing means attached to a vehicle is irreversibly compressed and is compressed image data, and a part of the compressed image data , which is equal to or larger than a predetermined size read from a predetermined address of the compressed image data The code is an inspection code, and at least a part of the state data output by the state detection means for detecting the state of the vehicle behavior, the surrounding situation, or the operation situation is the state code, and the inspection code and the state code . A data reading unit for reading out the protection code from storage means for storing at least associating the protection code for detecting falsification of the compressed image data;
A falsification analysis program for functioning as a falsification presence / absence determination unit that determines that the compressed image data has been falsified when there is no protect code that can be read by the data reading unit. Computer
An image photographed by a photographing means attached to a vehicle is irreversibly compressed and is compressed image data, and a part of the compressed image data , which is equal to or larger than a predetermined size read from a predetermined address of the compressed image data The code is an inspection code, and at least a part of the state data output by the state detection means for detecting the state of the vehicle behavior, the surrounding situation, or the operation situation is the state code, and the inspection code and the state code . A data reading unit for reading out the protection code from storage means for storing at least associating the protection code for detecting falsification of the compressed image data;
An inspection code that is calculated backward from the protection code read by the data reading unit, and an inspection code comparison unit that compares the inspection code obtained from the compressed image data to be verified;
A falsification analysis program for causing the inspection code comparison unit to function as a falsification presence / absence determination unit that determines that the compressed image data has been falsified when the inspection codes do not match. A data analysis system comprising a drive recorder used by being attached to a vehicle, and an analysis device for analyzing data recorded by the drive recorder,
The drive recorder
Photographing means attached to the vehicle, and state detection means for detecting a state related to the behavior, surroundings or operation state of the vehicle;
Recording means for recording as compressed data at least associating compressed image data obtained by irreversibly compressing an image photographed by the photographing means and a protection code for detecting falsification of the compressed image data;
State data indicating a part of the compressed image data and having a code of a predetermined size or more read from a predetermined address of the compressed image data as an inspection code and indicating the state output by the state detection unit a state encoding at least a portion of the test code and status code is intended to be the protection code,
The analysis device includes:
A data reading unit for reading a protection code from the storage unit;
A data analysis system comprising: a tampering presence / absence determining unit that determines that the compressed image data has been tampered with when there is no protect code readable by the data reading unit. A data analysis system comprising a drive recorder used by being attached to a vehicle, and an analysis device for analyzing data recorded by the drive recorder,
The drive recorder
Photographing means attached to the vehicle, and state detection means for detecting a state related to the behavior, surroundings or operation state of the vehicle;
Recording means for recording as compressed data at least associating compressed image data obtained by irreversibly compressing an image photographed by the photographing means and a protection code for detecting falsification of the compressed image data;
State data indicating a part of the compressed image data and having a code of a predetermined size or more read from a predetermined address of the compressed image data as an inspection code and indicating the state output by the state detection unit a state encoding at least a portion of the test code and status code is intended to be the protection code,
The analysis device includes:
A data reading unit for reading a protection code from the storage unit;
An inspection code that is calculated backward from the protection code read by the data reading unit, and an inspection code comparison unit that compares the inspection code obtained from the compressed image data to be verified;
A data analysis system comprising a tampering presence / absence judging unit that judges that the compressed image data has been tampered with when the test code comparison unit does not match each other. Generates compressed image data by irreversibly compressing the image captured by the imaging means attached to the vehicle,
A part of the compressed image data , which is a code having a predetermined size or more read from a predetermined address of the compressed image data is used as an inspection code, and a state relating to the behavior of the vehicle, the surrounding situation, or the operating situation. At least a part of the status data output by the status detection means for detection is a status code,
The check code and status code, a protect code to detect tampering of the compressed image data,
An image alteration detection method for a drive recorder, wherein at least the compressed image data and the protection code are associated with each other and recorded as data in a recording means.