JP3497417B2 - Image recording system with image alteration discrimination function and image recording method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording system with an image tampering discrimination function and an image recording method.

[0002]

2. Description of the Related Art With the development of multimedia technology in recent years, JPE has been used in various fields.
G (Joint Picture Experts Group) and Motion JP
Digital images such as EG have come to be used. Such digital images include not only original images created by humans, such as animation, but also actual images captured by an imaging camera, for example, in the field of surveillance systems for monitoring a predetermined surveillance target. In
When an abnormal situation occurs, a digital image may be used to record the abnormal situation or notify the surveillance center by communication. As described above, when a real digital image that is actually taken is used, it is important not to allow subsequent tampering of the digital image in order to ensure its reliability (truth).

However, in the recent multimedia technology, a part of a digital image is combined with another digital image by using various application software programs such as a photo retouching software program or a part of the digital image is combined. It is easy to correct and delete, and it is possible to tamper with a digital image with relatively little effort.
Therefore, it is desirable to make a posterior decision as to whether or not the digital image has been tampered with.

However, conventionally, when a digital image is tampered with, there are not many means for knowing the tampered fact. Therefore, for example, when recording a digital image captured by a surveillance system in a predetermined recording device, it is difficult to know whether the digital image has been tampered with, and the reliability of the digital image is Improvement was desired.

It is to be noted that predetermined digital watermark information (DigitalWatermark) is embedded in a digital image by using, for example, a so-called digital watermark technique, and the digital image is converted into a digital image depending on whether the digital watermark information is distorted or deformed. A method of determining whether there has been tampering is also possible. However, this digital watermark technique is originally intended to detect an illegal copy of a digital image, and is unsuitable for use in detecting whether it has been tampered with. That is, in this digital watermark technology, the digital watermark information is taken out by obtaining the difference with respect to the original image. Therefore, in order to judge whether the digital watermark information has changed, it is necessary to individually check all digital images. After preparing the original image and obtaining the difference from the original image, it is necessary to further judge whether the digital watermark information is correct information. However, when handling an extremely large number of digital images such as motion JPEG, it is not realistic to prepare the original images of the digital images of all the frames, and there is a security problem in handling the original images themselves. From
It is practically impossible to use such a digital watermark technique for detecting falsification of a huge amount of digital images.

Therefore, an object of the present invention is to provide an image recording system with an image tampering discrimination function and an image recording method which can easily judge the fact of tampering of a digital image afterwards without preparing an original image. is there.

[0007]

[Means for Solving the Problems] In order to solve the above problems,
The invention according to claim 1 inputs one after another from the image input device.
As multiple digital images for each frame
The images are sequentially recorded in the image recording device, and
Whether the digital image recorded in the storage has been tampered with
Image record with image falsification discrimination function that can discriminate whether
A recording system, wherein the image recording device is the digital recording device.
Image recording means for recording and saving digital images, and the image input
Based on the information in each image that is input from the device one after another,
No. data is generated and the encrypted data is converted into a digital image.
It is added to the header part and recorded and stored in the image recording means.
Together with the digital image recorded in the image recording means.
The image in the digital image indicates whether the image has been tampered with.
Control unit for discriminating based on data and the encrypted data
And an operation input for giving a desired operation instruction to the control unit.
Input device, the control unit controls the image from the image input device.
Is input for each frame one after another, the frame
The image data in the digital image and the previous frame according to
Using the encrypted data in the digital image
The encrypted data is sought in a chain and the encrypted data is
It is added to the header part of the digital image and the header part is added.
The digital image stored in the image data storage device.
Function to record and save, and whether the digital image has been tampered with
Based on the operation on the operation input device when determining
The digital image of each frame to the image data
Read one after another from the storage device,
Before the image data in the digital image and the previous frame
The chained check is performed using the encrypted data in the digital image.
Check value and the check value and the encrypted data
Compare and judge that both match according to this comparison result
The digital image has not been tampered with.
On the other hand, if it is determined that they do not match, the
The digital image has a function of determining that the digital image has been tampered with .

[0008]

[0009]

[0010]

According to a second aspect of the present invention, in the image recording apparatus, predetermined table data including a plurality of numerical sequences for specifying a plurality of arbitrary pixel positions in the image data of the digital image, and A predetermined table in which a predetermined table number and a predetermined table number are stored is prepared in advance in the plurality of number sequences of the table data, and the control unit sets any one of the plurality of number sequences in the table data in the table. Selected in accordance with a predetermined procedure, the pixel data of a predetermined digit starting from the pixel position in the digital image according to the selected number sequence is respectively taken out as a numerical value,
The check value is obtained by calculating the total value of the numerical values, the check value is added as encrypted data to the header portion of the digital image, and the digital image to which the header portion is added is recorded in the image data storage device. In the case of determining the function of saving and whether or not the digital image has been tampered with, the digital image of each frame is sequentially read from the image data saving device based on the operation of the operation input device, and stored in the table. Select any one of the plurality of the number sequences in the table data of according to a predetermined procedure, the pixel data of a predetermined digit starting from the pixel position in the digital image according to the selected number sequence, respectively. Take out as a numerical value, calculate the check value by calculating the total value of the numerical values, compare the check value and the encrypted data, A function of determining that the digital image has not been tampered with when it is determined from the comparison result that the digital image has been tampered with, and a function of determining that the digital image has been tampered with. And the predetermined procedure, when the digital image to be processed in the procedure relates to the first frame,
The check value of the digital image of the previous frame is selected when the digital image to be processed by the procedure is related to the second and subsequent frames while the sequence of the table numbers corresponding to the first frame is selected. The number sequence of the table number corresponding to the value at a predetermined position in the table is selected.

According to a third aspect of the present invention, there is provided an image recording method for sequentially recording a plurality of images sequentially input from the image input device as a digital image for each frame, which is input from a predetermined image input device. When images are sequentially input frame by frame, the encrypted data is obtained in a chain using the image data in the digital image of the frame and the encrypted data in the digital image of the previous frame, When the encrypted data is added to the header portion of the digital image, the digital image to which the header portion is added is recorded and stored in a predetermined image data storage device, and it is determined whether or not the digital image has been tampered with, Based on the operation of the operation input device, the digital images related to each frame are sequentially read from the image data storage device, According to the comparison result, the check value is calculated in a chain using the image data in the digital image related to the above and the encrypted data in the digital image related to the previous frame, and the check value is compared with the encrypted data. When it is determined that the two match, it is determined that the digital image has not been tampered with, whereas when it is determined that the two do not match, it is determined that the digital image has been tampered with. .

According to a fourth aspect of the present invention, there is provided an image recording method for sequentially recording a plurality of images sequentially input from the image input device as a digital image for each frame, wherein a predetermined table recording means is provided with the digital signal. A predetermined table including a number sequence for specifying a plurality of arbitrary pixel positions in the image data of the image and a table number for identifying the number sequence is recorded in advance, and is related to the image input from a predetermined image input device. When recording the digital image, if the digital image relates to the first frame, the sequence of the table numbers corresponding to the first frame is selected, while the digital image is the second or subsequent one. In the case of a frame, the value corresponding to the value of the predetermined position in the check value of the digital image of the previous frame Selecting the number sequence of the table number and the step of obtaining pixel data dispersed as pixel values at pixel positions in the digital image corresponding to the selected number sequence and calculating the check value by calculating the total value of the numbers. And a step of adding the check value as encrypted data to the header part of the digital image and recording and saving the digital image to which the header part is added in the image data saving device.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment <Structure> FIG. 1 is a block diagram showing an image recording system with an image tampering discrimination function according to a first embodiment of the present invention. This image recording system holds in advance predetermined secret key data generated based on a predetermined unique environment number and a random number peculiar to the image recording system,
Some dispersed pixel data in a desired digital image are taken out as a numerical value, a total value of the numerical values (check value, hereinafter referred to as "checksum") is obtained, and this checksum is processed with secret key data. After the fixed-length encrypted data is generated, the encrypted data is stored in the header portion of the digital image and then recorded, and the image data in the recorded digital image (hereinafter referred to as “recorded image”). ), The encrypted data in the header part of each digital image is decrypted, and the checksum is obtained from each recorded image in the same manner as described above to obtain the decrypted value (decrypted data). It is designed to be compared with the checksum.

Specifically, this image recording system is shown in FIG.
As described above, the image (image) captured by the image capturing camera (image input device) 1 is recorded as a digital image by the image recording device 2, and the display of the image is later displayed on the monitor device 3 by an operation input device 4 such as a keyboard input device. It is designed to be executed based on the operation in.

The image pickup camera 1 picks up an image of a predetermined image pickup object using an image pickup device such as a CCD. The face image picked up by the image pickup camera 1 is output as an analog NTSC signal to record an image. Provided to device 2.

The image recording device 2 is an analog NTSC provided from the image pickup camera 1 through the video input terminal 11.
N for converting video data as a signal into a digital image
A TSC decoder 12, a gate array 13 that controls various types of data transfer and signal synchronization adjustment, and an image compression chip 15 that converts a digital image input through the gate array 13 into predetermined compressed data such as motion JPEG. An image memory 14 for temporarily storing the compressed data compressed by the image compression chip 15, and secret key data for generating the above-mentioned encrypted data for the compressed data compressed by the image compression chip 15 are stored in advance. The private key storage memory 16 and the private key storage memory 1
An image data storage device 17 for recording and storing a digital image after the encrypted data generated by using the secret key data in 6 and a central processing unit (CPU: control unit) for controlling all of these various arithmetic processes. ) 18 and a work memory 19 for temporarily storing various data when the CPU 18 performs arithmetic processing.

The CPU 18 operates according to a software program stored in advance in a storage device (not shown) such as a hard disk drive. In particular, the CPU 18 generates secret key data and stores it in the secret key storage memory 16. A secret key data generation mode to be stored in, and a recording mode for recording video data imaged by the imaging camera 1,
The tampering determination mode for deciding whether or not the image data (recorded image) in the already recorded digital image has been tampered with is switched to.

In the secret key data generation mode, the application software program that regulates the operation of the image recording system is automatically activated when it is first activated, and the CPU 18 is driven according to the application software program. The private key data unique to this image recording system is automatically generated. Specifically, the specific environmental information stored when the operating system (OS) stored in the image recording system is first installed (installed) is recorded in a specific recording device, and the specific environmental information is recorded. , Or using predetermined specific environment information when the application software program that regulates the operation of the image recording system is first started,
The secret key data described above is generated. For example, the date and the hour, minute, second at the time when the OS or application software program is first started are used as the unique environment information (unique environment number), and a predetermined random number table is provided. A value for a predetermined number of digits starting from the position corresponding to the unique environment number is stored in the private key storage memory 16 as private key data. The private key data once generated and stored in this way is referred to by an external operation,
It is stored in the private key storage memory 16 as a so-called hidden file so that it cannot be copied or moved.

The recording mode is activated by the operation of the operation input device 4. In this recording mode, the CPU 18 operates when image data is given from the image pickup camera 1 to the image input terminal 11. A function of instructing the NTSC decoder 12 to convert video data into a digital image, a function of giving a digital image converted by the NTSC decoder 12 to the image compression chip 15 through the gate array 13 and instructing compression processing, The compressed data compressed by the compression chip 15 is stored in the image memory 1
4 and a digital image compressed by the image compression chip 15 (reference numeral 2 in FIG. 2).
0) The image data (reference numeral 20a in FIG. 2) of the dispersed pixel data at some predetermined positions are taken out as numerical values, and the checksum (reference numeral 21 in FIG. 2) as the total value of the numerical values is obtained. Function and function of processing and encrypting the checksum 21 with the secret key data (reference numeral 22 in FIG. 2) in the secret key storage memory 16 to generate fixed-length encrypted data (reference numeral 23 in FIG. 2) And the encrypted data 23 in the header portion of the digital image 20 (reference numeral 20b in FIG. 2).
Digital image 2 with this header portion 20b
0 is recorded and stored in the image data storage device 17. In particular, in the encryption processing of the checksum 21, the checksum 21 and the secret key data 22 are
And are calculated by a predetermined arithmetic expression such as addition or integration to generate encrypted data. Also, by adding the encrypted data 23 as the header portion 20b of the digital image 20, it is generated in a format different from general-purpose data such as general motion JPEG.

Further, the tampering discrimination mode is activated based on the operation of the operation input device 4, and the image data storage device 17 is activated.
A function of calling a desired digital image 20 recorded and stored in the work memory 19 into the work memory 19, and a secret key storage of the encrypted data 23 in the header portion (reference numeral 20b in FIG. 3) of the digital image 20 called into the work memory 19. Memory 16
The function of decoding into the checksum format decoded data (reference numeral 24 in FIG. 3) using the private key data 22 in the above, and the distribution in the image data (recorded image) 20a of the digital image 20 called into the work memory 19. Checksums (reference numeral 2 in FIG. 3) from the pixel data of some predetermined positions
5) The function of obtaining the checksum 25 and the function of comparing the checksum 25 and the decrypted data 24 in the checksum format decrypted by using the secret key data 22, and when it is determined that the results match, A function of determining that the digital image 20 has not been tampered with, and a function of determining that the digital image 20 has been tampered when it is determined that they do not match, and the result of this determination, together with the recorded image 20a, are output through the video output terminal 5. It has a function of outputting to the monitor device 3 and displaying it on the monitor device 3.

<Operation> A method of recording the digital image 20 in the image recording system with the image tampering discrimination function having the above configuration will be described.

First, as a premise, in this image recording system, the secret key data generation mode is automatically activated when the application software program that regulates the operation is first activated, and the CPU 18 secrets the application software program. By driving in accordance with the key data generation mode, secret key data (reference numeral 22 in FIGS. 2 and 3) unique to this image recording system is automatically generated. For example, the operating system (O
The value of the date and the hour, minute, second when S) was first introduced (installed) is recorded as a unique environment number in a predetermined recording device, and the position corresponding to the unique environment number in a predetermined random number table is recorded. A value for a predetermined number of digits as a starting point is stored in the private key storage memory 16 as private key data 22.
Alternatively, the date and the hour, minute, and second values at the time when the application software program that regulates the operation of the image recording system is first activated are used as the unique environment number,
A value for a predetermined number of digits starting from the position corresponding to the unique environment number in the predetermined random number table may be stored in the private key storage memory 16 as the private key data 22. Thus, the private key data 22 once stored in the private key storage memory 16 is stored in the private key storage memory 16 as a so-called hidden file so that it cannot be referred to, copied, or moved by an external operation. .

Next, when recording the image data picked up by the image pickup camera 1 in the image recording device 2, a predetermined operation is performed by the operation input device 4 to activate the recording mode of the application software program as shown in FIG. .

In this recording mode, when the image pickup camera 1 inputs the image pickup image data to the image input terminal 11 of the image recording apparatus 2, the NTSC decoder 12 converts the image data into a digital image based on a command from the CPU 18. To do. The converted digital image is supplied to the image compression chip 15 through the gate array 13 and compression processing is performed by a predetermined method such as motion JPEG.

The digital image (reference numeral 20 in FIG. 2) compressed by the image compression chip 15 is temporarily stored in the image memory 14 and is dispersed in the image data (reference numeral 20a in FIG. 2). The pixel data at some predetermined positions are extracted as numerical values, and the checksum (reference numeral 21 in FIG. 2) as the total value of the numerical values is obtained.

The checksum 21 is added or integrated with the secret key data (reference numeral 22 in FIG. 2) in the secret key storage memory 16 to be encrypted, and fixed length encrypted data (reference numeral 23 in FIG. 2). ) Is generated.

Then, the CPU 18 sends the encrypted data 2
3 is a header portion of the digital image 20 (reference numeral 20 in FIG.
b), and in that state is recorded and stored in the image data storage device 17.

Next, a method for determining whether or not the digital image 20 recorded in the image recording device 2 has been tampered with will be described.

First, as shown in FIG. 1, when the CPU 18 is switched to the falsification discrimination mode by the operation of the operation input device 4, the CPU 18 reproduces the desired digital image 20 recorded and stored in the image data storage device 17. Call to the work memory 19. Then, the header section (reference numeral 2 in FIG. 3) in the digital image 20 called to the work memory 19
The encrypted data 23 in 0b) is decrypted into the decrypted data in checksum format (reference numeral 24 in FIG. 3) using the private key data 22 in the private key storage memory 16.

On the other hand, the CPU 18 obtains a checksum (reference numeral 25 in FIG. 3) from the pixel data of some dispersed predetermined positions in the image data (recorded image) 20a of the digital image 20 called to the work memory 19. Ask.
Then, the checksum 25 and the checksum format decrypted data 24 decrypted using the secret key data 22 are compared as shown in FIG.

If it is determined from the comparison result that they match, it is determined that the digital image 20 has not been tampered with. On the other hand, if it is determined that they do not match, it is determined that the digital image 20 has been tampered with. After that, the CPU 18 displays the determination result on the monitor device 3 together with the recorded image 20a.

As described above, in this embodiment, the predetermined secret key data 22 generated on the basis of the unique environment number and the random number unique to each image recording system are held in advance and desired. Some dispersed pixel data in the image data 20a of the digital image 20 are taken out as numerical values to obtain a checksum 21, and the checksum 21 is processed with the secret key data 22 to generate the fixed-length encrypted data 23. After that, the encrypted data 23 is stored in the header portion 20b of the digital image 20 and then recorded. When determining whether or not the recorded image 20a is falsified, the header portion 20b of each digital image 20 is determined.
Since the encrypted data 23 therein is decrypted to generate the decrypted data 24, the checksum 25 is obtained from each recorded image 20a in the same manner as described above, and the decrypted data 24 and the checksum 25 are compared. Even if the original image is not prepared unlike the digital watermark technique, the fact that the digital image has been tampered with can be easily determined from only the encrypted data 23 in the header portion and the recorded image 20a.

Further, the secret key data is determined based on the unique environment number unique to each image recording system, such as digitizing predetermined information such as date and time, hour, minute and second when the OS or application software program is first started. Therefore, it becomes impossible to obtain the secret key data of one image recording system from another image recording system, so that the confidentiality of the secret key data can be highly secured.

In this embodiment, the date and time and the hour, minute, second when the OS or application software program is first started are digitized and used as the unique environment number. The user name to be confirmed and the password arbitrarily decided by the user are digitized, and the numeric value is used as a unique environment number, and a numeric string of a predetermined digit starting from the position of the random number table corresponding to this unique environment number is kept secret. It may be key data.

Alternatively, the above-mentioned unique environment number may be used as the secret key data as it is without using the random number table.

Alternatively, of some information such as the year, month, day, hour, minute, second, user name and password when the OS or application software program is first started, for example, based on the environment in which the application software program is first started. You may select only one and digitize the selected information and use this as the unique environment number. In this case, when the selection branches are four of year, month, day, hour, minute, second, user name and password, for example, the hour, minute, second when the application software program is first started is divided by 4 and the remainder value If "0" indicates the date, "1" indicates the hour, minute, second, "2" indicates the user name, and "3" indicates the password. It may be prescribed in advance as a part of the application software program.

[Second Embodiment] <Structure> FIG. 4 is a schematic diagram showing an image tampering determination method of an image recording system with an image tampering determination function according to a second embodiment of the present invention, and FIG. It is a block diagram showing an image recording system. Note that, in FIG. 4, only the digital images 30A to 30D related to four frames are shown for convenience of description, but it goes without saying that digital images of more frames than this can be actually handled.
Further, in FIG. 5, elements having the same functions as those in the first embodiment are designated by the same reference numerals.

In the image recording system with the image tampering discrimination function of this embodiment, if digital images 30A to 30D of a plurality of frames are successively given like motion JPEG, the presence or absence of tampering of each digital image 30A to 30D is checked. Which is effective in determining
As described above, checksums 31A to 31 are obtained by taking out some dispersed pixel data in the image data 30Aa to 30Da of the digital images 30A to 30D as numerical values.
After obtaining D, the checksums 31A to 31D are processed to generate fixed-length encrypted data 33A to 33D, and the encrypted data 33A to 33D are converted to digital images 30A to 3D.
This is the same as the first embodiment in that it is stored in the 0D header sections 30Ab to 30Db and then recorded, but the secret key data is used when the checksums 31A to 31D are obtained. Instead, the selection target of the pixel data extracted from each image data (hereinafter simply referred to as “frame”) 30Aa to 30Da of the digital images 30A to 30D for each frame is set to each frame 30Aa to 30D.
It is changed for each a, and the total value selected here and the checksums 31A to 31C created in the previous digital images 30A to 30C are added, whereby the values different for each frame 30Aa to 30Da. The checksums 31A to 31D are generated based on the checksums 31A to 31D, and the checksums 31A to 31D are directly used as the encrypted data 33A to 3D
It is designed to be used as 3D.

The structure of this image recording system (FIG. 5)
1 is similar to that of the first embodiment shown in FIG. 1 except that the private key storage memory (reference numeral 16 in FIG. 1) included in the image recording system of the first embodiment is used. (See) is omitted.

Further, in the image data storage device 17, several different positions of pixel data are designated as shown in Table 1 below as targets for selecting the positions of the pixel data extracted from each of the frames 30Aa to 30Da. Multiple types of tables are prepared and stored in advance.

[0042]

[Table 1]

In Table 1, the numerical value in the left column indicates the table number, and the numerical value in the right column indicates the frame 30.
The starting point position of the pixel data selected within Aa to 30 Da is shown. For example, in the table data whose table number is 0, the sequence in the right column is {1, 15, 54, 108,
…}. This is because when the 0th table data in the table of Table 1 is selected by the CPU 18, the value of the pixel data selected at the time of generating the checksum (one of symbols 31A to 31D) is a predetermined value from the 1st Byte. Digit value, the value of a predetermined digit from the 15th byte, 54B
It is shown that it is a value of a predetermined digit from the y-th eye, a value of a predetermined digit from the 108-th eye, and so on, and the same meaning is given to the 1, 2 ... Tables.

Note that this table is for the digital image 30.
Since A to 30D are also stored in the image data storage device 17 in which the images A to 30D are recorded, the image data storage device 17 records image recording means and a table for recording and storing the digital images 30A to 30D. It also serves as a table recording means.

The application software program that regulates the operation of the CPU 18 has a data selection function in the table of Table 1 and is unique to this embodiment.

Specifically, this application software program regulates the following operations and functions of the CPU 18.

That is, based on the operation on the operation input device 4, the CPU 18 determines the recording mode for recording the video data imaged by the imaging camera 1 and the presence / absence of alteration of the recorded image in the already recorded digital image. The mode is switched to the tampering discrimination mode for discriminating.

The recording mode is activated by a predetermined operation on the operation input device 4. In this recording mode, the CPU 18 operates when image data is given from the image pickup camera 1 to the image input terminal 11. A function of instructing the NTSC decoder 12 to convert video data into a digital image, a function of giving a digital image converted by the NTSC decoder 12 to the image compression chip 15 through the gate array 13, and instructing compression processing, The function of instructing to temporarily store the processed compressed data in the image memory 14, and the 0th table data is selected when the checksum 31A of the first frame 30Aa is generated, and the top of the frame 30Aa is selected. To the position described in the table data (1 Byte, 15B)
y-th, 54-byte, 108-byte, ...) As a starting point, values of predetermined digits are extracted, and all of these values are added to generate a checksum 31A.
A function of recognizing a predetermined lower bit of the checksums 31A to 31C related to the previous digital images 30A to 30C when generating the checksums 31B to 31D of the second and subsequent images, and the previous frame 30Aa recognized here. ~ 30
A function of reading new table data (see the right column in Table 1) in the table of Table 1 using the value of the lower predetermined bit of Ca as the table number (see the left column in Table 1) and this newly read Starting from the position described in the table data, the values of predetermined digits are extracted, all of these values are added, and the previous digital image 3
Checksums 31A-31 generated within 0A-30C
The function of adding checksums 31B to 31D of the new digital images 30B to 30D by adding it to C, and these checksums 31A to 31D as they are as the encrypted data 33.
A function to store the digital images 30A to 30D in the header portions 30Ab to 30Db as A to 33D, and a function to record and store the digital images 30A to 30D to which the header portions 30Ab to 30Db are added in the image data storage device 17. Have.

Here, when the checksums 31B to 31D of the second and subsequent images are generated, the previous digital image 30 is generated.
When recognizing the lower predetermined bits of the checksums 31A to 31C related to A to 30C, the number of bits is determined in advance by the number of table data (the number of selection branches) in the table shown in Table 1, and, for example, 2 bits when there are 4 selection branches, 3 bits when there are 8 selection branches, 2 bits when the selection branches
In the case of individual pieces, it is 1 bit.

It should be noted that the digital images 30A-3
Encrypted data 3 as header parts 30Ab to 30Db of 0D
By adding 3A to 33D, general motion J
It is generated in a format different from general-purpose data such as PEG.

In addition, the tampering discrimination mode is operated by the operation input device 4
It is designed to be started based on a predetermined operation in
A function for sequentially calling the digital images 30A to 30D recorded and stored in the image data storage device 17 into the work memory 19 from the first frame 30Aa;
9. The encrypted data 33A to 33 in the header portions 30Ab to 30Db in the digital images 30A to 30D called in FIG.
The function of reading D and the frame 30Aa in the digital images 30A to 30D previously called in the work memory 19
Checksums 31A to 31 in the same manner as the recording mode using the table data in the table of Table 1 from ˜30 Da
The function of obtaining D, the function of comparing the checksums 31A to 31D with the encrypted data 33A to 33D, and the recorded digital images 30A to 30D are not falsified when it is determined that they match from the comparison result. However, if it is determined that they do not match, the recorded image 30
It has a function of determining that Aa to 30Da have been tampered with, and a function of outputting the determination result together with the recorded images 30Aa to 30Da to the monitor device 3 through the video output terminal 5 and displaying the result on the monitor device 3. .

<Operation> Digital images 30A to 30 in the image recording system with the image tampering discrimination function having the above configuration
The recording method of D will be described. However, as a premise, it is assumed that the table of Table 1 is previously stored in the image data storage device 17.

First, when recording the image data picked up by the image pickup camera 1 in the image recording device 2, as shown in FIG. 5, a predetermined operation is performed by the operation input device 4 to activate the recording mode of the application software program.

In this recording mode, the first frame of the video data picked up by the image pickup camera 1 is set to the image recording device 2.
Input to the video input terminal 11 of the NTSC decoder 1
2 converts the video data of the first frame into a digital image based on a command from the CPU 18. The converted digital image is sequentially supplied to the image compression chip 15 through the gate array 13 and the motion JPE
The compression process is performed by a predetermined method such as G. The compressed data subjected to the compression processing is temporarily stored in the image memory 14.

Then, as shown in FIG. 4, the image compression chip 15
With respect to the digital image 30A related to the first frame 30Aa compressed by
To generate.

Here, when the checksum 31A of the first frame 30Aa is generated, the 0th table data in the table shown in Table 1 is selected and the 0th table data from the head of the frame 30Aa is selected. Positions described in table data (1st byte, 15th byte,
(54th byte, 108th byte, ...) As a starting point, values of predetermined digits are extracted, and all of these values are added to generate a checksum 31A. The checksum 31A obtained here is directly used as the encrypted data 33A in the header portion 30Ab of the digital image 30A.
To store. Then, the digital image 30A provided with the header portion 30Ab is recorded and stored in the image data storage device 17.

Next, the second frame of the video data picked up by the image pickup camera 1 is set to the video input terminal 1 of the image recording apparatus 2.
When input to 1, the NTSC decoder 12
The video data of the second frame is converted into a digital image based on a command from the. The converted digital image is sequentially applied to the image compression chip 15 through the gate array 13 and compression processing is performed by a predetermined method such as motion JPEG. The compressed data subjected to the compression processing here is temporarily stored in the image memory 14.

Then, as shown in FIG. 4, the image compression chip 15
For the digital image 30B related to the second frame 30Ba compressed by
Generate B.

Here, when generating the checksum 31B of the second frame 30Ba, the lower predetermined bits of the checksum 31A in the first digital image 30A are recognized. The number of predetermined bits to be recognized at this time is predetermined according to the number of table data (the number of selection branches) in the table shown in Table 1. For example, in the case of four selection branches, 2 bits, 8 choices
The number of bits is 3 bits, and the number of selected branches is 2 bits.

First frame 30Aa recognized here
The value of the lower predetermined bit of is recognized as a table number (see the left column in Table 1), and new table data in the table of Table 1 (see the right column in Table 1) is read according to the table number. . Then, using the position described in the newly read table data as a starting point, the values of predetermined digits are extracted, and all of these values are added. Then, the checksum 31B created in the first digital image 30A is added to the addition result here to generate a checksum 31B. Thereafter, the checksum 31B is stored as it is as the encrypted data 33B in the header portion 30Bb of the second digital image 30B. Then, the digital image 30B provided with the header portion 30Bb is recorded and stored in the image data storage device 17.

In the following, the video data of the third and subsequent frames is also used for the previous frames 30Ba and 30Ca, respectively.
Checksum 3 of digital images 30B and 30C according to
The lower predetermined bits of 1B and 31C are sequentially recognized, and new table data (see the right column in Table 1) in the table of Table 1 is sequentially read by using this as a table number (see the left column in Table 1). Image data dispersed based on different positions are selected and extracted, and these are summed, and the digital image 30B of the previous time is added to the total value.
The checksums 31B and 31C created in 30C are added to sequentially generate checksums 31C and 31D, which are stored in the header portions 30Cb and 30Db of the digital images 30C and 30D as encrypted data 33C and 33D. , The digital images 30C and 30D are recorded and stored in the image data storage device 17.

To exemplify this concretely, for example, when four table data in the table shown in Table 1 are prepared, the checksums 31A to 31C of the previous digital images 30A to 30C are represented by binary numbers. For example, "1011
If it is “0010”, the lower 2 bits “10” are recognized, the second table data in the table of Table 1 is used, and the 8th byte and the 11th byte, respectively.
Checksums 31B to 31 are obtained by adding a value of a predetermined number of digits starting from the e-th eye, the 35-byte eye, the 84-byte eye, ...
It is sufficient to generate D, generate digital images 30A to 30D as encrypted data 33A to 33D, and record and store them in the image data storage device 17.

The recorded images 30Aa-30 of the digital images 30A-30D recorded in the image recording apparatus 2 are also included.
When determining whether Da has been tampered with, the operation input device 4
After the CPU 18 is switched to the tampering discrimination mode by the operation of, the digital images 30A to 30D are sequentially read from the first frame from the image data storage device 17, and the checksums 31A to 31D are respectively read in the same manner as the image recording.
After generating the checksums 31A to 31D and the encrypted data 33A to 33D in the header parts 30Ab to 30Db.
When it is determined that the digital images 30A to 30D match with each other as a result of the comparison, it is determined that the digital images 30A to 30D have not been tampered with. Has been tampered with, and the result of this determination is recorded images 30Aa to 30Da.
It is also displayed on the monitor device 3.

As described above, in this embodiment, the digital images 30A to 30D in frame units are changed while changing the method of generating the checksums 31A to 31D (extraction position of pixel data to be selected). Since the recording of 30A to 30D is performed, the encryption method of the digital images 30A to 30D of a specific frame and the encryption method of the digital images 30A to 30D of other frames are significantly different, and thus the digital image 30A is recorded. Since it is extremely difficult to tamper with the tampering of ˜30D so that it cannot be discriminated later, it contributes to the prevention of tampering and improves the accuracy of determining the presence or absence of tampering.

In each of the above embodiments, the image pickup camera 1
However, the image pickup camera 1 is not installed as a standard, but can be detachably installed according to the user's request. As an image input device other than video data, for example, a scanner or other external connection device is installed. You may be able to capture the image from. Or, as such an image input device,
Image information may be freely fetched from various information recording media such as magnetic disks and optical disks, and encrypted data may be added to the header portion of the image information.

Further, in the second embodiment, Table 1
The table of FIG. 3 was also stored in the image data storage device 17 in which the digital images 30A to 30D are recorded. However, the table of FIG. It may be installed separately from the image recording means (image data storage device 17) for recording and storing 30D to 30D.

[0067]

According to the inventions of claims 1 to 4 , an image is input from the image input device for each frame.
In case of
Is added to the header part of the digital image, and the header part
The added digital image is recorded in the image data storage device.
Since it is recorded and saved, it is possible to tamper with digital images.
Based on the operation of the operation input device,
Then, the check value is calculated again in a chain, and the check value
Compared with the encrypted data, and the result of this comparison indicates that they match
If the digital image is tampered with when it is determined that
When it is determined that they do not match, but when it is determined that they do not match
It is possible to determine that the digital image has been tampered with.
It becomes Noh. Therefore, the digit of a particular frame
Image encryption method and digital image of other frames
The encryption method is very different and
When falsifying a digital image, falsify it so that it cannot be identified later.
Contributing to the prevention of tampering
At the same time, the effect of improving the accuracy of discrimination of tampering is improved.
There is a fruit.

[0068]

[Brief description of drawings]

FIG. 1 is a block diagram showing an image recording system with an image tampering discrimination function according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing an image recording method of the image recording system with the image tampering discrimination function according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing an image tampering determination method of the image recording system with the image tampering determination function according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing an image recording method of an image recording system with an image tampering discrimination function according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing an image recording system with an image tampering discrimination function according to a second embodiment of the present invention.

[Explanation of symbols]

1 Imaging Camera 2 Image Recording Device 3 Monitor Device 4 Operation Input Device 11 Video Input Terminal 12 NTSC Decoder 13 Gate Array 14 Image Memory 15 Image Compression Chip 16 Secret Key Storage Memory 17 Image Data Storage Device 18 CPU 19 Work Memory 20, 30A ˜30D Digital image 20a, 30Aa to 30Da Image data (frame) 20b, 30Ab to 30Db Header part 21, 31A to 31D Check value 22 Private key data 23, 33A to 33D Encrypted data 24 Decrypted data 25 Check value

Claims (4)

(57) [Claims] 1. A plurality of images sequentially input from an image input device are sequentially recorded as digital images for each frame in an image recording device, and whether or not the digital images recorded in the image recording device have been tampered with. An image recording system with an image tampering discrimination function capable of determining whether the image recording device is an image recording device for recording and storing the digital image, and each image input one after another from the image input device. The encrypted data is generated based on the information in the digital image, the encrypted data is added to the header portion of the digital image to be recorded and stored in the image recording unit, and the digital image recorded in the image recording unit is falsified. A control unit for determining whether or not the digital image is based on the image data in the digital image and the encrypted data, and a desired operation for the control unit. And an operation input device for giving an indication, the control unit, when images are sequentially input from the image input device for each frame, image data in the digital image related to the frame and the previous frame. Obtaining encrypted data in a chained manner using the encrypted data in the digital image, and adding the encrypted data to the header portion of the digital image,
A function of recording and storing the digital image to which the header portion has been added in the image data storage device, and in the case of determining whether the digital image has been tampered with, based on the operation of the operation input device, each frame The digital images according to the above are sequentially read from the image data storage device, and the check value is calculated in a chain using the image data in the digital image related to the frame and the encrypted data in the digital image related to the previous frame. If the check value and the encrypted data are compared, and it is determined from the comparison result that the two match, it is determined that the digital image has not been tampered with, and if it is determined that they do not match. An image recording system with an image tampering determination function, which has a function of determining that the digital image has been tampered with. 2. An image recording system with an image tampering discrimination function according to claim 1 , wherein a plurality of pixel positions for specifying a plurality of arbitrary pixel positions in the image data of the digital image are provided in the image recording device. A predetermined table in which a predetermined table data including a number sequence and a predetermined table number is stored in the plurality of number sequences of each of the table data is prepared in advance, and the control unit includes the table data in the table. Select one of the plurality of the number sequence according to a predetermined procedure, take out the pixel data of a predetermined digit starting from the pixel position in the digital image according to the selected number sequence as a numerical value, and The check value is obtained by calculating the total value of the numerical values, and the check value is added as encrypted data to the header section of the digital image. A function of recording and storing the added digital image in the image data storage device, and in the case of determining whether the digital image has been tampered with, based on the operation of the operation input device, the digital image of each frame Are read one after another from the image data storage device, and one of the plurality of numerical sequences in the table data in the table is selected according to a predetermined procedure, and the digital image in the digital image according to the selected numerical sequence is selected. The pixel data of a predetermined digit starting from the pixel position is taken out as a numerical value, the total value of the numerical values is calculated to obtain a check value, the check value and the encrypted data are compared, and both are determined by this comparison result. When it is determined that the digital images do not match, it is determined that the digital image has not been tampered with, while it is determined that the digital images do not match. In this case, the digital image has a function of determining that the digital image has been tampered with, and the predetermined procedure corresponds to the first frame when the digital image processed in the procedure relates to the first frame. While selecting the sequence of the table numbers, if the digital image to be processed by the procedure is related to the second and subsequent frames, the value at the predetermined position in the check value of the digital image of the previous frame is set. An image recording system with an image tampering discrimination function, characterized in that the sequence of corresponding table numbers is selected. 3. An image recording method for sequentially recording, as a digital image for each frame, a plurality of images sequentially input from an image input device, wherein the images input from a predetermined image input device are sequentially input for each frame. When input, the encrypted data is obtained in a chain using the image data in the digital image related to the frame and the encrypted data in the digital image related to the previous frame, and the encrypted data is stored in the digital image. When a digital image is added to a header part, the digital image to which the header part is added is recorded and stored in a predetermined image data storage device, and when it is determined whether the digital image has been tampered with, a predetermined operation input device is operated On the basis of the above, the digital images of each frame are sequentially read from the image data storage device, and the digital images of the frame are read. A check value is determined in a chain using the image data in the image and the encrypted data in the digital image related to the previous frame, the check value and the encrypted data are compared, and the comparison result shows that they match. An image recording method that determines that the digital image has not been tampered with when it is determined that the digital image has been tampered with. 4. An image recording method for sequentially recording, as a digital image for each frame, a plurality of images sequentially input from an image input device, wherein a plurality of images in the image data of the digital image are stored in a predetermined table recording means. When a predetermined table including a number sequence for specifying an arbitrary pixel position and a table number for identifying the number sequence is recorded in advance and the digital image relating to an image input from a predetermined image input device is recorded, In the case where the digital image is related to the first frame, the number sequence of the table number corresponding to the first frame is selected, while the digital image is related to the second and subsequent frames. , The numerical sequence of the table number corresponding to the value at the predetermined position in the check value of the digital image of the previous frame A step of selecting, a step of obtaining pixel data dispersed as pixel values at pixel positions in the digital image corresponding to the selected number sequence as a numerical value and calculating a total value of the numerical values, and a check value; An image recording method, which comprises: providing the header portion of the digital image as encrypted data, and recording and storing the digital image provided with the header portion in the image data storage device.