JP2003309833A - Radio image transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure security when an image is wirelessly transmitted. <P>SOLUTION: The wireless image transmission system comprises: a slave unit 11 for wirelessly an image; and a master unit 1 for receiving the image, and is configured such that the slave unit 11 encrypts the image by using a standard encryption key set in advance as a default key and wirelessly transmits the encrypted image when no encryption key setting is entered, and the master unit 1 decodes the image data received from the slave unit 11 by using the same standard encryption key as the standard encryption key set in advance as a default key. Since the transmission image is encrypted without fail in this way, the security of the image can be assured. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless image transmission system that encrypts an image captured by a surveillance camera or the like and wirelessly transmits it to a surveillance room.

[0002]

2. Description of the Related Art When surveillance systems are introduced in various places due to heightened awareness of crime prevention, and surveillance objects are scattered in various places, surveillance cameras are installed near each surveillance object. As described in the official gazette, a picked-up image has been transmitted to a monitoring room by radio waves.

In such a surveillance system, since the picked-up image of the surveillance camera is wirelessly transmitted, a function of encrypting the picked-up image to be transmitted using an encryption key so that another person cannot see the picked-up image. Is provided.

[0004]

However, the encryption function must increase the number of digits of the encryption key in order to make it difficult for the encryption to be decrypted. For this reason, it becomes troublesome for the user to input and set the multi-digit encryption key when using the surveillance system, and even if the manufacturer of the surveillance system installs the encryption function, the encryption There is a problem that the function is not used effectively.

It is an object of the present invention to provide a wireless image transmission system having a high security function which always performs encryption even when a user does not input an encryption key when transmitting an image.

[0006]

In order to achieve the above object, a wireless image transmission system of the present invention comprises at least one slave unit for wirelessly transmitting image data and a master unit for receiving the image data. The slave unit includes means for wirelessly transmitting the image data by encrypting the image data using a standard encryption key set as a default value when no encryption key setting is input. Is equipped with means for decrypting the image data received from the slave unit with the same standard encryption key as the standard encryption key set as a default value in advance. With this configuration, image security is ensured because the image is always encrypted when it is transmitted.

[0007] Preferably, the standard encryption key includes a calling code of a radio set for the slave. With this configuration, the uniqueness of the encryption key is increased and the security is further improved.

More preferably, when the setting input of the encryption key is made, an encryption key obtained by combining the set and input encryption key and the standard encryption key is used. This configuration also avoids duplication of the encryption key with other systems and further improves security.

More preferably, when an encryption key generation instruction based on image data is input, the encryption key generated based on the image data is used instead of the standard encryption key. To do. With this configuration, the encryption key becomes image-dependent data, so that the transmission image is further prevented from leaking.

More preferably, when an encryption key generation instruction based on image data is input, the image data for generating the encryption key is updated each time the slave unit transmits the image data. To do. With this configuration, security is further enhanced, and the wireless image transmission system can be applied to the monitoring of important facilities.

More preferably, the image wirelessly transmitted by the slave unit is an image captured by a surveillance camera connected to the slave unit. With this configuration, the security of the image wirelessly transmitted by the surveillance system is improved, and the surveillance system can be spread.

More preferably, when the number of the slaves is two or more, each slave has a function of relaying image data wirelessly transmitted to the master by another slave. .
With this configuration, it is possible to monitor a place where direct wireless transmission with the base unit is not possible.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a monitoring system to which a wireless image transmission system according to an embodiment of the present invention is applied. This monitoring system is connected to a wireless transmitter / receiver (hereinafter referred to as a master) 1 installed in a monitoring room, a monitor 2 installed in the monitoring room for displaying an image received by the master 1, and a master 1. And a controller 3.

A plurality of wireless transmission / reception devices (hereinafter referred to as slaves) are wirelessly connected to the master 1, and in the illustrated example, a first slave 11 and a second slave 12 are provided. Third
The child device 13 and the fourth child device 14 are connected to the parent device 1. Each of the slave units 11, 12, 13, and 14 has a monitoring camera 2 capable of capturing, for example, 20 frames of monitoring images per second.
1, 22, 23, 24 are connected to each of the slave units 11, 1
2, 13, and 14 have the ability to capture an image of 20 frames per second, encrypt it, and then transmit it.

The radio frequency band that can be used in the surveillance system belongs to a high frequency band of 2.4 G (giga), for example, and since the radio wave has a high straight traveling frequency, the radio wave reaches a place that cannot be seen through. It has the property of being difficult. Therefore, the master unit 1 and the third and fourth slave units 1 shown in FIG.
If there is a large shield 4 between 3 and 14, the cordless handset 1
It is not possible to directly transmit from 3 and 14 to the base unit 1.

Therefore, each of the slave units 11, 12, 13, and 14 which constitute the monitoring system according to the present embodiment has a radio wave relay function, and a wireless transmission image from the slave unit 13 to the master unit 1 is transmitted. Has a configuration in which the second child device 12 installed at a position where it can be seen through from the parent device 1 once receives, and the child device 12 wirelessly transmits the received image to the parent device 1.

The image transmitted from the fourth slave unit 14 to the master unit 1 is received by the third slave unit 13 and then transmitted to the second slave unit 12 by the second slave unit 12. 12 is transmitted to the master device 1. If the radio wave of the handset 14 reaches the handset 12, the handset 13 does not need to be relayed. The slave unit that serves as a relay station is dedicated to the relay station during relay, and does not transmit the captured image of the surveillance camera connected to itself.

Here, for example, when the slave unit 13 transmits a monitor image to the master unit 1, 1 second 20 captured by the monitor camera 23
All the frame images are transmitted to the child device 12, and the child device 1
If 2 is configured to transmit an image of 20 frames per second to the base unit 1, the handset 13 sends to the handset 12 while the handset 12 is wirelessly transmitting to the base unit 1. The image of the next 20 frames cannot be transmitted, and a time delay occurs in the transmission of the monitoring image to the master device 1, and the simultaneity of monitoring cannot be protected.

Therefore, the slave unit 13 selects half of the 20 frames taken by the surveillance camera, for example, an odd numbered 10 frames image, and the 10 frames image is selected within 0.5 seconds in the first half of 1 second. 12 and the slave unit 12 transmits an image of 10 frames to the master unit 1 in the latter half 0.5 seconds of 1 second, so that the master unit 1 transmits the image to the master unit 1 and the monitoring camera 23 connected to the slave unit 13.
It is possible to monitor the monitoring image of 10 frames per second every 10 frames. Thus, when relaying is performed, wireless transmission is performed in time division.

When the monitor image of the slave unit 14 is transmitted to the master unit 1, the number of frames that can be transmitted from the slave unit 14 is further increased because it passes through the two slave units 13 and 12 as a relay station. It becomes half and 5 frames are transmitted every second. However, since the monitoring image can be transmitted every second, the simultaneity of monitoring is protected.

As described above, the child device which transmits an image by using the relay station needs to select an image to be transmitted among the picked-up images. To do so, the child device must know that it must use the relay station.

Therefore, when the monitor 3 specifies by the controller 3 that the surveillance camera 24 performs surveillance, the master unit 1
With respect to the slave unit 14, the master unit 1-the slave unit 12-the slave unit 13-
The image transmission command is wirelessly transmitted through the route of the child device 14. Receiving the image transmission command, the slaves 12, 13 learn that they must be dedicated to the relay station, and the slaves 14
Will select and transmit an image of 5 frames per second from the captured images of 20 frames per second, and the master device 1 will receive the monitoring image of 5 frames per second.

The image transmission command transmitted from the master unit 1 to the slave unit 14 is wirelessly transmitted as a packet. This packet is transmitted not only to the slave unit 12 but also to the master unit as shown in FIG. It is also received by the child device 11 installed at a position visible from 1. However, since the data indicating itself is not specified in this received packet, the child device 11 discards this packet.

The "1 second" used in the above description,
"0.5 seconds" or "20 frames", "10 frames"
It is needless to say that the above numerical values are merely examples for explanation, and depend on the performance of the surveillance camera, the parent device, and the child device.

FIG. 2A shows a slave unit 11 (another slave unit 12,
13 and 14 are also structural diagrams). Cordless handset 11
A video input unit 31 that captures a captured image from the surveillance camera 21, an encryption unit 32 that encrypts a surveillance image to be transmitted with an encryption key, and an encrypted surveillance image that is received from the encryption unit 32. A transmission means 34 for transmitting from 33, a storage means 35 for storing a difference image between the monitoring image or the previous transmission image which is the encryption target of the encryption means 32, and a receiving means 37 connected to a receiving antenna 36, A key management unit 38 that receives the stored image data of the storage unit 35 and the received data of the reception unit 37, creates an encryption key, and passes the encryption key to the encryption unit 32 is configured.
In the illustrated example, the transmitting antenna 33 and the receiving antenna 36
Although and are separately provided, one transmitting / receiving antenna is actually switched by the antenna switch.

In this slave unit 11, the image data to be transmitted (or the difference image data) is always encrypted by the encryption means 32 and passed to the transmission means 34, and has the function of canceling the encryption function. Absent. As an encryption key, this system (master device 1, slave devices 11, 12, 13, 1
4 set), a standard encryption key of, for example, about 30 digits is set in the encryption means 32 at the time of factory shipment, and when the user does not set anything, encryption is always performed by the standard encryption key. Be seen.

When the user sets and inputs the encryption key, the set encryption key is used, and the set encryption key matches the encryption key used by another person's monitoring system. There is a possibility that In such a case, if the other person's monitoring system and his own monitoring system are installed adjacent to each other in the same area, the content of the monitoring image may be seen by another person.

In order to avoid such a situation, in the surveillance system according to the present embodiment, when the user sets and inputs, for example, a 10-digit encryption key, a different value is set for each surveillance system described above. The image data is encrypted using a 40-digit encryption key that is a combination of the standard 30-digit encryption key and the user-set 10-digit encryption key.

As the encryption key, the standard encryption key set by default at the time of factory shipment and the identifiers of the slave unit and the master unit (set by the Radio Law in order to identify the wireless unit for each wireless unit are obligatory It can also be used as an encryption key.

Alternatively, without using the standard encryption key,
It is also possible to set a complicated encryption key without requiring the user to input a complicated setting. In this embodiment,
When an instruction to create an encryption key is input from "Image" without using the standard encryption key, the encryption key is sequentially generated from the transmitted image data and this encryption key is used. To encrypt the image data.

The encryption key is stored in the storage means 35, for example.
In the image data such as the luminance signal and the color signal, or the red signal, the green signal, the blue signal, etc. stored in, the luminance signal data is used.
When the pixel data is 0 × 240, this pixel data is divided into, for example, a total of 64 blocks of 40 × 30, and only the pixel data in the upper right corner of each block is collected to form a 64-bit encryption key.

As described above, in this embodiment, as the encryption key, (1) standard encryption key (2) standard encryption key + user-set encryption key (3) standard encryption key + radio call The code (4) is characterized in that any one of the encryption keys generated from the image is selected to encrypt the transmission image data.

Further, the cordless handset 11 is provided with a path 39 for directly connecting the receiving means 37 and the transmitting means 34 when it operates exclusively as a relay station, and when it operates as a relay station, it receives another child. The image data from the machine is transmitted as it is, and the image data is not encrypted.

FIG. 2B is a block diagram of the base unit 1. The parent device 1 receives from the operation input means 41 that receives the operation input from the monitoring staff, the transmitting means 43 that transmits the command input from the operation input means 41 from the transmitting antenna 42 to the child device, and the receiving antenna 44. Receiving means 45 for receiving image data and the like, decrypting means 46 for decrypting the encrypted image data received by the receiving means 45, video output means 47 for outputting the decrypted image data to the monitor 2, and immediately before. Storage means 48 for storing the image data decoded into
A key management means 49 is provided which creates an encryption key for image data from the setting input data from the operation input means 41 or the image data fetched from the storage means 48 and transfers this encryption key to the decryption means 46. To be done. Base unit 1
In the case of, the transmitting antenna 42 and the receiving antenna 44 are set to 1
It is preferable that the two transmitting and receiving antennas are used in common.

When the encryption key is not set and input, the master unit 1 decrypts the received image data by using the standard encryption key (1) described above, and the encryption key is set and input. If so, the received image data is decrypted with the standard encryption key + user-set encryption key (2) described above,
If the designated input to encrypt using the call code of the wireless device is made, the received image data is decrypted using the standard encryption key + the call code (3) of the wireless device, and the encryption created from the image When the setting input for encryption using the encryption key (4) is made, an encryption key is created from the data stored in the storage means 48 and the received image data is decrypted.

Next, the operations of encryption and decryption in the above-mentioned monitoring system will be described. FIG. 3 shows a sequence of signal exchange between the slave unit and the master unit in this operation.
It should be noted that, in this operation description, the operation when the child device uses another child device as a relay station will not be described, but since the relay station simply transmits the received image data as described above,
The relay station has no influence on the operations of encryption and decryption.

To compress the moving image transmission data,
It is preferable to sequentially obtain and send difference data between images. However, here, for simplification of description, it is assumed that the image data itself is transmitted, not the difference data, one by one, but the operation of encryption and decryption is the same even when the data is compressed by taking the difference data. Is.

The video input means 31 of the child device 11 sequentially takes in the picked-up images which are analog signals from the surveillance camera 21, converts them one by one into digital data, and sends them to the encryption means 32. The encryption unit 32 encrypts the image data to be transmitted by using the standard encryption key one by one and sends the encrypted image data to the transmission unit 34 even if no setting input of the encryption key is made. The image data is transmitted to the master device 1.

If the encrypted and transmitted image data is image data A, the image data A before being encrypted is stored in the storage means 35. When the transmission image data B next to the image data A is encrypted by the encryption means 32, the encrypted image data B is transmitted from the transmission means 34 to the parent device 1,
The data stored in the storage unit 35 is the image data B before being encrypted.

When the image data A is normally received, the receiving means 45 of the master unit 1 outputs a reception notification issuing command to the transmitting means 43, and the transmitting means 43 receives the instruction.
Transmits a normal reception signal ACK to the child device 11.
On the side of the handset 11 receiving this normal reception signal ACK, the next encrypted image data B is transmitted, and similarly, the base unit 1 transmits the normal reception signal ACK to the handset 11.

The receiving means 45, which has received the image data A,
The received image data A is delivered to the decoding means 46. The decryption means 46 decrypts the image data A using a standard encryption key, and the decrypted image data A is stored in the storage means 48.
The decoded image data A is returned to an analog signal through the video output means 47 and is displayed on the monitor 2. As a result, the monitor will monitor the image data A on the monitor 2.

Receiving means 45 which has received the next image data B
Passes the received image data B to the decoding means 46. The decryption means 46 decrypts this image data B using a standard encryption key, rewrites the contents stored in the storage means 48 with this decrypted image data B, and outputs the decrypted image data B to the video output means 47. To monitor 2 through. As a result, the image data B is displayed on the monitor 2. By performing such an operation one after another, the surveillance staff monitors the surveillance video of the surveillance camera 21 as a moving picture.

Here, as shown in FIG. 3, it is assumed that an observer inputs an image-based encryption key generation instruction from the controller 3. This instruction is taken into the operation input means 41 of the parent device 1 and outputted to the key management means 49, and at the same time, outputted to the transmission means 43.

When this encryption key generation instruction is input, the slave unit 11 has already encrypted the next image data C following the image data B with the standard encryption key and transmitted the image data C to the master unit 1. Suppose The transmitting means 43 of the parent device 1 returns the normal reception signal ACK to the child device 11 in a normal sequence, and at the same time, the encryption key generation instruction is also issued to the child device 1.
Send to 1.

In the master unit 1, the image data C is decrypted using the standard encryption key, the image data C is displayed on the monitor 2, and the decrypted image data C is stored in the storage means 48. The means 49 generates an encryption key used for the next decryption from the decrypted image data C according to a predetermined generation algorithm.

On the other hand, in the handset 11, when receiving the encryption key generation instruction, the receiving means 37 notifies the key management means 38. The key management unit 38 reads the data stored in the storage unit 35 when receiving this notification, that is, the image data C before encryption, and based on the image data C, the encryption key to be used next time is specified. Generate according to an algorithm. Then, the next image data D is encrypted using the encryption key generated from the image data C and transmitted to the master unit 1.

Upon receiving the encrypted image data D, the master unit 1 returns the normal reception signal ACK to the slave unit 11, and the encrypted image data D is generated based on the image data C. The image data D is decrypted using the activation key and displayed on the monitor 2. After that, the encryption and the decryption of the image data are performed using the encryption key generated based on the image data C.

The master unit 1 and the slave unit 11 independently generate the encryption key based on the image data C as described above, but the slave unit 11 encrypts the image data C before transmission.
Then, if the image data C decrypted after being received by the base unit 11 does not match, the same encryption key is not generated.
For this reason, transmission and reception of image data is performed using an error correction code such as a BCH code, and when there is a data error, a procedure for sending a data resend instruction signal instead of the normal reception signal and resending it is incorporated. , And guarantees that the encryption keys independently generated in the parent device 1 and the child device 11 match.

In the embodiment described with reference to FIG. 3, the encryption key generated based on the image data C is continuously used after the input of the encryption key generation instruction based on the image is input. Can be configured to be updated. That is, the image data D is encrypted and decrypted by the encryption key generated from the image data C, and the image data E after that is decrypted.
Can use the encryption key generated from the image data D, the next image data F can use the encryption key generated from the image data E, and so on. In this case, the processing load becomes high, and the high performance CP is applied to the parent device and the child device.
Although it is necessary to mount U etc., there is an advantage that the security level can be further improved.

When the encryption key is generated by using the image data, it is possible to use all the image data of one sheet or to use only a part of the image data. It is also possible to generate one encryption key using a plurality of pieces of image data.

As described above, in the surveillance system to which the wireless image transmission system of this embodiment is applied, the standard encryption key set by default at the time of factory shipment when no encryption key setting instruction is input by the user. When the transmitted image data is encrypted using, and the received image data is decrypted using the standard encryption key on the receiving side as well, the security of the monitoring system increases, and when multiple monitoring systems coexist in the same area. However, you can safely monitor high security locations with wireless video.

[0053]

According to the present invention, since the image is always encrypted when it is transmitted, it is possible to provide a wireless image transmission system in which image security is ensured.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a monitoring system to which a wireless image transmission system according to an embodiment of the present invention is applied.

FIG. 2A is a configuration diagram of a child device of the wireless image transmission system according to the embodiment of the present invention, and FIG. 2B is a configuration diagram of a parent device of the wireless image transmission system according to the embodiment of the present invention.

FIG. 3 is a sequence diagram between a master unit and a slave unit of the wireless image transmission system according to the embodiment of the present invention.

[Explanation of symbols]

1 base unit 2 monitors 4 Shield 11, 12, 13, 14 cordless handset 21, 22, 23, 24 Surveillance camera 32 encryption means 35, 48 storage means 38,49 Key management means 46 Decoding means 33, 36, 42, 44 antennas

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshihiro Hide             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             Matsushita Communication Industry Co., Ltd. (72) Inventor Masami Okeshita             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             Matsushita Communication Industry Co., Ltd. (72) Inventor Atsushi Nomura             3-1, Tsunashima-Higashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa             Matsushita Communication Industry Co., Ltd. F-term (reference) 5C054 AA02 CA04 CC03 CD03 EA03                       HA18                 5C064 BA07 BB05 BC10 BC20 BD05                       BD09 BD13 CA14 CB01 CC04                       DA14                 5J104 AA12 JA03 PA07

Claims (7)

[Claims] 1. At least one for wirelessly transmitting image data
The standard encryption key is configured by two slaves and a master that receives the image data, and the slave is a standard encryption key that is preset with the image data as a default value when there is no encryption key setting input. Means for wirelessly transmitting after encrypting using the, the master unit decrypts image data received from the slave unit with the same standard encryption key as the standard encryption key set as a default value in advance. A wireless image transmission system comprising: 2. The wireless image transmission system according to claim 1, wherein the standard encryption key includes a call code of a wireless device set for the slave device. 3. When the setting input of the encryption key is made, an encryption key obtained by combining the set and input encryption key and the standard encryption key is used.
The wireless image transmission system according to. 4. When an encryption key generation instruction based on image data is input, an encryption key generated based on the image data is used instead of the standard encryption key. 1. The wireless image transmission system according to 1. 5. When the encryption key generation instruction based on the image data is input, the image data for generating the encryption key is updated every time the slave unit transmits the image data. 4. The wireless image transmission system according to item 4. 6. The wireless image transmission system according to claim 1, wherein the image wirelessly transmitted by the slave unit is an image captured by a surveillance camera connected to the slave unit. . 7. When there are two or more cordless handsets, each cordless handset is
7. The wireless image transmission system according to claim 1, further comprising a function of relaying image data wirelessly transmitted to another child device to the parent device.