JP3920764B2 - Surveillance camera system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surveillance camera system that photographs a surveillance area with a plurality of surveillance cameras.
[0002]
[Prior art]
Currently, surveillance cameras are not only installed in financial institutions and convenience stores, but are also widely used in ordinary houses and condominiums. In the prior art, when an abnormality occurs in a house or a condominium, a technique is known in which a resident on the go can monitor the abnormality by transferring image data captured by a monitoring camera to a facsimile machine. (For example, see Patent Document 1)
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 09-191455
[Problems to be solved by the invention]
However, in the surveillance system described in Patent Document 1, when a surveillance area is photographed from different angles using a plurality of surveillance cameras, a motion of a suspicious person or the like is photographed simultaneously by a plurality of cameras. All the images will be sent to the recipient. For this reason, a great burden is placed on the communication means. In addition, image data that is insufficient to confirm the movement, such as an image with little movement detected at the edge of the image, is also transmitted. It also costs money.
[0005]
It is an object of the present invention to provide a surveillance camera system that reliably monitors movement from images taken by a plurality of surveillance cameras without incurring communication costs.
[0006]
[Means for Solving the Problems]
A plurality of surveillance cameras that capture the surveillance area from different angles, a motion detection means that detects the motion of the image based on the images captured by each surveillance camera, and a position where the motion of the image is detected in the captured image. A position determining means for determining; a determining means for determining the importance of each captured image from the amount of motion of the image obtained from the motion detecting means and the position determined by the position determining means; and each shooting determined by the determining means Comparing means for comparing the importance of images, and communication means for transmitting only image data of a photographed image determined to have the highest importance by the comparing means to a distant electronic device.
[0007]
Each surveillance camera is provided with a motion detection means, a position determination means, and a determination means.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1 showing the embodiment of the present invention, the surveillance camera system 2 is composed of three surveillance cameras 10 to 12, a host computer 13, and a facsimile machine 17. The monitoring cameras 10 to 12 photograph the monitoring target 5 in the same monitoring area from different angles. The surveillance cameras 10 to 12 are provided with an antenna 14 for wireless communication, and the operation is controlled by the host computer 13 via the antenna 15 connected to the host computer 13. If it does in this way, the freedom degree of the installation place of the surveillance cameras 10-12 will improve significantly compared with the case where it connects by electrical wiring. The host computer 13 is connected to the facsimile machine 17 via a telephone line, and images taken by the monitoring cameras 10 to 12 are sent to the facsimile machine 17 via the host computer 13. In addition, images taken by the monitoring cameras 10 to 12 can be displayed on the monitor 16 of the host computer 13.
[0009]
The electrical configuration of the monitoring camera 10 is shown in FIG. The CPU 20 controls each part of the monitoring camera 10 via the data bus 21. The imaging unit 22 includes an imaging lens (not shown), a CCD image sensor, and the like, and converts an optical subject image from the imaging lens into an electrical imaging signal by the CCD image sensor. The image signal from the image capturing unit 22 is subjected to various signal processing such as contour enhancement, gamma correction, and white balance adjustment by the signal processing unit 23, and is converted into image data as digital data by the A / D converter 24.
[0010]
The system memory 25 includes a ROM that stores various programs for performing a shooting sequence, and a RAM that temporarily stores various data necessary for executing the programs. The CPU 20 reads out programs and data stored in the system memory 25 via the data bus 21 and controls each part of the monitoring camera 10 based on these.
[0011]
The nonvolatile memory 26 includes a rewritable storage medium such as an EEPROM, and stores various setting information necessary for operating the monitoring camera 10. The various setting information is rewritten with new information when a new function is added. The frame memory 27 temporarily stores the image data for one frame digitally converted by the A / D converter 24 until the next shooting is executed. The image data stored in the frame memory 27 is sent to the image compression / decompression circuit 28 and subjected to compression processing in JPEG format in order to shorten the transmission time of the image data.
[0012]
The wireless communication I / F 29 receives a control signal from the host computer 13 via the antenna 14 and transmits JPEG format image data compressed by the image compression / decompression circuit 28 to the host computer 13. In the monitoring camera 10, the monitoring target 5 is photographed with a megapixel size (number of pixels: 1280 × 960), and normally, image data of VGA (Video Graphics Array) size (number of pixels: 640 × 480) is detected. It transmits to the host computer 13.
[0013]
The operation of the strobe device 30 is controlled by a strobe control circuit 31. The strobe device 30 is used when strobe photography is required, such as during night photography. In addition to the above, a power supply unit 36 for supplying power to each unit is provided. The monitoring cameras 11 and 12 have the same configuration as the monitoring camera 10.
[0014]
An electrical configuration of the host computer 13 is shown in FIG. The system controller 40 controls the entire system of the host computer 13 and also transmits control signals to the monitoring cameras 10 to 12. The ROM 41 stores a control program for controlling each unit of the host computer 13, threshold data for detecting motion, and the like. The host computer 13 has a function of determining the importance of each image in which motion is detected and transmitting only the image data of the image having the highest importance to the remote facsimile machine 17.
[0015]
In the first and second frame memories 43 and 44, image folders corresponding to the monitoring cameras 10 to 12 are provided. In the image folders of the frame memories 43 and 44, the image data previously captured by the monitoring cameras 10 to 12 or the image data currently captured is alternately stored.
[0016]
The motion detection unit 45 obtains an absolute value of a difference between the previously captured image data stored in each image folder corresponding to the monitoring cameras 10 to 12 and the currently captured image data, and the obtained absolute When the value is greater than or equal to a preset threshold value, the motion of the image is detected and the amount of motion is detected from the difference value. The position discriminating unit 46 divides each captured image in which motion is detected, and determines in which divided area the motion of the image is detected, thereby discriminating a detection position in which the motion of the image is detected. . Note that the motion of the image is detected using the absolute value of the difference between the previously captured image data and the currently captured image data, but the motion may be detected using other known techniques. .
[0017]
A plurality of divided areas of the photographed image are weighted in advance. This weighting is set so that the divided area at the center of the photographed image is the heaviest and the weighting decreases as the distance from the center increases. The comparison / determination unit 47 determines the importance of each captured image from the amount of motion of the image and the weight of the divided region corresponding to the position where the motion of the image is detected, and compares the determined importance of each captured image. The most important photographed image is determined. The importance here means that the movement of the image can be sufficiently confirmed in the captured image.
[0018]
The image data determined to have the highest importance by the comparison / determination unit 47 is sent to the modem 48. The modem 48 converts image data, which is digital data, into analog data so that it can be transmitted over a telephone line. The image data converted into analog data is transmitted to the remote facsimile machine 17 via the line I / F 49 via the analog telephone line network.
[0019]
Further, by operating the host computer 13, each image data whose motion is detected by the motion detection unit 45 can be displayed on the monitor 16 via the image display circuit 50 and confirmed.
[0020]
The operation of the above configuration will be described above. As shown in FIG. 4, the host computer 13 transmits an imaging instruction to the monitoring cameras 10 to 12. Upon receiving the shooting instruction, the monitoring cameras 10 to 12 shoot the monitoring area from different angles, and transmit the shot image to the host computer 13 in the VGA size. In this way, it is possible to shorten the transmission time and processing time of image data.
[0021]
The host computer 13 calculates the absolute value of the difference between the currently captured image transmitted by the monitoring cameras 10 to 12 and the previously captured image, and obtains a preset threshold value and the determined absolute value. By comparing, the motion of the image in each captured image is detected, and when the motion is detected, the amount of motion is also detected by the difference value. Further, each position where the motion is detected is determined by dividing each image in which the motion is detected into a plurality of regions and determining which divided region the motion is included in. Note that the threshold for detecting motion is preferably set to a value that is not detected due to an error caused by JPEG image compression.
[0022]
The importance level of each captured image is determined from the amount of motion of each captured image and the determined position, and the captured image having the highest importance level is determined by comparing the determined importance levels of the captured images. Then, only the image data of the photographed image determined to have the highest importance is transmitted by the host computer 13 to the remote facsimile machine 17 via a telephone line.
[0023]
The monitor 16 of the host computer 13 can display a captured image in which the motion of the image is detected by the motion detector. Therefore, when a surveillance camera is installed in a house or a condominium, it can be used as a security camera by viewing this photographed image from within the house or condominium.
[0024]
Although the image data having the highest importance is transmitted to a remote facsimile apparatus, the image data may be transmitted to a personal computer or a mobile phone capable of displaying an image using the Internet.
[0025]
In this embodiment, a system composed of three surveillance cameras has been described. However, the system may be composed of two surveillance cameras, and of course, three or more. In addition, the surveillance camera is photographed at the megapixel size, but it is also possible to photograph at the megapixel size only when the image is usually photographed at the VGA size and a detailed image is required when an abnormality occurs.
[0026]
In this embodiment, the host computer detects the motion of the image, determines the position where the motion is detected, and determines the importance of each image. However, each surveillance camera detects the motion, and the image in the captured image is detected. The host computer may compare the importance by determining the position where the motion is detected and determining the importance of the image.
[0027]
【The invention's effect】
As described above, according to the surveillance camera system of the present invention, even when motion of an image is detected in each captured image by a plurality of surveillance cameras capturing the surveillance area at different angles, it is important for each captured image. Since only the image data of the photographed image having the highest importance is transmitted to a distant electronic device, it is possible to reliably monitor the movement without incurring communication costs.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a surveillance camera system of the present invention.
FIG. 2 is a block diagram showing an electrical configuration of the surveillance camera shown in FIG.
FIG. 3 is a block diagram showing an electrical configuration of the host computer shown in FIG. 1;
FIG. 4 is a flowchart showing the operation of the surveillance camera system.
[Explanation of symbols]
10 to 12 Monitoring camera 13 Host computer 17 Facsimile device 40 System controller 43 First frame memory 44 Second frame memory 45 Motion detection unit 46 Position determination unit 47 Comparison determination unit

Claims (2)

A plurality of surveillance cameras that capture the surveillance area from different angles, a motion detection means that detects the motion of the image based on image data captured by each surveillance camera, and the motion of the image detected in the captured image A position determining means for determining the position; a determining means for determining the importance of each captured image from the amount of motion of the image obtained from the motion detecting means and the position determined by the position determining means; Comparison means for comparing the importance of each captured image, and communication means for transmitting only the image data of the captured image determined to be the most important by the comparison means to a distant electronic device. Characteristic surveillance camera system. The surveillance camera system according to claim 1, wherein each of the surveillance cameras includes the motion detection unit, the position determination unit, and the determination unit.

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