JP2002247564A - Monitoring camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate a processing for detecting a traveling object in an image picked-up object to be monitored and to improve reliability. SOLUTION: In this monitoring camera system provided with a controller for detecting the abnormality of the object to be monitored on the basis of image signals obtained by picking up the image of the object to be monitored by a monitoring camera, the controller is provided with a traveling object detection part 55. The traveling object detection part 55 is provided with a frame image data computing means 73 for dividing many pixels constituting the frame of picked-up image signals into a plurality of groups, obtaining group image data for which the respective image data of the pixels are added for the respective groups and obtaining frame image data F by adding/subtracting the group image data, an averaging means 74 for averaging the obtained frame image data over the past several frames and computing a mean value ME, a subtraction circuit 75 for taking a difference between the frame image data F and the mean value ME and a comparing means 76 for comparing the difference MI in the subtraction circuit 75 with a preset threshold TH and outputting alarm signals ARM when the absolute value of the difference MI exceeds the threshold TH.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveillance camera system for imaging and monitoring an object to be monitored, and more particularly to a highly reliable detection of a moving object appearing on a photographing screen which causes an abnormality in the object to be monitored. The present invention relates to a surveillance camera system that can be performed by using

[0002]

2. Description of the Related Art In order to ensure the safety of homes and offices, a surveillance camera system for monitoring entrances and windows of buildings is used. In recent years, as this kind of surveillance camera system, a surveillance camera that uses a CCD (charge transfer device) or other imaging device to image a monitored object has been used, and an image obtained by imaging with a surveillance camera has been used. Is monitored on a monitor or recorded on a VTR (video tape recorder) or the like, and furthermore, the image is subjected to data processing, thereby detecting a moving object on the screen of the monitored object, that is, detecting an intruder or the like. . In particular, there is provided one configured to determine that an abnormality has occurred when a moving object is detected, and to output an alarm signal.

As a technique (algorithm) for detecting a moving object on a screen captured by such a surveillance camera,
Conventionally, various proposals have been made. For example, as an example, an image of a monitoring target continuously or intermittently taken with time is A / D converted at a certain point into image data, which is stored in a memory. Remember. Next, at a point in time when a predetermined time has elapsed, the captured image is A / D converted into image data, and compared with the image data previously stored in the memory in units of pixels. Then, the number of pixels in which the difference between the values (gradation values) of both image data exceeds a predetermined value (threshold value) is counted, and when the counted value exceeds the predetermined number, a moving object is detected. And When comparing the image data, there are a case where all pixels are compared and a case where some pixels set in advance are compared. In addition, the difference between the values of the two image data when comparing the image data is set to a predetermined threshold value so that the change in the value of the image data due to the environmental change such as the sunshine situation is not erroneously detected as a moving object. There is also a method of averaging the gradation values of the pixels exceeding the threshold value to obtain a gradation average, and performing correction using the gradation average as an offset.

[0004]

In such a conventional detection method in a surveillance camera system, image data stored in a memory in the past and image data obtained by imaging at the present time are compared in pixel units. Therefore, there is a problem that the number of processing steps is large and the processing takes time. In particular, when a recent high-pixel-count CCD imaging camera is used, the number of pixels on one screen may reach several million, and it is relatively difficult to compare all of these pixels on a pixel-by-pixel basis. It takes a long time. For this reason, it is difficult to perform real-time detection on a captured image, and there is a time delay in detection or inevitable detection intermittently, resulting in a time zone that cannot be monitored on a time axis,
It becomes difficult to perform reliable monitoring. When processing is performed only on a part of a captured image, the absolute processing time can be reduced, but the relative processing time of processing on a part of the image cannot be reduced. However, the above-mentioned problem still remains.

SUMMARY OF THE INVENTION An object of the present invention is to realize a highly reliable monitoring by realizing a high-speed processing on an image of a monitoring target area while reducing processing steps for detecting a moving body. A surveillance camera system is provided.

[0006]

According to the present invention, there is provided a monitoring camera for capturing an image of a monitored object, and a controller for detecting an abnormality of the monitored object based on image data of the monitored object captured by the monitoring camera. In the surveillance camera system provided, the controller includes a moving object detecting unit that detects a moving object to detect an abnormality in the monitored object, and the moving object detecting unit configures a captured image of the monitored object. A large number of pixels into multiple groups,
A frame image data calculating means for obtaining frame image data by adding and subtracting the group image data to obtain group image data obtained by adding the respective image data of the pixels for each group; Averaging means for averaging over several frames to calculate an average value; a subtraction circuit for taking a difference between the frame image data and the average value; comparing an output of the subtraction circuit with a preset threshold value; Comparing means for outputting an alarm signal when the absolute value of the threshold value exceeds the threshold value.

[0007] For example, the frame image data calculation means divides a large number of pixels constituting the monitored image picked up by the surveillance camera into a predetermined number of line units and forms each section as one group. A method of obtaining the frame image data by alternately adding and subtracting the group image data calculated for the group from one direction orthogonal to the line toward the other.

The surveillance camera system according to the present invention further includes a VTR (video tape recorder) for recording image data of the monitored object captured by the surveillance camera,
It is preferable that the VTR has a recording pause function, and the controller has an alarm timer for canceling the recording pause function of the VTR for a predetermined time based on the alarm signal and executing recording.

According to the present invention, frame image data is obtained by performing addition / subtraction processing on pixels of captured image data, averaging of the frame image data is performed, and the frame image data and the average value are calculated. By performing the subtraction, data for detecting the moving object in the monitored object can be obtained. Therefore, the inter-comparison processing of the image data of a large number of pixels is unnecessary, and the moving object detection is performed at high speed and with high reliability. It is possible to get in.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the overall configuration of the surveillance camera system of the present invention. Floodlight 1 for illuminating the monitored object, CCD for imaging the monitored object
(Charge transfer element) A monitoring camera 2 having an image sensor, a monitor 3 for displaying an image captured by the monitoring camera 2, a VTR 4 for recording the captured image, the monitoring camera 2, and the monitor 3 , VTR 4. The controller 5 includes:
A monitoring camera control unit 51, a monitor control unit 52, and a VTR that control the monitoring camera 2, the monitor 3, and the VTR 4, respectively.
A control unit 53 is provided, and an image signal processing unit 54 for processing a captured image signal and outputting the processed signal to the monitor 3 and the VTR 4 is further provided. The captured image signal is converted into data, and the data is converted into a predetermined method (algorithm). And a moving body detecting unit 55 for detecting a moving body in the monitored object.

FIG. 2 is an external view of the light projector 1. A light source (not shown) is provided in a cylindrical housing 11, and light emitted when the light source is turned on is emitted from the housing 11. Condenser lens 12 mounted on the front opening of the camera
And is configured to illuminate the monitored object in a spot manner. In particular, this type of projector is of a condensing type that allows illumination light to reach far away so as to be able to monitor sufficiently far within the viewing distance of the monitoring camera 2 that performs imaging. In addition, a configuration may be adopted in which not only visible light but also infrared light is irradiated so that monitoring can be performed at night or in a dark place.

A gate-shaped cover 13 is provided so as to cover the side and upper part of the housing 11,
A lens holder 15 is rotatably supported by a hinge 14 at a front end of one side surface of the cover 13. The lens holder 15 is formed of a plate-like member made of a magnetic metal that can rotate between one side surface and the front surface of the cover 13 about the hinge 14, and is provided on the lens holder 15. A diffusion lens 16 made of a milky white plate or a concave lens is attached to the circular opening.
A first magnet 17 is attached to the front end of the other side of the cover 13, and a second magnet 18 is attached to a rear end of the outer surface of one side of the cover 13.

In the projector 1, as shown in FIG.
When the lens holder 15 is rotated to a position along one side surface of the cover 13, the lens holder 15 is magnetically held by the second magnet 18, and in this state, light emitted from a light source (not shown) is collected. The light is condensed by the lens 12 and spot-illuminates a required range of the monitored object. Also,
As shown in FIG. 3, when the lens holder 15 is rotated to the front side of the condenser lens 12 around the hinge 14 by manual operation, the lens holder 15 is magnetically held by the first magnet 17, In this state, light emitted from a light source (not shown) is collected by the condenser lens 12,
The light is diffused when transmitted through the diffusion lens 16 and can be illuminated in a diffuse state over a wide range of the monitored object.

The surveillance camera 2 is a generally provided CCD camera, ie, as schematically shown in FIG.
It comprises a camera having an imaging lens 21 for forming an image of the monitored object and a CCD image pickup device 22 for converting the formed image of the monitored object into an electric signal. Omitted. An image signal of the monitored object output from the monitoring camera 2 is captured by the controller 5.
And the image signal processing unit 5 in the controller 5
In step 4, the image signal is processed by a predetermined processing method and output to the monitor 3 and the VTR 4. In addition, as described later, the moving object is input to the moving object detection unit 55 to detect the moving object.

The monitor 3 is composed of, for example, a CRT (cathode ray tube) or an LCD (liquid crystal display), and displays an image of a monitored object based on an image signal captured by the monitoring camera 2. This monitor 3
Is also generally provided, and a detailed description thereof will be omitted.

The VTR 4 uses a generally-used home VTR. Here, a function for temporarily stopping the recording operation during the recording operation, that is, “recording PAUS”
A VTR having an "E" function is used. Note that the VTR used here is preferably a configuration in which the “recording PAUSE” function is not reset.
In the TR, when the recording is paused by the “recording PAUSE” function, a reset is automatically performed after a predetermined time elapses, the pause is released, and the recording is stopped (a state in which no operation is performed). ), The present embodiment has a configuration in which this type of VTR can be used.

The controller 5 is, as described above,
The image signal processing unit 54 can process the image signal input from the imaging camera 2 by a predetermined processing method, display a captured image of the monitored object on the monitor 3, or record the image on the VTR 4. It has been. The monitoring camera control unit 51, the monitor control unit 52, and the VTR control unit 53 input and output the image signal, and simultaneously perform an image capturing operation with the monitoring camera 2, an image display operation with the monitor 3, and a VTR 4 with the video signal. Recording and playback operations can be controlled respectively.

Here, the image signal processing unit 54, the surveillance camera control unit 51, and the monitor control unit 52 can be used as they are with the conventionally provided circuit configuration. Omitted. On the other hand, the VT
As shown in FIG. 4, the R control unit 53 includes an intermittent timer 61 that outputs an intermittent timer ON signal S1 for about several seconds at predetermined time intervals, and an alarm signal ARM that is output when an abnormality is detected as described later. And an alarm timer 62 that outputs a timer ON signal S2 continuously for several tens of seconds to several minutes with the trigger as a trigger. These timer ON signals S1 and S2 are O
"Recording P" of the VTR is inputted to the VTR 4 through the R gate 63 and only when the timer ON signals S1 and S2 are active.
“AUSE” is canceled, and recording with the VTR is executed. Note that the time interval of the intermittent timer ON signal S1 is set to a time shorter than the time at which the reset is performed in the case of a VTR that automatically resets “recording PAUSE” as described above. .

Therefore, in this embodiment, the VTR 4
Is set to the “recording PAUSE” state, as shown in the timing chart of FIG. 5, every time the intermittent timer ON signal S1 is output from the intermittent timer 61 of the VTR control unit 53,
The “recording PAUSE” of the VTR 4 is released, and the recording based on the image signal captured by the surveillance camera 2 is performed only for a few seconds while the intermittent timer ON signal S1 is ON. Intermittent timer ON
When the signal S1 is turned off, the VTR 4 returns to "Recording PAU".
SE ”. The intermittent timer ON signal S
Since the time interval of 1 is shorter than the time of the automatic reset of the VTR 4 as described above, the “recording PAUS”
Even in a VTR of the type in which “E” is automatically reset, the “recording PAUSE” state is maintained without performing the automatic reset by operating the intermittent timer 61. On the other hand, when the alarm signal ARM is output, the alarm timer 62 outputs the timer ON signal S2 only for a predetermined time, and during this time, the “recording PAUSE” of the VTR 4 is released, and the image signal captured by the monitoring camera 2 is output. Based recording is performed.

As described above, by utilizing the recording pause function of the VTR 4 composed of a home VTR,
It becomes possible to reduce the delay of the recording start timing, which is a problem when a home VTR is adopted, that is, the delay time from when a recording start signal such as an alarm signal is input to when the recording is actually started, Intermittent recording, suitable for surveillance
And recording based on the abnormality detection signal. Simultaneously, intermittent recording by the intermittent timer 61 enables so-called frame-by-frame recording, and enables recording of a large number of frame images within the continuously recordable time of the VTR 4. As a result, a dedicated VTR, which is used in a surveillance camera system of a store and performs intermittent recording in a frame-by-frame manner to enable long-time recording, that is, a recording operation similar to a time-lapse VTR is realized. Thus, the surveillance camera system of the present invention does not require the use of an expensive and large time-lapse VTR, which is advantageous in reducing the cost of the surveillance camera system.

On the other hand, FIG. 6 shows a block configuration of the moving object detecting section 55 of the controller 5. A / D converter 71 for converting an image signal from surveillance camera 2 into 8-bit digital image data, that is, image data of 256 gradations
A frame memory 72 for storing the converted image data in units of one frame, a frame operation circuit 73 for adding and subtracting the image data stored in the frame memory 72 by a predetermined algorithm to obtain frame image data, An averaging circuit 74 for averaging the frame image data obtained by the circuit 73 over the past five frames to obtain an average value; a subtraction circuit 75 for subtracting the obtained average value from the current frame image data; A comparison circuit 76 for comparing the output of the comparator 75 with a preset threshold value TH
And an alarm signal ARM from the comparison circuit 76.
Is configured to be output.

As shown in FIG. 7, the frame memory 72 is configured as a memory having an address configuration corresponding to the image pickup pixels of the CCD image pickup device 21 of the monitoring camera 2.
The 256-gradation image data output from the A / D converter 71 is stored in the address corresponding to each pixel. As shown in the figure, the frame operation circuit 73 divides the pixel address m forming the frame memory 72 into four vertical line units, and makes each division one group. In this example, groups are sequentially formed for every four vertical lines from the lower address side to the higher address side of the H address of the frame memory 72. Then, each pixel address m
Are added in the V-address direction, and further added in the H-address direction in units of groups to obtain group image data G1, G2,. Further, with respect to the obtained group image data G1, G2,..., The odd-numbered group image data is added toward the H address direction, and the even-numbered group image data is subtracted. Is output as frame image data F.

Next, the obtained frame image data F is input to an averaging circuit 74. The averaging circuit 74 includes five delay circuits 81 to 85, an addition circuit 86 for adding the outputs of the delay circuits 81 to 85, and a division circuit 87 for dividing the added output by 5. . The frame image data output from the frame operation circuit 73 is sequentially delayed for each frame by five delay circuits 81 to 85, and each of the delayed five frame image data is added in the addition circuit 86. Then, the average value ME of the past five frame image data is calculated by dividing the frame image data added in the adding circuit 86 by 5 which is the number of addition in the dividing circuit 87. This averaging is intended to obtain a filter effect for removing variations in image data for each frame due to noise or the like. Further, the latest frame image data F output from the frame operation circuit 73 and the average value ME obtained by the averaging circuit 74 are subtracted by a subtraction circuit 75, and the output obtained by subtraction by the subtraction circuit 75, that is, The absolute value of the difference MI is compared with a preset threshold value TH in a comparison circuit 76. The comparison circuit 76 outputs an alarm signal ARM on the assumption that the monitored object captured by the monitoring camera 2 has been moved when the absolute value of the difference MI exceeds the threshold value TH.

The operation of the moving object detection unit will be described using a specific example. Now, at a certain timing, the surveillance camera 2
It is assumed that the screen D imaged at is shown in FIG. At this time, it is assumed that required frame image data for the image is obtained in the frame operation circuit 73. At this time, when there is no moving object in the monitored object, each frame image data in a plurality of frames obtained over time has the same value or an approximate value even in consideration of an error. Therefore, if this state occurs over five frames, the average value obtained from the averaging circuit is close to the frame image data, and the latest frame image data F and average value M
The difference MI from E is almost a value close to zero. Therefore,
The absolute value of the difference MI is smaller than the threshold value TH, and the comparison circuit 76 does not output an alarm signal assuming that the moving object does not exist for the monitored object.

On the other hand, as shown in FIG. 8B, when the moving object X appears on the screen D of the monitored object, the image data at the pixel where the moving object X is imaged is changed. You. Now, it is assumed that the gradation value of the image data of the moving object X is high, and when the moving object X is moved into the first group, the group image data G1 of the first group is obtained.
And the value of the frame image data F also increases because the first group image data G1 is a value to be added. In addition, as shown in FIG.
When the group image data G1 and G2 are moved to the region over the second and second groups, the group image data G1 and G2 of each group are values to be added and subtracted, respectively. The value changes in a decreasing direction. Further, as shown in FIG.
When the image data is moved into the second group, the value of the group image data G2 of the second group increases, and the value of the frame image data F decreases because the group image data G2 is a value to be subtracted. As described above, when the moving body X is imaged, the value of the frame image data F fluctuates, the average value ME fluctuates accordingly, and the difference MI from the subtraction circuit 75 fluctuates. And
When the moving body X is moved to an area of a group having a large difference in tone value as compared with the surrounding image data, the difference MI of the subtraction circuit 75 fluctuates extremely, and the threshold in the comparison circuit 76 becomes large. The state exceeds the value TH. For example, a surveillance camera 2 and a floodlight 1 are installed at the entrance of a house, and when a person does not pass through, a dark view of the entrance is captured. When a person passes through the entrance, the light of the floodlight 1 is high by the person. In the case where the image is reflected and reflected at the luminance, the variation of the difference MI becomes extremely large.

FIG. 9 is a table showing image data of a simulation of the detection operation by the moving object detection unit 55.
0 is a graph of the data. FIG. 9 shows, from the left column, frame image data F of frame numbers F10400 to F10429, their average values, and a subtraction circuit 75.
Shows the value of the difference MI obtained by subtraction. Then, in this simulation, in a frame earlier than the frame number F10415, a moving object (human) already existing in the captured monitoring target is changed from an even-numbered group of the frame memory corresponding to the imaging screen to an odd number. This is an example of a case where the user moves to the next group and further moves from the next even-numbered group to the next odd-numbered group. Therefore, in the frame numbers F10415 to F10416 when the moving object moves to the odd-numbered group, the value of the frame image data sharply becomes larger than the frame image data of the previous frame. Are sequentially increased or decreased. Looking at the change in the output from the subtraction circuit at this time,
The output sharply increases after frame number F10417. Also, here, since the threshold value TH in the comparison circuit 76 is set to “1500”, the absolute value of the difference MI in the frame number F10417 and most of the subsequent frames exceeds the threshold value TH. Thus, the alarm ARM is output from the comparison circuit 76 at this point.

As described above, the moving object detecting method in the moving object detecting section 55 of the present invention performs the addition / subtraction processing, the delay processing for averaging, and the division processing for the pixels of the captured image data. The monitoring output of the monitored object can be obtained. Therefore, as described in the related art, it is not necessary to perform a process of comparing the image data of the individual pixels with each other and performing an arithmetic operation on the entire frame to be monitored as described in the related art. Can be realized. In particular, in the case of a system using a monitoring camera having several million pixels, the effect of reducing the number of processing steps is remarkable. It goes without saying that the circuit configuration for processing can be simplified. Further, since the present invention always monitors the entire frame, unlike the prior art in which the image data is compared for a part of the frame, the monitoring is not overlooked and reliable monitoring is possible. Become.

It should be noted that the moving body detecting unit 5 of the above-described embodiment is used.
In step 5, when obtaining frame image data from image data obtained by imaging, the image data is stored in the frame memory 72, the group image data is calculated, and then the calculation is performed in the order of addition and subtraction. But
As a result, it is sufficient that frame image data equivalent to the frame image data of the above embodiment can be obtained, and the actual calculation method may be changed. Therefore, the image data of each pixel serially output from the monitoring camera 2 is sequentially added and subtracted along the horizontal line direction of the imaging screen, and this is repeated in the vertical line direction to calculate the frame image data. A technique is also possible. When this technique is adopted, the frame memory 72 used in the present embodiment is used.
Can be omitted, which is advantageous in further simplifying the configuration. Further, the frame image data in the present invention does not necessarily mean image data including all pixels of one captured image, and when a partial region of one captured image is to be monitored, data of the partial region is used. Is defined as the frame image data, and the present invention is applied, it is possible to realize the effective monitoring as described above for the partial area.

In the above embodiment, one group is formed for each of the four H addresses for the image data obtained by the imaging. However, the number of the H addresses forming this group depends on the type of the monitored object and the request. It can be increased or decreased as appropriate according to the monitoring accuracy or the like. For example, the number of H addresses may be reduced for fine monitoring, and the number of H addresses may be increased for moderate monitoring. However, in the former case, the time required for the processing is slightly increased due to an increase in the number of man-hours for the calculation, and in the latter case, the time required for the processing can be reduced. Further, a group may be configured in units of a plurality of V addresses depending on the situation of the monitored object. The averaging circuit averages five frames, but this number can be set to an appropriate number according to the influence of noise. Further, the threshold value of the comparison circuit is
Instead of a fixed value, it is also possible to adopt a configuration in which the value can be changed from the outside to an appropriate value and set according to changes in the situation.

As described above, when the moving object detecting section 55 of the controller 5 detects an abnormality in the monitored object, an alarm signal ARM is output from the comparing circuit 77, and the alarm signal ARM is output from the VTR control section shown in FIG. 53 is input.
When the alarm signal ARM is input, the VTR control unit 53
In this case, the alarm timer 62 outputs the timer ON signal S2 continuously for several tens of seconds to several minutes with the alarm signal ARM as a trigger.
“AUSE” is released, and recording on the VTR 4 is executed. As a result, an image signal including the moving object captured by the monitoring camera 2 is recorded on the VTR 4.

When the surveillance camera system of the present invention is installed at a predetermined location, when the illumination light of the projector 1 is radiated in a spot-like manner, the image captured by the surveillance camera 2
A phenomenon called so-called overexposure may occur. This occurs because the reflected light from the whitish object having a high light reflectance is too strong, and the signal of the CCD image sensor of the monitoring camera 2 is saturated. In such a case, as shown in FIG. 3, the lens holder 15 is rotated about the hinge 14 by manual operation, and the lens holder 15 is moved from a position along one side of the cover 13 to the condenser lens 12. Set in front of. As a result, the light emitted from the light source is collected by the condenser lens 12, but is diffused when passing through the diffusion lens 16, and can be illuminated in a diffused state over a wide range of the monitored object. On the other hand, it is possible to prevent the phenomenon of overexposure described above. Also, by disposing the diffusion lens 16 in front of the condenser lens 12,
In a projector that uses infrared light, even if it was originally designed so that red light could not be seen with the naked eye, some red light was actually observed, indicating that a surveillance camera system was installed. However, the red light can be made inconspicuous by the diffusion lens 16. Note that the diffusion lens 16 is connected to the projector 1 by the hinge 1.
4, the diffusion lens 1
There is also an advantage that the storage space for 6 is unnecessary, and there is no risk of losing the diffusion lens 16, and workability is improved as compared with a method of attaching and detaching a separate diffusion lens.

[0032]

As described above, according to the present invention, a moving object detecting section for detecting a moving object on a picked-up screen is provided with a plurality of pixels constituting a picked-up image of a monitored object in a plurality of groups. Frame image data calculating means for obtaining group image data obtained by adding the image data of the pixels for each group, and adding and subtracting the group image data to obtain frame image data; and Averaging means for averaging data over the past several frames to calculate an average value, a subtraction circuit for taking a difference between the frame image data and the average value, and comparing an output of the subtraction circuit with a preset threshold value And comparing means for outputting an alarm signal when the absolute value of the output exceeds the threshold value, so that pixels of image data obtained by imaging And performing addition and subtraction processing to obtain frame image data, performing averaging processing on the frame image data, and performing subtraction between the frame image data and the average value to detect a moving object in the monitored object. Data can be obtained, and the inter-comparison processing of the image data of a large number of pixels is not required, and it is possible to obtain the moving object detection at high speed and with high reliability.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a surveillance camera system of the present invention.

FIG. 2 is an external perspective view of the projector.

FIG. 3 is an external perspective view in a state where a diffusion lens of a light projector is set.

FIG. 4 is a block diagram of a VTR control unit.

FIG. 5 is a timing chart for explaining the operation of the VTR control unit.

FIG. 6 is a block diagram of a moving object detection unit.

FIG. 7 is a schematic diagram of an imaging screen for explaining a method of calculating frame image data.

FIG. 8 is a schematic diagram for explaining a principle of detecting a moving object.

FIG. 9 is a diagram showing simulation data of moving object detection.

FIG. 10 is a graph showing FIG. 9 and showing a state in which an alarm signal is output by comparison with a threshold value.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projector 2 Monitoring camera 3 Monitor 4 VTR 5 Controller 12 Condenser lens 15 Lens holder 16 Diffusion lens 21 Imaging optical system 22 CCD imaging device 51 Camera control unit 52 Monitor control unit 53 VTR control unit 54 Image signal processing unit 55 Moving object Detector 61 Intermittent timer 62 Alarm timer 63 OR gate 71 A / D conversion circuit 72 Frame memory 73 Frame operation circuit 74 Averaging circuit 75 Subtraction circuit 76 Comparison circuit 81-85 Delay circuit 86 Addition circuit 87 Division circuit

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yasuyuki Mizutani 500 Kitawaki, Shimizu-shi, Shizuoka Pref. DD57 DD65 GG42 GG52 GG56 GG57 GG68 GG78 HH10

Claims (3)

[Claims] 1. A surveillance camera system comprising: a surveillance camera that images a monitored object; and a controller that detects an abnormality of the monitored object based on image data of the monitored object captured by the surveillance camera. Comprises a moving object detecting unit for detecting a moving object to detect an abnormality in the monitored object, wherein the moving object detecting unit divides a plurality of pixels constituting the captured image of the monitored object into a plurality of groups. Frame image data calculating means for obtaining group image data obtained by adding the image data of the pixels for each group, and adding and subtracting the group image data to obtain frame image data; and Averaging means for averaging data over the past several frames and calculating an average value; A subtraction circuit for calculating a difference between the average values, a comparison means for comparing an output of the subtraction circuit with a preset threshold value, and outputting an alarm signal when an absolute value of the output exceeds the threshold value; A surveillance camera system comprising: 2. The method according to claim 1, wherein the frame image data calculating means divides a large number of pixels constituting the monitored image picked up by the monitoring camera into a predetermined number of line units, and configures each section as one group. The surveillance camera system according to claim 1, wherein the frame image data is obtained by alternately adding and subtracting the group image data calculated for the group from one direction to the other direction orthogonal to the line. . 3. A VTR (video tape recorder) for recording image data of a monitoring target imaged by the monitoring camera.
The VTR has a recording pause function,
3. The surveillance camera system according to claim 1, wherein the controller includes an alarm timer configured to release a recording pause function of the VTR for a predetermined time based on the alarm signal and execute recording.