JP4508043B2 - Video surveillance device and video surveillance program - Google Patents

Description

  The present invention relates to a video monitoring apparatus and a video monitoring program, and when an image of an incoming video signal has a motion and the screen is dark, the region having the motion is clearly displayed on a monitor. The present invention relates to a video monitoring apparatus and a video monitoring program capable of performing the above.

  2. Description of the Related Art An image monitoring system that takes an image of a monitoring site with a monitoring camera and displays the image on a monitor installed at a location distant from the monitoring site has been put into practical use. This video surveillance system is installed in various environments, both indoors and outdoors, and often operates day and night. For example, if it is indoors, monitoring the inside of a building or in a store, and if it is outdoors, it is possible to monitor a parking lot or a construction site. In particular, in an intruder monitoring application, it is important to monitor the time zone after the evening when the popularity is low.

  However, in surveillance sites where only emergency lights are lit at twilight or at night, the surroundings of the surveillance camera and the subject are dark, so when monitoring is performed by displaying images on the monitor, the situation of the surveillance site cannot be seen well was there.

  Here, a motion detection unit for detecting the motion of the video and a motion range detection unit for detecting the moving range of the video are provided, and a frame indicating the moving range of the video is generated based on the detection signal from the motion detection unit. A monitoring camera device that can be superimposed and displayed on a monitor is known (see, for example, Patent Document 1). By using this surveillance camera device, it is possible to easily know that an abnormality has occurred from the monitor display of the captured image even when an intruder is captured as a subject in a dark surveillance site.

  However, when a surveillance camera device such as that disclosed in Patent Document 1 is used, even if it can be recognized from the display of the frame that an abnormality has occurred due to the intrusion of a suspicious person in a dim surveillance site, It is often difficult to clearly see the clothes and physical characteristics of an intruder.

On the other hand, there is known a surveillance camera capable of obtaining an image output capable of recognizing a subject even in a dark place (see, for example, Patent Document 2). This surveillance camera is a technology that opens the aperture of the camera and performs long exposure when the video output level is low. According to this surveillance camera, it is possible to visually recognize the situation in detail even in a dark subject.
JP 11-91467 A JP 2001-281718 A

  However, the surveillance camera described in Patent Document 2 makes the entire screen brighter even if the video is brightened, and when a motion is detected in the subject, only the part that the supervisor should pay attention to is brightened. Can not. In addition, movable means and drive means for changing the aperture of the imaging lens are necessary. In applications where continuous monitoring is performed day and night in various environments as described above, the use of drive means increases the failure rate. Has the disadvantages.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to make it easy to visually recognize an abnormality in a monitoring video when the subject is moving and the screen is dark. In addition, an object of the present invention is to provide a video monitoring apparatus and a video monitoring program capable of reducing the failure rate of the surveillance camera by making the drive control of the diaphragm movable portion indispensable.

In order to solve the above problems, the invention described in claim 1
A video monitoring device (12) provided with motion detection means (303) for detecting a motion of a video of a video signal supplied from a surveillance camera (11) and extracting a motion region from an image frame in which the motion is detected. And
For each image frame whose motion is detected by the motion detection means, a light / dark determination means (304) for determining the brightness of the image based on the statistical value of the luminance level of the entire image frame;
Modulation means (305) for modulating the luminance level of the corresponding motion region so as to increase the contrast of the motion region for the image frame determined to be dark by the brightness determination means;
Output means (306) for outputting an image frame including a motion region modulated by the modulation means;
Image monitoring device (12) equipped with
Is to provide.

The invention according to claim 2
The said modulation | alteration means was comprised so that it might modulate so that the brightness | luminance level of the said corresponding motion area might be made higher about the image frame determined to be dark by the said brightness / darkness determination means. An image monitoring apparatus is provided.

Furthermore, the invention described in claim 3
The video monitoring device (12) includes a motion detection step (S404) for detecting the motion of the video of the video signal supplied from the monitoring camera (11) and extracting a motion region from the image frame in which the motion is detected. A video monitoring program executed by the control means (213),
A light / dark determination step (S406) for determining the lightness / darkness of the image based on the statistical value of the luminance level of the entire image frame detected in the motion when the motion is detected in the motion detection step;
A modulation step (S408) for modulating the luminance level of the corresponding motion region so as to increase the contrast of the motion region for the image frame determined to be dark when it is determined that the image is determined to be dark in the contrast determination step;
An output step (S409) for outputting an image frame including the motion region modulated in this modulation step;
A video surveillance program for executing the above is provided.

  According to the present invention, even when the surveillance site imaged by the surveillance camera is dark, only the motion region in which the motion is detected in the video of the video signal supplied from the surveillance camera is brightened and output. When the output signal is displayed on the monitor, the monitor can better check the state of the moving part of the subject. In addition, since only the motion region is displayed brightly, particularly when the screen is entirely dark, the portion of the monitor that is most noticeable is highly visible.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to preferred embodiments.

  FIG. 1 is a schematic configuration diagram of a video monitoring system to which a video monitoring apparatus and a video monitoring program, which are examples based on the embodiment of the present invention, are applied. In the figure, a video surveillance system 1 has a configuration in which a surveillance camera 11 and a video surveillance device 12 are connected via a network 13 and a monitor 14 for displaying video is connected to the video surveillance device 12. ing. In this embodiment, for the sake of brevity, one monitoring camera 11 and one video monitoring device 12 are connected to the network 13. Of course, a plurality of monitoring cameras 11 and videos are connected to the network 13. The monitoring device 12 may be connected.

  FIG. 2 is a block diagram showing details of each component of the video surveillance system 1. In the figure, the surveillance camera 11 forms an image of a light beam from a subject on the surveillance site on an imaging unit 202 such as a charge coupled device (CCD) through an optical system 201 such as an imaging lens. The formed image is photoelectrically converted and then supplied to the video signal processing unit 203 as a video signal.

  In the video signal processing unit 203, the supplied video signal is subjected to data compression processing by a data compression method such as a motion JPEG method (hereinafter referred to as MJPEG method) or MPEG method, and then output as compressed image data (I / F) unit. 204. In the output I / F unit 204, the compressed image data is converted into known IP (Internet Protocol) packet data and transmitted to the video monitoring device 12 via the network 13.

  In the figure, the video monitoring apparatus 12 includes an input I / F unit 211, an input buffer unit 212, a control unit 213 having a CPU (Central Processing Unit) (not shown), a frame memory unit 214, and an output buffer unit. 215 and an output I / F unit 216, and an input buffer unit 212, a control unit 213, a frame memory unit 214, and an output buffer unit 215 are connected via a bus 217, respectively. .

  The input I / F 211 receives IP packet data supplied from the monitoring camera 11 via the network 13, extracts compressed image data from the IP packet data, and supplies the compressed image data to the input buffer unit 212. The input buffer unit 212 is a memory that stores compressed image data for at least one image frame (also referred to as one frame).

  The control unit 213 has a function of causing the video monitoring program of this embodiment to be executed. Specifically, the compressed image data for one frame stored in the input buffer unit 212 is read out and subjected to data expansion processing, and then stored in the frame memory unit 214 as expanded image data. The frame memory unit 214 has a capacity capable of storing decompressed image data of at least two frames.

  Also, the control unit 213 reads out the expanded image data of two or more frames stored in the frame memory unit 214 or executes a motion detection process, a light / dark determination process, and a luminance modulation process, which will be described later with reference to The expanded image data modulated by the luminance modulation process is output to the output buffer unit 215. Then, the output buffer unit 215 stores the supplied expanded image data after modulation, is converted into a video signal by the output I / F unit 216, and is output to the monitor 14. The monitor 14 to which the video signal is input displays an image that has been subjected to luminance modulation processing.

  Next, a video monitoring apparatus that receives IP packet data (including compressed image data) output from the monitoring camera 11 and executes data expansion processing, motion detection processing, light / dark determination processing, and luminance modulation processing 12 and the operation of the video monitoring program will be described with reference to the virtual hardware block diagram of the video monitoring apparatus 12 shown in FIG. 3 and the flowchart of FIG.

  First, as shown in FIG. 3, the video monitoring apparatus 12 includes an input processing unit 301, a data expansion processing unit 302, a motion detection processing unit 303, a light / dark determination processing unit 304, a modulation processing unit 305, and an output processing unit. 306. Each of these processing units is subjected to software processing by a CPU included in the control unit 213.

  The operation will be specifically described with reference to the flowchart of FIG. In this embodiment, the case where compressed image data is compressed by the MJPEG method will be described. According to the figure, the input processing unit 301 extracts the compressed image data for one frame while receiving the IP packet data transmitted from the monitoring camera 11 via the network 13 and stores it in the input buffer unit 212 ( Step S401).

  Next, the data expansion processing unit 302 reads compressed image data (JPEG data) for one frame from the input buffer unit 212, executes data expansion processing, and stores the expanded image data in the frame memory unit 214 (step S402). ). Then, the processes in steps S401 and S402 are executed until the decompressed image data for at least two frames close to the frame memory unit 214 is stored (step S403).

  Next, the motion detection processing unit 303 reads the decompressed image data for two frames from the frame memory unit 214 or refers to it, and extracts a portion in which motion has occurred between both frames (hereinafter referred to as a motion region) (step). S404). This is based on a method of calculating a difference between two frames of expanded image data and comparing the difference with a predetermined threshold value. Specifically, for example, the difference between the average values of the luminance levels for each subdivided block (for example, 8 × 8 pixels) of each frame between two frames is calculated. Then, when there are more blocks than the predetermined threshold (brightness threshold) whose difference value is determined in advance, it is determined that “the motion is detected” and the block is set as the motion region. It is determined that “no motion is detected” when the other difference value is equal to or smaller than the luminance threshold or when the number of blocks having the difference value larger than the luminance threshold is equal to or smaller than a certain number.

  When the motion is detected by the motion detection processing unit 303 (step S405 Yes), the light / dark determination processing unit 304 determines the brightness / darkness of the decompressed image data in the frame in which the motion is detected by a known statistical method (step S405). S406). Specifically, for example, an average value of the luminance levels of the entire frame is calculated and compared with a predetermined luminance reference value, and when the calculated average value of the luminance level is smaller than the luminance reference value, “dark” If the average value is equal to or greater than the luminance reference value, it is determined as “bright”.

  When the light / dark determination processing unit 304 determines that the image is dark (Yes in step S407), the modulation processing unit 305 executes luminance modulation processing on the motion region extracted by the processing of the motion detection processing unit 303 (step S408). . Specifically, for example, the maximum value Ymax and the minimum value Ymin of the average value of the luminance level of each block in the motion region are searched, and for each block in the motion region, Equation 1 is obtained. The luminance level average value Yin is modulated based on the maximum value Ymax and the minimum value Ymin, and the luminance Yout after modulation of the block is calculated.

<Formula 1>
Yout = (Yin−Ymin) × 255 / (Ymax−Ymin)

  By replacing the luminance level of each pixel included in the motion area of the expanded image data with the luminance You after modulation of the corresponding block by the modulation processing of Expression 1, the contrast is expanded to the range of 0 to 255 as the entire motion area. Is done.

  After the processing of the modulation processing unit 305 in step S408, when motion detection is not performed in step S405 (step S405 No), and when it is determined that the frame is bright in step S407 (step S407 No), The output processing unit 306 stores the expanded image data in the output buffer unit 215, converts it into a video signal by the output I / F unit 216, and outputs it (step S409).

  Next, the oldest decompressed image data stored in the frame memory unit 214 is deleted (step S410), and when processing the compressed image data for the next frame, the process proceeds to step S401 (step S411 No), and the other If there is no processing for the next frame, the processing is terminated (Yes in step S411).

  As described above in detail, the video monitoring device 12 and the video monitoring program according to the present embodiment have the brightness level of the compressed image data supplied from the monitoring camera 11 when the expanded image data after data expansion is bright. An image with normal brightness is supplied to the monitor 14 without performing modulation. When the decompressed image data is dark, an image in which the contrast is expanded by modulating the luminance level of only the portion where the motion is detected, that is, the motion region is supplied to the monitor 14. Accordingly, the video monitoring system 1 outputs only the motion region in which the motion is detected in the video of the video signal supplied from the monitoring camera 11 even when the monitoring site captured by the monitoring camera 11 is dark. Therefore, when this output signal is displayed on the monitor 14, the monitor can better confirm the state of the portion where the subject moves. In addition, since only the motion region is displayed brightly, particularly when the screen is entirely dark, the portion of the monitor that is most noticeable is highly visible.

  In the present embodiment, the modulation processing unit 305 is configured to increase the contrast of each block in the motion region. However, as another embodiment, the average value of the luminance level of the block is set to a maximum value of, for example, 255. The luminance level may be increased by providing the offset. By configuring in this way, it is possible to brighten and display only the moving part, so that it is easy to visually recognize the occurrence of an abnormality such as an intruder.

  Moreover, it is good also as a structure which reverses the bit of data about the average value of the luminance level of the said each block. With this configuration, there is an advantage that the calculation processing load is reduced.

  Also, in the motion detection processing unit 303 of the present embodiment, an example has been described in which a frame is divided into predetermined blocks and motion detection processing is performed in units of blocks. However, as another embodiment, a frame is divided into blocks. You may make it perform a motion detection process and a modulation | alteration process per pixel, without dividing | segmenting. Specifically, for each pixel in the motion region, the maximum value PYmax and the minimum value PYmin are respectively searched, and for each pixel in the motion region, the luminance level PYin is expressed as the maximum value PYmax and the minimum value as in Equation 2. Modulation is performed based on PYmin, and luminance PYout after modulation is calculated.

<Formula 2>
PYout = (PYin−PYmin) × 255 / (PYmax−PYmin)

  By the modulation process of Formula 2, the contrast of the luminance level of each pixel included in the motion region of the expanded image data is expanded to a range of 0 to 255. Thereby, it is possible to display a more detailed state of motion detection.

  Further, the video monitoring device 12 may be provided with a recording means such as a hard disk, and the modulated expanded image data may be recorded based on the control by the control unit 213.

  In addition, the image data compression / decompression processing function is not provided, the network between the monitoring camera 11 and the video monitoring device 12 is not a network but a single transmission line, for example, a video cable, and the video monitoring device 12 It goes without saying that the technical idea of the present invention can be sufficiently realized even in a configuration in which the function is provided on the monitoring camera 11 side.

  INDUSTRIAL APPLICABILITY The present invention is useful for a video surveillance system in which it is required to clearly see a moving subject captured darkly in a monitoring site where the brightness of the subject changes.

It is a schematic block diagram of the video surveillance system to which the example based on the best mode of the present invention is applied. 2 is a block diagram illustrating details of each component of the video surveillance system 1. FIG. 3 is a virtual hardware block diagram of the video monitoring apparatus 12. FIG. 5 is a flowchart for explaining the operation of the video monitoring device 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Video surveillance system 11 Surveillance camera 12 Video surveillance apparatus 13 Network 14 Monitor 201 Optical system 202 Imaging part 203 Video signal processing part 204 Output I / F part 211 Input I / F part 212 Input buffer part 213 Control part 214 Frame memory part 215 Output buffer unit 216 Output I / F unit 217 Bus 301 Input processing unit 302 Data expansion processing unit 303 Motion detection processing unit 304 Brightness / darkness determination processing unit 305 Modulation processing unit 306 Output processing unit

Claims (3)

A video monitoring device comprising motion detection means for detecting a motion of a video signal supplied from a surveillance camera and extracting a motion region from an image frame in which the motion is detected,
For each image frame whose motion is detected by the motion detection means, light / dark determination means for determining the brightness of the image based on the statistical value of the luminance level of the entire image frame;
Modulation means for modulating the luminance level of the corresponding motion region so as to expand the contrast of the motion region for the image frame determined to be dark by the brightness determination device;
Output means for outputting an image frame including a motion region modulated by the modulation means;
A video surveillance device.   The said modulation | alteration means was comprised so that it might modulate so that the brightness | luminance level of the said corresponding motion area might be made higher about the image frame determined to be dark by the said brightness / darkness determination means. Video surveillance device. A video monitoring program that executes a motion detection step of detecting a motion of a video signal supplied from a surveillance camera and extracting a motion region from an image frame in which the motion is detected by a control means included in the video monitoring device Because
When motion is detected in the motion detection step, a light / dark determination step for determining light / dark of the image based on a statistical value of the luminance level of the entire image frame detected with the motion;
A modulation step for modulating the luminance level of the corresponding motion region so as to increase the contrast of the motion region for the image frame determined to be dark when it is determined to be dark in the light / dark determination step;
An output step for outputting an image frame including the motion region modulated in the modulation step;
A video monitoring program that executes

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