JP4164762B2 - Light source detection device and crime prevention notification device - Google Patents

Description

  The present invention relates to a light source detection device capable of detecting a moving light source, and a crime prevention notification device capable of reporting by detecting a moving light source such as a flashlight.

At night, a crime prevention apparatus equipped with an infrared camera is installed in a room in order to detect a person who has entered the room.
According to this security device, an infrared camera can detect an object having a high temperature, so that a person who has entered the room at night can be found.

  However, if a crime prevention device equipped with the infrared camera tries to detect a person who has entered the room, it creates a temperature distribution image based on the image taken by the infrared camera, extracts moving objects from it, There is a problem that the determination process becomes complicated. If an attempt is made to increase the reliability of the determination, advanced image processing is required, and the cost of the entire security device increases.

Accordingly, an object of the present invention is to provide a light source detection device that can reliably detect a moving light source at night by simple image processing.
It is another object of the present invention to provide a crime prevention reporting device that can reliably detect a person who has entered a room with a moving light source such as a flashlight at night by simple image processing.

If the light of a moving light source such as a flashlight is projected on the floor or wall of a room, the present inventor is accompanied by light reflected from the light (projection light), and the light of the moving light source or the projection light is fixed. I noticed that it has a characteristic of moving at a certain speed and synchronously.
The light source detection device according to the present invention includes a camera for monitoring a room, search means for searching for a portion of light having a luminance change or position change from an image captured by the camera, and a plurality of searched light portions. When selecting a pair of large and small areas, a tracking means for tracking the selected pair and a change in a small light and a change in a large light among the lights constituting the pair are synchronized in time. Synchronization detecting means for checking whether or not they are output, and output means for outputting a predetermined signal when they are synchronized.

According to the above configuration, first, the searching means searches the moving light portion from the image taken by the camera based on the luminance change or the position change. The reason for seeing the movement is to exclude the lights in the room and the street light coming from the windows.
Next, the tracking means takes out the large and small pairs and tracks them. This pair assumes that one is a moving light source and the other is its projection light. Even if it is a moving light, it is excluded if a pair cannot be made. For example, when the headlight of the vehicle is not reflected in the camera, even if only the projection light of the headlight is reflected in the camera is excluded.

Next, the synchronization detection means checks whether the small light change and the large light change are synchronized in time. This is because if the small light and the large light change synchronously, they are found to be light emitted from the same light source.
In this way, a moving light source can be reliably detected based on the image captured by the camera.

  It is preferable that the synchronization detection means examines whether the luminance change or position change of small light and the position change of large light are synchronized in time. For example, if the moving light source is shaken by hand, the moving light source can be regarded as a change in position, and if only the angle of the moving light source is changed, it can be taken as a change in luminance reflected on the camera screen. Since the large light is the projection light, it can be regarded as a change in position.

  Moreover, the crime prevention notification apparatus of the present invention can regard small light as a moving light source such as a flashlight and large light as projection light when the large and small pairs of lights are synchronized. Thereby, it can be determined that there is an intruder and can be notified.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a system configuration diagram of a security notification device including a light source detection device. This security notification device includes a camera 1, a computer 2, an alarm buzzer 3, a mobile phone 4 installed in a room, and an Internet line connected to the outside. It consists of. The camera 1 is installed at an arbitrary position in the room (in FIG. 1, it is placed beside the computer 2).

2A and 2B are indoor screen views reflected in the field of view of the camera. FIG. 2A shows a screen showing the indoor structure, and FIG. 2B shows a night indoor screen. In FIG. 2 (b), the floor, wall, and window frame are drawn with white lines, but these are drawn for position reference, and are not actually shown on the captured screen.
FIG. 3 is a screen view of the room in the night actually reflected on the screen of the camera 1, and the size of this screen is, for example, 17 inches, 800 pixels × 600 pixels. The brightness of the image is in the range of values 0 to 255 (0 is the darkest and 255 is the brightest). The light source S of the flashlight and the projection light P onto the floor are shown on the screen of FIG.

The computer 2 performs image processing as shown in the flowchart (FIG. 4) based on the screen of the camera 1. All or part of these image processing functions are realized by the computer 2 executing a program recorded on a predetermined medium such as a CD-ROM or a hard disk.
In FIG. 4, first, an image captured on the screen of the camera 1 is captured (step S1), and binarization processing is performed using a threshold value (step S2). This binarization threshold is a threshold for night shooting screens of rooms without room light illumination, and is set to a considerably dark luminance. As a result, the screen is divided into either a bright light portion or a dark portion.

The computer 2 searches for a bright light portion based on the binarized screen (step S3).
Further, it is determined whether or not the light portion is moving (step S4). It is simple to determine this movement based on the movement of light on the screen of the camera 1. For example, when searching for a moving light portion, a threshold value of a time interval until the next change, for example, a threshold value of 10 seconds is used, and a motion is detected when a change in light position or brightness is detected within this threshold value. It is determined that a certain light is detected. Light that does not change within this threshold is not a moving light source, but a fixed light source (for example, light from a luminaire or streetlight).

  Alternatively, the determination may be made by calculating the speed of the real space (three-dimensional coordinates in the room) instead of determining the change on the screen of the camera 1. For this purpose, it is necessary to grasp in advance the relationship between the position on the screen of the camera 1 to be photographed and the position in the real space. For this purpose, it is necessary to incorporate into the program of the computer 2 a conversion formula between the two-dimensional coordinates on the screen of the camera 1 and the actual three-dimensional coordinates using the position and orientation of the camera 1 as parameters (special features). (See Kaihei 4-20189, JP-A-6-35443, etc.). However, in order to convert two-dimensional coordinates on the screen into three-dimensional coordinates, it is necessary to reduce the number of coordinates in the three-dimensional space by one. For this purpose, it is only necessary to set the height of the flashlight from the floor to a certain height (for example, 1 m), assuming that a human holds the flashlight. The computer 2 determines that the light portion is moving when the light portion is moving in a three-dimensional coordinate in the room at a speed exceeding the threshold. When moving at a speed equal to or lower than the threshold, the camera 1 is considered to be a fixed light source that does not actually move due to vibration or shaking of the camera 1.

  Next, it is determined whether or not there are a plurality of light portions (step S5). This is because the light of the flashlight is accompanied by light (projection light P) reflected from the floor or wall of the room when reflected. The projection light of a light such as a bicycle or a vehicle that travels outdoors behaves as a single light indoors, except when the light is reflected on the screen. Therefore, it is excluded by the determination in step S5.

  Next, the area (unit: area ratio with respect to the entire screen) of a region where light portions continuously exist is measured. When this area is larger than a threshold value (for example, 3%), it is set as a large light portion, and when it is smaller than the threshold value, it is set as a small light portion. Based on this measurement, a pair of large and small is taken out (step S6). Then, the smaller one is regarded as “light source S” and the larger one as “projection light P”, and the respective light portions are traced using a time difference method or the like (steps S7 and S8). If the light source S or the projection light P may be lost during tracking (step S9), the process returns to the start.

Then, it is checked whether or not the luminance change or position change of the light source S and the position change of the projection light P move in synchronization (step S10).
If the projection light P is the reflected light of the light source S, the projection light P should shake greatly if the light source S moves or changes the angle.
FIG. 5 is a diagram showing the relationship between the luminance change (a) of the light source S and the positional change (b) of the projection light P.

In FIG. 5A, the brightness of the light source S varies between the background (detection limit for the dark level of the camera) and the saturation value (detection limit for the bright level of the camera) by the rotation operation of the light source S. . In the state where the brightness of the projection light P is maximum, it indicates that the light source S faces the camera 1.
FIG. 5B shows a state where the position of the projection light P is shaken. The position where the shake of the projection light P corresponds to 0 is the position of the camera 1. When the projection light P is at this position, the brightness of the projection light P is maximum, and the brightness of the projection light P decreases as the projection light P moves away from this position. It can be seen that is synchronized.

  FIG. 6 is a diagram showing the relationship between the shake change (a) of the light source S and the shake change (b) of the projection light P. In FIG. 6A, the position of the light source S is changed by the movement of the light source S (for example, shaking of the hand holding a flashlight). FIG. 6B shows a state where the position of the projection light P is shaken. 6 (a) and 6 (b), it can be seen that the shake of the projection light P and the shake of the light source S have similar waveforms, and the light source S and the projection light P are synchronized.

As described above, when the light source S and the projection light P are moving in synchronism, the projection light P is reflected light from a portion illuminated by the light source S. Therefore, the light source S is a flashlight or the like. It turns out that it is a moving light source.
If it is determined that the light source is a moving light source, the video is stored in a non-volatile memory (step S11), and if a report or alarm is set to the computer 2, a report / alarm signal is sent to the outside.

As a result, the alarm buzzer 3 shown in FIG. 1 is sounded or a security company or police station is notified through the network. Further, the mobile phone 4 of the house owner may be called or an e-mail may be sent.
As described above, if a flashlight is used to enter a room at night by simple image processing, this can be reliably detected.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

It is a system block diagram of the light source detection apparatus and crime prevention notification apparatus of this invention. (a) is a structural diagram of the room, and (b) is a screen shot of the night room (including the outline of the wall that is not actually captured). It is the screen figure which image | photographed the room indoors at night. 5 is a flowchart illustrating a procedure for performing image processing for detecting a moving light source based on the screen of the camera 1. It is a graph which shows the relationship between the luminance change (a) of the light source S, and the position change (b) of the projection light P. 6 is a graph showing a relationship between a shake change (a) of the light source S and a shake change (b) of the projection light P.

Explanation of symbols

1 Camera 2 Computer 3 Alarm buzzer 4 Mobile phone P Projected light S Light source

Claims (4)

A camera to monitor the room,
Search means for searching for a portion of light having a luminance change or a position change from an image taken by a camera;
A tracking means for selecting a pair of large and small areas and tracking the selected pair when there are a plurality of searched light portions;
Synchronization detection means for examining whether a change in small light and a change in large light among the light constituting the pair are synchronized in time,
An output means for outputting a predetermined signal when they are synchronized with each other.   The light source detection device according to claim 1, wherein the search unit, the tracking unit, and the synchronization detection unit are executed as an image processing function of a program installed in a computer constituting the light source detection device.   The light source detection device according to claim 1, wherein the synchronization detection unit is configured to check whether a luminance change or position change of small light and a position change of large light are temporally synchronized. A camera to monitor the room,
Search means for searching for a portion of light having a luminance change or a position change from an image taken by a camera;
A tracking means for selecting a pair of large and small areas and tracking the selected pair when there are a plurality of searched light portions;
Synchronization detection means for examining whether a change in small light and a change in large light among the light constituting the pair are synchronized in time,
A crime prevention reporting apparatus comprising: a moving light source such as a flashlight when the light is synchronized; and a reporting means for reporting a large light as the projection light.

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