JP2999476B2 - Intruder detection device - Google Patents

Description

The present invention relates to an intruder detection device that detects an intruder or the like entering a house or the like using an imaging device such as a TV camera.

[Conventional technology]

Conventional devices of this type widely use a device that detects the presence or absence of an intruder based on a difference image between a current image obtained by imaging a monitoring area and a reference image stored in advance as a signal indicating a normal state of the monitoring area. Used.

In addition, in order to improve the reliability of detection, a mask area indicating a plurality of specific areas is set in the monitoring area, for example,
When the window is to be watched from the outside, the window portion is set to the watch level and the area around the window is set to the watch level, as shown in FIG. It has been proposed to make a judgment and output an alarm (Japanese Patent Laid-Open No. 62-086990). In addition, areas that do not require vigilance to reduce false alarms (eg, walls of houses without windows or other intruding openings)
, A non-caution mask is set as a non-caution area (shaded area in the figure).

In the above conventional example, as shown in FIG. 6, in the case of indoor monitoring, a pedestrian outside the window (not an intruder).
Since a vehicle or an automobile enters the monitoring area through the window, the non-security mask area M2 is set on the entire window, and the security mask area M1 is set on the entire indoor area other than the window. That is, if the target T exists indoors, the alarm is immediately issued. Now, let the target T1 be a pedestrian passing outside the window,
Let T2 be an intruder who appears indoors. The target T1 is located only in the non-security mask area M2, and is not considered as an intruder. Since the target T2 stands with the window as a back, it is detected both in the guard mask area M1 and in the non-guard mask area M2. Therefore, the area of the target T2 is divided, and it is determined whether or not the target T2 is an intruder based on the area occupied by the pixels having changed luminance in the alert mask area M1.

[Problems to be solved by the invention]

As described above, if the presence or absence of an intruder is determined based on the divided small area, there is a possibility that a report will be lost. In other words, when the large area non-security mask area M2 is adjacent to the small area security mask area M1, the target straddling both mask areas is divided, and the target within the divided security mask area M1 is divided. If the area occupied by the pixels having changed in luminance does not reach a predetermined value, there is a problem that the possibility of a false alarm increases.

The present invention has been made in view of the above points, and an object of the present invention is to be able to reliably detect an intruder even when a target exists over a plurality of mask areas. An intruder detection device is provided.

[Means for solving the problem]

The present invention stores imaging means for imaging a monitoring area, A / D conversion means for A / D converting an image signal output from the imaging means, and stores a current image output from the A / D conversion means. An input image memory, a reference image memory for storing a reference image indicating a normal state of the monitoring area, a difference unit for obtaining a difference image between the current image and the reference image, and a determination for determining the presence or absence of an intruder from the difference image Means, and an intruder detection device comprising an alarm output means for outputting an alarm based on the output of the determination means, wherein a plurality of sections are provided in which a specific area of the monitoring image is previously classified and a mutual relationship between the specific areas is distinguished. A mask image memory for storing a mask area, and selector means for selecting which of the mask areas stored in the mask image memory a pixel having a luminance change in the difference image belongs to, Comprises a plurality of counters for counting the number of pixels whose luminance exceed the threshold for each mask area selected by the selector means, in said determination means,
One mask area is selected from the mask areas exceeding the preset counter value based on the mutual positional relationship, and the counter value of the counter corresponding to the selected mask area exceeds the preset counter value. A counter value of a counter corresponding to an adjacent mask area is added, and the presence or absence of an intruder is determined based on a result of the calculation.

[Action]

In the present invention, mask areas corresponding to a plurality of specific areas are stored in advance in both monitoring areas, and a level indicating a positional relationship between the specific areas indicated by the mask areas is set, and each of the mask areas is set. Among the corresponding counters, among the counters whose counter values indicating the luminance change pixels have exceeded a predetermined value, based on the positional relationship, based on the mutual positional relationship among the mask regions exceeding the preset counter value. One mask area is selected, and the counter value of the counter corresponding to the adjacent mask area exceeding the preset counter value is added to the counter value of the counter corresponding to the selected mask area, and the intrusion is performed by the added value. Is to determine the presence or absence of a person.

〔Example〕

Hereinafter, the present invention will be described with reference to the drawings given as one embodiment.

FIG. 1 is a block diagram showing one embodiment of the present invention.
Reference numeral 1 denotes an imaging unit such as a TV camera, which captures an image of a monitoring area and obtains an image signal. Reference numeral 2 denotes A / D conversion means for A / D converting the image signal into a digital signal. Reference numeral 3 denotes an input image memory for temporarily storing a current image input from the two-dimensional imaging means every moment. A reference image memory 4 stores a background image indicating a normal state of the monitoring area in advance. 5 is a mask image memory,
The position of a mask image indicating a plurality of specific areas in the monitoring area is stored.

Here, levels are assigned to the plurality of mask areas according to the positional relationship of the specific areas. That is, when the target T exists over two mask areas, the level is assigned to indicate which mask area has priority. For example, in the example of FIGS. 2 and 3, the level of the mask area corresponding to the windows W1 and W2 is set to the level of the mask area corresponding to the partition P, and the level of the mask area corresponding to the floor, the wall K, and the like is set. Let the level be. Here, it is assumed that is the highest priority, and is lower in the order of. That is, assuming that the target T straddles the window W1 and the wall K, the target T (intruder) always exists indoors. Therefore, the level of the mask area corresponding to the wall K is higher than the level of the mask area corresponding to the window W1. When the target T straddles the partition P and the wall K, the target T (intruder)
Must exist before the partition P.
Accordingly, the level of the mask area corresponding to the partition P is higher than the level of the mask area corresponding to the wall K.

Reference numeral 6 denotes a pointing device such as a light pen, which is an external device for storing a position of a mask area in accordance with a screen in a mask image memory. Numeral 7 denotes a difference means which obtains a difference image between the current image stored in the input image memory 3 and the reference image stored in the reference image memory 4 and binarizes the image with a predetermined threshold value, and has a luminance change. This is for extracting pixels. Reference numeral 8 denotes a selector comprising a plurality of gates, which determines from the output of the difference means 7 and the output of the mask image memory 5 which specific area a pixel having a luminance change belongs to. The gate has the same number as the number of mask regions. Numeral 9 denotes a counter means, which has a plurality of counters corresponding to the respective gates of the selector means 1 on a one-to-one basis, and counts the number of changed pixels for each mask area. Numeral 10 denotes a judging means. Among the counters in which the counter value of each counter of the counter means 9 exceeds a predetermined value, the mask value of the counter corresponding to the highest level mask area is replaced by another low level mask. The counter value of the counter corresponding to the area is added, and the presence or absence of an intruder is determined based on the added counter value. Here, the reason why only the counter exceeding the predetermined value set in advance is set as the calculation target is that the counter of the mask area where a slight change pixel is generated due to noise or the like is determined from the calculation target regardless of the presence of the target T. This is to exclude.

Numeral 11 denotes an alarm output means for issuing an alarm when the judgment means 10 judges that there is an intruder.

Next, the operation of the present embodiment will be described using an example in which the monitoring area and the mask image shown in FIG. 2 are set.

FIG. 2 shows a scene for guarding an indoor corner, in which there are two windows W1 and W2 on the left wall and the partition P is visible on the right front.

As described above, for this scene, a mask area is set in order from the specific area close to the TV camera 1, and the levels of the partitions P, the floor, the ceiling, the wall K, and the window W
1, W2 becomes. The boundaries between the respective mask regions are indicated by alternate long and short dash lines.

FIG. 3 shows a case where the target T stands in the room with the window W1 behind. The target T is divided into a wall K and a window W1, and the counters C and C3 corresponding to the mask area indicating the wall K and the window W1 in the counter means 9 occupy each of the mask areas indicating the wall K and the window W1. A value corresponding to the area of the target T is shown.

Here, the level of the mask area indicating the wall K is higher than the level of the window W1.
Is higher than the level of the mask area indicating
Then, the counter value of the counter C3 is added to the counter value of the counter C2, and the presence or absence of an intruder is determined based on a predetermined threshold value using the addition result. If the addition result exceeds the threshold, it is determined that an intruder is present, and an alarm is issued by the alarm output unit 11. Therefore, even if the target T is divided into a plurality of mask regions indicating specific regions, it can be reliably detected.

In addition, as shown in FIG. 4, when the target T is visible outside the window W2, the counter value appears only in the counter C3, so that the addition between the counters is not performed. Even if the counter value of the counter C3 exceeds the threshold, the window W1,
If the mask area indicating W2 is set as the non-warning mask area,
No alarm output will be issued by mistake.

〔The invention's effect〕

The present invention stores imaging means for imaging a monitoring area, A / D conversion means for A / D converting an image signal output from the imaging means, and stores a current image output from the A / D conversion means. An input image memory, a reference image memory for storing a reference image indicating a normal state of the monitoring area, a difference unit for obtaining a difference image between the current image and the reference image, and a determination for determining the presence or absence of an intruder from the difference image Means, and an intruder detection device comprising an alarm output means for outputting an alarm based on the output of the determination means, wherein a plurality of sections are provided in which a specific area of the monitoring image is previously classified and a mutual relationship between the specific areas is distinguished. A mask image memory for storing a mask area, and selector means for selecting which of the mask areas stored in the mask image memory a pixel having a luminance change in the difference image belongs to, Comprises a plurality of counters for counting the number of pixels whose luminance exceed the threshold for each mask area selected by the selector means, in said determination means,
One mask area is selected from the mask areas exceeding the preset counter value based on the mutual positional relationship, and the counter value of the counter corresponding to the selected mask area exceeds the preset counter value. The counter value of the counter corresponding to the adjacent mask area is added, and the presence or absence of an intruder is determined based on the result of this calculation. An intruder detection device capable of reliably detecting an intruder can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 to 4 are schematic views of a screen for explaining the operation according to the above, and FIGS. It is a schematic diagram of a screen for explaining the operation. DESCRIPTION OF SYMBOLS 1 ... Image pick-up means, 2 ... A / D conversion means 3 ... Input image memory, 4 ... Reference image memory 5 ... Mask image memory 6 ... Pointing device 7 ... Difference means, 8 ... Selector means 9 ... Counter means, 10 ... Judgment means 11 ... Alarm output means

Continuation of the front page (72) Inventor Masami Hisada 1048 Odoma, Kazuma, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-2-207381 (JP, A) JP-A-61-146085 (JP, A) JP-A-63-138283 (JP, A) JP-A-62-222393 (JP, A) JP-A-61-195093 (JP, A)

Claims (1)

(57) [Claims] An imaging unit for imaging a monitoring area, an A / D conversion unit for A / D converting an image signal output from the imaging unit, and a current image output from the A / D conversion unit are stored. An input image memory, a reference image memory for storing a reference image indicating a normal state of the monitoring area, a difference unit for obtaining a difference image between the current image and the reference image, and determining whether there is an intruder from the difference image. In an intruder detection device including a determination unit and an alarm output unit that outputs an alarm based on an output of the determination unit, a plurality of regions are provided in which a specific region of a monitoring image is previously divided and a mutual relationship between the specific regions is distinguished. A mask image memory for storing the mask areas of the above, and selector means for selecting which of the mask areas stored in the mask image memory the pixels whose luminance has changed in the difference image, Comprises a plurality of counters for counting the number of pixels whose luminance exceed the threshold for each mask area selected by the selector means, in said determination means,
One mask area is selected from the mask areas exceeding the preset counter value based on the mutual positional relationship, and the counter value of the counter corresponding to the selected mask area exceeds the preset counter value. An intruder detection device characterized by adding a counter value of a counter corresponding to an adjacent mask area and determining the presence or absence of an intruder based on a result of the calculation.