JPS5931115B2 - Intruding object detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intruding object detection device, and more particularly to an intruding object detection device that can detect not only the presence or absence of an intruding object but also its size.

2. Description of the Related Art As a device for detecting an intruding object or a passing object, a light beam alarm device or the like consisting of a light projecting device and a light receiving device has conventionally been used.

However, with conventional optical beam warning devices, it has been impossible to determine the size of an intruding object.

For this reason, the configuration shown in FIG. 1, in which a plurality of light receiving devices are arranged, has been considered.

In this figure, a convex lens 2 is provided in front of each light receiving element 1 such as a light receiving diode arranged at a predetermined interval, so that the light beam passing through the convex lens 2 is focused on the light receiving element 1. It has become.

By the way, when such an independent light-receiving element 1 is used, since the size of the light-receiving surface of the light-receiving element 1 is relatively large, on the order of several dragons, a wide range of light rays will be received through the convex lens 2.

In other words, the monitoring range of one light-receiving element is a dog, which has the disadvantage that the resolution for identifying the size of an object is correspondingly poor.

Furthermore, at a position away from the convex lens 2, the monitoring range of each light-receiving element 1 overlaps with each other as shown by the diagonal lines in the figure, so there is no point in providing multiple light-receiving elements, and it is difficult to identify the size of an object. becomes difficult.

In order to avoid this inconvenience, the light-receiving surface of the light-receiving element 1 may be made smaller, but then the detection sensitivity decreases and object detection becomes practically difficult.

In order to eliminate the above-mentioned inconveniences, 1 has been developed in recent years.
Dimensional photodiode array (also called image sensor)
Figure 2 shows a configuration using the .

This one-dimensional light receiving diode array has a large number of light receiving diode elements of several tens of microns arranged linearly at a pitch of several tens of microns, and has the features of high sensitivity and high resolution.

In reality, the structure is such that not only the light receiving diode elements but also peripheral circuits for extracting the outputs of the individual light receiving diode elements as serial pulses are formed as an integrated circuit and housed in an IC chip.

Now, in Fig. 2, one-dimensional light receiving diode array 1
A convex lens 11 is provided on the front surface of the monitor 0, so that light rays arriving from the monitoring point pass through the convex lens 11 and form an image on the one-dimensional light receiving diode array 10.

Here, a one-dimensional light receiving diode array 10 and a convex lens 1
When the distance from C1 to the monitoring point is B, the length of the one-dimensional light receiving diode array 10 is C1, and the monitoring range at the monitoring point is D, there is a relationship D=-C.

For example, A=20mm, B=40m, C=5mm
Then, D=10m.

On the other hand, if the size of each diode element is E and the individual monitoring range thereof is F, there is a relationship F--E similar to B.

Here, if E-50 μm (microns) is assumed and the values of A and H above are substituted as they are, F-10Crn is obtained.

That is, with respect to the entire monitoring range Iom, the individual monitoring ranges do not overlap each other if lens aberrations and the like are ignored.

Therefore, with such a configuration, it is possible to sufficiently detect the intrusion of an object and the size of the object at a relatively distant monitoring position.

However, the configuration of FIG. 2 has the following drawbacks.

In other words, there is no problem when monitoring the ground from above a building (if the monitoring distance is fixed, but if the monitoring distance is not constant, for example, when an object enters the vicinity of the convex lens 11) , when the object enters a far place, the size of the image on the one-dimensional light receiving diode array 10 differs even if the size of the object is the same.

That is, distant objects are perceived as small even if they are large, and close objects are perceived as large even if they are small.

Therefore, it becomes impossible to identify the size of the actual object.

The present invention aims to eliminate the above-mentioned drawbacks of the prior art and provide an intruding object detection device that can detect the size of an intruding object regardless of the monitoring distance.

Embodiments of the intruding object detection device according to the present invention will be described below with reference to the drawings.

In FIG. 3, inside the housing 20, there is a one-dimensional light-receiving diode array 21 and a one-dimensional light-receiving diode array 21.
A convex lens 22 and a plane mirror 23 are installed to form an image upward.

In the opening of the housing 20, n plane mirrors G1 to Gn are provided.

Here, considering the case where parallel rays are incident on the plane mirrors G1 to Gn, the parallel rays are reflected by each of the plane mirrors G1 to Gn, further reflected by the plane mirror 23, and the rear convex v7
The light passes through a lens 22 and reaches a one-dimensional light-receiving diode array 21 located near its focal point.

More specifically, the light beam reflected by the plane mirror G1 reaches the 1st to mth of the individual light receiving diode elements constituting the one-dimensional light receiving diode array 21,
The light rays reflected by the plane mirror G2 reach the m+1 to 2m-th elements, and similarly, the light rays reflected by the plane mirror Gn reach the 2(n-1)m+1 to 2i'tm-th light receiving diode elements.

If the plane mirrors 23, G1 to Gn are arranged as in the above configuration, only parallel light rays incident from a certain direction will finally reach the one-dimensional light receiving diode array 21, so that the light receiving corresponding to each plane mirror G1 to Gn will be Diode element group 1~m, m+1~2m, 2m+1~3m, -m-
, 2(H-1)m+1 to 2 mm, by extracting the output from each element by one element to the outside, it is possible to detect changes in the light rays incident on the plane mirrors G1 to Gn.

For example, if m is an even number, the first group consisting of elements 1 to m will pick up the output of the first element, and the second group consisting of elements m+1 to 2m will pick up the output of the first element. Then, in the same manner, in the nth group, the output of the nm □th element can be picked up.

If the arrangement pitch H of the plane mirrors G1 to Gn is set in advance to a constant value, the size of the intruding object can be detected regardless of the monitoring distance.

For example, if the number of plane mirrors is 10 and the arrangement pitch is 20 cr/L, the monitoring range will be about 2 m.

If a person enters, most of the light beams incident on the plane mirrors 01 to GIO will change, and most of the light receiving diode elements from the first group to the tenth group will also change.

If this is taken outside, human intrusion can be easily determined.

In the case of dogs, cats, etc., the intrusion is distinguished from human intrusion because the change only affects a part of the light receiving diode element group.

Note that a combination of a plurality of lenses may be used instead of the convex lens 220, a concave mirror may be used and a diode array may be provided at its focal point, and the plane mirror 23 may be omitted.

In this case, the parallel light beams may be directly reflected toward the center of the convex lens 22 by the plane mirrors G1 to Gn.

However, the total length of the casing 20 becomes longer, and the device becomes larger.

As shown above, according to the present invention, only parallel light rays arriving from a specific direction are added to the light receiving diode array.
It is possible to detect the presence or absence of an intruding object, as well as the size of the object, regardless of the monitoring distance.

[Brief explanation of drawings]

1 and 2 are schematic diagrams showing a conventional intruding object detection device, and FIG. 3 is a schematic diagram showing an embodiment of the intruding object detection device according to the present invention. 20-... Housing, 21... One-dimensional light receiving diode array, 23-... Single plane mirror, G1 to Gn...
-・One-plane mirror.

Claims (1)

[Claims] 1 A one-dimensional light-receiving diode array in which a large number of light-receiving diode elements are arranged in a straight line, and a convex lens or concave mirror that forms an image of incident light on its surface, arranged at a predetermined interval and incoming from a specific direction. An intruding object detection device comprising a plurality of plane mirrors that reflect only parallel light rays to the center of the convex lens or concave mirror, and capable of detecting the size of an intruding object.