JPH02272390A - Detection of moving object - Google Patents

Abstract

PURPOSE:To surely and quickly detect a moving object by radially arranging plural detection zones, where even the outside of a virtual boundary line surrounding infrared sensors is monitored, and plural detection zones, where only the inside of the virtual boundary line is monitored, to constitute a detection area. CONSTITUTION:A virtual boundary line A surrounding infrared sensors 1 and 2 attached in a prescribed position is set, and plural detection zones where even the outside of the virtual boundary line A is monitored and plural detection zones where only the inside of the line A is monitored are radially arranged to constitute the detection area. When the moving object like a human body crosses the virtual boundary line A, detection signals are outputted from infrared sensors with a time difference. Thus, the moving body is surely and quickly detected whichever direction the moving object trespasses on the detection area from.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an infrared radiation object detection technology and a moving object detection technology using a pyroelectric infrared sensor, and is applicable to, for example, a human body detection device for crime prevention. Regarding the most effective techniques.

[Prior Art] Pyroelectric infrared sensors are used as moving object detection devices to detect moving objects that emit infrared rays, such as human bodies, to activate building security alarm systems or generate control signals to open and close automatic doors. There was something there.

A conventional method of detecting a moving object using a pyroelectric infrared sensor is, for example, as shown in Figure 5, two sensors are arranged along the direction of movement of a human body, etc., and a split type sensor is placed facing the light-receiving surface of the sensor. By arranging mirrors (or split lenses), the infrared rays emitted from the moving object are reflected by the split mirrors 4a to 4a.
4g so that the light is incident on the two sensors 1 and 2 with a time difference (Japanese Patent Laid-Open No. 1938/1983).

[Problem to be solved by the invention] In the conventional moving object detection method, a sensor and a mirror (
Detection is possible only when an object enters the detection area parallel to the sensor arrangement direction (direction of arrow A in Figure 5), which is formed by If an object moves toward the mouth), the two sensors simultaneously output detection signals, making it impossible to detect the object and allowing it to penetrate deep into the detection area.

This invention was made in view of the above-mentioned problems, and its purpose is to detect a moving object such as a human body reliably and promptly even if it enters the detection area from any direction. The object of the present invention is to provide an object detection method.

The present inventors set a circular or line-shaped boundary line near the sensor, and configured the detection area so that it can detect objects that cross the boundary line, so that intrusion from any direction can be detected. Considering that it is possible, we decided to configure the detection area as follows.

That is, in a moving object detection device that detects a moving object when an infrared detector monitoring a predetermined area outputs a signal with a time difference, a virtual boundary line is set to surround the sensor attached at a predetermined position. The detection area is configured by radially arranging a plurality of detection zones that monitor the outside of this virtual boundary line and a detection zone that monitors only the inside of the virtual boundary line.

[Function] With the above configuration, when a moving object crosses the virtual boundary line, the infrared sensor will output a detection signal with a time difference, so no matter which direction it enters the detection area, it will be detected with certainty. and can be detected quickly.

[Embodiment] Figure 1 shows an example of the configuration of a detection area in the moving object detection method according to the present invention, and Figure 2 shows the configuration of a sensor and an optical system (lens) for forming such a detection area. An example of this is shown.

In FIG. 1, a dashed-dotted line A is a virtual boundary line set to surround the mounting position of the sensor S at a substantially constant distance, and in this embodiment, it is set to form a curve similar to a parabola. Ru. The elongated wedge-shaped regions extending radially from the sensor S are detection zones each formed by an infrared detector and a segmented lens, and these detection zones collectively constitute a usage detection area. ' That is, for example, as shown in FIG. 2(A).

Infrared sensors 1 and 2 made of dual-type pyroelectric elements are arranged in parallel with a lens 3, and the lens 3 has a structure in which a plurality of rectangular split lenses 3a to 3k are arranged side by side as shown in FIG. 2(B). In addition, each of the divided lenses 3a to 3 is a Fresnel lens in which unevenness is formed so that the center position of the lens 3 is higher at the center and lower toward the sides. and,
A lens 3 is arranged vertically, and the infrared sensors 1 and 2 are arranged at the focal point of the lens 3 so as to be at the same height. In addition, when the detection device consisting of an infrared sensor and a lens is installed on the upper part of the wall of a building, it is possible to form a detection area where sensors 1 and 2 look diagonally down on the floor as shown in Figure 4. , FIG. 2(B) Throat sensors 1 and 2 are positioned higher than the center of each of the divided lenses 38-3.

In this way, as can be seen from FIG. 3, which schematically shows the case where there are two split lenses, it is possible to create four The pyramid becomes the detection zone, and due to the difference in height between the two divided lenses, the detection zone of sensor 1 and the detection zone of sensor 2 are not only left and right, but also front and back.

As a result, the detection zone formed by one of the infrared sensors 1 or 2 and each of the divided lenses 3a to 3 constitutes a detection area that extends radially from the sensor position S, as shown in FIG.

Symbols 1-a, 1- of each detection zone shown in FIG.
b...2- indicates the detection zone formed by the combination of the sensor 1 or 2 and the split lenses 3a to 3, respectively.

Note that the focal length of lens 3 is 301+1!1. sensor 1
If the size of the electrodes 2 and 2 is 2×1 nn, and the tip of the detection zone is 15 m ahead of the lens, the size (cross-sectional area) of the tip of each detection zone is 1100×50a.

When an object enters the detection area configured as described above and crosses the virtual boundary line A shown in FIG. 1, it is always detected by the two sensors 1 and 2 with a time difference. Therefore, it is possible to detect whether the intrusion direction is parallel or perpendicular to the sensor.

In this case, the order in which the objects are detected by the sensors 1 and 2 does not matter, and the objects can be detected if there is a one-hour difference. Also,
The subsequent signal processing system is configured so that it can detect even if the output signal of only one sensor changes with a time difference.

The configuration of the detection area is the same as the above example (Figure 1).
The present invention is not limited to this, and any detection zone may be used as long as a plurality of detection zones are arranged across a virtual boundary line. Therefore, a split mirror may be used instead of a split lens,
Instead of arranging the centers of multiple split lenses to form a chevron shape as shown in Figure 2 (B), one infrared sensor can be constructed by arranging high and low lenses alternately so that the whole forms a chevron shape. It is also possible to construct a detection area as shown in FIG. In that case, it becomes possible to detect movement of the object in the left-right and front-back directions with one sensor. In addition, the virtual boundary line is not limited to a parabola,
Any shape that surrounds the sensor, such as a circle, may be used.

Furthermore, in the above embodiment, by arranging the two sensors 1 and 2 at the same height and parallel to the lens,
The difference in the position of the sensor mainly constitutes a detection zone that detects movement in the direction parallel to the sensor, and the difference in the height of the lens constitutes a detection zone that detects movement in the direction toward the sensor. However, by arranging two sensors vertically and setting the height of the split lens to be approximately constant, the difference in the sensor can be used to detect movement in the front and back directions, and the difference in the lens can be used to detect movement in the left and right directions. It is also possible to configure the detection area so that

Note that the infrared sensor in the above embodiments is not limited to a differential type in which two reverse polarized pyroelectric elements are connected in series, but may be one in which two pyroelectric elements are connected in parallel. Also,
It is not necessarily necessary to use a differential type, it is possible to use a single type, and it is not necessary to use a pyroelectric type sensor.
A thermopile, thermistor bolometer, etc. may also be used.

Further, in the above embodiments, the case where the invention is applied to an infrared detection device for a security alarm has been described, but the present invention is not limited thereto, and may be applied to detecting whether or not a human is present in a certain area, or when detecting a body other than a human body. It can also be applied to the detection of infrared emitting objects.

[Effects of the Invention] As explained above, the present invention is a moving object detection device that detects a moving object when an infrared detector monitoring a predetermined area outputs a signal with a time difference. We set a virtual boundary line surrounding the sensor, and configured the detection area by radially arranging multiple detection zones that monitor outside the virtual boundary line and detection zones that monitor only the inside of the virtual boundary line. This has the effect that it can be detected reliably and quickly no matter which direction an infrared emitting object enters the detection area.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of the configuration of a detection area in a moving object detection method according to the present invention, and FIG. 2 (A) is a side view showing an example of the configuration of a lens and an infrared sensor in a moving object detection device to which the present invention is applied. Figure 2 (B) is a front view showing an example of the lens configuration, Figure 3 is an enlarged perspective view of a part of the detection zone that makes up the detection area, and Figure 4 is a schematic diagram of the entire detection area. FIG. 5 is a plan view showing an example of a conventional moving object detection method. 1゜2...Infrared sensor. 3...Divided lens. Figure (B>

Claims (3)

[Claims] (1) In a moving object detection device that detects a moving object when an infrared detector monitoring a predetermined area outputs a signal with a time difference, a virtual boundary line is set to surround the sensor attached to a predetermined position. A moving object detection method is characterized in that a detection area is configured by radially arranging a plurality of detection zones that monitor the outside of this virtual boundary line and a plurality of detection zones that monitor only the inside of the virtual boundary line. (2) Two or more infrared detectors are arranged at focal positions of the split lens or split mirror, and the detection zone formed by each infrared detector and the split lens or split mirror is defined by the virtual 2. The moving object detection method according to claim 1, wherein the detection areas are configured to be located outside and inside the boundary line, respectively. (3) The moving object detection method according to claim 2, wherein the infrared detectors are arranged at the same height, and the heights of the centers of the split lenses or mirrors are set to be different from each other.