JPH02116991A - Detector for the number of persons - Google Patents

Abstract

PURPOSE:To obtain a detector for the number of persons which can easily and inexpensively set an arbitrary detection area by providing a circular scanning optical system with a light shielding plate which intercepts the light in a part of a visual field. CONSTITUTION:A light shielding plate P1 is provided in a prescribed position of the circular scanning optical system and is rotated together with the system. Infrared rays from an object surface are condensed on a light reception face D, when an infrared ray detecting element is installed, by a reflection mirror M' of a deformed toric mirror M. Infrared rays B1 and B3 are reflected at end points M1 and M2 of the mirror M and are made incident on the face D, and the momentary visual field angle to the object surface is theta0. When a light shielding plate P is provided in the front of a condensation point T to shield a part of the momentary visual field, infrared rays B2 passing an end point P2 of the light shielding plate P are made incident on the face D through the reflection point M2 of the mirror M. That is, the light shielding plate P is provided to change the momentary visual field angle from theta0 to theta1. Consequently, the installation position and the height of the light shielding plate P are changed to obtain an arbitrary momentary visual field angle. The obtained momentary visual field is rotated around an axis Q of rotation to form a desired detection area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an infrared receiving type people detection device, which detects the number of people by detecting infrared rays emitted from a detected human body.

[Prior Art] As a device of this type, a device for detecting the number of people as shown in FIG. 5 has been proposed (Japanese Patent Application Laid-open No. 134981/1981). This number of people detection device includes an infrared detection element 2, a circular scanning optical system 1 that circularly scans the field of view of the infrared detection element 2, a preamplification section 3 that amplifies the output signal of the infrared detection element 2, and a preamplification section. a signal processing section 4 that converts the output signal of No. 3 into a signal necessary for detecting the number of people; a determining section 5 that determines the number of people based on the output signal of the signal processing section 4; and a determining section 5 that outputs the number of people information from the output signal of the determining section 5. The output unit 6 is configured to detect the number of people within a wide detection area with high precision.

The field of view (detection area) obtained by the circular scanning optical system 1 is as shown in FIG. When the human body to be detected is viewed from above, the image extends in the radial direction. In order to efficiently detect a human body and secure a wide detection area, the instantaneous field of view F of the circular scanning optical system 1 is long in the radial direction, and narrow in the scanning direction to increase the number of people resolution. Then, a circular scan is performed in which the instantaneous field of view F is rotated based on the center of the field of view C. In this way, a circular detection area F0 can be obtained.

Here, the device is installed at position 1s in the detection area F.
. The instantaneous viewing angle θ is the detection field width on the object surface 1,
It is expressed by the following formula, where R6 is the distance from the detection area surface to the device.

A circular scan of θ=L a n -' Ll / Rb or more should be performed (A cylindrical mirror (Japanese Patent Application Laid-open No. 134981/1983) is used as the condensing part of the circular scanning optical system 1.
Deformed saddle-shaped mirror (Japanese Unexamined Patent Publication No. 134982/1982),
and deformed toric mirror (patent application No. 62-10133)
No. 6) etc. have been proposed.

[Problem to be solved by the invention]

When using the above-mentioned number of people detection device, locations such as conference rooms, elevator halls, etc. can be considered, and the detection area F may have various sizes depending on the location of use.

Is required. However, detecting unnecessary areas poses the problem of detecting heat sources other than the human body, which can lead to malfunctions. Therefore, it is necessary to prepare circular scanning optical systems 1 having various detection areas F0 depending on the place of use.

The present invention has been made in view of the above points, and its purpose is to provide a number of people detection device that can set an arbitrary detection area with a simple and inexpensive configuration.

[Means for Solving the Problems] The present invention includes an infrared detection element, a circular scanning optical system that circularly scans the field of view of the infrared detection element, and a preamplifier that amplifies the output signal of the infrared detection element. a signal processing section that converts the output signal of the preamplifier into a signal necessary for detecting the number of people; a determining section that determines the number of people based on the output signal of the signal processing section; and a determining section that determines the number of people from the output signal of the determining section. A number of people detection device comprising an output section that outputs information is characterized in that the circular scanning optical system is provided with a light-shielding plate that blocks light from a part of the field of view, and the light-shielding plate has a cylindrical shape. This is a number of people detection device.

[Effect]

A desired detection area is formed by installing a light shielding plate at a predetermined position of the circular scanning optical system to form a desired instantaneous field of view, and rotating the light shielding plate together with the circular scanning optical system. Moreover, if a cylindrical shape is used as the light shielding plate, a desired detection area can be obtained without rotating the light shielding plate.

(Example) Hereinafter, the present invention will be explained based on the drawings as an example.

The block diagram showing the overall configuration of the number of people detection device according to the present invention is the same as that shown in FIG.
I will only explain about.

First, the light condensing situation in the radial direction by the deformed toric mirror will be explained using FIG. By the reflecting surface M° of the deformed toric mirror M, infrared rays from the object surface are focused onto the light receiving surface where the infrared detecting element 2 is installed. Infrared B
1 and infrared rays B3 are reflected at the end points M and M of the mirror M and enter the light receiving surface, and the instantaneous viewing angle with respect to the object surface is θ. becomes.

Here, if the light-shielding plate P is installed in front of the condensing point T so as to block a part of the instantaneous field of view F, the infrared rays B2 passing through the end point P2 of the light-shielding plate P will pass through the reflection point M2 of the mirror M. The light is incident on the light receiving surface. That is, by installing the light shielding plate P, the instantaneous viewing angle becomes θ. changes from to θ.

In this way, by changing the installation position and height of the light shielding plate P, any instantaneous viewing angle can be obtained.

By rotating the instantaneous field of view thus obtained about the rotation axis Q, a desired detection area as shown in FIG. 4 can be formed. Circular scanning optical system 1 when the number of people detection device is installed at a position of height R5 from the object surface and no light shielding plate P is provided
The instantaneous viewing angle with respect to the object surface is θ. , the instantaneous viewing angle when the light-shielding plate P is provided is θ1, then the detection area F0 when the light-shielding plate P is not provided and the detection area l? when the light-shielding plate P is provided. , are each circular on the object plane.

Detection area F. and the radius of the detection area F1 is L, respectively.
, L, the following equation holds true.

tanθ,=L,/R.

tanθ+=L+/Ri.

Therefore, by determining the size of the detection area, the instantaneous viewing angle is determined, and the installation position of the light shielding plate is determined.

FIG. 1 shows a concrete installation example of the light shielding plate P.

M is a mirror suitable for forming a field of view F that is short in the rotational direction and long in the radial direction, such as a cylindrical mirror. A light shielding plate P1 is installed. When the mirror M rotates around the rotation axis Q, the light shielding plate P1 also rotates together with the mirror M via the support member A. As a result, a circular detection area F with a radius of about 100 mm is formed as shown in FIG.

FIG. 2 shows another example of how the light shielding plate P is installed. A cylindrical light shielding plate P2 is installed with the rotation axis Q as the center. However, the installation position and height I are set so that the instantaneous viewing angle is θ. In this embodiment, a circular detection area F1 with a radius L1 can be formed without rotating the light shielding plate P2. Therefore, since the light shielding plate P2 does not become a load on the motor, there is an effect that the life of the motor can be improved.

Any detection area can be formed by moving the light shielding plates P1 and B2 listed in the above embodiments in the vertical direction or by changing the height H. In addition, light shielding plates P1 and B2
It is desirable to use a material with high emissivity, such as a black body, in order to suppress the incidence of infrared rays from outside the detection area due to reflection.

〔Effect of the invention〕

As described above, according to the present invention, in a people detection device having a circular scanning optical system, a light shielding plate is provided to shield a part of the field of view, so that a detection area of an arbitrary shape can be formed with a simple and inexpensive configuration. We were able to provide a number of people detection device that can set the number of people. Further, by using a cylindrical light shielding plate, there is no need to rotate the light shielding plate.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts according to one embodiment of the invention, FIG. 2 is a perspective view showing the main parts according to another embodiment of the invention, and FIG. 3 is the principle of the invention. FIG. 4 is a schematic diagram showing the field of view according to the above, FIG. 5 is a block diagram showing a conventional example, and FIG. 6 is a schematic diagram showing the field of view according to the above. 1-Circular scanning optical system 2-Infrared detection element 3-Preamplifier 4-Signal processing section 5-Judgment section 6
- Output part M - Mirror P, PI, B2 - Light shielding plate M゛・
- Reflective surface D - Light receiving surface A - Support member Q - Rotation axis S - Number of people detection device F - Instantaneous field of view Fo, F+'
- Detection areas B1, B2, B 3 - Infrared patent applicant Matsushita Electric Works Co., Ltd. Agent Patent attorney Toshimaru Takemitsu (2 persons) Figure II2 Figure s3 Figure

Claims (2)

[Claims] (1) An infrared detection element, a circular scanning optical system that circularly scans the field of view of the infrared detection element, a preamplification section that amplifies the output signal of the infrared detection element, and an output signal of the preamplification section that A number of people detection unit that includes a signal processing unit that converts into a signal necessary for detection, a determination unit that determines the number of people based on the output signal of the signal processing unit, and an output unit that outputs number of people information from the output signal of the determination unit. A number of people detection device, characterized in that the circular scanning optical system is provided with a light shielding plate that blocks light from a part of the field of view. (2) The number of people detection device according to claim 1, wherein the light shielding plate has a cylindrical shape.