JPH01112476A - Device for detecting number of person - Google Patents

Abstract

PURPOSE:To stably detect the number of person with high accuracy by obtaining an input waveform as a referring waveform when there is no human body to be detected, detecting person number information from difference between both waveforms and prohibiting the updating of the referring waveform with an external signal and the output of the person number information. CONSTITUTION:An infrared detecting element 2 is scanned by a scanning optical system 1 and the output is supplied through an amplifying part 3 to a signal processing part 4. The processing part 4 obtains the input waveform, when the human body does not exist, as the referring waveform and stores it to a storing part 41. Then, when there is no updating prohibiting signal from an external part, the referring waveform is updated by an updating part 42 and the difference between the input waveform and the referring wave form is obtained in a comparing part 43. A deciding part 5 counts the person number information from a differential waveform by a counting part 51. Then, when there is no output prohibiting signal from the external part, an output control part 52 outputs a counted result to an output part 6. Thus, the updating of inconvenient referring waveform and the fluctuation of person number output can be prevented and the number of person can be stably detected with the high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an infrared receiving type people detection device that detects the number of people by detecting infrared rays emitted from a detected human body.

(Background Art) The present inventors have developed a highly accurate number of people detection device having a wide detection area with a simple and inexpensive configuration (Japanese Patent Application No. 61-281301).
) has already been proposed. FIG. 6 shows its configuration diagram.

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 preamplifier 3 that amplifies the output signal of the infrared detection element 2, and a preamplifier 3 that amplifies the output signal of the infrared detection element 2. a signal processing section 4 that converts the output signal of the amplifier section 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 an output signal of the determining section 5. The output section 6 outputs information on the number of people in a wide range of detection areas, making it possible to detect the number of people within a wide detection area with high precision.

In the signal processing unit 4 of this number of people detection device, an input waveform when there is no human body within the detection area is stored in advance as a reference waveform, and the input waveform is compared with the reference waveform to obtain a difference waveform. The zero determination unit 5 simultaneously determines the presence or absence of a human body and the number of people from this differential waveform. FIG. 3 is an explanatory diagram showing this situation, in which a comparison operation is performed between the input waveform to the judgment unit 5 (FIG. 3(b)) and the reference waveform (FIG. 3(a)), and the result is updated. The difference waveform (Figure 3 (
C)). In the differential waveform, the voltage level is almost zero in the part where the human body is not present, and an upwardly convex waveform appears in the part where the human body is present. Local maximum points are detected for this differential waveform, and the number of local maximum values is counted as the number of people. In the difference waveform, if the number of detected persons is 0, the current input waveform is updated and stored as a reference waveform. In this way, by storing the reference waveform when there is no human body to be detected as background data in advance and performing comparison calculations with the input waveform, the number of people can be detected without being affected by environmental changes within the detection area. be able to.

By the way, in this conventional example, the reference waveform is always updated when the number of detected people is 0, but depending on the use of the number of people detection device, even if the number of detected people is 0, the reference waveform It may be better not to update. For example, when using this person detection device to count the number of people waiting for an elevator in an elevator hall, the elevator arrives, the elevator doors open, passengers get on and off, the doors close,
It is better not to update the reference waveform until the elevator starts moving, because during this period the input waveform becomes unstable due to movement of people. In addition, even if there are no passengers getting on or off and the number of people detected is zero, while the elevator door is open, the lighting inside the elevator causes a change in brightness within the detection area of the number of people detection device. , as this may affect the reference waveform, it is better not to update the reference waveform.Furthermore, during the period when people are getting on and off the elevator, people are moving, so the people counting output may fluctuate. However, this is also not preferable for such uses.

For these reasons, it is considered effective to be able to select whether or not to update the reference waveform and whether or not to output the people counting information using external control input.

(Object of the invention) The present invention has been made in view of the above points, and
The purpose is to provide a number of people detection device that can prevent inconvenient updates of reference waveforms and fluctuations in the number of people output.

(Disclosure of the Invention) In order to achieve the above object, the number of people detection device according to the present invention has an infrared detection element 2 as shown in FIG.
, a scanning optical system 1 that scans the field of view of the infrared detection element 2, a preamplifier 3 that amplifies the output signal of the infrared detection element 2, and an output signal of the preamplifier 3 necessary for detecting the number of people. a signal processing unit 4 that converts the signal into a signal; a determination unit 5 that determines the number of people based on the output signal of the signal processing unit 4;
In the number of people detection device comprising an output section 6 that outputs number of people information from the output signal of the judgment section 5, the signal processing section 4
includes a reference waveform storage unit 41 that stores in advance an input waveform when a detected human body is not present as a reference waveform, a reference waveform update unit 42 that updates the reference waveform when there is no update prohibition signal from the outside, The judgment section 5 includes a comparison section 43 that calculates a difference waveform between the waveform and the reference waveform, and the judgment section 5 includes a number information counting section 51 that counts the number of people from the difference waveform obtained by the comparison section 43, and an output prohibition signal from the outside. The present invention is characterized in that it includes an output control section 52 that outputs the counting result of the number information counting section 51 as the output of the judgment section 5 when there is no number of people.

As described above, in the number of people detection device of the present invention, two types of prohibition signals are inputted from the outside. First, the update prohibition signal is input to the reference waveform update section 42 in the signal processing section 4, and by making it possible to select whether or not to update the reference waveform, unnecessary update of the reference waveform is prevented. Further, the output prohibition signal is input to the output control section 52 in the judgment section 5, and by making it possible to select whether or not to give the counting result of the number of people information counting section 51 to the output section 6, unnecessary number of people output is avoided. For example, when the number of people detection device of the present invention is installed in an elevator hall and used for counting the number of people waiting for an elevator, the update prohibition signal and the output prohibition signal can be used to detect the arrival of an elevator. It would be sufficient to acquire a signal that detects the opening of the elevator door or a signal that detects that the elevator door is open.

This makes it possible to realize a more accurate and stable number of people detection operation than in the past.

FIG. 4 is a diagram illustrating the configuration of the scanning optical system 1 used in the above-mentioned number of people detection device. This scanning optical system 1 is constructed by rotating a rotary plate 10, which is attached to a concave cylindrical mirror 11 so that its generatrix direction is parallel to the radial direction, by a motor 12. is arranged on the field of view center C of the light-receiving surface of the infrared detection element 2. Infrared rays emitted from the background or the human body are
The light is reflected by a mirror 11 attached to a rotating plate 10 and guided to an infrared detection element 2 . FIG. 5 is a diagram showing the instantaneous field of view F and the entire field of view S by the scanning optical system 1.

The instantaneous field of view F is rotated and scanned as shown by arrow A with the center of field of view C of the infrared detection element 2 as an axis, and the entire field of view S is circular.
It forms the

Infrared energy collected by the scanning optical system 1 is received by an infrared detection element 2 and converted into an electrical signal. After the output of the infrared detection element 2 is amplified by the preamplifier 3,
The signal is input to a bandpass filter, where unstable low frequency components and unnecessary high frequency components are cut, improving the S/N ratio. In this embodiment, the output of the bandpass filter is sampled at a predetermined sampling period that is sufficiently shorter than the rotation period of the scanning optical system 1, A/D converted, and stored in a large power buffer of the microcomputer. The functions of the signal processing section 4 and the judgment section 5 are realized by a microcomputer. The scanning optical system 1 gives a synchronization signal to the microcomputer every rotation. When the microcomputer receives this synchronization signal, it executes the interrupt process shown in FIG.

First, the operation when no external prohibition signal is input will be described. When a synchronization signal is input, one cycle of the input waveform accumulated in the input buffer is taken in.

Since the memory in the microcomputer stores in advance the output waveform when no human body is present in the detection area as a reference waveform, this is read out. A comparison operation is performed between the input waveform and the reference waveform, and the result is used as a new difference waveform. For this difference waveform, local maximum points of a predetermined level or higher are detected, and the number of local maximum points is counted as the number of people information.

The obtained number of people information is given to the output unit 6 and displayed or transmitted. If the number of detected people is 0, all reference waveforms are updated with the input waveform. Further, even if the number of detected persons is not zero, the reference waveform is partially updated with the input waveform for a portion where it can be determined that no human body is clearly present.

In the present invention, whether or not to update the number of people and the reference waveform can be selected depending on whether or not an external prohibition signal is input. In other words, if the output prohibition signal is input,
The number of people information obtained by counting the maximum points is not provided to the output unit 6. In this case, the immediately preceding number of people information is used as it is as the number of people information for display or transmission on the output unit 6. Furthermore, if a reference waveform update prohibition signal is input, the reference waveform will not be updated.The microcomputer is equipped with an input terminal for inputting such an output prohibition signal and an update prohibition signal. The level of the input terminal is '
By determining whether the input signal is at the "High" level or the "Low" level, it is determined whether or not the prohibition signal is input.

(Effects of the Invention) As described above, the present invention provides an infrared receiving type people detection device that detects the number of people by scanning the field of view of an infrared detection element and detecting infrared rays emitted from the detected human body. The input waveform when the input waveform does not exist is stored as a reference waveform, the number of people information is detected from the difference waveform between the input waveform and the reference waveform, and the update of the reference waveform and the output of the number of people information can be prohibited by external signal input. As a result, unnecessary updating of the reference waveform and fluctuations in the number of people output can be prevented, and a highly accurate and stable number of people detection operation can be performed.

In addition, when the number of people detection device of the present invention is installed in an elevator hall and used for counting the number of people waiting in an elevator, the arrival signal of the elevator or the opening signal of the elevator door can be used as a prohibition signal from the outside. ,
This eliminates the influence on the number of people detection operation caused by the opening and closing of elevator doors and the movement of passengers getting on and off the elevator.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a flowchart for explaining the operation of the same as above, FIG. 3 is an operation waveform diagram of the same as above, and FIG. 4 is a scanning optical system used in the number of people detection device of the present invention. A schematic configuration diagram of the system, FIG. 5 is an explanatory diagram of the field of view by the scanning optical system same as above, and FIG. 6 is a block diagram of a conventional example. 1 is a scanning optical system, 2 is an infrared detection element, 3 is a preamplification section, 4 is a signal processing section, 5 is a judgment section, 6 is an output section, 41 is a reference waveform storage section, 42 is a reference waveform update section, 43 is the comparison part,
51 is a number of people information counting section, and 52 is an output control section.

Claims (1)

[Claims] (1) An infrared detection element, a scanning optical system that 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 is used to detect the number of people. A number of people detection device comprising a signal processing section that converts into a necessary signal, a determining section that determines the number of people based on an output signal of the signal processing section, and an output section that outputs number of people information from the output signal of the determining section. , the signal processing unit includes a reference waveform storage unit that stores in advance an input waveform when a detected human body is not present as a reference waveform, and a reference waveform update unit that updates the reference waveform when there is no update prohibition signal from the outside. and a comparison section that calculates a difference waveform between the input waveform and the reference waveform, and the judgment section includes a number of people information counter that counts the number of people from the difference waveform obtained by the comparison section, and a number of people information counter that calculates the number of people information from the difference waveform obtained by the comparison section, and an output prohibition signal from the outside. A number of people detection device comprising: an output control section that outputs the counting result of the number of people information counting section as an output of the judgment section when there is no number of people.