JPH0678888B2 - Detected object identification device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an identification device for photoelectrically identifying an object to be detected, and more specifically to reliably identify the object to be detected without being affected by external light. The present invention relates to a detected object identifying device.

(Prior Art) Conventionally, using a photoelectric sensor of the reflection type, for example, an object to be detected that is attached so as to move on the current surface of a plane plate, or fixedly attached to the plate and moves together with the plate. In the case of detecting such an object to be detected, for example, infrared rays are emitted from the light projector in the direction of the plate, and when the infrared rays are reflected by the plate or the object to be detected, the reflected light is received by the light receiver, A detection voltage corresponding to the amount of reflected light is output from the light receiver. This detection voltage is configured to be input to an identification circuit for identifying the detection target, and if the detection target has a property of absorbing the infrared rays, for example,
As shown in FIG. 5, when the infrared rays hit the object to be detected, the detection voltage becomes lower than the set voltage set lower than the detection voltage when the infrared rays are reflected by the plate, that is, the “threshold value”. The existence of the detected object can be identified.

On the other hand, if the object to be detected has a property of reflecting infrared rays higher than the plate, for example, detection voltage when infrared rays hit the object to be detected becomes high, so detection when infrared rays are reflected by the plate Since the voltage becomes higher than the set voltage that is set higher than the voltage, the detected object is identified.

(Problems to be Solved by the Invention) In the case of the above-mentioned conventional photoelectric sensor, for example, sunlight is applied to an object to be detected that has a characteristic that the detection voltage decreases as shown in FIG. 5 when infrared rays are reflected by the object to be detected. If it hits, the infrared reflected light and the sun reflected light will enter the light receiver at the same time, so the detected voltage will be the set voltage (b) as shown in (a) of FIG.
Since it does not fall below, there is a problem that the identification circuit for identifying the detected object cannot identify the existence of the detected object.

On the other hand, in order to avoid the above-mentioned problem of sunlight, if adjustment is made in advance so that the level of the detection voltage is lowered in consideration of sunlight, there will be a problem in identifying the detection target at night. That is, at night, the amount of light received by the light receiver decreases, and the detected power falls below the set voltage as shown in FIG. 6 (c). Therefore, the discrimination circuit cannot discriminate the existence of the object to be detected. There's a problem.

Therefore, the present invention has a technical problem to be solved in which it is possible to reliably identify an object to be detected without being affected by sunlight or external light from an illumination lamp or the like.

(Means for Solving the Problem) Technical means for solving the above-mentioned problems include a light projecting unit that projects an object identification device in the direction of the object, and a reflected light reflected by the object. Light-receiving means for receiving a voltage signal corresponding to the amount of light received, and a voltage-frequency conversion means for inputting the voltage signal output from the light-receiving means, converting the voltage signal into a frequency signal and outputting the frequency signal, Counting means for inputting the frequency signal output from the voltage frequency conversion means and counting the number of pulses of the frequency signal at every predetermined sampling time, and the number of pulses counted at every predetermined sampling time by the counting means When a change occurs, the time width in which the pulse number is changing is calculated, and when the time width corresponds to the size of the detected object,
And a detected object identifying means for identifying the detected object.

(Operation) According to the detected object identifying device having the above configuration, when the light is projected from the light projecting unit in the direction of the detected object and the projected light is reflected by the detected object, the light receiving unit corresponds to the received light amount. The generated voltage signal is output to the voltage frequency conversion means. The voltage frequency conversion means is
The voltage signal is converted into a frequency signal and output to the counting means. The counting means inputs the frequency signal output from the voltage frequency converting means, counts the number of pulses of the frequency signal at every predetermined sampling time, and then outputs the count signal to the detected object identifying means.
When the detected pulse number changes, the detected object identifying means calculates a time width in which the pulse number is changing, and when the time width corresponds to the size of the detected object,
The object to be detected is identified.

(Example) Next, an example of an apparatus for identifying a detected object will be described with reference to the drawings.

FIG. 1 is a front view of a shutter drive device relating to a shutter 1 installed in a store or the like as seen from the indoor side, and FIG. 2 is a side view of the shutter drive device.

When the infrared rays are projected onto the upper and lower corners of the shutter 1, the mark plates 2, 3 whose surfaces are coated with, for example, brown so as to absorb the infrared rays and reflect a part of the infrared rays.
Is attached. Further, the shutter 1 is painted, for example, milky white so as to sufficiently reflect infrared rays.
Further, the shutter 1 is configured to be opened and closed by a motor 5 provided in the shutter case 4.

A mark detecting / identifying device 6 for detecting and identifying the mark plates 2 and 3 is attached to a lower portion of the shutter case 4.

FIG. 3 shows a block configuration of the mark detection / identification device 6, and a motor control unit for controlling the opening / closing of the shutter 1.
15 shows a shutter control block diagram in which a mark detection / identification device 6 is electrically connected with a manual switch 16 operated when the shutter 1 is opened and closed.

As shown in FIG. 3, the mark detection / identification device 6 is provided with a light emitting element 11 and a light receiving element 12. When the infrared ray is emitted from the light emitting element 11 toward the shutter 1, the light receiving element is detected.
Reference numeral 12 receives the reflected light reflected by the shutter 1 or the mark plates 2 and 3. Then, the light receiving element 12 outputs a detection voltage according to the amount of received light. When the shutter 1 is driven by the motor 5 in the opening direction or in the closing direction, when the infrared light emitted from the light emitting element 11 hits the mark plate 2 or the mark plate 3, the infrared light is absorbed, Since the amount of light received by the light receiving element 12 decreases, the detection voltage P output from the light receiving element 12 becomes low for the time corresponding to the width of the mark plate 2 or the mark plate 3 as shown in FIG.

The detection voltage P output from the light receiving element 12 is input to the voltage frequency converter (V / F converter) 13 and converted into a frequency signal corresponding to the detection voltage as shown in FIG. 4 (B). As shown in FIGS. 4 (A) and 4 (B), when the detection voltage is reduced for the time corresponding to the width of the mark plate 2 or the mark plate 3, the voltage frequency converter (V / F converter) 13 changes the output frequency. , Increase from 70 Kz to 91 Kz, for example.

The frequency signal output from the voltage frequency converter (V / F converter) 13 is input to the microprocessor 14. The microprocessor 14 counts the number of pulses of the input frequency signal every sampling time of 2 milliseconds. The number of pulses counted for each sampling time is 140 (700
00Hz × 2 / 1000sec) to 182 (91000Hz × 2 / 1000se)
When c) is increased, the microprocessor 14 calculates the time during which the count value is increasing. As a result of the calculation, when it is determined that the time width is equal to the width of the mark plate 2 or the mark plate 3 stored in advance, it is determined that the light receiving element 12 detects the mark plate 2 or the mark plate 3.

When the microprocessor 14 recognizes the mark plate 2 while the shutter 1 is in the process of being closed, the microprocessor 14 determines that the shutter 1 is closed, and outputs a stop signal for stopping the motor 5 to the motor controller 15. Shutter 1
Stop the closing drive of. Meanwhile, the microprocessor 14
When the mark plate 3 is recognized while the shutter 1 is in the process of opening, it judges that the shutter 1 is opened, and outputs a stop signal for stopping the motor 5 to the motor control unit 15, and the shutter 1 Stop the opening operation.

A manual switch 16 connected to the microprocessor 14
Is to be started when the shutter 1 is opened and closed.

In the mark detection / identification device 6 configured as described above, as the light received by the light receiving element 12, in addition to the infrared rays emitted from the light emitting element 11, sunlight or indoor illumination light is reflected. Even in this case, the change in the detection voltage output from the light receiving element 12 when reflected by the mark plate 2 or the mark plate 3 can be detected as a frequency change. Therefore, the mark plate 2 or the mark plate 3 can be detected without these influences. You can Further, the microprocessor 14 calculates the time during which the count value is changing, and when it judges that the time width is equal to the width of the mark plate 2 or the mark plate 3 stored in advance, the mark plate 2 or the mark plate 2 Since the number 3 is recognized, the object to be detected can be surely identified.

As an application example of the mark detection / identification device 6, in addition to being used for automatic stop control of the shutter 1 as described above,
For example, it can be used as an indicator member of a pressure gauge attached at a position for receiving external light, or a device for recognizing a water level indicator.

(Effect of the invention) As described above, according to the present invention, a change in the detection voltage from the light receiving means that receives the reflected light of the detected object is detected as a change in frequency, and the change time of the frequency is detected by the detected object. Since it is configured to recognize that it is the detected object when it corresponds to the size, there is an effect that the detected object can be surely identified even if external light from the sun, an illumination lamp, or the like is received.

[Brief description of drawings]

FIG. 1 is a front view showing an application example of an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is an overall block diagram, and FIGS. 4 (A) and 4 (B) are functions. Explanatory drawing, FIG. 5 and FIG.
The figure is an explanatory view showing a conventional technique. 1: Shutter 2: Mark plate 3: Mark plate 4: Shutter case 5: Motor 6: Mark detection and identification device 11: Light emitting element 12: Light receiving element 13: V / F converter 14: Microprocessor 15: Motor controller

Claims (1)

[Claims] 1. A light projecting means for projecting light in the direction of an object to be detected, a light receiving means for receiving the reflected light reflected by the object to be detected, and outputting a voltage signal corresponding to the amount of light received, and the light receiving means. Inputting the output voltage signal, converting the voltage signal into a frequency signal and outputting the frequency signal, and inputting the frequency signal output from the voltage frequency converting means, and inputting the frequency signal every predetermined sampling time. Counting means for counting the number of pulses of the frequency signal, and when a change occurs in the number of pulses counted at each predetermined sampling time by the counting means, the time width in which the number of pulses is changing is calculated, and the time An object-to-be-identified discriminating apparatus comprising: an object-to-be-identified identifying means for identifying the object to be detected when the width corresponds to the dimension of the object to be detected.