JP3565456B2 - Light source illuminance automatic control device in intrusion monitoring device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an intrusion monitoring device for monitoring a suspicious person entering a site or facility, and more particularly to an automatic light source illuminance control device.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 4-175998 proposed by the present applicant discloses an image pickup means for picking up an image of a monitored area and detecting whether or not a level change of a video signal from the image pickup means exceeds a predetermined value. As shown in FIG. 4A, a light source 12 is disposed opposite to an imaging unit (camera) 11 across a monitoring area and generates a light beam directed to the imaging unit 11. Is disclosed.
[0003]
[Problems to be solved by the invention]
However, in the conventional imaging apparatus, as shown in FIG. 5, the diameter of the light source is larger in the nighttime (b) than in the daytime (a), and the surroundings of the light source are brighter. However, the video for identification is affected.
[0004]
That is, in FIG. 6, since the light source is equivalent to the lens diameter in “day”, there is no problem in discrimination, and the upper part of “evening” does not matter if a person is located, but the lower part of “evening” does not matter. When a person tries to overlap the pole, the light source becomes too bright, causing halation and making it difficult to identify the image. Secondly, "night" will only see a much larger light source than "evening". That is, as shown in FIG. 7, the EE lens 14 of the camera 11 is automatically stopped down by the light source and the surroundings are darkened, so that the person to be monitored does not appear with insufficient illuminance.
[0005]
For this reason, as shown in FIG. 4B, it is conceivable to provide the illumination 13 in order to increase the illuminance of the subject at the time of intrusion detection at night. This makes the video even more difficult to identify.
[0006]
Therefore, an object of the present invention is to provide a light source that reduces the illuminance of the light source and that does not affect the detection of the video sensor in order to make an image that can identify an intruder at night.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, an automatic light source illuminance control device in the intrusion monitoring device of the present invention is provided with a light source in one of the intrusion monitoring areas and a video sensor in the other, and an image of the light source monitored by the video sensor. In an intrusion monitoring device that determines that there is an intruder when disappears, an illuminance sensor that detects ambient brightness, and a first illuminance sensor that determines whether an output of the illuminance sensor is greater than a preset evening illuminance. A second comparing means for determining whether or not the output of the illuminance sensor is greater than a preset nighttime illuminance; and an output of the first and second comparing means for controlling the light source. A light source illuminance control means for controlling the brightness of the surroundings to be bright when it is bright, dark at night, and intermediate in the evening.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
According to an experiment, as shown in FIG. 2, the illuminance of the light source is switched in the first stage at 30 lux in the evening and 5 lux in the night, and the halation can be eliminated by finely adjusting the illuminance according to the distance.
[0009]
In the evening, halation is suppressed, and the image becomes identifiable. At night, halation is completely suppressed, and the EE lens 14 is opened, so that a person can be identified. Usually, the camera selects the EE lens 14 according to the distance.
[0010]
Hereinafter, examples of the present invention will be specifically described.
FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which 1 is an LED used as a light source, 2 is a condenser lens, 3 and 4 are first and second comparators, and 5 is a transistor for driving an LED. , 6 and 7 are LED illuminance adjusting transistors, and 8 is a CdS for detecting ambient illuminance. In this circuit, compared to the detection voltage of CdS8, the circuit is switched from day to evening to night to increase or decrease the current of LED1. Further, the current can be slightly adjusted by the amplifiers 9 and 10 according to the illuminance curve.
[0011]
Hereinafter, the operation in each case of the ambient illuminance will be described with reference to FIG.
[0012]
(1) Daytime (including morning)
Since the CdS detection voltages of the first and second comparators 3 and 4 are higher than both the evening comparison voltage and the night comparison voltage, the output voltages of the first and second comparators 3 and 4 are set to “L ( (Low level) ", and the collectors of the LED illuminance adjustment transistors 6 and 7 become" H (high level) ". Therefore, the base of the LED drive transistor 5 is maintained at" H ", and the current flows through the-path. Maximum current flows. Thus, the LED 1 emits light at the maximum illuminance.
[0013]
(2) Evening (including early morning)
When the ambient illuminance reaches a preset “evening comparison voltage”, the first comparator 3 operates, the collector of the LED illuminance adjustment transistor 6 changes from “H” to “L”, and the transistor 6 is turned on. And the LED drive transistor 5 is turned off. A moderate current flows through the LED 1 through the negative current path of the collector current of the LED illuminance adjustment transistor 6. The current is adjusted by the first amplifier 9 in accordance with a decrease in illuminance from evening to night.
[0014]
(3) When the nighttime ambient illuminance reaches a preset “nighttime comparison voltage” (<evening comparison voltage), the second comparator 4 operates, and the collector of the LED illuminance adjustment transistor 6 becomes “L”. , The transistor 6 is turned on, and the LED drive transistor 5 is turned off. At the same time, the first comparator 3 is turned off via the diode D3 → the resistor R2, and the minimum current flows through the LED1 through the negative current path of the collector current of the LED illuminance adjustment transistor 7. The current is adjusted by the second amplifier 10 in accordance with an increase in illuminance from night to early morning.
[0015]
The illuminance of the LED 1 for evening and night can be adjusted by the variable resistors VR1 and VR2.
[0016]
In this manner, as shown in FIG. 3, in the related art (a), halation is caused by the light of the light source and a person cannot be imaged, whereas as shown in (b), the illuminance in the evening and night is adjusted. This makes it possible to monitor a person.
[0017]
In the device of the present invention, if the lighting is activated, the subject is illuminated by the lighting, so that the intruder can be easily identified from the video camera image.
[0018]
【The invention's effect】
As described above, the present invention has the following effects.
(1) By adjusting the light source current according to the ambient illuminance, it is possible to suppress the halation of the image of the imaging device, and to obtain an easily identifiable image by the original automatic aperture effect of the EE lens.
(2) If the lighting is activated during the above operation, an easily identifiable image can be obtained with the original lighting effect.
(3) In the middle, a maximum rated current is required to secure a high-brightness part by the light source, but at night, only about 1/10 of the current is required, so that there is an energy saving effect.
(4) By keeping the light source diameter in the daytime constant until the night, stable detection of an imaging device such as a video camera becomes possible.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a graph showing changes in ambient illuminance from daytime to nighttime.
FIG. 3 is an explanatory diagram showing an improvement effect of the present invention over the conventional art.
FIG. 4 is a schematic explanatory diagram of a conventional monitoring device.
FIG. 5 is an explanatory diagram of an image of a light source in the imaging device.
FIG. 6 is an explanatory diagram showing an example of a conventional monitoring image.
FIG. 7 is a schematic diagram of a camera configuration.
[Explanation of symbols]
Reference Signs List 1 light source (LED), 2 condenser lens, 3 first comparator, 4 second comparator, 5 LED drive transistor, 6, 7 LED illuminance adjustment transistor, 8 CdS, 9 first amplifier, 10 Second amplifier

Claims (2)

A light source is installed on one side of the intrusion monitoring area, and a video sensor is installed on the other side. In the intrusion monitoring device that determines that there is an intruder when the image of the light source monitored by the video sensor disappears, the surrounding brightness is detected. Illuminance sensor, first comparing means for determining whether or not the output of the illuminance sensor is greater than a preset evening illuminance, and the output of the illuminance sensor is greater than a preset nighttime illuminance And a second comparing means for determining whether or not the light source is bright when the ambient brightness is bright, dark at night, and intermediate brightness in the evening. An automatic light source illuminance control device for an intrusion monitoring device, comprising: a light source illuminance control means for controlling the illuminance of the light source. 2. The automatic light source illuminance control device in an intrusion monitoring device according to claim 1, wherein the light source is an LED, and the current supplied to the LED is controlled by the light source illuminance control means.

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