JPH09115065A - Light source illuminance automatic controller for trespass monitor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image with which a night trespasser can be discriminated by controlling a light source so that the light source is light when its periphery, is light dark in the night, and intermediately light in the evening. SOLUTION: In daytime, since the CdS detection voltage of 1st and 2nd comparators 3 and 4 are higher than comparison voltages for the evening and night, the collectors of transistors(TR) 6 and 7 for LED light intensity adjustment at H level, and the base of a Tr5 for LED driving is held at H and a maximum current flows, so that an LED1 emits light with maximum illuminance. In the evening, when the ambient illuminance reaches an evening comparison voltage, the comparator 3 operates to turn on the Tr6 and turns off the Tr5 , thereby supplying an intermediate current to the LED1. In the night, when the ambient illuminance reaches a night comparison voltage, the comparator 4 operates to turn on the Tr6 and turn off the Tr5 . At the same time, the comparator 3 turns off via a diode D3 and a resistance R2 in order and the minimum collector current of the Tr7 flows to the LED1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intrusion monitoring device for monitoring intrusion of a suspicious person into a site or equipment, and more particularly to a light source illuminance automatic control device thereof.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 4-17 previously proposed by the applicant.
Japanese Patent No. 5998 discloses imaging means for imaging a surveillance area,
In a monitoring device having level change detection means for detecting whether or not there is a level change of a video signal from the image pickup means or more, which is equal to or more than a predetermined value, a monitoring device is provided with a monitoring area separated as shown in FIG. 4 (a). A monitoring device is disclosed that includes a light source 12 that is disposed so as to face the imaging means (camera) 11 and that emits a light beam toward the imaging means 11.

[0003]

However, in the conventional image pickup apparatus, as shown in FIG. 5, the light source diameter is larger at night (b) than at daytime (a), and the surroundings of the light source become brighter. Since the marker fits within the light source, it is not a problem, but it affects the image for identification.

That is, in FIG. 6, since the light source is equivalent to the lens diameter in "daytime", there is no problem in identification, and there is no problem in the upper part of "evening" because the person is located. When a person tries to overlap the pole as in the lower part, the light source becomes too bright, causing halation, which makes the image difficult to identify. Second, "night" only sees a much larger light source than "evening." This is because, as shown in FIG. 7, the EE lens 14 of the camera 11 is automatically narrowed down by the light source, and the surroundings become dark, so that the person who is the monitoring target is not displayed due to insufficient illuminance.

Therefore, as shown in FIG. 4 (b), it is conceivable to provide the illumination 13 to increase the illuminance of the subject at the time of detecting the intrusion at night, but the illumination under the night halation condition makes the surroundings of the light source brighter. Therefore, the image becomes more difficult to identify.

Therefore, an object to be solved by the present invention is to provide a light source which lowers the illuminance of the light source and which does not affect the video sensor detection in order to form an image capable of identifying a nighttime intruder.

[0007]

In order to solve the above-mentioned problems, the light source illuminance automatic control device in the intrusion monitoring device of the present invention has a light source installed in one of the intrusion monitoring areas and a video sensor installed in the other intrusion monitoring region. In an intrusion monitoring device that determines that there is an intruder when the image of the light source being monitored by, disappears, an illuminance sensor that detects ambient brightness, and the output of this illuminance sensor with respect to the preset evening illuminance A first comparing unit that determines whether the illuminance sensor is large, a second comparing unit that determines whether the output of the illuminance sensor is greater than a preset night illuminance, and the first and second According to the output of the comparison means, the light source illuminance control means is provided to control the light source so that it is bright when the surrounding brightness is bright, dark at night, and intermediate brightness in the evening.

[0008]

According to the 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 at night, and the illuminance is finely adjusted according to the distance. It can eliminate halation.

In the evening, halation is suppressed and the image becomes identifiable. Halation is completely suppressed at night, and the EE lens 14 opens, so that a person can be identified. Normally, the camera selects the EE lens 14 according to the distance.

Examples of the present invention will be specifically described below. 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
Reference numerals 4 and 1 are first and second comparators, reference numeral 5 is an LED drive transistor, reference numerals 6 and 7 are LED illuminance adjustment transistors, and reference numeral 8 is a CdS for detecting ambient illuminance. In this circuit, compared with the detection voltage of CdS8, the current of LED1 is adjusted by switching the circuit from day to evening to night. Further, the amplifiers 9 and 10 can finely adjust the current according to the illuminance curve.

The operation in each case of ambient illuminance will be described below with reference to FIG.

(1) Daytime (including morning) Since the CdS detection voltage of the first and second comparators 3 and 4 is higher than both the evening comparison voltage and the nighttime comparison voltage, the first and second comparators The output voltage of the comparators 3 and 4 is "L"
(Low level), and the collectors of the LED illuminance adjustment transistors 6 and 7 are "H (high level)", so the base of the LED drive transistor 5 is "H".
Is maintained, and the maximum current flows through the negative path. As a result, the LED 1 emits light with the maximum illuminance.

(2) Evening (including early morning) When the ambient illuminance reaches a preset "evening comparison voltage", the first comparator 3 operates and the collector of the LED illuminance adjusting transistor 6 becomes "H". To "L", the transistor 6 is turned on and the LED drive transistor 5 is turned off. A medium current flows through the LED 1 through a path where the collector current of the LED illuminance adjusting transistor 6 is negative. It should be noted that the first amplifier 9 adjusts the current according to the decrease in illuminance from the evening to the night.

(3) Night When the ambient illuminance reaches a preset "night comparison voltage"(<evening comparison voltage), the second comparator 4 is activated and the LED
The collector of the 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 LED1 is set to L
The minimum current flows through the path where the collector current of the ED illuminance adjusting transistor 7 is negative. The second amplifier 10 adjusts the current according to the increase in illuminance from night to early morning.

The illuminance of the LED 1 for evening and night can be adjusted by the variable resistors VR1 and VR2.

In this way, as shown in FIG. 3, in the conventional case (a), a person cannot capture an image due to halation caused by the light from the light source, whereas as shown in (b), the illuminance in the evening and at night. By adjusting the, it becomes possible to monitor the person.

In the apparatus of the present invention, when the illumination is activated, the subject is illuminated by the illumination, so that the intruder can be easily identified from the image of the video camera.

[0018]

As described above, according to the present invention, the following effects can be obtained. (1) By adjusting the light source current according to the ambient illuminance,
It is possible to suppress halation of the image of the image pickup device, and it is possible to obtain an easily identifiable image due to the original automatic diaphragm effect of the EE lens. (2) When the illumination is started during the above operation, an easily recognizable image can be obtained by the original illumination effect. (3) In the middle, the maximum rated current is required to secure the high-brightness part by the light source, but at night, about 1/10 of the current is enough to save energy. (4) By keeping the light source diameter in the daytime constant until nighttime, stable detection of an image pickup 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 a change in ambient illuminance from daytime to nighttime.

FIG. 3 is an explanatory diagram showing an improvement effect of the present invention with respect to a conventional one.

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]

DESCRIPTION OF SYMBOLS 1 light source (LED), 2 condensing lens, 3 first comparator, 4 second comparator, 5 LED drive transistor, 6, 7 LED illuminance adjustment transistor, 8 C
dS, 9 first amplifier, 10 second amplifier

Claims (2)

[Claims] 1. An intrusion monitoring device, wherein a light source is installed in one of the intrusion monitoring areas and a video sensor is installed in the other, and an intruder is discriminated when an image of the light source monitored by the video sensor disappears. Illuminance sensor for detecting the brightness of the illuminance, first comparing means for determining whether the output of the illuminance sensor is larger than the preset evening illuminance, and night when the output of the illuminance sensor is preset. The light source is controlled to be bright when the surrounding brightness is bright, dark at night, and evening by the output of the second comparing unit that determines whether the illuminance is large or not and the outputs of the first and second comparing units. Is a light source illuminance automatic control device in an intrusion monitoring device, characterized in that it is provided with a light source illuminance control means for controlling the brightness to be an intermediate level. 2. The automatic light source illuminance control device in the intrusion monitoring device according to claim 1, wherein the light source is an LED, and the light source illuminance control means controls the energizing current of the LED.