JPH071204B2 - Electronic scanning radiation detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electronic scanning capable of determining a fire phenomenon by detecting the amount of radiated light of an object to be inspected existing within a range from a short distance to a long distance. Type radiation detector.

(Prior Art) Conventionally, a fire detector has been known as a radiation detector for determining a fire phenomenon by detecting the amount of radiated light of an object to be inspected existing in a range from a short distance to a long distance. This fire detector guides the amount of radiated light of the test object at a predetermined location to the photoelectric conversion element, and determines whether the test object detection signal as the detection output of the photoelectric conversion element exceeds the reference level. We are trying to determine if there is a fire.

However, this fire detector detects the presence or absence of a fire by comparing it with the reference level, and the detection output differs depending on whether the fire phenomenon is at a short distance or at a long distance. If the reference level is set by setting the fire level, the detection output of a fire phenomenon at a long distance will be smaller than the reference level, and even if a fire has occurred, it cannot be detected as a fire, and the If the reference level is set low, there is a problem that a cigarette or the like that is not a short-distance fire phenomenon is erroneously detected as a fire phenomenon, and the fire phenomenon occurs depending on whether the fire phenomenon is near or far. There is a problem that the phenomenon cannot be detected accurately.

(Problems to be Solved by the Invention) Therefore, in Japanese Patent Laid-Open No. 59-186094, based on the fact that there is an infrared ray peculiar to a fire as a fire detector, the infrared ray is in In order to detect each different position of the object to be inspected, slits are formed at a predetermined angle in the rotation direction of the rotating disk, and the positions where the slits are formed are shifted in the radial direction, and at a distance from a short distance. In order to scan the test object within the range of the distance, rotate the rotating disk to pass the radiated light amount of the test object through the slits at different positions to the infrared detection element, and the infrared detection element We propose a method that corrects the detection output according to the slit passing position so that the fire phenomenon can be accurately detected regardless of whether the fire phenomenon is at a short distance or a long distance. However, this Japanese Patent Laid-Open No. 59-186094
The one disclosed in the publication is a means for forming each slit on a rotating disk, detecting an object to be inspected by passing through each slit, and generating an origin signal for correcting the slit passing position, the origin thereof. Since the configuration is such that a control circuit that generates a reference signal for correcting the distance to the object to be inspected based on the signal is provided, the structure becomes complicated and large, and the rotating disk is rotated to perform scanning. Since the scanning is performed, the scanning speed is limited, and it is difficult to increase the scanning speed.

(Object of the Invention) The present invention has been made in consideration of the above circumstances, and an object of the present invention is to achieve a high speed from a short distance to a long distance even when the detection visual field is enlarged. An object of the present invention is to provide a small-sized electronic scanning radiation detector that can accurately detect a fire phenomenon existing within the range.

(Means for Solving the Problems) A feature of the electronic scanning radiation detector according to the present invention is that radiation within a range from a short range to a long range is scanned and radiation emitted from an object to be inspected is present. Scanning means for sequentially outputting a detection target detection signal by sequentially scanning a plurality of light receiving elements each of which composes the light reception part and each position corresponds to a distance; Reference signal forming means for generating a reference signal whose level changes in correspondence with each position of the light receiving element in order to determine whether or not there is a fire phenomenon, the level of the reference signal and the detection object detection signal And a means for determining whether or not the object to be inspected has a fire phenomenon.

(Operation) According to the electronic scanning radiation detector of the present invention, the radiation light of the object to be inspected existing in the range from the short distance to the long distance is guided to the light receiving element. The light receiving element converts the emitted light into a test object detection signal. When the scanning means sequentially scans the light receiving elements, the detection signal of the test object is sequentially output. on the other hand,
The reference signal forming means generates a reference signal that changes according to the scanning position of the light receiving element. The means for determining the fire phenomenon determines that it is the fire phenomenon based on the level of the reference signal and the level of the detection signal of the test object.

(Example) Hereinafter, an example in which the electronic scanning radiation detector according to the present invention is applied to a fire detector will be described with reference to the drawings.

In FIG. 1, 10 is a scanning means of an electronic scanning type radiation detector. The scanning means 10 has a function of scanning the light receiving section 11. The light receiving unit 11 has an objective lens 12 and a plurality of light receiving elements 13. For the light receiving element 13, a linear sensor is used here. The objective lens 12 is this light receiving element
13 has a function of forming an image of an object to be inspected existing within a range of short distance to long distance. Here, the cigarette fire 14 which is not a fire phenomenon and which is a test subject is shown at the closest distance, the fire 15 as a fire phenomenon is shown at an intermediate distance, and the fire 15 as a fire phenomenon is shown at the farthest distance. 16 fires of the same scale are shown.

On the light receiving element 13, the images of the object to be inspected existing in the range from the short distance to the long distance are formed in a one-dimensional array. Here, the image corresponding to the fire 14 of the cigarette is formed in the range from the address n ₁ to the address n _2, and the image corresponding to the fire 15 is formed in the range from the address n ₃ to the address n ₄ . An image corresponding to the fire 16 is formed in the range from n ₅ to address n ₆ . The scanning means 10 includes a clock pulse generator 17 and a driver circuit 18, and the clock pulse generator 17 has a function of outputting a clock pulse to the driver circuit 18, the address setting unit 19 and an operation unit described later. . The address setting unit 19 is a reference signal forming unit described later.
Serves as part of 20. The driver circuit 18 has a function of sequentially driving the light receiving elements 13 based on the clock pulse.

The light receiving element 13 is sequentially scanned from the short distance (address 0) to the long distance (address n) based on the drive signal of the driver circuit 18, and the long distance from the image corresponding to the object to be inspected existing at the short distance. The images corresponding to the object to be inspected that are present in sequence are sequentially extracted, amplified by the amplifier 21, and sequentially output to the comparator 22 as a series of inspected object detection signals L. For example, if the range from address n ₁ to address n ₂ is scanned, the image corresponding to the cigarette fire 14 is extracted and the test object detection signal indicated by the symbol L ₁ in FIG. 2 is obtained, and the address from n ₃ to address
When the range up to n ₄ is scanned, the image corresponding to the fire 15 is extracted and the test object detection signal indicated by the reference symbol L ₂ in FIG. 3 is obtained,
When the range from address n ₅ to address n ₆ is scanned, the image corresponding to fire 16 is extracted and the test object detection signal indicated by the symbol L ₃ in FIG. 4 is obtained. The light receiving element 13 has a different amount of received radiated light when the same test object is near and far, and the received light amount becomes smaller as the same test object is farther away. The detection signal L will decrease as the distance increases.

The reference signal forming means 20 has a memory 23, and this memory 23 digitally stores a reference value corresponding to a reference signal that changes according to the scanning position of the light receiving element 13. A reference value corresponding to a short distance is stored in the address 0 of the memory 23, and a reference value corresponding to a long distance is stored in the address n. Between address 1 and address n-1, reference values from the short distance side to the long distance side are stored in order. The reference value stored in each address 0 to n is the address setting unit.
It is sequentially read based on 19 addressing signals. The reference value output is converted into an analog signal by the D / A converter 24, and the analog signal is input to the comparator 22 as the reference signal K. Here, the address setting unit 19 and the D / A converter 24 function as a reference level setting unit that reads out the reference value corresponding to the scanning position and forms the reference signal K. This reference signal K is shown in FIGS.
As shown in the figure, as the distance from the light receiving unit 11 to the subject increases, an envelope curve is drawn that is attenuated in inverse proportion to the square of the approximate distance. Here, the envelope of the reference signal K is used as the threshold level Th.

The comparator 22 has a function of comparing the threshold level Th with a series of detection object detection signals L, and outputs a comparison output P to the arithmetic unit 25 when it is determined that a fire phenomenon occurs. . For example, when the detection target detection signal L ₁ corresponding to the cigarette fire 14 is input to the comparator 22, the comparator 22 detects the level of the detection target detection signal L ₁ rather than the threshold level Th as shown in FIG. The comparison output P is not output because of low, and the detection target detection signal L ₂ corresponding to fire 15 and the detection target detection signal corresponding to fire 16 are detected.
When L ₃ and are input to the comparator 22, FIG.
As shown in FIG. 4, since the levels of the detection signals L ₂ and L ₃ to be tested exceed the threshold level Th, the comparison output P is output from the comparator 22. That is, when the object to be inspected is near, even if the amount of emitted light is small, the output level of the object to be inspected is large, and when the object to be inspected is far, the amount of emitted light is large and the output level of the object to be inspected becomes small. However, since the threshold level Th is attenuated in inverse proportion to the square of the approximate distance, it is possible to prevent the cigarette 14 near the place which is not a fire phenomenon from being determined to be a fire phenomenon, and at the same time far away. It is possible to prevent an error in determining that a certain fire phenomenon 15 or 16 is not a fire phenomenon.

The arithmetic unit 25 functions as a unit that cooperates with the comparator 22 to obtain a fire phenomenon based on the reference signal and the detection target detection signal. When a fire phenomenon is detected, the computing unit 25 displays the fact that a fire has occurred on the display 26, and activates a sprinkler, a water gun or the like via the interface 27 to start extinguishing the fire.

FIG. 5 shows that, instead of providing the comparator 22, the detection signal of the object to be inspected is converted from analog to digital by the A / D converter 28, and the digital signal is directly input to the arithmetic unit 25. The reference value that increases in proportion to the square of the distance as the distance to becomes longer is stored, and the reference value is directly input to the calculation unit 25, and the calculation unit 25 attenuates with the change in distance. The processing for canceling the attenuation of the detection signal of the object to be detected, which is attenuated according to the received light amount, is performed. As shown in FIG. 6, the reference value as the reference signal K has a long distance. An envelope curve that increases in proportion to the square of the distance is drawn, and the arithmetic unit 25 corresponds to the addresses n _{1 to} n ₂ when the test object detection signal L ₁ shown in FIG. 7 is input. the reference value by integrating, by correcting the test target signal L ₂ 8 generates a correction inspected object detection signal L ₁ 'as shown in FIG, when a subject detection signal L ₂ shown in FIG. 9 is input, a reference value corresponding to the address n ₃ ~n ₃ integrating the corrected through the inspected object detection signal L _2,
When the corrected test object detection signal L ₂ ′ shown in FIG. 10 is generated and the test object detection signal L ₃ shown in FIG. 11 is input, the reference values corresponding to the addresses n _{5 to} n ₆ 12th
A corrected test object detection signal L ₃ ′ as shown in the figure is generated.

Since this corrected detection target detection signal is obtained by canceling the change in distance, it is possible to obtain the radiated light amount as an absolute value, and the fire phenomenon is detected based on this correction detection target detection signal. You will be able to ask. Since the other structure is almost the same as that of the above-mentioned embodiment, its detailed description is omitted.

In the above description, the reference signal K is formed so as to be approximately proportional to the square of the distance as the distance increases, and is integrated with the detection signal of the object to be inspected. However, this is inversely proportional to the square of the distance. It may be formed and divided by the detection signal to be detected.

In the above embodiment, the linear sensor is used as the light receiving element for detection on one vertical plane, but if a scanning optical system is added or the light receiving element is an area sensor, it is possible to detect in the horizontal direction. Become.

(Effect of the invention) Since the electronic scanning radiation detector according to the present invention is configured as described above, even when the detection field of view is expanded,
It is possible to accurately detect a fire phenomenon in a range from a short distance to a long distance at a high speed and to be small in size.

[Brief description of drawings]

1 to 4 are views showing a first embodiment of an electronic scanning type radiation detector according to the present invention, and FIG. 1 is an overall configuration diagram of the electronic scanning type radiation detector, and FIGS. FIG. 4 is an explanatory view for explaining the operation of the electronic scanning type radiation detector, and FIGS. 5 to 12 are diagrams showing a second embodiment of the electronic scanning type radiation detector according to the present invention. FIG. 5 is an overall configuration diagram of the electronic scanning type radiation detector of the second embodiment, and FIGS. 6 to 12 are explanatory views of the operation of the electronic scanning type radiation detector of the second embodiment. 10 ... Scanning means, 11 ... Light receiving part, 13 ... Light receiving element, 17 ...
… Clock pulse generator, 18 …… Driver, 19 …… Address setting module, 22 …… Comparator, 23 …… Memory, 25…
… Calculator,

Claims (6)

[Claims] 1. A light receiving part for scanning within a range from a short distance to a long distance to receive radiated light from an object to be inspected existing in the range, and each position constitutes the distance. Scanning means for sequentially outputting a detection target detection signal by sequentially scanning a plurality of light receiving elements corresponding to, and each of the light receiving elements for determining whether or not the test target is a fire phenomenon. A reference signal forming unit that generates a reference signal whose level changes corresponding to a position, and a level of the reference signal and a level of the detection target detection signal are compared with each other, and the detection target is a fire phenomenon. And a means for determining whether or not it is an electronic scanning type radiation detector. 2. The light receiving section has an objective lens which converges the emitted light and forms an image on the light receiving element, and a linear sensor is used for the light receiving element. The electronic scanning radiation detector according to item 1. 3. The reference signal forming means, based on a memory for storing the reference signal as a reference value, the reference value corresponding to the scanning position of each of the light receiving elements, and the read reference value. The electronic scanning radiation detector according to claim 1, further comprising a reference level setting unit that forms the reference signal. 4. The means for determining the fire phenomenon sequentially compares the level of the detection target detection signal and the level of the reference signal for each scanning position, and the level of the detection target detection signal is the reference level. The electronic scanning type according to claim 1, further comprising a comparator that determines whether or not the test object is a fire phenomenon based on whether or not the signal level is exceeded. Radiation detector. 5. The reference signal forming means generates a reference signal whose level is attenuated in inverse proportion to the square of the distance as the distance from the light receiving portion to the object to be inspected increases. An electronic scanning radiation detector according to claim 4. 6. The reference signal forming means cancels a change in the amount of received light which decreases as the distance to the object to be inspected increases, so that the reference signal forming means changes the distance substantially as the distance to the object to be inspected increases. A unit for generating a reference signal whose level changes proportionally or inversely proportionally to the square and for determining the fire phenomenon, corrects the detection target detection signal based on the reference signal, and detects the detection target detection signal based on a change in distance. The electronic scanning radiation detector according to claim 1, further comprising a calculation unit that cancels the decrease of