JPH0829344A - Air pollution monitor apparatus using laser - Google Patents

Abstract

PURPOSE:To detect whether smoke or dust is generated or not, by detecting the back scattering light due to suspended solid particles in the atmosphere generated when laser beam is projected. CONSTITUTION:The distances, azimuth angles theta and elevations a to a plurality of predetermined points to be monitored from a watchhouse are calculated to be stored in a memory and successively read by a computer 2 and the sweep mirror 18d of the scanner 18 in a laser riser 1 is moved toward the points to be monitored to be positioned. Laser beam is projected and the back scattering beam thereof is condensed by a telescope 14 to be detected by a photodetector 15 and this detection value is taken in the computer 2 to be subjected to filtering processing and compared with a predetermined reference value to judge the presence of smoke etc., at every point to be monitored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention can automatically monitor the presence or absence of smoke or dust at a plurality of places where smoke or dust may occur in a factory where a large number of large facilities such as steel mills are arranged. The present invention relates to an air pollution monitoring device using a laser.

[0002]

2. Description of the Related Art For smoke, dust, etc., to prevent air pollution in conventional steelworks, an ITV camera or the like is installed near the monitoring target point, and the image is displayed on a receiver and monitored by a monitor. Also, there has been proposed a monitoring device in which image processing is performed on an image to automatically determine whether smoke or dust is generated, instead of arranging a monitoring member (Japanese Patent Laid-Open No. 4-358285). However, there is a problem in that monitoring based on such images is easily affected by fog, rainy weather, etc. and often causes malfunctions.

On the other hand, in recent years, as an environmental sensing technique, a technique has been known in which laser light is projected and the backscattered light is used to monitor the concentration and distribution of suspended solid particulate matter such as smoke and dust (Optical Technology Contact Vol. .29.No8 1991). There are two types of methods using this laser radar, one with a fixed laser light source and the other with a mobile type installed in a car, etc.In both cases, the purpose is to monitor a wide range of environment in the atmosphere. Scanning is carried out by using it to obtain a three-dimensional distribution of aerosol or the like in the atmosphere.

However, even when such a laser radar is used, it is necessary for the operator to directly or indirectly operate the laser lidar, and it is automated and unmanned when applied to the case where periodical monitoring is performed for each of a plurality of places in a factory. The current situation is that it is difficult to achieve this. The present invention has been made in view of the above circumstances, and an object thereof is to provide an air pollution monitoring device by a laser capable of automatically monitoring the presence or absence of smoke at each of a plurality of monitoring target points. .

[0005]

An air pollution monitoring apparatus using a laser according to the present invention irradiates a predetermined monitoring target area with laser light, receives reflected light from the monitoring target area, and detects the reflected light based on the received light output. In an air pollution monitoring device for determining the presence or absence of pollution in a monitored area, a laser oscillator, a scanner equipped with a sweep mirror for projecting laser light from the laser oscillator to the monitored area, and a reflected light from the monitored area A detector that detects through a telescope, and a memory that stores the monitored area data including the azimuth angle and elevation angle of the sweep mirror for facing each of the monitored areas and the distances of each of the plurality of monitored areas set in advance. , A control unit for sequentially reading the monitoring target area data from the memory and moving and positioning the sweep mirror, and a signal from the monitoring target area from a detection signal of laser reflected light from the monitoring target area Characterized by comprising a signal processing unit for extracting only.

[0006]

According to the present invention, this makes it possible to automatically monitor suspended solid particulate matter at a plurality of monitoring target points having different distances, azimuth angles, and elevation angles.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments.

FIG. 1 is a perspective view showing the configuration of an air pollution monitoring apparatus using a laser according to the present invention, in which 1 is a laser lidar, 2 is a computer, and 3 is a display unit of the computer 2. The laser lidar 1 includes a laser oscillator 11, a total reflection mirror 12, and a half mirror 1 arranged in a box 1a.
3, a telescope 14, a photodetector 15, a transjet recorder 16, a power supply 17, a scanner 18 installed on the box 1a, and the like. Laser light emitted upward from the laser oscillator 11 in the box 1a is reflected at a right angle by the total reflection mirror 12, enters the half mirror 13 and is partially reflected at a right angle, and the sweep mirror 18d of the scanner 18 is reflected. And is sequentially projected toward each monitoring target point. On the other hand, a part of the backscattered light from the angle monitoring target point is reflected by the sweep mirror 18d, and the telescope 14
The light is collected by the photodetector 15, converted into an electric signal by the photodetector 15, and recorded in the transient recorder 16.

The scanner 18 is axially supported facing the window 1b opened in the upper plate of the box 1a, and a support frame 18b is provided on a rotary table 18a which is rotationally driven by a motor (not shown). The sweep mirror 18d is axially supported between the facing both side plates 18c, 18c, and an elevation angle adjusting motor M is provided on this shaft.
The motor of the rotary base 18a and the elevation angle adjusting motor M are driven based on the command to set the horizontal rotation angle θ of the rotary base 18a (hereinafter, the azimuth angle with 0 ° true north) and the elevation angle α of the sweep mirror 18d as appropriate. The laser light can be projected toward the corner monitoring target point.

The computer 2 has a distance L (distance from the monitoring point O, which is the setting position of the laser lidar 1 to each monitoring target point) L, an azimuth θ to each of a plurality of predetermined monitoring target points.
In addition to reading these data from an external storage device or the like which stores the data of the elevation angle α and controlling the scanner 18 based on the data, the data is read from the transient recorder 16 and a filtering process is performed for the data to monitor each point to be monitored. The presence or absence of smoke, dust, etc. at each monitored point is determined based on the data. This determination is made by comparing the detection signal of the photodetector 15 when there is no smoke or dust with the detection signal of the photodetector 15 when there is smoke or dust.

FIG. 2 is a graph showing the relationship between the distance to the point to be monitored and the detection signal intensity of the backscattered light. The abscissa indicates the distance and the ordinate indicates the signal intensity. Figure 2
FIG. 2A shows the relationship when there is no contamination in the projection area of the laser light, and FIG. 2B shows the relationship when there is contamination. As is clear from FIG. 2A, when the laser beam is projected from the monitoring station toward the monitoring target point, the detected signal strength temporarily increases as the distance from the monitoring station increases with no smoke. After that, as the distance increases, it decreases in an inversely proportional relationship. On the other hand, if there is a pollution source such as a chimney on the way and there is smoke from this,
As shown in (b), the detection signal intensity projects like a mountain at a position corresponding to the distance from the monitoring station to the pollution source. Therefore, the presence or absence of smoke or the like can be detected depending on whether or not such a rapid increase in signal intensity exists at a position corresponding to the distance to the monitoring target point in the detection signal.

Incidentally, in the middle from the monitoring station to the chimney position,
For example, even if water vapor or dust is present, the detection signal strength becomes stronger at the positions corresponding to the respective distances, so in order to eliminate this, signals other than the position corresponding to the distance to the monitoring target point are removed. Then, the presence or absence of smoke is determined based on the detection signal after the filtering process.

FIG. 3 is an explanatory view showing a monitoring mode by the laser-based air pollution monitoring device according to the present invention, where O is a monitoring station in which the monitoring device as shown in FIG. 1 is installed.
Is a place where there is a risk of smoke, dust, etc. set in advance, that is, a monitoring target point. The point to be monitored is not limited to a place where smoke or dust may be generated,
For example, the place where steam or the like is generated may be included. The monitoring station O observes from here, and the positions of the respective monitoring target points ~ do not overlap as much as possible, in other words, the azimuth angle θ of the respective monitoring target points ~.
Select a place with different values.

For each of the points to be monitored, the distance L, the azimuth angle θ, and the elevation angle α from the monitoring station O are measured and tabulated. Table 1 shows an example.

[0015]

[Table 1]

Laser light is automatically projected from the laser lidar 1 installed at the monitoring station O to each of the monitoring target points to each of them, and the backscattered light from each of the monitoring target points of each of them is sent to the monitoring station O. It is determined whether or not smoke, dust or the like is generated at each of the monitoring target points to each of the monitoring target points based on this detection signal, and the result is displayed on the display unit 3, the smoke,
An alarm is automatically issued to the monitoring target points where dust is generated to suppress smoke and dust generation.

FIG. 4 is a flow chart showing the monitoring procedure by the device of the present invention. First, set the sweep mirror 18d to the azimuth angle θ.
= 0 and elevation angle α = 0 (step S1), and the monitoring target point No. Setting n = 1 (step S2), the monitoring target point N
o. Load the monitoring point data of 1 into the computer 2
(Step S3). The motor is controlled based on the control signal from the computer 2, the sweep mirror 18d is set to a predetermined azimuth angle θ and elevation angle α (step S4), and the laser oscillator 11 is operated (step S5).

The reflected light from the monitoring target point is detected by the detector 15, and only the signal of the portion corresponding to the distance from this detection signal to the monitoring target point is extracted (step S6). The extracted signal is compared with a reference signal obtained in advance, and the reference value>
It is determined whether or not it is the extracted value (step S7). If the reference value> the extracted value, the monitoring target point No. Increment
(Step S8), if the reference value is not greater than the extracted value, the monitoring target point number. An alarm is issued to 1 (step S9). n> 6
It is determined whether or not (step S10), and if n> 6, the monitoring target point number. n is set to 1 (step S11), and n
If it is not> 6, the process returns to step S1 to repeat the above process.

In the above-mentioned embodiment, each monitoring target point
Although the distance L, the azimuth angle θ, and the elevation angle α are stored in the external memory, they may be stored in the internal memory of the computer 2. Further, in the above-described embodiment, the case where each monitoring target point is grasped as a point has been described, but it may be a region having a predetermined width. The swing motion may be performed in the upward, downward and / or horizontal directions.

[0020]

As described above, in the apparatus of the present invention, laser light is sequentially projected to each of a plurality of monitoring target areas, reflected light from each of them is detected, and only the signals of the monitoring target area are detected from the detection signals. Since it was decided to extract the presence or absence of pollution in each of the monitoring target areas, it is possible to perform accurate monitoring automatically for each of the multiple monitoring target areas, and also to monitor without being affected by weather such as rain, Further, the present invention has excellent effects such as high reliability by extracting only the signal in the monitored area from the detection signal.

[Brief description of drawings]

FIG. 1 is a perspective view of an air pollution monitoring device using a laser according to the present invention.

FIG. 2 is a graph showing the relationship between the distance to a monitoring target point and the detection signal intensity of reflected light according to the present invention.

FIG. 3 is an explanatory diagram showing a monitoring mode of an air pollution monitoring device using a laser according to the present invention.

FIG. 4 is a flowchart showing a monitoring procedure by an air pollution monitoring device using a laser according to the present invention.

[Explanation of symbols]

 1 Laser lidar 2 Computer 3 Display part 11 Laser oscillator 12 Total reflection mirror 13 Half mirror 14 Telescope 15 Photodetector 16 Transient recorder 17 Power supply 18 Scanner 18a Rotating table 18b Support frame 18d Sweeping mirror M Elevation angle adjusting motor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 000001199 Kobe Steel, Ltd. 1-3-18 Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo (72) Inventor Hiroshi Haraki 4--5 Kitahama, Chuo-ku, Osaka-shi, Osaka 33 Sumitomo Metal Industries, Ltd. (72) Inventor Takafumi Takafumi Marunouchi 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan KK (72) Inventor Katsumi Ino 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama None) Kawasaki Steel Co., Ltd. Mizushima Steel Works (72) Inventor Tohro, Kanazawa-machi, Kakogawa-shi, Hyogo Prefecture 1 Kamito Steel Works Kakogawa Steel Works (72) Inventor, Katsuhiro Terai Kanazawa-machi, Kakogawa-shi, Hyogo Stock Company Kado Steel Works Kakogawa Steel Works

Claims (1)

[Claims] 1. An air pollution monitoring device for irradiating a predetermined monitoring target area with laser light, receiving reflected light from the monitoring target area, and determining the presence or absence of pollution in the monitoring target area based on the received light output, A laser oscillator, a scanner equipped with a sweeping mirror for projecting laser light from the laser oscillator onto the monitored area, a detector for detecting reflected light from the monitored area through a telescope, and a plurality of predetermined monitored areas A memory that stores the monitoring target area data including the azimuth and elevation of the sweeping mirror for facing the respective distances and the sweeping mirrors to the respective monitoring target areas, and the monitoring target area data is sequentially read from the memory, and the sweep mirror is A laser characterized by comprising a control unit for moving and positioning, and a signal processing unit for extracting only a signal from the monitoring target region from a detection signal of laser reflected light from the monitoring target region. Air pollution monitoring device.