JP4300496B2 - Optical profile measuring method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical profile measuring method for measuring the profile of the top surface of a blast furnace furnace, and more particularly to an optical position detecting method and apparatus for detecting a laser irradiation position on a measured surface.
[0002]
[Prior art]
In a blast furnace for melting iron ore, coke and iron ore are usually inserted alternately from the top of the furnace, and then the profile of the top surface of the furnace (surface shape) is set to be V-shaped by a stirrer. Making the furnace top profile the desired V shape has important implications for saving fuel consumption in the blast furnace, so a means for accurately measuring the furnace top profile is required.
[0003]
In order to satisfy this requirement, an optical profile measuring means applying triangulation has been proposed and applied (for example, Japanese Patent Laid-Open No. 54-65059). As schematically shown in FIG. 6, this “profile measurement device” scans the surface to be measured 3 with a laser beam 5 using a pulsed laser that oscillates repeatedly as a light source, and scatters light 6 from the surface to be measured 3 in a predetermined manner. The light is collected by the light receiving optical system 7 having an aperture diameter, and the profile of the measured surface 3 is obtained from the locus of the image drawn on the focal plane of the light receiving optical system 7.
[0004]
[Problems to be solved by the invention]
In the optical profile measuring means described above, as shown in FIG. 7, the beam projection point A and the beam receiving point B are set apart from the reference length L, and the projection angle α and the receiving angle with respect to the reference length L are set. From β, the vertical height H of the surface to be measured 3 and its horizontal position (for example, the horizontal distance C from the projection point A) are calculated.
[0005]
Further, in the actual profile measuring apparatus, in order to increase the measurement accuracy of the light receiving angle β, a light receiving mirror (or scanning mirror: not shown) is provided in front of the light receiving optical system 7 in FIG. The position of the irradiation point P is detected by an optical position detector 8 positioned on the focal plane of the light receiving optical system 7 so as to follow the spot light position (irradiation point P). That is, the light receiving angle β is calculated from the light receiving angle of the light receiving mirror and the position of the irradiation point P on the optical position detector 8.
[0006]
Further, the optical position detector 8 is a linear arrangement of a large number of photoelectric converters, and the position of the irradiation point P is compared with the output level of each photoelectric converter by the scattered light 6 and its maximum output position. It is said.
[0007]
However, in such an optical profile measuring apparatus, the laser beam 5 irradiated from the projection point A reaches the irradiation point P on the top surface of the furnace while being scattered by internal dust. Therefore, when the dust at the top of the furnace is intense, scattered light from the dust (hereinafter referred to as Mie scattered light) is strong, two peaks of the output of the photoelectric converter appear, and if the difference between the peak values is small, the noise signal The position of the irradiation point P may be erroneously detected due to the influence of.
[0008]
That is, in a triangulation type profile measuring apparatus using an optical position detector, a multi-channel detector such as a PSD (Position Sencing Device) or a linear CCD is conventionally used for detecting the optical position, and the peak of the output is obtained. Although the position is the position of the irradiation point P on the surface 3 to be measured, as described above, in the high dust environment, two peaks of output can be generated by strong Mie scattered light, and the spot light position can be detected erroneously. is there. When such a false detection occurs, not only does the measurement accuracy of the light receiving angle β in FIG. 6 significantly deteriorate, but also the light receiving angle of the light receiving mirror (scanning mirror) changes greatly following this false detection, and the measurement is performed as a result. There was a problem that data could not be used at all.
[0009]
The present invention has been developed to solve such problems. That is, the object of the present invention is to reliably detect the laser irradiation position P on the surface to be measured even when the dust is intense and the Mie scattered light from the dust is strong, which results in a large noise signal and a measurement error. In some cases, it is an object to provide an optical profile measuring method and apparatus that can greatly reduce the false detection and accurately measure the profile of the surface to be measured.
[0010]
[Means for Solving the Problems]
According to the present invention, the beam projection point A and the beam reception point B are set apart from each other by the reference length L, the laser beam (5) is scanned from the beam projection point A to the measurement surface (3), and the beam reception is performed. In the optical profile measuring method of collecting the scattered light (6) from the surface to be measured at point B and guiding it to the optical position detector (20) and measuring the shape of the surface to be measured from the output, The detector (20) is composed of a plurality of photoelectric converters (20a) arranged linearly from the beam projecting side to the beam receiving side, and the light receiving sensitivity of each photoelectric converter is from the beam projecting point A to the subject. The inclination sensitivity is set so that the side receiving the scattered light from the beam optical path before reaching the irradiation point on the measurement surface (3) is relatively low and the side receiving the reflected light from the irradiation point is relatively high. In addition, the output level of each photoelectric converter is compared and its maximum output Position is determined that the irradiation point P of the surface to be measured on the light position detector, an optical profile measuring method, characterized in that there is provided.
Further, according to the present invention, the beam projection point A and the beam receiving point B are set apart from the reference length L, and the laser beam (5) is scanned from the beam projection point A to the surface to be measured (3), In the optical profile measuring apparatus for collecting the scattered light (6) from the surface to be measured at the beam receiving point B and guiding it to the optical position detector (20) and measuring the shape of the surface to be measured from its output. The optical position detector (20) includes a plurality of photoelectric converters (20a) linearly arranged from the beam projecting side to the beam receiving side, and the light receiving sensitivity of each photoelectric converter is determined from the beam projecting point A. The inclination sensitivity is set so that the side that receives the scattered light from the beam optical path before reaching the irradiation point of the surface to be measured (3) is relatively low and the side that receives the reflected light from the irradiation point is relatively high. Furthermore, the output level of each photoelectric converter is compared and Comprising a system controller for determining the large output position and the irradiation point P of the surface to be measured on the light position detector, the optical profile measuring apparatus is provided, characterized in that.
[0011]
Mie scattering by dust, since the beam projected laser beam emitted from the light spot A (5) is a scattered light from the beam path to reach the irradiation point P of the surface to be measured (3), wherein the photoelectric converter The side that receives scattered light from the beam light path from the beam projection point A to the point before the irradiation point of the surface to be measured (3) is strong is strong, but hardly occurs on the side that receives the reflected light from the irradiation point P. Further, since the measurement is performed under the condition that the laser beam sufficiently reaches the surface to be measured, the reflected light intensity from the irradiation point P is the strongest in the steady state. Therefore, when Mie scattered light from dust is strong and two peaks of output from the photoelectric converter appear, the peak on the beam projection side is due to Mie scattered light from the dust, and the peak on the beam receiving side is It is always reflected light from the irradiation point P. Therefore, in order to identify this, the light receiving sensitivity of the plurality of photoelectric converters (20a) arranged linearly from the beam projecting side to the beam receiving side is determined from the beam projecting point A to the measured surface (3). By setting the tilt sensitivity so that the side that receives the scattered light from the beam optical path before reaching the irradiation point P is relatively low and the side that receives the reflected light from the irradiation point is relatively high, it is usually weak The intensity of scattered light from the beam optical path can be further reduced, and the intensity of reflected light from the irradiation point P can be relatively increased. Thereby, by comparing the output level of each photoelectric converter and detecting the maximum output position, even when the noise signal is large and there is a measurement error, the irradiation point P on the surface to be measured can be reliably detected, False detection can be greatly reduced.
[0012]
In other words, Mie scattering, which is an optical physical phenomenon, always occurs only on the upstream side of the optical path of the spot position and does not occur at the tip of the spot light. In this processing, reliable measurement can be performed, and both prevention of erroneous detection and simplification of the system can be achieved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram of an optical profile measuring apparatus to which the method of the present invention is applied. In this figure, an optical profile measuring apparatus 10 includes a light projecting unit 12 that projects a laser beam 5 (laser light) onto a surface to be measured 3 and a laser from a spot light position (irradiation point P) on the surface to be measured 3. A light receiving unit 14 that receives the scattered light 6 of the light. The surface to be measured 3 is a laminated surface of coke and iron ore charged in a blast furnace in this figure, but the present invention is not limited to this and can be applied to other surfaces to be measured.
[0014]
1, the light projecting unit 12 includes a laser controller 12a, a laser power source unit 12b, a laser oscillator 12c, and a mirror scanner 13. The light projecting unit 12 reflects the laser beam 5 emitted from the laser oscillator 12c toward the measurement surface 3, Further, the surface to be measured 3 is scanned by swinging the mirror.
The light receiving unit 14 includes a mirror scanner 14 a, a lens 14 b, a rotary optical attenuator 14 c, a light receiver array 20 (optical position detector), and a light reception control panel 15, and the measured surface 3 to be projected by the light projecting unit 12. The mirror is oscillated according to the irradiation point P, and the scattered light 6 from the irradiation point P on the surface to be measured 3 is always reflected toward the optical position detector 20 stably. Further, in the figure, 16 is a system control unit, 16a is a system control panel, and 16b is a display. The profile of the surface to be measured 3 is displayed on the display 16b based on the data obtained by the optical position detector 20. It has become.
[0015]
FIG. 2 is an example in which the profile was actually measured by the apparatus of FIG. In this figure, (A) is an output diagram of the photoelectric converter 20a constituting the optical position detector 20, and (B) is a profile diagram of the surface to be measured 3 obtained from this output data.
As shown in FIG. 2A, the light receiver array, that is, the optical position detector 20, is a plurality of (in this example, 32 channels) photoelectric converters 20a arranged linearly from the beam projecting side to the beam receiving side. Consists of. Further, the system control panel 16a compares the output levels of the photoelectric converters 20a, and determines the maximum output position (the 17th channel in this example) as the irradiation point P on the optical position detector. Therefore, as shown in FIG. 2B, the light receiving angle β is obtained from the light receiving angle of the mirror scanner 14a (light receiving mirror) and the detected position of the irradiation point P on the optical position detector, and the light is projected to the reference length L. By calculating the vertical height H of the surface to be measured 3 and its horizontal position from the angle α and the light receiving angle β, the profile of the surface to be measured 3 can be obtained.
[0016]
FIG. 3 shows another output example of each photoelectric converter by the optical position detector of FIG. In this figure, (A) is a conventional output example, (B) is a sensitivity ratio in the method of the present invention, and (C) is an output example to which the method of the present invention is applied. That is, in the optical profile measurement method of the present invention, the light receiving sensitivity of each photoelectric converter 20a is scattered from the beam optical path from the beam projection point A to the irradiation point P of the surface to be measured (3). The inclination sensitivity is set so that the side receiving light is relatively low and the side receiving light reflected from the irradiation point is relatively high . In this example, the ratio of the gradient sensitivity is set such that the sensitivity of the adjacent photoelectric converters 20a of 32 channels is 1% higher on the side that receives the reflected light than the side that receives the scattered light. The thirty-second channel on the light receiving side is set to have a sensitivity of about 1.36 times that of the first channel. In addition, the ratio of the tilt sensitivity is preferably linear, and the higher the ratio, the stronger the dust and disturbance (noise signal), but if it is too high, another position adjacent to the accurate peak position is used as the irradiation point P. There is a risk that the detection position accuracy is slightly lowered. Therefore, as a whole, the ratio is preferably set to about 1.2 to 2.0 times on the side that receives the reflected light with respect to the side that receives the scattered light .
[0017]
FIG. 3C is obtained by correcting the output data of (A) with the sensitivity ratio of (B). From this figure, when the output level of each photoelectric converter in FIG. 3A is compared, and the maximum output position is determined to be the irradiation point P of the surface to be measured on the optical position detector, the peak position is this In the example, since the third channel and the 17th channel have peaks, when the disturbance (noise signal) is large, the third channel may be erroneously detected as a peak.
[0018]
FIG. 4 shows a measurement example of the profile of the measurement target surface 3 when such erroneous detection occurs. Both (A) and (B) are false detections that occur under almost the same conditions as in FIG. 3, and not only the measurement accuracy of the light receiving angle β is greatly deteriorated, but also the light receiving mirror (scanning mirror) follows this false detection. ) Also changes greatly, so that a position far from the actual irradiation point P is calculated as the irradiation point P, and as a result, the measured data cannot be used at all.
[0019]
On the other hand, as shown in FIGS. 3B and 3C, the light receiving sensitivity of a plurality of photoelectric converters (20a) arranged linearly from the beam projecting side to the beam receiving side is expressed as the beam projecting point. Inclination is such that the side that receives scattered light from the beam optical path before reaching the irradiation point P on the surface to be measured (3) is relatively low, and the side that receives the reflected light from the irradiation point is relatively high. By setting the sensitivity, the intensity of the scattered light from the normally weak beam path (in this example, the third channel) can be further reduced, and the reflected light intensity from the irradiation point P (in this example, the seventeenth channel) is made relative. Can be enhanced. As a result, the output levels of the photoelectric converters can be compared to reliably detect the maximum output position (the 17th channel).
[0020]
FIG. 5 is an example of profile measurement by the method of the present invention. Both (A) and (B) are measured under substantially the same conditions as in FIG. 3, but there is almost no false detection, and even when the noise signal is large and there is a measurement error, the irradiation point P on the surface to be measured is surely obtained. It was confirmed that can be detected.
[0021]
It should be noted that the method of the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist of the present invention.
[0022]
【The invention's effect】
As described above, Mie scattering, which is an optical physical phenomenon, always occurs only on the upstream side of the optical path of the spot position, and does not occur at the tip of the spot light. By simply attaching, it is possible to perform reliable measurement simply by taking a peak value, and it is possible to achieve both prevention of erroneous detection and simplification of the system.
[0023]
That is, the optical profile measurement method and apparatus of the present invention can reliably detect the laser irradiation position P on the surface to be measured even when the dust is intense and the Mie scattered light from the dust is strong. Even when the signal is large and there is a measurement error, it has an excellent effect that the false detection can be greatly reduced and the profile of the surface to be measured can be accurately measured.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an optical profile measuring apparatus to which a method of the present invention is applied.
FIG. 2 is a profile measurement example using the apparatus of FIG.
FIG. 3 is an output example of each photoelectric converter by the optical position detector of FIG. 1;
FIG. 4 is an example of profile measurement by a conventional method.
FIG. 5 is a profile measurement example according to the method of the present invention.
FIG. 6 is a schematic configuration diagram of a conventional optical profile measuring device.
FIG. 7 is a principle diagram of an optical profile measuring apparatus.
[Explanation of symbols]
3 Measurement surface 5 Laser beam 6 Scattered light 7 Light receiving optical system 8 Optical position detector 8a Photoelectric converter 10 Optical profile measuring device 12 Light projecting unit 12a Laser controller 12b Laser power source unit 12c Laser oscillator 13 Mirror scanner 14 Light receiving unit 14a Mirror scanner 14b Lens 14c Rotating optical attenuator 15 Light reception control panel 16 System control unit 16a System control panel 16b Display 20 Light receiver array (light position detector)
20a photoelectric converter

Claims (2)

A beam projection point A and a beam reception point B are set apart from each other by a reference length L, the laser beam (5) is scanned from the beam projection point A to the surface to be measured (3), and the surface to be measured at the beam reception point B. In the optical profile measuring method of collecting the scattered light (6) from the side and guiding it to the optical position detector (20) and measuring the shape of the surface to be measured from its output,
The optical position detector (20) includes a plurality of photoelectric converters (20a) arranged linearly from the beam projecting side to the beam receiving side,
The light receiving sensitivity of each photoelectric converter is relatively low on the side that receives scattered light from the beam light path from the beam projection point A to before reaching the irradiation point of the surface to be measured (3). The tilt sensitivity is set so that the side that receives the reflected light is relatively high , and the output level of each photoelectric converter is compared, and the maximum output position is set as the irradiation point on the surface to be measured on the optical position detector. An optical profile measuring method, characterized in that P is determined. A beam projection point A and a beam reception point B are set apart from each other by a reference length L, the laser beam (5) is scanned from the beam projection point A to the surface to be measured (3), and the surface to be measured at the beam reception point B. In the optical profile measuring device that collects the scattered light (6) from the side and guides it to the optical position detector (20) and measures the shape of the surface to be measured from its output,
The optical position detector (20) includes a plurality of photoelectric converters (20a) arranged linearly from the beam projecting side to the beam receiving side,
The light receiving sensitivity of each photoelectric converter is relatively low on the side that receives scattered light from the beam light path from the beam projection point A to before reaching the irradiation point of the surface to be measured (3). The tilt sensitivity is set so that the side that receives the reflected light is relatively high,
The optical profile measuring device further comprises a system control unit for comparing the output levels of the photoelectric converters and determining the maximum output position as the irradiation point P on the surface to be measured on the optical position detector. .

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