JP2001066138A - Measurement system and prism type optical path control device used for this measurement system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a measurement system with a simple configuration that can measure a target with a wide field of view and can measure the target with high accuracy even with a wide field of view. SOLUTION: A pair of rotatably provided wedge prisms 7a and 7b, and the wedge prisms 7a and 7b are provided.
A pair of motors 8a and 8b each rotating individually;
It includes a pair of encoders 9a and 9b for detecting the rotation angles of the wedge prisms 7a and 7b, and measures the target 5 by refracting the optical path. By rotating the combined wedge prisms 7a and 7b, the wedge prism 7 is rotated.
The optical path is refracted in an arbitrary direction according to the wedge angles a and 7b. The refraction angle of this optical path is determined by wedge prisms 7a, 7
By controlling the rotation angle of b, it is precisely controlled. In this way, if the target is measured by refracting the optical path, the target can be measured with a simple configuration and the field of view can be expanded.
A measurement system that can measure a target with high accuracy even when the field of view is expanded can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measurement system for measuring a target, and more particularly to a measurement system for measuring displacement, automatic tracking, or dynamic measurement of a target within a limited field of view, or monitoring a target. About the system.

[0002]

2. Description of the Related Art Conventionally, a total station for automatically tracking a target as shown in FIG. 14 has been known as a measurement system for measuring such a target. This total station is a surveying instrument having a cylindrical telescope 1, and turns the telescope horizontally and vertically according to the position of the target 2 to automatically collimate the target 2. Then, the total station calculates the position of the target 2 based on the rotation angle of the telescope 1 and the distance from the target 2. With this total station, the three-dimensional position of the target 2 can be measured.

As another measurement system, an electronic staff for measuring a target vertical displacement is also known. The electronic staff arranges a plurality of light-receiving elements in the vertical direction. The electronic staff calculates the height of the light-receiving elements that receive the laser light emitted from the laser level, and calculates the target vertical position due to land subsidence. Measure the directional displacement.

Further, as another measurement system, a CCD camera such as an anti-theft surveillance camera is known. This CCD camera performs pattern recognition of the target and measures the position of the target.

[0005]

However, the above prior art has the following problems.

[0006] Since the total station has a mechanism for rotating the telescope 1 in the horizontal and vertical directions, the mechanism becomes highly complicated and expensive. In addition, since the target position is calculated based on the amount of rotation of the telescope, measurement accuracy is insufficient. Moreover, measuring targets within a limited range would be overkill.

The electronic staff can measure the displacement in the vertical direction, but cannot measure the displacement of the target in the horizontal direction, the distance of the target, and the like, and the function as a measurement system is insufficient.

Further, neither the total station nor the electronic staff can perform dynamic measurement for measuring the target dynamic behavior.

[0009] CCD cameras have intermediate capabilities between the total station and the electronic staff, but have a narrow field of view. Also, in the CCD camera, changing the zoom,
If you expand your field of view, the accuracy of target measurement will decrease. In order to widen the field of view, the camera itself has a rotation mechanism, and some cameras rotate the camera to recognize a wide range. However, a space for rotating the camera is required, and since the camera is exposed, it is uncomfortable.

Accordingly, the present invention provides a measurement system having a simple configuration capable of measuring a target with a wide field of view and measuring the target with high accuracy even with a wide field of view, and a prism used in this measurement system. It is an object of the present invention to provide an optical path control device.

[0011]

Hereinafter, the present invention will be described. In addition, in order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are added in parentheses, but the present invention is not limited to the illustrated embodiment.

According to the first aspect of the present invention, a pair of rotatable wedge prisms (7a, 7b) and a pair of drive means (8a, 7a, 7b) for individually rotating the pair of wedge prisms (7a, 7b) are provided. 8b) and a pair of angle detecting means (9a, 9b) for detecting the rotation angle of each of the pair of wedge prisms (7a, 7b), and a measuring system for refracting the optical path to measure the target (5). To solve the above-mentioned problem. Here, the driving means (8a, 8
A motor or the like can be used for b), and an encoder and a potentiometer can be used for the angle detecting means (9a, 9b).

According to the present invention, by rotating the combined wedge prisms (7a, 7b), the optical path is refracted in an arbitrary direction according to the wedge angles of the wedge prisms (7a, 7b). The refraction angle of this optical path is precisely controlled by manipulating the rotation angle of the wedge prisms (7a, 7b). Thus, by measuring the target by refracting the optical path, it is possible to measure the target with a simple configuration by expanding the field of view, and to obtain a measurement system capable of measuring the target with high accuracy even when the field of view is expanded. .

According to a second aspect of the present invention, in the measuring system according to the first aspect, the measuring system is provided on the target (5) and a laser emitting means (16) for irradiating the target with laser light, A light receiver (15) to which the refracted laser light is applied.

According to the present invention, the wedge prisms (7a, 7a) are irradiated so that the laser beam irradiates the light receiver (15).
By rotating b), the position of the target (5) can be measured from the rotation angle of the wedge prisms (7a, 7b).

According to a third aspect of the present invention, in the measurement system according to the second aspect, the rotation angle of the wedge prisms (7a, 7b) is manipulated so that the laser light is irradiated onto the light receiver (15). The output value of the device (15) is feedback-controlled.

According to the present invention, even if the position of the light receiver (15) changes, the laser light can be automatically applied to the light receiver (15). Therefore, the displacement of the moving target can be measured, and automatic tracking and dynamic measurement can be performed.

According to a fourth aspect of the present invention, in the measuring system according to the second or third aspect, the wedge prism (7
A computer (18) for calculating the position of the target (5) based on the detected value of the rotation angle of a, 7b) is provided.

According to the present invention, the position of the target (5) can be automatically calculated.

According to a fifth aspect of the present invention, in the measurement system according to any one of the second to fourth aspects, the light receiving device (1)
Distance measuring means (20, 27) for measuring the distance to 5)
It is characterized by having. Here, the distance measuring means (2
For 0, 27), a distance measuring device such as one comprising a light emitting system for emitting laser light and a light receiving system, or one for detecting a distance from a phase difference when a plurality of laser lights having different wavelengths are received is used. be able to.

According to the present invention, the position of the target can be measured three-dimensionally.

According to a sixth aspect of the present invention, there is provided an image pickup device (24) for detecting visual information of a target, and a prism type optical path control device (3) for refracting light emitted from the target (5). The above-mentioned problem is solved by a characteristic measurement system.

According to the present invention, since the optical path is refracted by the prism type optical path control device (3) and the field of view of the imaging element (24) moves, the field of view can be maintained while maintaining the measurement accuracy of the imaging element (24). Can be spread.

According to a seventh aspect of the present invention, in the measurement system according to the sixth aspect, the prism type optical path control device (3).
Is a pair of rotatable wedge prisms (7
a, 7b) and this pair of wedge prisms (7a, 7b).
b) a pair of drive means (8a,
8b) and the pair of wedge prisms (7a, 7b)
A pair of angle detection means (9) for detecting each rotation angle
a, 9b).

According to the present invention, by rotating the combined wedge prisms (7a, 7b), the optical path is refracted in an arbitrary direction according to the wedge angle of the wedge prisms (7a, 7b). The refraction angle of this optical path is precisely controlled by manipulating the rotation angle of the wedge prisms (7a, 7b).

According to an eighth aspect of the present invention, in the measurement system according to the sixth or seventh aspect, the position of the target is calculated based on the visual information and a detected value of a rotation angle of the wedge prism (7a, 7b). A computer (26) is provided.

According to the present invention, the position of the target (5) can be automatically calculated.

According to a ninth aspect of the present invention, in the measurement system according to any one of the sixth to eighth aspects, the imaging element (24) is a CCD camera or a CCD video camera.

According to the present invention, it is possible to decompose a subject image in accordance with the number of pixels, perform image processing (pattern matching), and know a target position. Further, by using a CCD video camera, a target dynamic behavior of about 30 to 60 Hz can be measured.

According to a tenth aspect of the present invention, in the measurement system according to the sixth or seventh aspect, the imaging element (24) is provided.
Is a surveillance camera.

According to the present invention, by refracting the optical path using the wedge prism having a large wedge angle, the field of view can be expanded even with the surveillance camera fixed.

According to an eleventh aspect of the present invention, a pair of wedge prisms (7a, 7b) rotatably provided and a pair of drive means (8a, 7a, 7b) for individually rotating the pair of wedge prisms (7a, 7b) are provided. 8b) and a pair of angle detecting means (9a, 9b) for detecting the rotation angle of each of the pair of wedge prisms (7a, 7b). Solve.

According to the present invention, by rotating the combined wedge prisms (7a, 7b), the optical path is refracted in an arbitrary direction according to the wedge angles of the wedge prisms (7a, 7b). The refraction angle of this optical path is precisely controlled by manipulating the rotation angle of the wedge prisms (7a, 7b). As described above, when the target is measured by refracting the optical path, the target can be measured with a simple configuration while widening the field of view, and the target can be measured with high accuracy even when the field of view is widened.

[0034]

FIG. 1 shows a prism type optical path control device according to an embodiment of the present invention. The prism type optical path control device 3 includes a laser irradiator, a CCD
Attached to an optical device 4 such as a camera or a video, and refracts laser light emitted from a laser irradiator to a target 5, natural light reflected from the target 5, or light emitted from a point light source as the target 5. It is. The prism type optical path control device 3 includes a cylindrical hood 6 attached to the optical device 4 via an adapter 14, and a pair of wedge prisms 7a rotatably provided in the hood 6.
7b and motors 8a, 8 as driving means for individually rotating the pair of wedge prisms 7a, 7b.
b and encoders 9a and 9 as angle detecting means for digitally detecting the rotation angles of the wedge prisms 7a and 7b.
b. The wedge prisms 7a and 7b are covered with a dust filter 10 to prevent dust and the like from adhering. Here, the angle detecting means is not limited to the encoders 9a and 9b that detect digitally, but may be a potentiometer that detects analogly.

As shown in FIG. 2, the wedge prism 7
a and 7b are prisms having a small ridge angle σ (wedge angle). As shown in FIG.
Are refracted at a refraction angle (declination) ε. (B) in the figure shows a case where two wedge prisms 7a and 7b are combined. Two wedge prisms 7a, 7b
Are the same material and have the same ridge angle σ. (B) in the figure
When the two wedge prisms 7a and 7b are arranged so that the inclined surfaces 11 are parallel as shown in FIG. Go straight. That is, the incident light beam 12 and the refracted light beam 13 have the same optical axis. However, here, illustration of the fine refraction state of the wedge prisms 7a and 7b is omitted. As shown in FIG. 3C, one wedge prism 9b is shifted from the state shown in FIG.
Is rotated 180 °, the incident light beam 12 is refracted to the maximum, and the incident light beam 12 is refracted at a refraction angle (combined deflection angle) of 2ε. Therefore, when the pair of wedge prisms 7a and 7b are relatively rotated by a predetermined angle, the incident light 12
Is a predetermined refraction angle from 0 to 2ε. By rotating the entire wedge prisms 7a and 7b in a state where a predetermined refraction angle is obtained, an arbitrary two-dimensional position on the target surface can be irradiated.

According to the prism type optical path control device 3 of the present invention, the pair of wedge prisms 7a and 7b inside the hood 6 are rotated without rotating and swinging the optical device 4, so that the optical device 4 is viewed through the optical device 4. It is possible to widen the area where it can be performed, that is, the field of view.

First, a trial calculation of the visual field will be performed. For example,
The distance from the wedge prisms 7a, 7b to the target 5 is L
= 100 m, and the refraction angles by the two wedge prisms 7a and 7b are set to θ = 3 °, the field of view D becomes D = θ ×
L × 2 (π / 180) = 10.5 m. Therefore, by moving the field of view having a diameter of 1 m within a circle having a diameter of 10 m on the target, the field of view can be expanded to a diameter of 10 m.

The refraction angle of the optical path is determined by the wedge prisms 7a and 7a.
It is precisely controlled by manipulating the rotation angle of b.
Here, a trial calculation of the accuracy of measuring the target 5 will be performed. Assuming that the accuracy of the encoder is 3600 pulses / revolution, the accuracy e
Is e = ± (θ / (2 × 3600)) × (π / 180)
× L = ± 0.7 mm ≒ 1 mm. From now on, diameter 1
It is expected that the position (two-dimensional) of the target 5 can be measured with a high accuracy of about ± 1 mm in a field of view of 0 m. The actual accuracy varies depending on the properties of the laser beam, the performance of the CCD camera / video, the performance of the telescope, and the like, and particularly in the case of the CCD camera / video, varies in a complicated manner depending on the number of pixels and the field of view.

FIG. 3 shows a system configuration diagram of the measurement system according to the first embodiment of the present invention. This measuring system includes a laser beam emitting device 16 as a laser emitting means for emitting laser light, a prism type optical path control device 3 for refracting the laser light,
A light meter as a light receiver 15 to which the refracted laser light is irradiated; a software servo 17 for operating the prism type optical path control device 3 so that the laser light is irradiated to the light receiver 15; And a calculator 18 for calculating the position of Then, as described above, the prism type optical path control device 3 includes a pair of wedge prisms 7.
a, 7b; motors 8a, 8b for rotating the pair of wedge prisms 7a, 7b;
and encoders 9a and 9b for detecting the rotation angles of a and 7b. This measurement system is used to measure, for example, nighttime displacement or subsidence of a tunnel or the like, and irradiates a laser beam to a photodetector 15 provided on a target 5 so that the laser beam follows even when the photodetector 15 is displaced. By operating the rotation angles of the wedge prisms 7a and 7b, the relative displacement of the target 5 is measured from the detected values of the encoders 9a and 9b. In the encoders 9a and 9b, the wedge prism 7
360 degrees of one rotation of a and 7b are, for example, 4000 to 8000
If the wedge prisms 7a and 7b are disassembled and the wedge prisms 7a and 7b are relatively rotated by 180 degrees to obtain a refraction angle of, for example, about 3 degrees, the refraction angle of the optical path can be controlled with extremely high accuracy.

FIG. 4 shows a feedback control system using the output value of the light receiver 15 as a control amount. In this feedback control system, the light receiver 15 detects the amount of laser light received, compares the output value of the received light amount with the target output value, and automatically controls the software servo 17 so that the difference becomes zero. And the wedge prisms 7a and 7b
Operate the rotation angle of. In this feedback control system,
The rotation angles of the wedge prisms 7a and 7b are controlled so that the spot of the laser beam always irradiates the center of the light receiver 15 even if the light receiver 15 provided on the target 5 is displaced. In this way, by performing feedback control of the output value of the light receiver 15, even if the target 5 is displaced, the laser light follows and the target 5 can be constantly irradiated with the laser light. Further, in the present embodiment, in order to measure the position of each of the plurality of targets 5, switching means 19 is provided, and the light receiver 15 to be controlled is switched.

As shown in FIG. 3, the wedge prism 7
The rotation angles of a and 7b are detected by encoders 9a and 9b. This rotation angle is calculated by the computer 18, and the position of the target 5 is calculated based on the rotation angle. This position is automatically displayed on the monitor of the computer 18.

From the rotation angles of the two wedge prisms 7a and 7b, the combined displacement (X0, Y0), combined deflection angle δT, and combined deflection direction ΔT of the target 5 when combined are obtained.
The calculation method of will be described.

FIG. 5 shows the combined wedge prism ♯.
1 shows a main cross section of Nos. 1 and 2. The wedge prisms 1 and 2 are thin, substantially cylindrical prism lenses having a small apex angle (wedge angle) w. When the laser light is deflected only by the wedge prism 1, it is assumed that the laser light is vertically incident on the first surface of the wedge prism 1.
Is represented by the following general formula.

[0044]

(Equation 1)

Assuming that w is minute, δ ≒ (n−1) w where n is the refractive index.

The two combined wedge prisms 1,
2 are of the same material and have the same wedge apex angle w.
The pair of wedge prisms 1 and 2 independently rotate around the center line, and the laser beam enters from the center line. When the two wedge prisms 1 and 2 are arranged close to each other so that the inclined surface 37 is parallel, the wedge prisms 1 and 2 are
The laser beam that has passed through goes straight as if it passes through parallel glass. On the other hand, by separately rotating the wedge prisms 1 and 2 around the center line, the laser light can be deflected in an arbitrary direction inside a predetermined sharp cone.

FIG. 6 shows the refraction of laser light by the wedge prisms 1 and 2 in a coordinate system. Here, on the optical path of the incident laser light, that is, the wedge prisms 1 and 2
Are taken on the Z axis, and the XY plane is taken on a plane orthogonal to the center lines of the wedge prisms 1 and 2. Also, X
In the Y plane, the X axis is taken in the horizontal direction and the Y axis is taken in the vertical direction. As shown in this figure, when laser light is incident on the center line of the wedge prisms 1 and 2, the wedge prism 1 deflects the laser light and the wedge prism 2
Further deflects the laser light. Here, the declination of the wedge prism 1 is δ1, the polarization direction is ψ1, the declination of the wedge prism 2 is δ2, and the deflection direction is ψ2. The polarization directions ψ1 and ψ2 of the wedge prisms 1 and 2 are 0 degrees when the deflection direction is located on the XZ plane, and the angles from this position are represented by ψ1 and ψ2. The deflection directions ψ1 and ψ2 are
It is obtained from the rotation angles ψ1 and ψ2 of the wedge prisms 1 and 2, respectively. When the line connecting the thickest part and the thinnest part of each wedge prism 1 and 2 is horizontal (X
Is set to 0 degrees, and angles from this position are represented by ψ1 and ψ2.

The deflection angle δ of each of the wedge prisms 1 and 2
1, δ2, the rotation angles ψ1, ψ2 of each of the wedge prisms 1 and 2 obtained by the encoder, and the distance L measured by the angle measuring means are input to the computer 18 and combined displacement (X0, Y0) when combined. Is calculated by the computer 18.

Here, since the wedge apex angle w is very small, both δ1 and δ2 are made small to simplify the calculation, and the wedge prism 1 and the wedge prism 2
Shall be approaching. In the present embodiment, the deflection vector (deflection angle δ1, deflection direction ψ1) when only the wedge prism 1 is used and the deflection vector (deflection angle δ2, deflection direction ψ2) when only the wedge prism 2 is used are expressed in the XY coordinate system. Vectors are displayed, and the two vectors are added to calculate a combined displacement (X0, Y0), a combined deflection angle δT, and a combined deflection direction ΔT. When the wedge prisms 1 and 2 having different declinations are used, a plurality of declinations are stored in the memory of the computer 18.

FIG. 7A shows a deflection vector by the wedge prism 1 and FIG. 7B shows a deflection vector by the wedge prism 2. From this figure (a), the following formula is established for the wedge prism 1.

[0051]

(Equation 2)

The following formula is similarly established for the wedge prism 2 as well.

[0053]

(Equation 3)

From Expressions 2 and 3, X of the deflection vector when wedge prism 1 and wedge prism 2 are summed up
The combined component δTX in the direction is represented by the following Expression 4.

[0055]

(Equation 4)

Similarly, the combined component δTY in the Y direction is represented by the following equation (5).

[0057]

(Equation 5)

The beam irradiation position (X0, Y0) on the XY plane at a distance L from the prism unit is X
0 = L × δTX, Y0 = L × δTY.

The combined deflection angle δT and the combined deflection direction ΔT are expressed by the following equation (6).

[0060]

(Equation 6)

Here, the difference angle Δψ between the two wedge prisms
Is Δψ = ψ1-ψ2, δT is expressed by the following equation 7.

[0062]

Equation 7

From Equation 7, it can be seen that the composite argument δT is a function of only the difference angle. Further, by using these formulas, the combined displacement (X0, Y0) and the combined declination δ when combined from the rotation angles of the two wedge prisms.
T and the combined deflection direction ΔT can be easily calculated.

The software servo 17 controls the rotation angles of the wedge prisms 1 and 2 so that the laser beam deflected by the prism type optical path control device 3 automatically comes to the center of the light receiver 15 as described above. .

The algorithm of the software servo 17 will be described. The software servo 17 controls the laser receiver 15 so that the laser beam irradiates the center of the receiver 15.
Of the wedge prisms 1, 2
Is operating the rotation angle of.

FIG. 8 shows a flowchart of the algorithm. First, it is determined whether or not the input level from the light receiver 15 is equal to or higher than e1 (step S1). In the case where the photodetector 15 is a two-axis photoelectric sensor combining four photoelectric sensors extending in four directions of + X, -X, + Y, and -Y from the center, the output value is close to 0 when the laser beam is at the center. If the input level from the light receiver 15 <e1, it is determined that the laser beam is at the center of the light receiver 15 and the wedge prisms 1 and 2
Do not change the rotation angle of. Input level from light receiver 15 ≧
In the case of e1, assuming that the laser beam is not at the center of the light receiver 15, the rotation angles of the wedge prisms 1 and 2 are manipulated so as to be centered as follows.

As shown in FIGS. 9 and 10, first, a v1 vector is detected as a first position vector starting from the center O of the light receiver 15 and ending at the irradiation position Q.
That is, the displacement (X1, Y1) is detected from the output value of the light receiver in the light receiver coordinate system with the center O as the origin (step S2). Then, the calculation formula θ1 = tan ⁻¹ (Y1 / X1)
, The direction θ1 of the v1 vector is calculated. Next, a v0 vector as a second position vector having a point of intersection P between the line extending the center line of the pair of wedge prisms and the light receiver as a start point and an irradiation position Q as an end point is used as a pair of wedge prisms 1 and 2. It is calculated from the rotation angle (step S3). X0 and Y0 of the X-direction component and the Y-direction component of the v0 vector of the prism coordinate system are given by X0 = δTX ×
L, Y0 = δTY × L is calculated. Then, the direction ΔT of the v0 vector is calculated from Expression 6 described above. Here, the prism coordinate system refers to a coordinate system having the origin at the intersection P intersecting the plane on the light receiver 15 by extending the prism center line from the prism unit 6, and the light receiver coordinate system is the center O of the light receiver 15. Means a coordinate system with the origin as.

In order for the laser light to irradiate the center O of the light receiver 15, the v1 vector only needs to be 0. Receiver 1
5 and the coordinates X1 and Y1 are obtained with high precision, the rotation angles of the wedge prisms 1 and 2 are determined based on the coordinates X1 and Y1 so that the irradiation position is located at the center O of the light receiver 15. However, since the accuracy of the light receiver 15 is generally not so high, it is necessary to perform a process for bringing the irradiation position Q closer to the center O of the light receiver 15 in the following steps. As a method of approach, a method of comparing displacements (r, ψ) of the v0 vector and the v1 vector in plane polar coordinates, first matching the direction ψ, and then setting the absolute value | r | of the v1 vector to 0 is adopted. .

First, the direction ΔT of the v0 vector is compared with the direction θ1 of the v1 vector, and two wedge prisms are simultaneously rotated while keeping the difference angle Δψ constant in the matching direction.
T is changed (step S4). As shown in FIG.
When the two wedge prisms 1 and 2 are simultaneously turned while the difference angle Δψ between the two wedge prisms 1 and 2 is kept constant, the irradiation position Q becomes constant with the absolute value of the v0 vector kept constant.
Draw a circular locus about the origin P. Two wedge prisms 1 and 2 until the quadrants and angles of ψT and θ1 become equal (from the position indicated by the two-dot chain line to the position indicated by the solid line in the figure)
Are simultaneously turned, the angles ψ in the plane polar coordinates match, and v1
The vector and the v0 vector overlap. Here, the amount of one rotation of the wedge prisms 1 and 2 is set to, for example, の of the difference so as not to vibrate.

Next, | v1 | is compared with | v0 |
With the angle kept constant, the difference angle Δ is set so that | v1 |
ψ changes. As shown in FIG. 12, when the two wedge prisms are rotated by the same amount in opposite directions, the irradiation position Q
Draws a substantially linear trajectory passing through the intersection P, and the v0 vector changes its absolute value while keeping ΔT substantially constant. As shown in this figure, the difference angle Δψ between two wedge prisms is | v
When 1 | is changed to 0, the absolute value of the v0 vector changes from the position indicated by the two-dot chain line to the position indicated by the solid line in FIG.
The irradiation position Q moves to the center O of the light receiver. | V1 | and |
By comparing v0 |, it is possible to know whether to increase or decrease the difference angle Δψ so that | v1 | Here, | v1 | = √ (X1 ² + Y
1 ² ), | v0 | = L√ (δTX ² + δTY ² ). The amount of change of the difference angle Δψ at one time is set to, for example, の of the difference so as not to vibrate.

Next, at step S5 shown in FIG.
It is determined whether or not the change amount of ψ is, for example, 10 ″ or less (step S6). If it is 10 ″ or less, it is determined that the laser beam is irradiating the center O of the light receiver 15 and the process returns to the start. If not less than 10 ″, step 2 to step 5
Are repeated, and the rotation angles of the wedge prisms 1 and 2 are operated so that the v1 vector becomes 0 again.

As described above, the irradiation position Q can be brought to the center O of the light receiver 15 by operating the rotation angle of the wedge prism. The displacement (X0, Y0) of the irradiation position 9 in the prism coordinate system at this time is calculated by the computer 1.
8, the displacement of the center O of the light receiver 15 can be known by calculating from X0 = δTX × L and Y0 = δTY × L.

Further, a distance measuring means 20 such as a range finder may be provided to measure the distance between the point where the wedge prisms 7a and 7b are installed and the point where the target 5 is installed. By providing the distance measuring means 20, a three-dimensional position of the target 5 can be measured. The distance measuring means 20 may be composed of a light projecting system and a light receiving system, and the output value of the light receiving system may be input to a known measuring circuit to detect the distance to the target 5, or the wavelength of the wavelength may be detected by the light receiving device. The distance may be based on the phase difference when a plurality of different laser beams are received.

By configuring the measurement system as described above, the light receiver 15 as the target 5 is installed on the rock or the like, and the target 5 is tracked, and the relative displacement of the target 5 is measured three-dimensionally. can do. Further, by refracting the laser beam by the prism type optical path control device 3, the target 5 can be measured with high accuracy even if the field of view is widened.

Next, the effect on the measurement accuracy when the prism type optical path control device 3 attached to the optical device 4 such as the laser beam emitting device 16 moves slightly will be described. Since the prism-type optical path control device 3 moves in a three-dimensional space, it has three degrees of freedom to translate in the X, Y, and Z axes, and three types of rolling, pitching, and yawing of a rotating system.
It has a total of 6 degrees of freedom. Here, the rolling causes the wedge prisms 7a and 7b to rotate, which changes the refraction angle and affects the measurement accuracy. However, the translation, pitching, and yawing are different from the lens.
The refraction angle hardly changes and does not affect the measurement accuracy. For this reason, the prism type optical path control device 3 is roughly
Can be attached to

FIG. 13 shows a system configuration diagram of a measurement system according to the second embodiment of the present invention. This measuring system includes a point light source 23 such as a pencil light provided on the target 5, a CCD camera 24 as a photographing element for detecting visual information of the target 5, and a prism type for refracting light emitted from the target 5. Optical path control device 3 and target 5
A software servo 25 that operates the prism type optical path control device 3 so that the target enters the field of view, and a computer 26 that calculates the position of the target 5. As described above, the prism type optical path control device 3 includes a pair of wedge prisms 7a,
7b, motors 8a and 8b for rotating the pair of wedge prisms 7a and 7b, and an encoder 9 for detecting the rotation angle of each of the wedge prisms 7a and 7b.
a, 9b. The measurement system is used for measuring, for example, nighttime displacement or subsidence of a tunnel or the like. Light emitted from a point light source 23 as a target 5 is refracted by a prism type optical path control device 3, and a CCD as a photographing element is used.
The pattern recognition is performed by the camera 24, and the position of the target 5 is calculated from the recognition value and the detection values of the encoders 9a and 9b.

Generally, a CCD of 1000 × 1000 pixels
When the camera detects a field of view of 1m, 1m / 1000 = 1
The target 5 can be detected with an accuracy of mm. But,
If the field of view is expanded to 10m, the accuracy will be 10m / 1000 = 1
cm. On the other hand, by using the prism type optical path control device of the present invention, by moving the field of view of 1 m in diameter, the field of view of 10 mm in diameter can be maintained while maintaining the accuracy of 1 mm.
m. As described above, by moving the field of view by the prism type optical path control device 3, it is possible to widen the field of view while maintaining the measurement accuracy of the CCD camera 24. In this measurement system, the approximate positions of a plurality of targets 5 are input to the software servo 25 in advance, and the field of view of the CCD camera 24 moves so that the targets 5 can be recognized. Also, if necessary, a three-dimensional position of the target 5 can be measured by providing a distance measuring means 27 such as a range finder to the measuring system.

In this measurement system, the point light source 23 is provided on the target 5 so that measurement can be performed even at night. However, the present invention is not limited to the point light source 23, and a marker may be provided. The position of the target 5 is calculated by recognizing the natural light reflected from the marker with the CCD camera.

Further, a CCD camera 2 as a photographing element
By providing a CCD video camera instead of 4, the dynamic displacement of the target 5 can also be measured. For example, in a pile impact test, attach a marker to the pile and measure the rebound of the pile, analyze the bearing capacity of the ground where the pile was driven, and find out whether the pile was driven to the specified support base Can be. Note that a CCD video camera can perform dynamic measurement at a maximum of about 30 Hz. A target such as a CCD camera or CCD without a marker
Video cameras can also measure slope and rock displacement.

Further, a surveillance camera for preventing theft may be used as a photographing element. When a wedge prism having a large refraction angle is used, the prism type optical path control device 3 refracts natural light to widen the field of view, so that a wide range can be monitored without having a rotation mechanism of the camera itself.

[0081]

As described above, according to the present invention,
By rotating the paired wedge prisms, the optical path is refracted in an arbitrary direction according to the wedge angle of the prisms. The refraction angle of this optical path is precisely controlled by manipulating the rotation angle of the wedge prism. In this way, refracting the optical path and measuring the target, with a simple configuration,
It is possible to obtain a measurement system in which a target can be measured with a wide field of view and the measurement accuracy does not decrease even if the field of view is widened.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a prism type optical path control device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a wedge prism ((a) in the figure shows a case where there is one wedge prism, (b) in the figure shows a combination of wedge prisms that travel incident light straight, and (c) in the figure) Indicates a combination of wedge prisms that refract incident light rays to the maximum.)

FIG. 3 is a system configuration diagram showing a measurement system according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a feedback control system of the software servo shown in FIG. 3;

FIG. 5 is a sectional view showing a combined wedge prism.

FIG. 6 is a diagram illustrating deflection of a beam in an XYZ coordinate system.

FIG. 7 is a view showing a deflection vector ((a) in the figure shows a prism 1, and (b) in the figure shows a prism 2).

FIG. 8 is a flowchart showing an algorithm of software servo.

FIG. 9 is a diagram showing an irradiation position of laser light on a light receiver.

FIG. 10 is a diagram showing a prism coordinate system and a light receiver coordinate system.

FIG. 11 is a diagram showing a prism coordinate system and a light receiver coordinate system.

FIG. 12 is a diagram showing a prism coordinate system and a light receiver coordinate system.

FIG. 13 is a system configuration diagram showing a measurement system according to a second embodiment of the present invention.

FIG. 14 is a schematic view showing a conventional total station.

[Explanation of symbols]

 5 Target 7a, 7b Wedge prism 8a, 8b Motor (driving means) 9a, 9b Encoder (angle detecting means) 15 Light receiver 16 Laser beam emitting device (laser emitting means) 20, 27 Distance measuring means 24 CCD camera (imaging element) 18,26 Computer

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Claims (11)

[Claims] 1. A measurement system for measuring a target by refracting an optical path, comprising: a pair of rotatably provided wedge prisms; a pair of driving means for individually rotating each of the pair of wedge prisms; A measurement system comprising: a pair of angle detection means for detecting a rotation angle of each of a pair of wedge prisms. 2. The system according to claim 1, wherein the measurement system includes a laser light emitting unit that irradiates the target with laser light, and a light receiver provided on the target and irradiated with the refracted laser light. Item 2. The measurement system according to Item 1. 3. The measurement according to claim 2, wherein an output value of the light receiver is feedback-controlled by operating a rotation angle of the wedge prism so that the laser light irradiates the light receiver. system. 4. The measurement system according to claim 2, further comprising a calculator that calculates the position of the target based on a value detected by the angle detection unit. 5. The measurement system according to claim 2, further comprising a distance measurement unit that measures a distance to the light receiver. 6. An image sensor for detecting visual information of a target,
A measurement system, comprising: a prism type optical path control device that refracts light emitted from the target. 7. A pair of wedge prisms rotatably provided, a pair of driving means for individually rotating each of the pair of wedge prisms, and a rotation of each of the pair of wedge prisms. The measuring system according to claim 6, further comprising a pair of angle detecting means for detecting an angle. 8. The measurement system according to claim 7, further comprising a calculator that calculates the position of the target based on the visual information and a detection value of the angle detection unit. 9. The measuring system according to claim 6, wherein the photographing element is a CCD camera or a CCD video camera. 10. The measurement system according to claim 6, wherein the imaging element is a monitoring camera. 11. A pair of rotatably provided wedge prisms, a pair of driving means for individually rotating the pair of wedge prisms, and a pair of angle detection for detecting a rotation angle of each of the pair of wedge prisms. Means, comprising: a prism-type optical path control device;