JP2987540B2 - 3D scanner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional scanner for three-dimensionally measuring the shape of an object to be measured.
An irradiation optical system for irradiating the measuring object with the measuring light beam, and a light receiving optical system for guiding the scattered light beam reflected from the surface of the measuring object to the light receiving means, and an output signal of the light receiving means The present invention relates to a three-dimensional scanner capable of calculating a distance from a measurement surface to a measurement reference surface.

[0002]

2. Description of the Related Art A three-dimensional input device for obtaining CAD data for creating a final design drawing by inputting an external shape from a molding die or a mock-up prototype made at the time of designing various products. Also, there are three-dimensional shape measuring devices as input devices for three-dimensional video materials used for education and sales, medical diagnostic devices, or visual sensors of robots.

The three-dimensional shape measuring apparatus includes an irradiation optical system for scanning a measurement light beam from a light source onto an object to be measured on a reference surface, and receives a scattered light beam reflected from the surface of the object to be measured. It comprises a light receiving optical system for guiding to the means, and an arithmetic processing means for calculating the distance of the measured surface from the measurement reference plane based on the output signal of the scattered light by the light receiving means.

The irradiation optical system includes a first movable mirror for scanning a measurement light beam from a light source, and a first movable mirror for reflecting the measurement light beam scanned by the first movable mirror to an object to be measured. The light receiving optical system includes a second fixed mirror for reflecting the scattered light beam reflected from the surface of the object to be measured, and the scattered light beam reflected by the second fixed mirror. And a second movable mirror for guiding the light to the light receiving means.

The irradiation optical system and the light receiving optical system have been arranged so that the entire measurement system is substantially symmetrical with respect to a certain reference axis in order to make the conditions the same. Therefore, the rotation axis of the first movable mirror intersects the above-described reference axis, and the first fixed mirror and the second fixed mirror are arranged substantially line-symmetrically with respect to the reference axis. For this reason, the assumed area where the distance measurement by the scanning light beam is possible is assumed to be substantially line-symmetric with respect to the measurement optical axis, and the reference point located at the center of the assumed area is also
It crossed the reference axis.

[0006]

The measurement principle of the above-mentioned conventional scanner is as follows. When scanning, when the galvanomirror is at a predetermined angle, a point on the reference plane and one point on the light receiving surface are one.
It is based on a one-to-one correspondence. That is, by hitting the object to be measured, an image point on the light receiving surface of the scattered light having a different optical path forms an image at a position different from an image point of the scattered light on the measurement reference plane. By detecting the distance on the light receiving surface from the image forming point due to the scattered light on the measurement reference plane, the distance of the measured object from the reference plane is calculated. However, in practice, the fluctuation of the imaging point on the light receiving surface due to the scanning of a certain plane is not limited to the fluctuation on the light receiving surface, and the fluctuation in the normal direction of the light receiving surface also occurs. The fluctuation in the normal direction of this image point is because the scattered light does not form an image on the light receiving surface, so that the scattered light flux on the light receiving surface becomes blurred, and the incident position on the light receiving surface becomes unclear, and at the same time, the unit Since the amount of light per area also decreases, there is a problem that the output of the light receiving unit decreases and the influence of external noises other than the measurement light increases.

When the scattering efficiency of the surface of the object is low,
The measurement itself becomes difficult. As a countermeasure, there is a method of increasing the output of the light source to increase the amount of the illuminating light beam. There was a concern that the power would also increase, causing a problem in operation stability. Further, there is a problem that it becomes difficult to shield the irradiation light with an increase in the amount of light.

On the other hand, since the above-mentioned image forming point fluctuates in one scanning process, the measurement accuracy fluctuates depending on the installation position of the measurement object on the measurement reference plane, so that measurement cannot be performed with stable accuracy. There was a problem.

Therefore, even if the measuring light beam is scanned, the image position of the scattered light beam is always incident on the light receiving surface without shifting, and stable and accurate measurement is possible, and the light receiving efficiency of the scattered light beam is excellent. Without increasing the output of the illuminating beam
The emergence of a three-dimensional scanner capable of measuring even a substance having a surface with low scattering efficiency has been strongly desired.

[0010]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above problems, and has a light source, a deflector for deflecting and scanning a measurement light beam from the light source, and a measuring device deflected by the deflector. An irradiation optical system for irradiating a light beam onto the object to be measured, a light receiving optical system for forming an image of the scattered light beam from the object to be measured, and a light-receiving optical system in the vicinity of the image forming point of the scattered light beam light receiving means for receiving surface is formed by the output signal from the light receiving means, wherein consists of a processing means for calculating the distance to the measured surface, run of the measuring beam
The measurable area in the inspection plane is within the scanning plane.
With respect to the reference axis of the optical system, a predetermined
They are arranged with a distance .

Further, according to the present invention, the light receiving surface of the light receiving means is
It can also be formed inclined with respect to the measured object.

[0012]

According to the present invention constructed as described above, the deflector deflects and scans the measurement light beam from the light source, and the irradiation optical system irradiates the measurement light beam deflected by the deflector onto the object to be measured. A light receiving optical system forms an image of the scattered light flux from the object to be measured, a light receiving means forms a light receiving surface near an image forming point of the scattered light flux by the light receiving optical system, and an arithmetic processing means outputs an output from the light receiving means. The distance from the measured surface to the measurement reference surface is calculated based on the signal. Area where measurement beam can be measured in the scanning plane
The area illuminates the reference axis of the optical system in the scan plane.
It is arranged at a predetermined distance toward the optical system.

Further, according to the present invention, the light receiving means can be formed inclined with respect to the reference axis.

[0014]

【Example】

An embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a three-dimensional scanner 100 of this embodiment receives a light source 1, a galvanometer 2 for deflecting and scanning a measurement light beam from the light source 1, and a measurement light beam deflected by the galvanometer 2. An irradiation optical system 3 for irradiating the object 200 to be measured, a light receiving optical system 4 for forming an image of the scattered light beam from the object 200 to be measured, and a light receiving optical system 4
Receiving means 5 for photoelectrically converting an image formed by the
And an arithmetic processing means 6 for calculating the distance of the measured surface from the measurement reference plane based on the output signal from the light receiving means 5.

The light source 1 has a laser oscillator and can output a spot light. The galvanometer 2 corresponds to a deflector, and deflects and scans the spot light from the light source 1. Not limited to the galvanometer 2, any deflector can be used.

The irradiation optical system 3 is composed of a first fixed mirror 31 and irradiates a measurement light beam deflected by the galvanometer 2 onto the object 200 to be measured.

The light receiving optical system 4 includes a second fixed mirror 41
, A galvanometer 2 and an imaging lens 42. The second fixed mirror 41 reflects the scattered light flux from the device under test 200, and the galvanometer 2 receives the scattered light reflected by the second fixed mirror 41 via the imaging lens 42, It is for leading to 5. The galvanometer 2 is commonly used by the light receiving optical system 4 and the irradiation optical system 3. The imaging lens 42
The scattered light reflected by the galvanometer 2 is
This is for forming an image.

The galvanometer 2 according to the present embodiment comprises a double-sided reflecting mirror having a reflecting surface on both surfaces of a transparent substrate coated with aluminum, and a motor for rotating the double-sided reflecting mirror. .

The light receiving means 5 is for photoelectrically converting the scattered light imaged by the imaging lens 42. In this embodiment,
A CCD line sensor is employed. The light receiving means 5 is C
The sensor is not limited to a CD line sensor, and any sensor can be used as long as it is a photoelectric conversion element.

The arithmetic processing means 6 calculates the distance of the surface to be measured from the measurement reference plane based on the output signal from the light receiving means 5. The arithmetic processing means 6 is constituted by a microcomputer including a CPU. In this embodiment, a scanning position control unit 61 for controlling the scanning position of the galvanometer 2 and a galvanometer driving unit for driving an electric motor of the galvanometer 2 are provided. Means 62.

The arithmetic processing means 6 includes a three-dimensional model generator 7
Is connected, and the three-dimensional model generation unit 7 performs the measurement on the DUT 20 based on the distance data calculated by the arithmetic processing unit 6.
0 can be calculated.

The present embodiment constructed as described above firstly
By driving the galvanometer driving means 62, the measurement light beam is scanned in the X direction. Along with the scanning in the X direction,
By moving the entire optical system in the Y direction, scanning is performed on the ZY plane.

As shown in FIG. 2, the distances S ₀ and S ₁ detected by the light receiving means 5 are proportional to the delta dX ₀ on the device under test 200 and are further determined from a reference plane 50 serving as a reference. The distance Z from the measured reference plane of the surface position Z ₀ of the DUT 200 to the measured reference plane can be obtained by using the relationship Z = dX ₀ / tan θ.

Here, the intersection between the measurement reference plane 50 and the reference axis is defined as H ₀ (X ₀ , Y ₀ , 0). When the measurement light beam enters from the first fixed mirror 31 in a state where the object to be measured is not mounted, when the irradiation light beam enters the point H ₀ during scanning,
The reflected light is a scattered light beam 4A directed to the second fixed mirror 41.
This light flux 4A is deflected by the galvanometer 2 and then passes through the imaging lens 42 to a point S on the light receiving surface of the light receiving means 5.
_It is designed to image at ₀ .

On the other hand, when the object to be measured is placed, the irradiation light beam originally incident on the point H ₀ is reflected on the point H ₁ (X ₁ , Y ₁ ,
Z). Light reflected in the point H _1, the second
The scattered light beam 4B is directed toward the fixed mirror 41. This light beam 4B is deflected by the galvanometer 2 and then formed by the imaging lens 4B.
2 and an image is formed at a point S ₁ on the light receiving surface of the light receiving means 5.
The positional relationship between the S ₁ and the point S ₀ point when this was calculated dX, by the above calculation from the dX, it is possible to obtain the height Z of the Z-axis direction of the point H _1.

Then, the three-dimensional model generation section 7 grasps the measurement points on the XY plane from the rotation angle of the galvanometer 2 recognized by the scanning position control section 61, and the height of the above-mentioned measurement points in the Z-axis direction. Can be generated from the method for obtaining the shape model of the device under test 200.

In this embodiment, as shown in FIG. 4, a fixed mirror is used instead of the galvanometer 2 of the above embodiment,
By using the fixed mirror 31 as a rotating mirror, the measurement light beam can be scanned. Further, as shown in FIG.
A configuration is also possible in which a reflecting mirror that can rotate around an axis parallel to the X axis is arranged so that a plane formed by the measurement light beam and the scattered light beam is scanned in the Y axis direction.

Next, the measurable area will be described with reference to FIGS.

FIG. 6 shows the arrangement of the measurable area according to the present invention and the prior art, respectively. The assumed area of the conventional measurable area is like an area P (P1, P7, P9, P3) symmetrical with respect to a reference axis 1000 assumed by the irradiation optical system 3 and the light receiving optical system 4. Was set. However, in the present invention, this area is moved in a direction parallel to the scanning line, and is set as an area Q (Q1, Q7, Q9, Q3).

Here, with the scanning of the irradiation light beam in the X direction,
The state of the image forming point of the present invention on the light receiving surface of the scattered light beam will be described in comparison with the prior art. The light receiving surface of the light receiving means is arranged to be inclined with respect to the reference axis.

A specific image forming point position by the light receiving optical system in the vicinity of the light receiving surface is defined by a reference point (P4 to P6) which is a scan on the measurement reference surface, and a plane parallel to the measurement reference surface and far from the measurement reference surface. In the case of the upper far point (P1 to P3), in the case of the near point (P7 to P9) on the plane close in distance, FIG.
Is illustrated in FIG.

Looking at the trajectory of the focal position accompanying the scanning in the case of the conventional region P, the focal point and the light receiving surface are often separated from each other at the near point, the reference point, and the far point. Not imaged. Further, the distance between the imaging point and the light receiving surface in the reference axis direction with respect to the deflection angle of the galvanometer is as shown in FIG. 8, and the balance is poor.

On the other hand, the locus of the focal position accompanying the scanning in the present invention is shown in the same manner as in the prior art in FIG.
10 and FIG. 10, and it is clear from FIG. 9 that the focal point exists near the light receiving surface as compared with the related art. Further observing FIG. 10 more specifically, the distance between the light receiving surface and the focal point is about １, and the state is well balanced with respect to the deflection angle of the galvanometer. And figure
11 shows FIG. 10 to show the effect of this embodiment, and FIG.
It is shown on a scale similar to that of FIG.
Things.

That is, in this embodiment, the region Q (Q1, Q7, Q9, Q3) of the measuring light beam in the scanning plane is a predetermined distance from the center of the area Q with respect to the reference axis of the optical system in the scanning plane. They are arranged with a distance. Note that the reference axis is a reference axis assumed as a reference in the entire optical system including the irradiation optical system and the light receiving optical system. Further, the scanning surface is a plane formed by scanning the measurement light beam.

The three-dimensional scanner 100 of the present embodiment
Is three-dimensional coordinates and two-dimensional light / dark information (contrast)
And the like can be applied to all measurement devices that read such information.

[0038]

According to the present invention having the above-described structure, a light source, a deflector for deflecting and scanning a measurement light beam from the light source,
An irradiation optical system for irradiating the measurement light beam deflected by the deflector onto the object to be measured, a light receiving optical system for forming an image of the scattered light beam from the object to be measured, and a light receiving optical system. A light receiving means having a light receiving surface formed in the vicinity of the image forming point of the scattered light flux; and an arithmetic processing means for calculating a distance to the surface to be measured by an output signal from the light receiving means . The measurable area in the scanning plane is
With respect to the reference axis of the optical system in the scanning plane,
It is located at a certain distance to the projection optical system
The focus can be set near the light receiving surface, and the scanning of the measurement light
Focus position where scattered light from within the measurable area is imaged due to
Can be reduced with respect to the light receiving surface
effective. Also, the spot diameter of the incident light on the light receiving surface is small.
If it gets smaller, the light receiving position can be calculated with higher accuracy.
The effect that the shape of the object to be measured can be measured accurately
There is fruit. Furthermore, fluctuations in the focal position with respect to the light receiving surface are
Well-balanced against the deflection angle of the rubanometer, receiving light
There is an effect that the amount of incident light on the surface is made uniform.

Further, since the scattered light beam is always imaged on the light receiving surface, it can be efficiently focused on the light receiving means.
It is possible to accurately measure even an object with low scattering efficiency and to reduce the irradiation light amount of the measurement light beam irradiated to the object to be measured, so that if the output of the light source is reduced without lowering the measurement accuracy, And an excellent effect that simplification of a circuit and power saving can be realized.

[0040]

[Brief description of the drawings]

FIG. 1 shows a three-dimensional scanner 100 according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating the configuration of FIG.

FIG. 2 is a diagram illustrating an optical configuration of an embodiment of the present invention.

FIG. 3 is a diagram illustrating an image forming position on a light receiving unit 5 according to the present embodiment.

FIG. 4 is a diagram illustrating a modification of the present invention.

FIG. 5 is a diagram illustrating a modification of the present invention.

FIG. 6 is a diagram illustrating a measurable area according to the present embodiment.

FIG. 7 is a diagram illustrating measurement performance when the measurable area is not moved.

FIG. 8 is a diagram illustrating measurement performance when the measurable area is not moved.

FIG. 9 is a diagram illustrating measurement performance when a measurable area is moved.

FIG. 10 is a diagram illustrating measurement performance when a measurable area is moved.

FIG. 11 is a diagram illustrating a comparison with a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 light source 2 galvanometer 3 irradiation optical system 31 first fixed mirror 4 light receiving optical system 41 second fixed mirror 42 imaging lens 5 light receiving means 6 arithmetic processing means 61 scanning position control unit 62 galvanometer driving means 100 three-dimensional scanner

────────────────────────────────────────────────── ─── Continuing on the front page (72) Fumihiko Kamizono 75-1, Hasunumacho, Itabashi-ku, Tokyo Inside Topcon Corporation (72) Inventor Shuji Sonoda 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa Prefecture Kanagawa Science Park B Bldg. 11F 1113 (56) References JP-A-5-12414 (JP, A) JP-A-5-18726 (JP, A) JP-A-5-187833 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G01B 11/00-11/30 102 G02B 26/10-26/12

Claims (2)

(57) [Claims] A light source; a deflector for deflecting and scanning a measurement light beam from the light source; an irradiation optical system for irradiating the measurement light beam deflected by the deflector onto an object to be measured;
A light receiving optical system for forming an image of the scattered light beam from the object to be measured, a light receiving unit having a light receiving surface formed near an image forming point of the scattered light beam by the light receiving optical system, and an output from the light receiving unit the signal, the composed and processing means for calculating the distance to the measured surface, the scan plane of the measuring beam
The measurable area in the optical system in the scanning plane
A predetermined distance toward the illumination optical system with respect to the reference axis of the system.
A three-dimensional scanner characterized by being arranged with a. 2. The three-dimensional scanner according to claim 1, wherein the light receiving means is formed to be inclined with respect to the measured object.