JPH0771943A - Shape measuring system - Google Patents

Abstract

PURPOSE:To accurately measure the shape of an object to be measured in all directions by varying the position of application of a light beam to the object to be measured which is supported by a supporting member inside a transmissive capsule, and detecting the light beam reflected from the object to be measured. CONSTITUTION:A laser beam from a laser oscillator 1 undergoes intensity modulation by a light modulator 2 and is split by a beam splitter 4 into two light beams, a reference light beam La and a measuring light beam Lb. The measuring light beam Lb transmitted through the splitter 4 passes through an opening in a reflecting member 5 and illuminates by way of a capsule 7 one point of an object 6 to be measured. The capsule 7 is driven by a drive means 16 in a predetermined direction so that the light beam is made incident on the object 6 in all directions. The light beam reflected and scattered by the object 6 is made incident on the member 5, again by way of the capsule 7. The light beam reflected by the member 5 is introduced into a photodiode 10 via a lens 8. A phase measuring instrument 11 measures the phase difference between the reference light beam La and the measuring light beam Lb which are made incident on the respective photodiodes 9, 10, and this measurement is inputted to an information processing means 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring apparatus, and more particularly, it irradiates an object to be measured held in a capsule made of a light transmissive material with a light beam from a laser and utilizes a light beam reflected from the object to be measured. Thus, the shape of the object to be measured is obtained, which is suitable for, for example, volume measurement or CAD input.

[0002]

2. Description of the Related Art Conventionally, an object (object to be measured) is irradiated with a light beam, and a reflected light beam from the object is used to obtain a distance to the object. Various so-called range finders have been proposed in which distance information regarding the object is obtained by optically scanning the object.

In the range finder, a method for measuring the distance to an object is to apply an optical pulse to the object,
A method of obtaining the distance by measuring the time until the object reflects and returns, or a method in which the intensity of the light flux is modulated into a sine wave, emitted and made incident on the target object, and the light flux reflected from the object and the original light flux. There is a method of obtaining the distance by detecting the phase difference between

In recent years, with the development of semiconductor lasers and high-frequency circuit technology, distances can be measured with a resolution of 1 mm or less, and they are used for position measurement of short-distance objects, identification of objects, and the like.

Similarly, a light beam from a light source is irradiated onto an object via a reflecting mirror, and at this time, the reflecting mirror is driven by a driving means to scan the object two-dimensionally with the light beam and A shape measuring device has been proposed which detects the displacement of the optical path length by using the reflected light flux of the object and measures the shape of the object from this (Reference: Optoelectronics (1985), No. 1).
2, pp, 59, Seiji Iguchi and others).

[0006]

The above-mentioned shape measuring apparatus spatially holds or places an object to be measured. Therefore,
There is a problem in that it is necessary to perform two-dimensional optical scanning from a limited direction, and it is not possible to measure the back surface, top surface, bottom surface, etc. of the object.

The present invention irradiates a light beam from a light source onto an object to be measured, detects the reflected light beam from the object to be measured at this time, and measures the shape of the object to be measured. It is an object of the present invention to provide a shape measuring device capable of accurately measuring the omnidirectional shape of an object to be measured by housing it in the capsule.

[0008]

The shape measuring apparatus of the present invention supports an object to be measured in a capsule made of a light transmissive material by a supporting member, and causes a light beam from a light source provided outside the capsule to guide the object. When irradiating the object to be measured through the capsule, the capsule is relatively displaced with respect to the incident direction of the light beam by the driving means provided in the capsule, and the irradiation position of the light beam to the object to be measured is changed. Variously, variously, at this time, the reflected light flux from the measured object is detected by the detection means, and the shape of the measured object is measured by using the signal from the detection means.

[0009]

Embodiment 1 FIG. 1 is a schematic configuration diagram of Embodiment 1 of the present invention, and FIG.
FIG. 2 is an enlarged explanatory view of a part of FIG. 1. In the figure, 1 is a laser oscillator as a light source, which emits laser light.

Reference numeral 2 is an optical modulator for intensity-modulating the laser light from the laser oscillator 1. Reference numeral 3 is an oscillator for driving the optical modulator 2.

Reference numeral 4 denotes a beam splitter, which is a laser oscillator 1
The laser light from is divided into a reference light La and a measurement light Lb. A photodiode 9 detects the intensity of the reference light La split by the beam splitter 4.

Reference numeral 5 is a reflecting member having an opening 5a at the center. The measurement light Lb from the beam splitter 4 passes through the opening 5a of the reflecting member 5 and is incident on the measured object 6.

The object 6 to be measured is supported in a spherical capsule 7 made of a light-transmissive material (eg glass).
Reference numerals 13 and 14 denote motors, respectively, which form an element of drive means 16 for driving the capsule 7.

A condenser lens 8 condenses the measurement light Lb reflected by the object 6 to be measured and reflected by the reflecting member 5 and guides it to the photodiode 10.

The photodiode 10 detects the intensity of the measuring light Lb based on the reflected light flux from the object 6 to be measured, as will be described later.

Reference numeral 11 denotes a phase measuring device, which calculates the phase difference between the reference light La detected by the photodiodes 9 and 10 and the measurement light Lb. Reference numeral 12 denotes an information processing means, which drives and controls the driving means 16 to change variously the incident position of the measurement light Lb on the measured object 6 and a signal from the phase measuring device 11 for each incident position of the measurement light Lb. The shape of the measured object 6 is calculated and obtained from the optical path length difference based on

In this embodiment, in the above structure, the laser light from the laser oscillator 1 is intensity-modulated by the light modulator 2 and is split by the beam splitter 4 into two light fluxes of the reference light La and the measurement light Lb. ing.

Of these, the measuring light Lb which has passed through the beam splitter 4 passes through the opening 5a of the reflecting member 5 and irradiates a point 6a of the measured object 6 via the capsule 7 as shown in FIG. The reflected light beam reflected and scattered by the object 6 to be measured passes through the capsule 7 again, and then enters the reflecting member 5. Then, the light flux reflected by the reflecting member 5 is guided to the photodiode 10 via the condenser lens 8.

On the other hand, the reference light Lb reflected and split by the beam splitter 4 is incident on the photodiode 9.

The phase measuring device 11 includes photodiodes 9 and 1
The phase difference between the reference light La and the measurement light Lb incident on 0 is measured, and the measurement result is input to the information processing means 12. The information processing means 12 obtains the optical path difference between the reference light La and the measurement light Lb from the phase difference information and the modulation frequency of the optical modulator 2.

At this time, the driving means 16 drives the capsule 7 in a predetermined direction, which will be described later, so that the light beam enters all directions of the object to be measured. Then, the optical path difference is obtained in all directions of the object to be measured, and from this, the shape of the object to be measured is obtained by a known method.

3 (A) and 3 (B) are an explanatory view of a main part of a support mechanism of the object 6 to be measured in this embodiment and an explanatory view of a part of the AA cross section. In the figure, 15a is a screw hole formed in the capsule 7, and 15b is a screw (supporting member) screwed into this hole.
Is.

In this embodiment, the object 6 to be measured is attached to the support member 15
The object to be measured 6 stored in the capsule 7 is fixed at approximately the center of the capsule 7 by adjusting the length of each supporting member 15b projecting into the capsule 7.
After fixing, the portion of the capsule 7 that is exposed to the outside is cut off.

FIG. 4 is an explanatory view of the data structure of the geodesic dome for obtaining the rotation direction and the rotation angle of the capsule 7 by the driving means of FIG. 1, and FIG. 4A is an external view of the geodesic dome.
(B) is a development view thereof.

The information processing means 12 calculates the latitude or longitude information of each vertex of the geodesic dome shown in FIG. The motor 13, so that the measurement light Lb is emitted,
14 is driven and controlled.

The relationship between the vertex position (i, j, k) and the latitude / longitude (θ, φ) at this time (where 0 ≦ θ ≦ π, 0 ≦ φ ≦
2π) is κ = 2π / 5, τ = atan (2)

[0027]

[Equation 1] Represented by (CHChen and ACKak, "A robot vision s
ystem for recognizing3-D object in low-order polyn
omial time, "IEEE Transaction on Systems, Man, and C
ybernetics, Vol.19 No.6, pp.1535-1563,1989.).

The shape of the portion where the support member 15b is in contact with the object 6 to be measured is interpolated from the neighboring values.

In this embodiment, the object 6 to be measured is stored in a spherical capsule 7 and is rotated by the rotation direction and the rotation angle obtained from the geodesic dome shown in FIG. 4 with respect to the incident direction of the light beam from the light source. Although the object to be measured is configured to be optically scanned, the configuration is not limited to this, and the following configuration may be used. (1) Store the object to be measured in a rectangular parallelepiped transparent capsule,
It is rotated 90 degrees with respect to the incident direction of the light flux from the light source so that each surface of the rectangular parallelepiped faces, and the object to be measured is two-dimensionally optically scanned to measure the shape. (2) The object to be measured is stored in a rectangular parallelepiped transparent capsule, which is rotated by 90 degrees with respect to the incident direction of the light flux from the light source, and the shape is measured by irradiating two-dimensional pattern light or slit light several times. To do. (3) The object to be measured is stored in a spherical transparent capsule, and the shape is measured by rotating the object and irradiating it with two-dimensional pattern light or slit light several times.

In this embodiment, the capsule 7 does not necessarily have to be hermetically sealed, but may be any one that surrounds the object to be measured and can be rotated at a desired angle by the driving means. At this time, the capsule 7 does not have to uniformly transmit the light flux from each direction.

[0031]

According to the present invention, when the object to be measured is optically scanned to measure its shape, by configuring each element as described above, it is possible to measure the shape in all directions with high accuracy. A device can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a shape measuring apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a part of FIG.

FIG. 3 is an explanatory view of a support mechanism for an object to be measured.

FIG. 4 is an explanatory diagram of the data structure of the geodesic dome.

[Explanation of symbols]

 1 Laser oscillator 2 Optical modulator 3 Oscillator 4 Beam splitter 5 Reflecting member 6 Object to be measured 7 Capsule 8 Condensing lens 9,10 Photodiode 11 Phase measuring device 12 Information processing means 13, 14 Motor 15a Screw hole 15b Supporting member 16 Drive means

Claims (1)

[Claims] 1. An object to be measured is supported by a supporting member in a capsule made of a light transmissive material, and when a light beam from a light source provided outside the capsule is applied to the object to be measured through the capsule, By driving means provided on the capsule, the capsule is relatively displaced with respect to the incident direction of the light beam, and the irradiation position of the light beam on the object to be measured is changed variously.
At this time, the shape measuring device is characterized in that the reflected light beam from the object to be measured is detected by the detecting means, and the shape of the object to be measured is measured using the signal from the detecting means.