JPH05187837A - Three-dimensional shape measuring instrument - Google Patents

Abstract

PURPOSE:To reduce the measuring time of the title instrument as a whole by providing a bundle-of-rays transformer which transforms a spotlight into slit light between a light source and optical system for measurement and, at the same time, constituting a light receiving section of a two-dimensional image sensor. CONSTITUTION:A bundle-of-rays transformer 4C composed of a beam expander, etc., which transforms a spotlight which is a bundle of measuring rays of light from a light source 3 into slit light which is spread in the direction perpendicular to the main scanning direction of a main scanning optical system M4 is provided between the light source 3 and optical system M4. On the other hand, a measurement control section 8 makes the bundle of measuring rays of light to scan in X-direction by rotating a motor MOT and, at the same time, to scan an X-Y plane 1 by moving an optical system unit U in the Y-axis direction by means of a moving mechanism composed of a motor, pulley, etc. In other words, an optical system 4 for measurement is constituted of the optical system M4 and an auxiliary scanning optical system S4 and the section 8 controls the optical system S4 so that the system S4 can make scanning in the auxiliary scanning direction obtained by one time of main scanning by a pitch P, namely, the P corresponding to the length of the slit light at the moment, when the main scanning is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to, for example, a CAD data input device for inputting an external shape from a molding die or a model of various designed products to finish a final design drawing, or for educational or sales purposes. Input device for 3D image material used,
Regarding a tertiary shape measuring device used as a medical diagnostic device or a visual sensor of a robot, a light source, and a measuring optical system for scanning a measurement light flux from the light source toward an object to be measured on an XY plane, A light receiving unit that detects a scattered light beam reflected from the surface of the object to be measured among the measurement light beams, a light receiving optical system that guides the scattered light beam to the light receiving unit, and detection of the scattered light beam by the light receiving unit. X based on the output
A main scanning optical system configured to scan and measure the measurement light flux in the X-axis direction, the signal processing unit configured to calculate and derive a distance of the surface of the object to be measured from the Y plane. The present invention relates to a three-dimensional shape measuring apparatus including a sub-scanning optical system that scans in the axial direction.

[0002]

2. Description of the Related Art As a three-dimensional shape measuring apparatus of this type,
As shown in FIG. 5, the light source is provided with a laser oscillator or the like so as to emit spot light toward the object to be measured, and the measurement optical system receives the spot light emitted from the light source. The measurement object is configured to perform main scanning in the X-axis direction and sub-scanning in the Y-axis direction, and the light receiving unit is configured using a one-dimensional image sensor, and the position of the scattered light flux detected by the sensor. Was made to correspond to the height from the XY plane to the surface of the object to be measured, that is, the distance in the Z-axis direction.

[0003]

According to the above-mentioned prior art, since the measuring light beam bundle scanned by the measuring optical system toward the object to be measured on the XY plane is spot light, the object to be measured is spotted. In order to detect the shape of the measurement object in detail, it is necessary to increase both the sampling density in the main scanning direction and the scanning line density in the sub scanning direction. Here, in order to increase the sampling density in the main scanning direction, the scanning speed must be slowed down because the response speed of the one-dimensional image sensor is limited, and in order to increase the scanning line density in the sub-scanning direction. In the same way, the scanning speed must be slowed down, and there is a drawback that the measurement time becomes long as a whole. An object of the present invention is to eliminate the above-mentioned conventional drawbacks.

[0004]

In order to achieve this object, the three-dimensional measuring apparatus according to the present invention is characterized in that a measuring light beam from the light source is provided between the light source and the measuring optical system. A light flux converter for converting into a slit light beam that spreads in a direction different from the scanning direction of the main scanning optical system on the XY plane is provided, and the light receiving unit is configured by a two-dimensional image sensor.

The beam of light converted by the beam of light converting means into a slit beam that is spread in a direction different from the scanning direction of the main scanning optical system is used for main scanning, and the scattered beam of light from the object to be measured at that time is scanned. If it is detected by the two-dimensional image sensor, data in the main scanning direction can be obtained by one main scanning only for the length of the mapping in the direction orthogonal to the main scanning with respect to the length in the spreading direction of the slit light. The sub-scanning by the sub-scanning optical system can be intermittently performed at high speed by the length of the mapping, and the scanning time can be shortened. For example, if the light beam conversion means converts the spot light into slit light that spreads in a direction orthogonal to the main scanning direction, that is, in a direction parallel to the sub-scanning direction,
Since data can be sampled by the length of the slit light in the spreading direction by one main scan, the number of main scans by the main scanning optical system can be reduced.

[0005]

Therefore, according to the present invention, it is possible to provide a three-dimensional shape measuring apparatus capable of measuring in a short time even when the shape of an object to be measured is detected in detail.

[0006]

EXAMPLES Examples will be described below. As shown in FIG. 1, a three-dimensional shape measuring apparatus, which is an example of a measuring apparatus, includes a light source 3 provided with a laser oscillator and a measurement light flux from the light source 3 on a reference surface 1 which is an XY plane. X toward the object 2
A main scanning optical system M4 that performs main scanning in the axial direction, a light receiving unit 6 that detects a scattered light beam bundle that is reflected from the surface of the DUT 2 among the measurement light beam bundles, and a light receiving optical system 5 that guides it to the light receiving unit 6. An optical system unit U, a moving mechanism for moving the optical system unit U in the Y-axis direction, and a sub-scanning optical system S4 including the optical system unit U; The DUT 2 from the reference surface 1
A signal processing unit 7 for calculating and deriving the distance of the surface, a measurement control unit 8 for controlling the optical system unit U, an X, Y, Z three-dimensional data obtained from the signal processing unit 7 and the measurement control unit 8. The model generation unit 9 generates a shape model of the object to be measured 2.

Between the light source 3 and the main scanning optical system M4, a light beam bundle composed of a beam expander or the like for converting spot light, which is a measurement light beam bundle from the light source 3, into slit light which spreads in a direction orthogonal to the main scanning direction. A converter 4C is provided. The first movable mirror 4 that scans the main scanning optical system M4 with the slit light, which is the measurement light flux from the light flux converter 4C, in the X-axis direction.
A and a first fixed mirror 4B that reflects the measurement light flux scanned by the first movable mirror 4A toward the object to be measured 2.
And a second fixed mirror 5B for reflecting the scattered light flux from the surface of the object to be measured 2 in addition to the above.
And a second movable mirror 5A for guiding the scattered light beam reflected by the second fixed mirror 5B to the light receiving unit 6, and an imaging lens for converging the scattered light beam reflected by the second movable mirror 5A at the light receiving unit 6. And 5C.

First movable mirror 4A and second movable mirror 5
As shown in FIG. 2, A is a double-sided reflecting mirror M in which the reflecting surfaces are formed by aluminum coating on both sides of the transparent substrate M1.
And a motor MOT for rotating the double-sided reflecting mirror M. That is, the two surfaces of the reflecting mirror M are separated from each other by different mirrors 4.
A and 5A.

The measurement controller 8 rotates the motor MOT to scan the measurement light beam in the X direction, and moves the optical system unit U in the Y axis direction by a moving mechanism including a motor and a pulley (not shown). Move and scan on the XY plane.
That is, the main scanning optical system M4 and the sub-scanning optical system S4 constitute the measurement optical system 4, and the measurement control unit 8 can obtain the sub-scanning optical system S4 by one main scanning. Intermittent driving is performed by scanning at the time when main scanning is completed by a pitch P (pitch corresponding to the length of slit light) in the sub-scanning direction. As shown in FIG. 2, the signal processing unit 7 is such that the inter-pixel distance X ₀ X _{1 in} one direction of the pixel array of the two-dimensional image sensor CCD forming the light receiving unit 6 is proportional to ΔX ₀ , and The surface position Z ₀ of the measuring object 2 from the reference plane 1 is
Z ₀ · theta = and requests Z ₀ from having [Delta] X ₀ becomes relation, a pixel that exists on the same X-coordinate in one scan, the image width of the scattered light beam by the imaging lens 5C Data Z _{0 in} the sub-scanning line direction, that is, the Y-axis direction is obtained by the number of arrays. Here, the scattered light flux from the reference plane 1 is always
Focus on point X ₀ . The model generation unit 9 includes a first movable mirror 4A and a second movable mirror 5A by the measurement control unit 8.
The measurement point on the XY plane is grasped from the rotation angle of (the rotation angle of the motor MOT), and the shape model of the DUT 2 is generated from the Z coordinate at that point derived by the signal processing unit 7.

Another embodiment of the present invention will be described below. In the previous embodiment, the scanning mechanism of the optical system unit U in the Y-axis direction,
That is, although the sub-scanning optical system has not been described in detail, this may be configured so that the entire optical system unit U can be reciprocally driven by using an existing technique, for example, a driving mechanism such as a motor and a pulley. The configuration of the optical system unit U is not limited to this configuration, and any configuration may be used as long as it derives the three-dimensional coordinates based on the principle described in the previous embodiment. For example, as shown in FIG. , The movable mirror 4 in the previous embodiment
A and 5A may be fixed, and the first fixed mirror 4B may be rotated to scan the measurement light beam bundle.
The configuration of the sub-scanning optical system is, as shown in FIG. 6, rotated about an axis parallel to the X axis for scanning the plane formed by the measurement light beam bundle and the scattered light beam bundle in the Y axis direction. It may be composed of a free reflecting mirror 40 and a motor 41. In the above-described embodiment, the sub-scanning optical system is driven by the pitch P in the sub-scanning direction (pitch corresponding to the length of the slit light) obtained in one main scan when the main scan is completed. Although the intermittent driving is described, the invention is not limited to this, and the driving may be performed at a low speed during the main scanning by the main scanning optical system.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the principle of the main part.

[Fig. 2] Overall configuration diagram of the three-dimensional shape measuring apparatus

FIG. 3 is an overall configuration diagram of a three-dimensional shape measuring apparatus showing another embodiment.

FIG. 4 is an overall configuration diagram of a three-dimensional shape measuring apparatus showing another embodiment.

FIG. 5 is an overall configuration diagram of a three-dimensional shape measuring apparatus showing a conventional example.

[Explanation of symbols]

 1 XY plane 2 object 3 light source 4 measurement optical system 5 light receiving optical system 6 light receiving section 7 signal processing section M4 main scanning optical system S4 sub scanning optical system

Claims (1)

[Claims] 1. A light source (3) and a measuring optical system (4) for scanning a measuring ray bundle from the light source (3) toward an object to be measured (2) on an XY plane (1). , A light receiving part (6) for detecting a scattered light beam reflected from the surface of the object (2) to be measured among the measured light beam, and a light receiving optical system (5) for guiding the scattered light beam to the light receiving part (6). ) And a signal processing section (7) for calculating and deriving the distance of the surface of the DUT (2) from the XY plane (1) based on the detection output of the scattered light flux by the light receiving section (6). The measurement optical system (4) includes a main scanning optical system (M4) that scans the measurement light beam bundle in the X-axis direction and a sub-scanning optical system (S4) that scans the measurement light beam bundle in the Y-axis direction. A three-dimensional shape measuring apparatus provided, wherein the light source (3) is provided between the light source (3) and the measurement optical system (4). A light flux converter (4C) is provided for converting the measurement light flux into slit light that spreads on the XY plane in a direction different from the scanning direction of the main scanning optical system (M4), and the light receiving section (6). A three-dimensional shape measuring device that consists of a two-dimensional image sensor.