JPH10267624A - Measuring apparatus for three-dimensional shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a three-dimensional shape with high accuracy and at a high speed on the basis of an obtained signal by a method wherein an object to be measured is irradiated with one light spot, the light spot is scanned sequentially in different points on the object, to be measured, with the passage of time and parts which are irradiated with the light spot are put into visual fields of a plurality of a plurality of PSD cameras from mutually different directions. SOLUTION: Light which is radiated from a light source 101 is polarized by a galvanometer mirror 102, it is polarized via a rotating polygon mirror 103, and an object 10 to be measured is irradiated with a light spot. Tow PSD cameras 201, 202 are directed to the object 10 to be measured, and the light spot on the object 10 to be measured is image-formed on PSDs arranged on image-formation faces of the cameras 201, 202. When the light spot on the object 10, to be measured, at this point of time is situated in a point P, a computing operation which finds a visual-line angle looking t the point P on the basis of signal obtained by the PSD cameras 201, 202 is executed inside a computer 300, and the position in the three-dimensional space of the point P is found. In addition, an optical scanning device 100 is scanned, and a three-dimensional shape is found.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a three-dimensional shape measuring device for measuring a three-dimensional shape of an object.

[0002]

2. Description of the Related Art In recent years, non-stop tollgates have been considered as a form of tollgates on expressways, in which the shape of a vehicle running at a high speed of 100 km / h is reduced in order to finely collect correct tolls. For example, high-speed measurement of a three-dimensional shape of an object has been demanded.

Conventionally, a technique disclosed in Japanese Patent Publication No. 6-65964 has been known as a three-dimensional shape measuring apparatus for an object. This publication discloses a technique for measuring the three-dimensional shape of an object by irradiating the object with linear light and observing the irradiated line light with a CCD camera.

This method is based on the principle of triangulation in which an angle formed between an irradiation path of light irradiating an object and a direction in which a CCD camera looks at a light irradiation line on the object (light reflection path). I have.

[0005]

In the case of the method described in the above publication, there are two problems in measuring the three-dimensional shape of an object: measurement accuracy and measurement speed. I do. As a problem in measurement accuracy, the above-described principle is a method for obtaining an angle between a light irradiation path and a reflection path, and thus the light irradiation path needs to be strictly determined. In other words, the linear light that irradiates the object must be strictly linear light, and if it deviates from the straight line, an error will occur in the irradiation path of the deviated spectrum, an error will occur in triangulation, and measurement accuracy will decrease. Will do.

For this reason, the irradiation optical system for irradiating the object with this linear light in preparation for an increase in cost may employ a high-precision optical member having very little aberration, or reduce the cost by sacrificing the measurement accuracy. It is necessary to plan. Also,
Regarding the measurement speed, it seems that high-speed measurement is possible at first glance because it can be measured simultaneously for one line.
In case of D camera, it takes 1/30 to capture one image
Since it takes about a second, it is impossible to perform higher-speed measurement per line. As a scanning method in a direction intersecting with the one line, it is conceivable to scan the linear beam. However, when such a linear beam is scanned, the linear beam is scanned at each point of the scanning. It is necessary to maintain a strictly straight line, and it is extremely difficult to construct such a highly accurate optical system. On the other hand, it is conceivable to realize scanning in a direction intersecting with the linear light by moving the object on a moving table. Would be contrary.

The present invention has been made in view of the above circumstances, and has as its object to provide a three-dimensional shape measuring apparatus capable of performing high-accuracy and high-speed measurement.

[0008]

A three-dimensional shape measuring apparatus according to the present invention for achieving the above object is a three-dimensional shape measuring apparatus for measuring a three-dimensional shape of an object to be measured. Light scanning means for irradiating two light spots and sequentially moving the light spots to different points on the object to be measured with the passage of time, and moving the light-irradiated portions of the object to be measured in different directions from each other. Based on signals obtained by a plurality of PSD cameras in which a two-dimensional PSD is arranged on an image plane, and signals obtained by the plurality of PSD cameras.
A calculation unit for obtaining a three-dimensional position of the light spot on the measured object.

The three-dimensional shape measuring apparatus according to the present invention comprises a PS
Because it uses a D camera, it is suitable for high-speed measurement. Further, in the present invention, since a plurality of PSD cameras (here, for example, two) are used, in the present invention, each of the two PSD cameras gazes at a light spot irradiated on the measured object. The angle formed between the directions (reflection paths of light in two directions) is determined, and the fluctuation of the irradiation path for irradiating the light spot to the object to be measured does not cause any measurement error. Since the position of the center of gravity of the light spot is required, the size and shape of the light spot hardly affect the error, and an inexpensive optical scanning device is sufficient.

Therefore, according to the present invention, an apparatus for performing high-accuracy and high-speed three-dimensional shape measurement can be configured at low cost.

[0011]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram of an embodiment of the three-dimensional shape measuring apparatus of the present invention. The three-dimensional shape measuring apparatus shown in FIG. 1 includes an optical scanning device 100 that irradiates a light spot on a measured object 10 and two-dimensionally scans the light spot, two PSD cameras 201 and 202, A personal computer 300 corresponding to an arithmetic unit according to the present invention is provided.

The optical scanning device 100 includes a light source 101 such as a semiconductor laser or an LED, a galvanometer mirror 102 for deflecting light emitted from the light source in a direction perpendicular to the plane of FIG. 1, and light reflected by the galvanometer mirror 102. Is deflected in the plane of the paper of FIG.
It is composed of As described above, the irradiation position of the light spot, the shape of the light spot, and the like hardly cause an error, and each optical component may be an inexpensive one with low accuracy.

The two PSD cameras 201 and 202 are oriented in the direction of the object to be measured 10, and the light spot on the object to be measured 10 is arranged on the image plane of each of the two PSD cameras 201 and 202. An image is formed on each of the PSDs.
PSD sensor (Position Sensitive)
Although the device itself is widely known, a detailed description thereof will be omitted. However, the PSD is a sensor that outputs an analog signal indicating the position of the center of light amount of the light spot irradiated on the sensor surface.

Signals obtained by the two PSD cameras 201 and 202 and representing the positions of the centers of gravity of the light spots on the respective PSD surfaces provided in the respective PSD cameras 201 and 202 are transmitted to the computer 300, and are transmitted to the computer 300. The signal is converted into a digital signal by the conversion and is taken into the computer 300. Assuming that the light spot on the measured object 10 at the present time is at the point P shown in FIG. 1, the computer 300 generates two PSDs based on signals obtained by the two PSD cameras 201 and 202. Camera 2
In steps 01 and 202, an operation for obtaining the angle θ between the lines of sight looking at the point P or an operation equivalent thereto is executed, whereby the position of the point P in the three-dimensional space is obtained. Similar calculations are performed on the light spots at each point on the measured object scanned by the optical scanning device 100, and thereby the three-dimensional shape of the measured object 10 is obtained.

FIG. 2 is a schematic configuration diagram of another embodiment of the three-dimensional shape measuring apparatus of the present invention. Here, the measured object 10 is arranged at the center position of the virtual cube 400, and at each of the eight vertices of the virtual cube 400, the PSD camera 200 facing the center position where the measured object 10 is arranged is arranged. A light beam 100a is emitted from the center position of each surface of the virtual cube 400 toward the measured object 10, and each of the light beams 100a is scanned. However, when scanning with the light beam 100a, switching is performed such that the light beams 100a are not simultaneously irradiated on the measured object 10.

In the case of the three-dimensional shape measuring apparatus shown in FIG. 1, only the three-dimensional shape of the surface of the measured object 10 facing upward in FIG. 1 can be measured, and the three-dimensional shape of the entire measured object can be measured. In order to measure the measurement, it is necessary to rotate the object to be measured 10. However, when the object to be measured 10 is rotated, the rotation may cause a decrease in measurement accuracy. In contrast,
When the three-dimensional shape measuring apparatus shown in FIG. 2 is configured, even in the case of a measurement target having a complicated shape, almost no blind spot
Very high-precision measurement of the three-dimensional shape of the measured object becomes possible.

[0017]

As described above, according to the present invention,
High-accuracy three-dimensional shape measurement can be performed at high speed, and an inexpensive apparatus can be configured.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram of another embodiment of the three-dimensional shape measuring apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 10 object to be measured 100 optical scanning device 100a light beam 101 light source 102 galvanometer mirror 103 rotating polygon mirror 200, 201, 202 PSD camera 300 computer 400 virtual cube

Claims (1)

[Claims] 1. A three-dimensional shape measuring apparatus for measuring a three-dimensional shape of a measured object, comprising: irradiating the measured object with one light spot at one time;
An optical scanning means for sequentially moving a light spot to a different point on the object to be measured with time, and an image plane for bringing a portion of the object to be measured irradiated with the light spot into fields of view from different directions. A plurality of PSD cameras each having a two-dimensional PSD arranged therein, and a calculation unit for obtaining a three-dimensional position of a light spot on the measured object based on signals obtained by the plurality of PSD cameras. Characteristic three-dimensional shape measuring device.