JP2003075139A - Three-dimensional shape measuring device and three- dimensional shape measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional shape measuring device capable of acquiring the whole shape data in a short time, while removing a dead angle generated on a measuring object. SOLUTION: This three-dimensional shape measuring device 1 is equipped with a holding means 2 capable of holding the measuring object 10 and rotating it around a rotation axis 2a, a laser beam source 9 for irradiating the measuring object 10 with a laser beam, a laser floodlight system 3 equipped with a scanning means 11 for changing the irradiation direction of the laser beam at a fixed angle around a laser optical axis 9b of the laser beam, and a light receiving system 4 including a light receiving element 13 for receiving reflected light reflected by the measuring object 10. In the device 1, the rotation axis 2a of the holding means 2, the laser optical axis 9b of the laser floodlight system 3, and a center axis 12a of the light receiving system 4 are arranged on the same plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional shape measuring apparatus and method, and more particularly, to a non-contact type three-dimensional shape such as a tooth impression model used for manufacturing a dental prosthesis such as a denture. Relates to a three-dimensional shape measuring device and a three-dimensional shape measuring method.

[0002]

2. Description of the Related Art Conventionally, various devices have been used for non-contact measurement of a three-dimensional shape such as a tooth impression model.
For example, the three-dimensional shape measuring apparatus described in Japanese Patent Laid-Open No. 10-332349 includes an XYZC axis (C axis is a rotation axis around the Y axis) moving mechanism and a laser displacement measuring sensor, and performs preliminary measurement. Without this, it is configured so that accurate three-dimensional shape data can be obtained by one measurement.

The three-dimensional shape measuring apparatus described in Japanese Patent Laid-Open No. 10-286271 has an XYZ axis moving mechanism,
A laser displacement measuring sensor is provided, and the visible camera and the laser sensor head are integrally fixed so that the optical axis of the visible camera and the optical axis of the laser light projected from the laser light source are parallel to each other, and It is configured to be able to remove blind spots and the like that occur in the measured object.

[0004]

However, in the conventional three-dimensional shape measuring apparatus as described above, all the laser measuring points on the object to be measured such as the tooth impression model are moved by using the mechanical moving mechanism. Therefore, there is a problem that it takes a long time to obtain the entire shape data.

Further, in the three-dimensional shape measuring apparatus and the like disclosed in Japanese Patent Laid-Open No. 10-286271, it is necessary to dispose a plurality of light receiving sensors at different positions in order to remove or reduce the blind spots, which complicates the light receiving section. There was a problem.

Further, the distance between the light receiving sensor or the laser light source and the laser irradiation point on the object to be measured is determined from the triangle formed by the laser light source, the laser irradiation point on the object to be measured, and the light receiving sensor, and the measured object is measured. The triangulation method, which is a distance-coordinate conversion method that gives coordinate values in the Cartesian coordinate space by recalculating the laser irradiation point on the object to the coordinates for a certain reference point, requires a long time because the calculation is complicated. age,
There is a problem that it is difficult to move the laser irradiation point at a high speed and continuously measure.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is capable of obtaining the entire shape data in a short time and removing the blind spots or the like generated in the object to be measured. It is an object of the present invention to provide a possible three-dimensional shape measuring device, and an object of the present invention is to provide a three-dimensional shape measuring method capable of simplifying and speeding up acquisition of shape data.

[0008]

According to a first aspect of the present invention, there is provided a three-dimensional shape measuring apparatus according to the first aspect of the present invention, wherein a holding means for holding an object to be measured and rotating about a rotation axis, and a laser beam to the object to be measured. A laser light source for irradiating the laser beam, a laser projection system having a scanning means for changing the irradiation direction of the laser beam at a constant angle around the laser optical axis of the laser beam, and the reflected light reflected by the object to be measured. A light receiving system including a light receiving element, wherein the rotation axis of the holding means, the laser optical axis of the laser projecting system, and the central axis of the light receiving system are arranged in the same plane.
The object to be measured is a tooth-shaped impression model, and the base of the tooth of the tooth-shaped impression model can be irradiated with laser light. The above-mentioned configuration is a means for solving the conventional problems.

Further, the three-dimensional shape measuring method according to the present invention uses a standard three-dimensional object when measuring the three-dimensional object using the three-dimensional shape measuring apparatus according to claim 1 or 2. Prepare a data table that covers the output signal value of the light receiving element that received the reflected light reflected by the laser beam with different irradiation angles and the coordinates of the standard DUT corresponding to the irradiation angle, and then perform the measurement. The laser beam is emitted to the object to be measured by changing the irradiation angle, the output signal value of the light receiving element at each irradiation angle is compared with the output signal value of the standard object to be measured, and the output of the object to be measured is compared. It is characterized in that the coordinates of the standard object to be measured corresponding to the signal value are interpolated using the output signal value of the object to be measured to obtain three-dimensional shape data of the object to be measured.

[0010]

According to the three-dimensional shape measuring apparatus of the first aspect of the present invention, only the means for holding the object to be mechanically moved mechanically, and the time required for moving the measuring device can be greatly reduced. The entire shape data can be obtained in a short time.

According to the three-dimensional shape measuring apparatus of the second aspect of the present invention, the same effect as that of the first aspect can be obtained, and at the same time, the blind spot of the object to be measured generated by the conventional method is removed. The entire shape data can be obtained in a short time. As a result, it is possible to measure with high accuracy a margin line that requires particularly high accuracy, that is, a part of the joining line with the crown of the abutment tooth, at the root of the tooth of the tooth impression model that is the object to be measured. it can.

According to the three-dimensional shape measuring method of the third aspect of the present invention, the coordinates are directly obtained from the electric signal from the light receiving sensor without using the triangulation method and the distance / coordinate conversion method. In addition, the three-dimensional shape data of the object to be measured can be obtained by high-speed coordinate calculation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a three-dimensional shape measuring apparatus and a three-dimensional shape measuring method according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a three-dimensional shape measuring apparatus according to the present invention. This three-dimensional shape measuring apparatus 1 is a tooth-shaped impression model (hereinafter referred to as "impression model") as an object to be measured. ) 10 and the rotating table 2 as a holding means for holding and holding the adjacent teeth 14 and 15, the laser projection system 3 including the laser light source 9 and the polygon mirror 11, and the reflected light reflected by the impression model 10. A laser light receiving system 4 including a light receiving system optical lens 12 for condensing and a light detecting element 13,
A display / operation touch panel LCD 5 for operating the three-dimensional shape measuring apparatus 1 and a shape calculation for controlling the entire three-dimensional shape measuring apparatus 1 while calculating the shape of the impression model 10 from the detection value of the light detection element 13 and the like. It is composed of a control unit 6 and a communication control unit 7 that transmits the obtained three-dimensional shape data to a personal computer or a server via a communication line 8 such as a LAN or a telephone line.

The rotary table 2 is formed in a disk shape rotatable about a vertical axis, and the impression model 10 and the adjacent teeth 14, 15 to be measured are fixed to the top plate of the rotary table 2. In the measurement, the adjacent teeth 14 and 15 are moved so as not to block the laser optical axis and the light receiving axis.

As shown in FIGS. 1 and 2, the laser projecting system 3 includes a laser light source 9 and a polygon mirror (only the mirror surface is shown in FIG. 2) 11.
The irradiation direction of the laser beam moves according to the rotation of 1, and the scanning operation is performed. In addition, in FIG.
The scanning angle θ is 45 °, and scanning can be performed with a width of 10 ° to the left and right around this angle.

As shown in FIGS. 1 and 2, the laser receiving system 4 is provided with an optical lens 12 and a light detecting element 13, receives the reflected light reflected by the impression model 10 and, as will be described later, the impression model. Obtain 10 three-dimensional coordinates. In Figure 2,
The viewing angle is 11.3 °, the line shown by the alternate long and short dash line 19 in the drawing is the focus line of the laser / light receiving system, the hatched region 16 is the high precision measurement range, and the hatched regions 17 and 18 are the effective measurement range.

It should be noted that the laser beam spot surely hits the base portion of the impression model 10 which requires particularly high measurement accuracy, and the diffuse reflection light from the impression model 10 is incident on the photodetecting element 13. As shown, the laser light source 9 and the light detection element 13 are placed at an oblique position with respect to the impression model 10, and the laser optical axis 9 from the laser light source 9 is arranged.
b and the central axis 1 of the optical lens 12 shown in FIGS. 2 and 3.
2a and the rotary shaft 2a of the rotary table 2 are arranged in the same vertical plane.

Next, the operation of the three-dimensional shape measuring apparatus 1 having the above structure will be described.

As shown in FIG. 3, the impression model 10 is fixed to the central portion of the rotary table 2 and the polygon mirror 11 is rotated or vibrated to generate a laser light source (optical axis 9b).
The laser beam spot from 9 is moved on the impression model 10 on a line passing through the rotary shaft 2a of the rotary table 2 for scanning. Here, the laser light source 9 is not continuous light, but intermittent light pulse-modulated in synchronization with a predetermined minute scanning angle.

Two outputs (Ia, 1
From b) and the scanning angle (θ) data, the position coordinate P (x,
y) is calculated as follows.

First, a laser beam linear equation is obtained from the scanning angle θ and the scanning center coordinates 9a.
Next, the reflected light axis linear formula is obtained from the position 13a of the light receiving surface obtained from the two outputs (Ia, 1b) of the light detection element 13 and the linear formula of the reflected light axis 12a passing through the center of the light receiving system optical lens 12. Then, the intersection point P (x, y) of both straight lines can be obtained by solving the simultaneous equations of binary. This operation is performed by rotating the rotary table 2 by 360 ° while changing the scanning angle θ, so that the three-dimensional shape data of the entire impression model 10 can be obtained.

Before measuring the shape of the impression model 10,
Output of the photodetector element 13 obtained by preparing a plurality of standard shape test pieces (hereinafter abbreviated as “test pieces”) whose shapes (coordinates) are known in advance and scanning the surface of the test pieces with the intermittent laser beam. Signal value (Ia, Ib)
And the coordinate values (x, y) of the laser beam spot geometrically determined on the test piece are made to correspond to each other, and a standard coordinate table is created and stored in the shape calculation / control unit 6 (FIG. 1). . Then, when the impression model 10 is measured, the data (Ia, Ib, θ) acquired in the above manner is corrected using the standard coordinate table, and the coordinates of the laser beam spot irradiated to the impression model 10 whose coordinates are unknown. Ask for.

More specifically, a plane test piece as shown in FIG. 5 is used, and as shown in FIG. 4, the scanning angle θ and two data of the s value calculated by the following equation and X A corresponding data table of the −Y coordinate is created in advance, the s value is calculated from Ia and Ib acquired at the time of measurement, and the s value (measured value) calculated at the scanning angle θ (θ = θ _{3 in the} illustrated example) is Two test pieces that fall between the s value of the test piece and the s value are determined (No.
2 and No. 3) The XY coordinates of these two tables are interpolated to obtain the calibrated coordinates of the measurement point P (x, y).

[0025]               s = (Ia-1b) / (Ia + 1b) (Equation 1)

This makes it possible to obtain accurate coordinate values in the orthogonal coordinate space without using the triangulation method and the distance / coordinate conversion method.

[Brief description of drawings]

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

FIG. 2 is a layout diagram of an optical system of the three-dimensional shape measuring apparatus of FIG.

FIG. 3 is a schematic diagram for explaining a calculation algorithm for obtaining three-dimensional shape data using the three-dimensional shape measuring apparatus of FIG.

FIG. 4 is a diagram showing a data table for obtaining three-dimensional shape data using the three-dimensional shape measuring apparatus of FIG.

5 is a schematic diagram for explaining a test piece for creating the data table of FIG. 4 and a step of obtaining three-dimensional shape data of a measured object.

[Explanation of symbols]

1 Three-dimensional shape measuring device 2 turntable 2a rotating shaft 3 Laser projection system 4 Laser receiving system 5 Display / operation touch panel LCD 6 Shape calculation / control unit 7 Communication control unit 8 communication lines 9 Laser light source 9a Scanning center coordinates 9b Laser optical axis 10 impression model 11 polygon mirror 12 Light receiving system optical lens 12a central axis 13 Photodetector 13a Light receiving surface position 14 adjacent teeth 15 adjacent teeth 16 High-precision measurement range 17 Effective measurement range 18 Effective measurement range 19 Laser / light receiving system focal line

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takayuki Kato             900 Fujiki, Tomioka City, Gunma Prefecture             Lee H. I Aerospace En             Inside the genie ring F term (reference) 2F065 AA04 AA53 CC16 DD06 GG04                       HH04 HH14 KK02 LL14 MM04                       PP13 QQ04 QQ13 QQ25 RR08                 4C052 AA20 LL08 NN01 NN15 NN16

Claims (3)

[Claims] 1. A holding means for holding an object to be measured and rotatable about a rotation axis, a laser light source for irradiating the object to be measured with laser light, and a laser light axis of the laser light at a constant angle. A laser projecting system having a scanning means for changing the irradiation direction of the laser light, and a light receiving system including a light receiving element for receiving the reflected light reflected by the object to be measured are provided. A three-dimensional shape measuring apparatus characterized in that the laser optical axis of the system and the central axis of the light receiving system are arranged in the same plane. 2. The three-dimensional shape measurement according to claim 1, wherein the object to be measured is a tooth impression model, and the root of the tooth of the tooth impression model can be irradiated with laser light. apparatus. 3. When measuring a three-dimensional object to be measured using the three-dimensional shape measuring apparatus according to claim 1, a standard object is irradiated with laser light while changing an irradiation angle. Prepare a data table that covers the output signal value of the light receiving element that receives the reflected reflected light and the coordinates of the standard measured object corresponding to the irradiation angle, and change the irradiation angle for the measured object. Laser light is emitted, the output signal value of the light receiving element at each irradiation angle is compared with the output signal value of the standard DUT, and the coordinates of the standard DUT corresponding to the output signal value of the DUT are compared. Is obtained using the output signal value of the measured object to be measured to obtain three-dimensional shape data of the measured object to be measured.