JPH0942941A - Three-dimensional shape measuring method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional shape measuring method and device capable of accurately measuring a three-dimensional shape independently of the shape of the measuring object, in the noncontact measurement of the three- dimensional shape of the measuring object such as a tooth pattern. SOLUTION: The device is a three-dimensional shape measuring device that is used for noncontactly measuring the three-dimensional shape of a measuring object M such as a tooth pattern required for designing and manufacturing a dental prosthesis, and also that is basically provided with a laser light source, lenes, and PSDs. The device is provided with a laser light source 1 for emitting laser beams L to the measuring point P of a measuring object M, and also at least two combinations of lenses 2a to 2d for converging the reflected light rays Ra to Rd from the measuring point P and the PSDs that receive the converged reflected light for outputting light-receiving position information at the light receiving surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional suitable for non-contact measurement of a three-dimensional shape of an object to be measured such as a tooth model necessary for designing and manufacturing a dental prosthesis such as a denture. The present invention relates to a shape measuring method and device.

[0002]

2. Description of the Related Art Conventionally, in designing and manufacturing a dental prosthesis, all processes such as shaping, impression making, tooth model making, wax-up, lost wax, casting, polishing, coalescence and adjustment are performed by a dentist and a dentist. It was done manually by a technician.

In such work, the first shaping and impression making and the last joining and adjusting are clinically performed by the dentist, but the steps from tooth model making to polishing are performed in the dental laboratory. Performed by a technician.

However, in the designing and manufacturing process of such a dental prosthesis, all the designing and manufacturing are performed by hand, so that it is not possible to improve the productivity and the quality varies. Yes, on the other hand,
There is a problem that it is difficult to train a large number of skilled technicians who are skilled technicians to meet the increasing demand for dental prostheses.

As a means for solving such a problem, for example, a device for designing a dental prosthesis as shown in FIG. 15 has been proposed.

FIG. 15 is an explanatory view showing an example of the configuration of a dental prosthesis designing apparatus, which is an abutment tooth that has been shaped (molded) by a dentist, an adjacent tooth of the abutment tooth, and the abutment tooth. Three-dimensional shape measuring means 101 for measuring the three-dimensional shape of the tooth model with the occlusal surface of the opposite tooth, and this three-dimensional shape measuring means 101
Multi-axis moving means 102 for moving an xyz three-dimensional coordinate position and / or an angular position around at least one of the xyz axes, and the multi-axis moving means 102.
Multi-axis positioning control means 103 for controlling the above, a standard tooth shape data storage means 105 in which standard tooth shape three-dimensional coordinate data is acquired and stored in advance, and an arbitrary one from this standard tooth shape data storage means 105. Selection instructing means 106 for specifying and calling tooth data of a place (number)
Then, the dentistry to be attached to the abutment tooth from the shape data selected and called from the standard tooth shape data storage means 105 by the instruction from the selection instruction means 106 and the tooth model shape data obtained from the three-dimensional shape measuring means 101. And a prosthesis shape automatic designing means 104 for automatically designing the prosthesis shape for use and examining the structural strength and correcting the shape.

According to such a dental prosthesis designing apparatus, by providing the three-dimensional shape measuring means 101, the abutment tooth with the defective portion shaped, the adjacent tooth of the abutment tooth, and the abutment tooth are provided. It becomes possible to automatically measure the three-dimensional shape of the tooth model produced based on the impression type with the occlusal surface of the opposing teeth of the tooth,
In addition, any of the standard tooth shape data stored in the standard tooth shape data storage unit 105 is read out, and this and the three-dimensional shape data of the tooth model obtained by the measurement by the three-dimensional shape measuring unit 101 are also included. In addition, by automatically designing the shape of the dental prosthesis for the prosthetic restoration of the abutment tooth by the automatic dental prosthesis designing means 104, it is possible to automate a series of operations conventionally performed by a dental technician or the like. As a result, the time required for designing / manufacturing can be significantly reduced, and the quality of the dental prosthesis can be made uniform.

By the way, as shown in FIG. 16, the three-dimensional shape measuring means 101 in the above-mentioned dental prosthesis designing apparatus is such that the shaped (molded) abutment tooth 203 and both adjacent teeth of the abutment tooth 203 are used. Tooth model 202 of 204, 205
When the contact probe 201 is moved by the multi-axis moving means 206 when measuring the three-dimensional shape of the contact probe 201, for example, the contact probe 201 is directly contacted with the abutment tooth 203 to signal the three-dimensional shape data of the abutment tooth 203. There is one that can be obtained in the processing device 207.

On the other hand, FIG. 17 shows a laser light source 301 which irradiates a laser beam 301L toward a measurement point Pm of a tooth model M which is an object to be measured, and a tooth model which is an object to be measured which is condensed through an optical lens 302. A light position detecting element (PS) for receiving the reflected light 301R from M and detecting the light receiving position.
D) shows a three-dimensional shape measuring means 101 for obtaining a three-dimensional shape of a tooth model by using a non-contact type distance sensor basically including 303, which is a light receiving position y of the PSD 303, and the PSD 303. The incident angle α (tan α) of the reflected light is geometrically determined from the light receiving surface edge distance y0 of the laser beam and the survey angle θ of the laser spot, and the incident angle α and the distance between the measurement point Pm of the tooth model and the sensor reference point Ps. To L
Is calculated and the distance L is obtained for a plurality of measurement points Pm, whereby the three-dimensional shape of the tooth model is specified.

[0010]

However, FIG.
In the contact probe type three-dimensional shape measuring means shown in, it is necessary to slow down the moving speed of the probe in order to maintain the measurement accuracy, so it takes a lot of time to obtain the three-dimensional shape data of the entire tooth model. In addition, there is a problem that the measurement accuracy deteriorates with time due to wear of the probe contact portion.

On the other hand, in the three-dimensional shape measuring means using the non-contact type distance sensor shown in FIG. 17, there is no problem as in the contact probe type three-dimensional shape measuring means.
For example, in a tooth model with a standing wall gradient and uneven shape,
Since scattered light from the measurement point Pm may strike the PSD 303 as a secondary reflected light and enter the PSD 303 as a secondary reflected light, a measurement error may occur due to the secondary reflected light. There is also a problem that it is difficult to accurately measure the three-dimensional shape of a tooth model with a tooth, and it has been a problem to solve these problems.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and in the non-contact measurement of the three-dimensional shape of an object to be measured such as a tooth model, it is accurate regardless of the shape of the object to be measured. It is an object of the present invention to provide a three-dimensional shape measuring method and apparatus that enable measurement of various three-dimensional shapes.

[0013]

A three-dimensional shape measuring apparatus according to a first aspect of the present invention determines a three-dimensional shape of an object to be measured such as a tooth model necessary for designing and manufacturing a dental prosthesis. A three-dimensional shape measuring device used for measuring by contact, comprising a laser light source for irradiating a measurement point of a measured object with a laser beam, a lens for condensing reflected light from the measurement point, and a condensing point. A light position detecting element that receives the reflected light and outputs the light receiving position information on the light receiving surface is provided, and the distance to the measurement point of the object to be measured is calculated based on the output of the light position detecting element. A three-dimensional shape measuring apparatus for specifying a three-dimensional shape of an object to be measured from the three-dimensional coordinates of the measuring points, is configured to include at least two or more combinations of a lens and an optical position detecting element. Combination of lens and optical position detector Among them, at least two or more combinations are arranged so that the primary reflected light from the measurement point irradiated with the laser light is directly incident, and according to claim 7, the signal of each optical position detection element is used as a basis. Included in the distance calculation means for calculating the distance from the reference position in the laser light source to the measurement point of the object to be measured, and the calculated distance from the reference position in the laser light source to the measurement point of the object to be measured calculated by the distance calculation means. An error correction means for correcting an error to obtain a new distance is provided, and the error correction means according to claim 8, the two calculated distances are appropriately selected from the plurality of calculated distances calculated by the distance calculation means. The difference between the calculated distance is calculated, and the error included in the calculated distance is estimated by a function that correlates the calculated difference and the error included in the calculated distance. Is set to a new distance, and the error correction means appropriately weights two calculated distances appropriately selected from the plurality of calculated distances calculated by the distance calculation means. And make the average value of both as a new distance,
According to a tenth aspect of the present invention, the error correction means according to the eighth aspect and the error correction means according to the ninth aspect are provided, and the two error corrections are performed according to the positional relationship of the optical position detection element on which the primary reflected light is incident. A multi-axis moving means and a multi-axis moving means for moving an optical system including a laser light source, a lens and an optical position detecting element to an arbitrary three-dimensional coordinate position are provided. 13. A structure comprising a positioning control means for positioning the moving means, wherein a plurality of objects to be measured measured while moving an optical system comprising a laser light source, a lens and an optical position detecting element by the multi-axis moving means. The three-dimensional coordinate position of each measurement point is calculated from the measurement point and the three-dimensional coordinate position of the optical system corresponding to each of the plurality of measurement points, and the three-dimensional coordinate positions of the calculated plurality of measurement points are calculated. A three-dimensional shape calculation means for calculating the three-dimensional shape of the measured object from the original coordinate data group is provided, and the measured object moving means for moving the measured object to an arbitrary three-dimensional coordinate position is defined as claim 13. According to claim 14, the laser light source, the lens, and the optical position detection element are used for measuring the distance in the height direction of the step of the object to be measured having the shape of a standing wall or a steep step. The distance between the reference point of the laser light source and the measured object is measured while the measured object is moved by the optical system and / or the measured object moving means by the multi-axis moving means in the direction in which the optical system and the step portion approach each other. In this case, each position of the optical system when the incident of the primary reflected light on each optical position detection element is blocked by the step portion is detected, and the height of the step portion is calculated based on this information. Equipped with step height calculation means A movable reflective mirror for irradiation that changes the direction of laser light emitted from a laser light source and / or a movable reflective mirror for reflected light that changes the direction of reflected light from an object to be measured. It has a configuration provided.

The three-dimensional shape measuring method according to a second aspect of the present invention uses each of the light beams when measuring the three-dimensional shape of the object to be measured using the three-dimensional shape measuring apparatus according to the first aspect. The error included in the calculated distance from the reference position of the laser light source to the measurement point of the DUT based on the signal from the position detection element, and the calculated distance from the calculated reference position of the laser light source to the measurement point of the DUT Is corrected to obtain a new distance, new distances are obtained for a plurality of measurement points to specify the three-dimensional shape of the object to be measured, and the laser is based on the signals of the respective optical position detection elements as claimed in claim 3. The distance from the reference position in the light source to the measurement point of the object to be measured is calculated, the difference between two calculated distances appropriately selected from the calculated plurality of calculated distances is calculated, and the calculated difference and calculated distance are calculated. Correlation with the error component included in An error component included in the calculated distance is estimated by a function, and the error component estimated from the calculated distance is removed to obtain a new distance. A laser according to claim 4 is based on a signal from each optical position detection element. The distance from the reference position in the light source to the measurement point of the object to be measured is calculated, and two calculated distances appropriately selected from the calculated plurality of calculated distances are appropriately weighted, and the average value of both is calculated as a new distance. According to Claim 5, the three-dimensional shape measuring method according to Claim 3 and the three-dimensional shape measuring method according to Claim 4 are applied to the positional relationship of the optical position detection element on which the primary reflected light is incident. The configuration is appropriately selected in accordance with the configuration to specify the three-dimensional shape of the object to be measured, and the above configuration is a means for solving the problem.

[0015]

The three-dimensional shape measuring apparatus according to the first aspect of the present invention has the above-mentioned configuration, and in the case of the three-dimensional shape measuring apparatus provided with only a single optical position detecting element, the object to be measured is Depending on the shape of, the measurement may not be possible because the primary reflected light does not enter. However, the three-dimensional measuring apparatus according to the present invention includes a plurality of optical position detecting elements. , Even if the reflected light is not incident on a part of the optical position detection elements, the reflected light is incident on the remaining optical position detection elements, so that the reference point of the laser light source and the measured object are irrespective of the shape of the measured object. The distance to the measurement point will be measured.

A three-dimensional shape measuring method according to a second aspect of the present invention has the above-mentioned structure, and when the three-dimensional shape of an object to be measured is measured using the three-dimensional shape measuring apparatus according to the first aspect. , Calculate the distance from the reference position of the laser light source to the measurement point of the DUT based on the signal of each optical position detection element, and the calculated distance from the calculated reference position of the laser light source to the measurement point of the DUT By correcting the error included in the new distance to obtain a new distance, when there is reflected light that is scattered from the measurement point and secondarily enters the optical position detection element from a site other than the measurement point of the DUT. The error caused in the calculated distance from the reference position in the laser light source to the measurement point of the measured object due to the secondary reflected light is corrected, and as a result, the three-dimensional shape of the measured object is accurately specified. Becomes

The three-dimensional shape measuring method according to the third aspect of the present invention has the above-mentioned structure, and usually an error caused in the calculated distance from the reference position in the laser light source to the measuring point of the object to be measured by the secondary reflected light. Is determined by the shape of the object to be measured, the position of the laser spot projected on the measurement point, the secondary reflection characteristic, the arrangement of the optical position detection element, etc.
It is difficult to obtain by geometrical calculation, but the distance from the reference position in the laser light source to the measurement point of the measured object is calculated based on the signal of each optical position detection element, and multiple calculated Calculating a difference between two calculated distances appropriately selected from the distances and estimating an error included in the calculated distance by a function for correlating the calculated difference and the error included in the calculated distance. As a result, the error can be accurately estimated and the distance can be accurately measured.

The three-dimensional shape measuring method according to a fourth aspect of the present invention is configured as described above, and the error components included in the two calculated distances appropriately selected from the plurality of calculated distances are in directions opposite to each other. When it occurs in (polarity), it is generally known that the ratio of these magnitudes is constant. Therefore, by weighting each appropriately and calculating the average value of both, Therefore, the error component is canceled out, and as a result, the error component is accurately corrected.

The three-dimensional shape measuring method according to a fifth aspect of the present invention has the above-mentioned configuration, and, for example, depending on the positional relationship between the two optical position detecting elements on which the primary reflected light is incident,
There are cases where the directions of the error components are the same (polarity) and the opposite directions (polarity), and when they are the same, the three-dimensional shape measuring method according to claim 3 of the present invention described above. By applying, the error can be accurately estimated,
In the case of the opposite directions, by applying the three-dimensional shape measuring method according to claim 4 of the present invention, which cancels the mutual error amount of the two optical position detecting elements, the error amount due to the secondary reflected light is applied. The correction will be performed accurately.

The three-dimensional shape measuring apparatus according to claim 6 of the present invention has the above-mentioned structure, and the combination of at least two or more lenses and the optical position detecting element is the primary reflection from the measuring point irradiated with the laser beam. Since the light is arranged so as to be directly incident on it, the information necessary for removing the error component contained in the output of the light position detection element can be surely acquired.

A three-dimensional shape measuring apparatus according to a seventh aspect of the present invention has the above-mentioned configuration. By using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of an object to be measured, The same effect as the three-dimensional shape measuring method can be obtained.

The three-dimensional shape measuring apparatus according to claim 8 of the present invention has the above-mentioned structure, and by using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of the object to be measured, the three-dimensional shape measuring apparatus according to claim 3 is obtained. The same effect as the three-dimensional shape measuring method can be obtained.

The three-dimensional shape measuring apparatus according to claim 9 of the present invention has the above-mentioned configuration, and by using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of an object to be measured, the three-dimensional shape measuring apparatus according to claim 4 is obtained. The same effect as the three-dimensional shape measuring method can be obtained.

A three-dimensional shape measuring apparatus according to a tenth aspect of the present invention has the above-mentioned structure. By using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of an object to be measured, The same effect as the three-dimensional shape measuring method can be obtained.

The three-dimensional shape measuring apparatus according to the eleventh aspect of the present invention is configured as described above, and by having the multi-axis moving means, the optical system including the laser light source, the lens and the optical position detecting element is automatically provided. The object to be measured is measured while being continuously moved, and the position optical system is moved so that the primary reflected light is incident on at least two or more optical position detecting elements.

The three-dimensional shape measuring apparatus according to the twelfth aspect of the present invention is configured as described above, and in the distance data group to the plurality of measurement points acquired by the error correcting means, the continuous outer shape of the object to be measured is still present. It is not shape data,
For example, when the object to be measured is a tooth model, it is necessary to make it into a data format necessary for designing and manufacturing a dental oil prosthesis. Three-dimensional shape data will be acquired.

The three-dimensional shape measuring apparatus according to the thirteenth aspect of the present invention is configured as described above, and if the object moving means is used together with the multi-axis moving means, the degree of freedom regarding the measuring direction, position, etc. is increased. The same measurement is maintained even if the number of axes of the multi-axis moving means is reduced.

A three-dimensional shape measuring apparatus according to a fourteenth aspect of the present invention is configured as described above, and measures the distance in the height direction of the step of an object to be measured having a standing wall shape or a steep step shape. In the measurement, the distance between the reference point of the laser light source and the object to be measured while moving the object to be measured by the optical system and / or the object to be measured moving means by the multi-axis moving means in the direction in which the optical system and the step portion approach each other. When measuring, the height of the step is estimated by the step height calculating means, so if the optical system is moved by the multi-axis moving means based on the estimated height of the step, the three-dimensional shape can be obtained. It does not go out of the measuring range of the measuring device, and even if, for example, the tooth model to be measured is manufactured at any height using dental plaster, the optical system automatically optimizes the optimum three-dimensional shape. The movement is adjusted to the coordinate position. To become.

The three-dimensional shape measuring apparatus according to the fifteenth aspect of the present invention is configured as described above, and when a multi-axis moving means for moving the optical system is also applied, the measuring range and the measuring direction can be freely set. Further, even if the multi-axis moving means or the like is not applied, the scanning of the object to be measured with the laser beam similar to the multi-axis moving means or the like is performed.

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing the structure of an embodiment of a measuring apparatus used for carrying out the three-dimensional shape measuring method according to the present invention, which is composed of optical lenses 2a, 2b, 2c and 2d and light. PSDs 3a, 3b, 3 which are position detecting elements
Two sets of optical systems combining c and 3d are arranged on both sides of the laser light source 1 for irradiating the measurement point of the object M with the laser light L.

When the object M to be measured has a standing wall Mw as shown in FIG. 1, when the laser light L is irradiated from the laser light source 1 toward the measuring point P, the measuring point P is measured.
A laser spot is projected on the screen, and the reflected light is scattered as shown in the figure.

At this time, of the scattered reflected light, the reflected light traveling to the left side of the drawing, that is, the reflected light Ra and Rb traveling to the side where the standing wall portion Mw does not exist, is the lenses 2a and 2 respectively.
An image is formed on the PSDs 3a and 3b through b.

On the other hand, among the scattered reflected light, the reflected light traveling to the right side of the drawing, that is, the reflected lights Rc and Rd traveling in the direction in which the standing wall portion Mw exists, if the standing wall portion Mw does not exist, the dotted line shown in the figure. Lens 2c,
The image is formed on PSDs 3c and 3d through 2d.
Since the standing wall portion Mw exists, no image is formed on the PSDs 3c and 3d.

Therefore, for example, in the case of a three-dimensional shape measuring apparatus that includes only the PSD 3c among the PSDs 3a to 3d that are optical position detecting elements, that is, the three-dimensional shape measuring apparatus including only a single optical position detecting element, If the vertical wall portion Mw is present, the reflected light does not enter the PSD 3c, so that the measurement cannot be performed. However, according to the three-dimensional measuring apparatus of the present invention shown in FIG. 1, since a plurality of PSDs are provided,
Even if the primary reflected light does not enter some PSDs, the remaining P
The reflected light is incident on the SD, and the measurement can be performed even if the standing wall portion Mw exists.

Contrary to the measured portion Ml located on the left side of the standing wall portion Mw described above, when the measured portion Mr located on the right side of the standing wall portion Mw is measured, that is,
When the standing wall portion Mw is located at the upper left rather than at the measurement point P, the PSDs 3a and P3
Although the incidence of the primary reflected light on the SD3b is hindered, the primary reflected light is incident on the PSD3c and the PSD3d, and therefore the measurement can be performed by the PSD3c and the PSD3d.

As described above, by providing a plurality of PSDs, it is possible to detect the primary reflected light that is directly incident on the PSD from the measurement point P by any of the plurality of PSDs. As will be described below with respect to the PSDs 3a and PSD3b, an error occurs due to secondary reflected light that is not directly incident on the PSD from the measurement point P but is reflected from a portion other than the measurement point of the DUT M and is indirectly incident on the PSD. There are cases.

2 (a) to 2 (e) are measured while moving an optical system including a laser light source 1, PSDs 3a to 3d and lenses 2a to 2d in a three-dimensional shape measuring apparatus in a direction approaching the standing wall Mw. It shows how secondary reflected light and an error are generated when going down. In addition, PSD
Illustrations of the lenses 3c and 3d and the lenses 2c and 2d are omitted.

First, FIG. 2A shows the optical system and the standing wall Mw.
And the primary reflection light from the measurement point P indicated by the dotted line is PSD3.
Although incident on a and 3b, the secondary reflected light shown by the solid line is PSD
Since the laser spot is not incident on 3a, 3b, or even if it is incident, the secondary reflected light becomes weak because the laser spot is away from the standing wall portion Mw, so that an error due to the secondary reflected light hardly occurs.

Next, as shown in FIG. 2B, when the optical system further approaches the standing wall portion Mw, the primary reflected light is 3
While being incident on a and 3b, the secondary reflected light indicated by the dotted line is incident on PSDs 3a and 3b, respectively.

As a result, when viewed from the PSDs 3a and 3b,
There is a virtual image at the positions of the points Ga and Gb, and it seems that the secondary reflected light enters from the virtual image points Ga and Gb, respectively. Therefore, the outputs of the PSDs 3a and 3b include an error due to the secondary reflected light. And P on which the secondary reflected light is incident
The distances from SD3a and 3b to the calculated measurement point P are closer to the virtual image points Ga and Gb, respectively, which are shorter than the actual distances.

When the laser light from the laser light source 1 is incident on the base end E of the standing wall Mw as shown in FIG. Does not happen.

On the other hand, FIG. 2 (d) is the opposite of the case of FIG. 2 (b) in the case where the laser light is incident on the standing wall Mw, and the secondary reflected light is the PSD 3a as shown in the figure. , 3b respectively, an error occurs, and in this case, the distances from the PSDs 3a, 3b on which the secondary reflected light is incident to the calculated measurement points P are near the virtual image points Ga, Gb, respectively. , Each longer than the actual distance.

Further, FIG. 2E shows a case where the laser light from the laser light source 1 is incident on a position further away from the base end portion of the standing wall portion Mw, similar to the case of FIG. 2A. In addition, there is almost no error due to the secondary reflected light.

As shown in FIGS. 2B and 2D, the two PSDs 3a located on one side of the laser light source 1,
When the primary reflected light is incident on 3b, the PSDs 3a, P
The errors due to the secondary reflected light included in the distance calculated based on the output from SD3b have the same direction (polarity).

By the way, although the object to be measured M having the standing wall Mw as shown in FIG. 1 has been described so far, for example, as shown in FIG. 3, the shape of the object to be measured is concave. In the case of the (dent) shape, in the recess Md of the object to be measured M, the PSD 3a and PSD 3d existing at a position farther from the laser light source 1 are each provided with the primary reflected light indicated by a dotted line. Inner wall of Md Md
Since it is shielded by l and Mdr, the primary reflected light Ra,
Rd does not enter or is difficult to enter.

Even in such a case, as shown in FIG.
Since there are multiple PSDs, some PSDs 3a, 3
Even if the primary reflected lights Ra and Rd do not enter d, the remaining P
Since the primary reflected lights Rb and Rc shown by the solid lines enter the SDs 3b and 3c, the distance to the measurement point P can be measured.

Further, in this case, the primary reflected lights Rb and Rc are incident on the PSDs 3b and 3c arranged so as to sandwich the optical axis of the laser light source 1, but such a concave shape is formed. The object M to be measured may also cause the above error, and the error will be described below.

FIGS. 4 (a) to 4 (e) show how secondary reflected light and error occur when the primary reflected light Rb, Rc is incident on the PSD 3b and PSD 3c as shown in FIG. 3 in the concave portion. Is shown. In addition, PSD3a,
Illustration of the 3d and the lenses 2a and 2d is omitted.

In the state where the optical system is separated from the inner wall Mdr of the recess Md to some extent as shown in FIG. 4A, almost no error occurs, as described in FIG. 2A.

On the other hand, FIG. 4 (b) corresponds to FIG. 2 (b), but in this case, the difference is that in FIG. 2 (b), the error generated in the two PSDs 3a, 3b will eventually occur. Also had the same direction (polarity), but in the state of FIG. 4B, PSDs 3b, 3c on which the secondary reflected light is incident
Since the calculated distances to the measurement point P are closer to the virtual image points Gb and Gc, the PSD 3b is longer than the actual distance, and the PSD 3c is shorter than the actual distance.

Therefore, the errors generated in the two PSDs 3b and 3c have different directions (polarities),
The respective errors are complementary to each other. This also applies to the relationship between FIG. 2 (d) and FIG. 4 (d).

Incidentally, FIGS. 4 (c) and 4 (e) correspond to the above-mentioned FIGS. 2 (c) and 2 (e).

As described above, even if the first-order reflected light is received by any of the PSDs 3a to 3d, the above-mentioned error may be included in some cases. Even if the distance to the measurement point P is calculated based on the output signal, an error may be included, and an accurate three-dimensional shape of the measured object M should be acquired from a plurality of calculated distances including the error. I can't.

A means for removing such an error and obtaining the true distance to the measurement point P as much as possible will be described below.

First, the distance calculating means calculates each PSD 3a.
The distances La, Lb, Lc and Ld from the reference position of the laser light source 1 to the measurement point P are calculated based on the output signals of 3d.

The distance calculating means is provided for each of the PSDs 3a-3d.
The incident angle of the reflected light is specified from the light receiving position of, and La, Lb, Lc, and Ld are geometrically calculated.
The distance calculated from the output signal of the PSD that does not receive the primary reflected light or does not reliably receive the primary reflected light is clearly compared with the distance calculated from the output signal of the PSD that reliably receives the primary reflected light. different.

From this, it is possible to specify the two PSDs that have received the primary reflected light.

Next, the true distance Lt can be obtained if the magnitude of the error of the distances La to Ld can be directly calculated. However, in reality, the magnitude of the error is determined by the standing wall portion. Is difficult to obtain by geometrical calculation, because it is determined by the inclination of, the position of the laser spot, the secondary reflection characteristic, the arrangement of PSD, and the like.

Therefore, in the present invention, the error is corrected by the two error correction means described below.

Here, two PSs that receive the primary reflected light
When D is the PSD 3a, 3b located on one side of the laser light source 1 as shown in FIG. 2 and the PSD 3b, 3c located so as to sandwich the laser light source 1 as shown in FIG. As described above, the directions (polarity) of the errors generated in the two PSDs are different, and in the case of FIG.
The directions of the errors generated in 3a and 3b are the same, and in the case of FIG. 4, the directions of the errors are different from each other.

Therefore, in the three-dimensional shape measuring apparatus according to the present invention, the error is corrected by the error correcting means according to the difference in the directions of the errors generated in the two PSDs.

First, the first error correction means will be described. Of the distances La, Lb, Lc, and Ld calculated based on the output signals of the PSDs 3a to 3d, as shown in FIG.
In the case of the error shown in (d), the measurement point P
To Lt, the error amount of PSD3a, 3b is e
If rra and errb, then PSD3a and PSD
The distances La and Lb obtained from 3b are: La = Lt + erra Lb = Lt + errb

Here, if the difference between the distances La and Lb is taken, then La-Lb = erra-errb. Since this value has a predetermined relationship with the error erra or errb, this value is used as the error correlation value Δ = er
Ra-errb.

Next, the relationship between the error erra and the error correlation value △, i.e., error of erra of PSD3a is a function correlating therebetween f (△) = m · △ estimated approximation to the ⁿ + k From the experimental results, it is clear that the true distance L is Lt = La-err = La-f (Δ).

If m, n, k, which are the approximate parameters of the estimated value f (Δ), are properly selected, Lt = Lb-errb = Lb-f (Δ) can be set for PSD3b. It can be calculated based on one of PSD3a and PSD3b.

On the other hand, in the case of the error as shown in FIGS. 4B and 4D, the error is corrected by the second error correction means described below, that is, the virtual image at the measurement point P is corrected. Since the directions of generation of the points Gb and Gc are opposite to each other and the distance between P and Gb is different from the distance between P and Gc, and the ratio of both distances is almost constant, the weighted average is calculated as follows. And the error is erased.

Lt = (Lb + k · Lc) / (1 + k) It has been confirmed by experiments that the desired accuracy can be easily obtained by weighted averaging. Note that k is a constant experimentally obtained from the ratio of the distance between P and Gb and the distance between P and Gc.

As described above, as shown in FIG.
Even if the error due to the secondary reflected light described in (d) and FIGS. 4B and 4D exists in each PSD,
In each case, the error can be appropriately removed, and more accurate measurement can be realized.

The distance calculating means and the error correcting means described so far can be realized in, for example, a signal processing device V as shown in FIG.

First, in FIG. 5, the signal processing device V is
The current output from each PSD 3a to 3d is converted into a digital value by the A / D converter 4, and the digital value is controlled.
Processing is performed by the arithmetic unit 5.

The control / arithmetic unit 5 may be basically constituted by a microprocessor, software, etc., and the control / arithmetic unit 5 can realize a distance calculating means and an error correcting means. it can.

Here, an example of the signal processing procedure in the signal processing device V shown in FIG. 5 will be described with reference to the flowchart shown in FIG.

In FIG. 6, first, the optical system is moved to a predetermined position where the measurement is started (S1).

This can be carried out, for example, by providing the signal processing device V with positioning control means and sending a position command from this positioning control means to a multi-axis moving means which will be described later.

Then, the output signals of the PSDs 3a to 3d are read by the A / D converter 4 (S2).
The light receiving positions ya to yd on the light receiving surfaces of the PSDs 3a to 3d are calculated from the output signals of D3a to 3d (S3).

Then, the distances La, Lb, Lc and Ld from each of the light receiving positions ya to yd to the measuring point P are geometrically calculated (S4).

Next, in step S5, of the distances La, Lb, Lc and Ld to the measurement point P calculated in S4, two data used for removing the error by the error correction means are specified, It is determined which of the first and second error correction means described above should be used to remove the error.

For example, when the primary reflected light is incident only on the PSDs 3a and 3b arranged as shown in FIG. 2, the distances La, Lb, and
Of Lc and Ld, Lc and Ld obviously have different values from La and Lb, so it is determined that the two data used to remove the error should be La and Lb.

Further, which of the first and second error correction means should be used to remove the error depends on, for example, if the two data used to remove the error are La and Lb. If the two data used to select the error correction means and remove the error are Lb and Lc, the first
Error correction means is selected.

When the first error correction means is selected in step S5, the process proceeds to step S6,
After calculating the error correlation value Δ, the estimated error value f (Δ)
Is calculated (S7). For example, when the reference data is La, the error estimated value f (Δ) is removed from La to perform error correction (S8).

On the other hand, when the second error correction means is selected in step S5, the process proceeds to step S9, and as described above, weighted averaging is performed to eliminate the error component. Next, the corrected distance acquired in step S8 or S9 is output to the output unit 6 such as a storage or display device (S10).

Then, the measurement position is moved (S11), it is judged whether or not it is within the range to be measured, and if it is within the range, the process proceeds to step S2 again, and if it is out of the range, the measurement is ended.

By measuring the distances to the plurality of measurement points P in this manner, the three-dimensional shape of the object to be measured can be accurately specified.

The laser light source 1 and the lens 2a have been used so far.
.About.2d and PSDs 3a to 3d, the configuration of the optical system has been described based on the configuration shown in FIG.
3d and the lenses 2a to 2d may not be arranged in a straight line, and the combination of the PSD and the lens is not limited to four and may be increased or decreased appropriately.

Further, when the error is removed only by the weighted averaging which is the second error correction means, as shown in FIGS. 8 and 9, the laser light L emitted from the laser light source 1 is emitted. It is also possible to adopt a configuration in which a plurality of sets of lenses and PSDs are arranged in a plane perpendicular to the optical axis. Note that FIG. 8 includes four sets of lenses 2a to 2d and PSDs 3a to 3d, and FIG.
Includes three sets of lenses 2a to 2c and PSDs 3a to 3c.

Next, FIG. 10 is an explanatory diagram showing the configuration of another embodiment of the three-dimensional shape measuring apparatus according to the present invention, which is an optical system 21 including a combination of a laser light source, a plurality of lenses and a PSD. Multi-axis moving means 22 for automatically and continuously moving the three-dimensional coordinate position of
It is configured to include the positioning control means 23 for performing the positioning control of No. 2.

In the signal processing device V, the distance calculating means 24, the error correcting means 25 and the three-dimensional shape calculating means 26 are provided.
The output of the signal processing device V is displayed by the output means 27. It should be noted that, as described above, the positioning control means 23 can be simultaneously realized in the signal processing device V.

Here, the three-dimensional shape calculation means 26 includes a plurality of measurement points Pi (i = 1, .. n) of the object to be measured measured by the multi-axis moving means 22 while moving the optical system 21 and the laser light source. From the relative distance Li (i = 1, .., n) with respect to the reference position and the three-dimensional coordinate position of the optical system 21 corresponding to each measurement point Pi, the three-dimensional position coordinates of the measurement point Pi are calculated, The continuous outer shape data of the object to be measured M is calculated from the calculated three-dimensional position coordinate data of the measurement point Pi.

Therefore, the relative distance Li (i = 1, .., n) between the plurality of measurement points Pi (i = 1, .. n) that are as accurate as possible by the error correction means 25 and the reference position of the laser light source. However, even though the continuous outer shape data of the object to be measured M is not obtained at this stage, the continuous outer shape data of the object to be measured M is calculated by the three-dimensional shape calculating means 26. When, for example, the object M to be measured is a tooth model, the continuous outer shape data of the tooth model obtained by the three-dimensional shape calculation means 26 for designing and manufacturing a dental prosthesis is used as it is. Can be used.

On the other hand, since the multi-axis moving means 22 is provided, the object M to be measured can be measured while moving the optical system 21 automatically and continuously, and at least two or more PSDs can be used. At the same time, it is possible to move the optical system 21 to the position where the primary reflected light enters.

Next, in FIG. 11, in addition to the multi-axis moving means 22 for moving the three-dimensional coordinate position of the optical system 21, the measured object M is automatically and continuously moved by the measured object moving means 28. It is configured to be movable to.

With this structure, the degree of freedom in the measurable range is widened and the number of axes of the multi-axis moving means 22 can be reduced.

FIG. 12 is an explanatory diagram showing how the distance in the height direction of the step of the object M to be measured having the shape of the stepped portion Wd in the shape of a standing wall is measured.

Now, toward the step Wd, the laser light source 1,
While measuring the lower bottom surface Pb in the figure while moving the optical system composed of the lenses 2a to 2d and the PSDs 3a to 3d in the direction of arrow A by the multi-axis moving means, the optical system detects the top surface Pt of the step Wd. When it reaches above, the first reflected light does not enter the PSD 3d first, and further advances, the first reflected light does not enter the PSD 3c.

When the laser light source 1 forms an image of the laser spot on the top surface Pt of the step Wd, the distance between the laser light source 1 and the measurement point suddenly approaches, which may deviate from the predetermined measurable range. .

Therefore, in order to measure the top surface Pt of the step portion Wd, it is necessary to move the optical system in the height direction of the step so that it falls within a predetermined range.

In this case, if the height X of the step Wd can be obtained while measuring, the multi-axis moving means 2 described above can be used.
Since it becomes possible to automatically move the optical system to an appropriate height by means of 2, the step height estimating means for estimating the height X of the step Wd will be described below.

First, the position of the optical system where the primary reflected light does not enter the PSD 3d is detected, and the position where the primary reflected light does not enter the PSD 3c is detected. The position of the optical system can be detected, for example, by providing the multi-axis moving means 22 with a position detector and sending this detection signal to the signal processing device V.

Then, the moving distance d of the optical system is obtained from the position of the optical system where the primary reflected light does not enter the PSD 3d and the position where the primary reflected light does not enter the PSD 3c,
Using this moving distance d, the height X of the step Wd can be estimated from X = d · l1 / h. However, h is the distance between the reference point S and the measurement point P calculated by measurement, and l1 is the reference point S and the center point C of the lens 2c.
And the distance.

Here, an example of a processing procedure when the step height estimating means is realized in the signal processing apparatus V will be described with reference to the flowchart shown in FIG.

In the flow chart shown in FIG. 13, the processing procedure of the step height estimating means is shown alone, but it is configured to be executed in parallel with the processing in the flow chart shown in FIG. 6, or shown in FIG. It is also possible to adopt a configuration in which it is executed at an appropriate step in the flowchart.

First, in step S51, each P
The output signal from SD is read and step S5
At 2, the signal level is determined. The signal level is determined for each PSD 3a to 3d,
It is determined whether or not the signal level is below a predetermined value, and as shown in FIG. 12, when the incident of the primary reflected light on the PSD 3d is blocked and the signal level is below a predetermined value. Goes to step S55, otherwise goes to step S54 to move the position of the optical system by a predetermined amount in the direction of arrow A by the multi-axis moving means, and then returns to step S51 again to read the PSD signal. To do.

In step S55, the distance h to the measurement point P is calculated and stored, and the three-dimensional position coordinates of the optical system are stored.

Then, in step S56, after the position of the optical system is moved in the direction of arrow A by a predetermined amount by the multi-axis moving means, the PSD signal is read again (S5).
9), similarly to step S53, the signal level is determined (S58).

Then, when the incidence of the primary reflected light on the PSD 3c is newly blocked and the signal level becomes below a predetermined value together with the PSD 3d, the process proceeds to step S60, and the three-dimensional optical system at the measurement position is measured. Acquire and store position coordinates. When the signal level of PSD3c is larger than the predetermined value, the process proceeds to step S54.

In step S61, step S5
The height X of the object to be measured is estimated from the three-dimensional position coordinates of the optical system and the distance h acquired in step 5 and the three-dimensional position coordinates of the optical system acquired in step S60.

Then, based on the estimated height X of the object to be measured, the optical system is moved by the multi-axis moving means 22 in the height direction of the step.

As a result, it becomes possible to automatically adjust the position of the optical system to the optimum position by the multi-axis moving means from the estimated height X of the step portion Wd. Even if the model is manufactured using dental plaster at an arbitrary height, the position of the optical system can be automatically adjusted to the optimum position.

Next, FIG. 14 is an explanatory view showing still another embodiment of the three-dimensional shape measuring apparatus according to the present invention, in which the direction of the laser light emitted from the laser light source can be changed. Movable reflecting mirrors 42, 4 for reflected light that can change the direction of the primary reflected light from the measuring point of the reflecting mirror 41 and the object to be measured.
It is equipped with 3.

In FIG. 14, the laser light L from the laser light source 1 first enters the irradiation movable reflecting mirror 41. At this time, the incident position on the object to be measured M can be changed by appropriately changing the angle of the irradiation movable reflecting mirror 41 with respect to the laser optical axis. In other words, it is possible to perform the same operation as mechanically scanning the object to be measured M by the multi-axis moving means 22.

The angle of the irradiation movable reflecting mirror 41 with respect to the laser optical axis is, for example, on the surface opposite to the light receiving surface of the irradiation movable reflecting mirror 41 which receives the laser light from the laser light source 1 for angle detection. The reflection mirror 41b is provided, and the angle detection light source 45 is arranged at a position facing the laser light source 1 with the irradiation movable reflection mirror 41 interposed therebetween, and the angle detection light source 45 faces the angle detection reflection mirror 41b. It can be detected by irradiating a laser beam and receiving the reflected light by the angle detection sensor 44.

The primary reflected light from the object M to be measured is received by the PSDs 3a and 3b through the lenses 2a and 2b. As shown in FIG. 13, the movable reflecting mirror 4 for irradiation is used.
By providing the movable reflection mirrors 42 and 43 for reflected light whose angles can be changed in synchronization with the change of the angle with respect to the laser optical axis of 1, the PSDs 3a and 3b can receive light. With such a configuration, if the multi-axis moving means for moving the optical system is also applied, the degree of freedom in the measurement range and the measuring direction can be further expanded, or the number of axes of the multi-axis moving means can be increased. In addition, it is possible to scan the object to be measured with the laser beam similarly to the multi-axis moving means without applying the multi-axis moving means.

[0114]

As described above, according to the three-dimensional shape measuring apparatus according to the first aspect of the present invention, in the case of the three-dimensional shape measuring apparatus having only a single optical position detecting element,
Depending on the shape of the object to be measured, there may be cases where the measurement cannot be performed because the primary reflected light does not enter. However, the three-dimensional measuring apparatus according to the present invention is provided with a plurality of optical position detecting elements. Therefore, even if the reflected light is not incident on a part of the optical position detecting elements, the reflected light is incident on the remaining optical position detecting elements, so that the reference point of the laser light source and the measured object are irrespective of the shape of the measured object. This has the excellent effect of making it possible to measure the distance between the measurement points of and.

According to the three-dimensional shape measuring method of the second aspect of the present invention, when the three-dimensional shape of the object to be measured is measured using the three-dimensional shape measuring apparatus of the first aspect, The distance from the reference position in the laser light source to the measurement point of the DUT is calculated based on the signal of the optical position detection element of and is included in the calculated distance from the calculated reference position of the laser light source to the measurement point of the DUT. By correcting the error that is generated and setting a new distance, when there is reflected light that is scattered from the measurement point and secondarily enters the optical position detection element from a site other than the measurement point of the DUT, It is possible to correct the error that occurs in the calculated distance from the reference position in the laser light source to the measurement point of the measured object due to the secondary reflected light, and as a result, it is possible to accurately specify the three-dimensional shape of the measured object. The excellent effect of becoming Is et al.

According to the third aspect of the present invention,
Usually, the magnitude of the error that occurs in the calculated distance from the reference position in the laser light source due to the secondary reflected light to the measurement point of the measurement object is the shape of the measurement object, the position of the laser spot projected on the measurement point, and the secondary It is difficult to obtain it by geometrical calculation because it depends on the reflection characteristics and the layout of the optical position detection element, etc., but it is difficult to obtain the measured object from the reference position of the laser light source based on the signal of each optical position detection element. The distance to the point is calculated, the difference between two calculated distances appropriately selected from the calculated plurality of calculated distances is calculated, and the calculated difference and the error included in the calculated distance are correlated. Since the error included in the calculated distance can be estimated by the function to be attached, the error can be estimated with high accuracy, and as a result, the distance can be measured accurately. It is.

With the configuration according to claim 4 of the present invention,
When the error components included in the two calculated distances appropriately selected from the calculated plurality of calculated distances occur in opposite directions (polarities), the ratio of these magnitudes is usually constant. Therefore, by appropriately weighting each and calculating the average value of both,
As a result of mutual error cancellation,
An excellent effect is brought about in that it is possible to perform accurate correction for an error amount.

According to the fifth aspect of the present invention,
For example, depending on the positional relationship between the two optical position detection elements on which the primary reflected light is incident, there are cases where the directions of the error components are the same direction (polarity) and the opposite directions (polarity),
In the case of the same direction, by applying the three-dimensional shape measuring method according to claim 3 of the present invention, it becomes possible to accurately estimate the error component, and in the case of the opposite direction, By applying the three-dimensional shape measuring method according to the fourth aspect of the present invention, which cancels the mutual error amount of the two optical position detecting elements, the error amount due to the secondary reflected light is accurately corrected. It has an excellent effect that it becomes possible.

Further, according to the three-dimensional shape measuring apparatus of the sixth aspect of the present invention, the primary reflected light from the measurement point irradiated with the laser beam is generated by the combination of at least two lenses and the optical position detecting element. Since it is arranged so as to be directly incident, there is an excellent effect that the information necessary for removing the error component included in the output of the optical position detection element can be surely acquired.

Furthermore, according to the three-dimensional shape measuring apparatus of the seventh aspect of the present invention, by using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of the object to be measured, The same effect as the three-dimensional shape measuring method can be obtained.

According to the eighth aspect of the present invention,
By using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of the object to be measured, the same effect as the three-dimensional shape measuring method according to the third aspect can be obtained.

According to the ninth aspect of the present invention,
By using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of the object to be measured, the same effect as the three-dimensional shape measuring method according to the fourth aspect can be obtained.

According to the tenth aspect of the present invention, the three-dimensional shape measuring apparatus according to the fifth aspect is used by using the three-dimensional shape measuring apparatus for measuring the three-dimensional shape of an object to be measured. A similar effect is brought about.

According to the eleventh aspect of the three-dimensional shape measuring apparatus of the present invention, since the multi-axis moving means is provided, the optical system including the laser light source, the lens and the optical position detecting element is automatically and continuously connected. It becomes possible to measure the object to be measured while moving it at the same time, and at least two or more optical position detecting elements are incident with the primary reflected light,
The excellent effect that the information necessary for the error correction means can be secured is brought about.

According to the twelfth aspect of the present invention, it becomes possible to perform the same operation as mechanically scanning the object to be measured by the multi-axis moving means, and the multi-axis moving means for moving the optical system. If the means are also applied, the measurement range,
This has the excellent effect that the degree of freedom in the measurement direction can be further expanded or the number of axes of the multi-axis moving means can be reduced.

According to the thirteenth aspect of the present invention, if the object moving means is used together with the multi-axis moving means, it is possible to increase the degree of freedom regarding the measuring direction, position, etc. Even if the number of axes of the multi-axis moving means is reduced, the same effect can be obtained that the same measurement can be performed.

According to the fourteenth aspect of the present invention, in the measurement of the distance in the height direction of the step of the object to be measured having the shape of a standing wall or a steep step, the optical system and the When measuring the distance between the reference point of the laser light source and the object to be measured while moving the object to be measured by the optical system and / or the object moving means by the multi-axis moving means in the direction in which the step portion approaches Since it becomes possible to estimate the height of the stepped portion by the section height calculation means, if the optical system is moved by the multi-axis moving means based on the estimated height of the stepped portion, the measurement of the three-dimensional shape measuring device can be performed. It is possible to prevent out-of-range, and even if, for example, the tooth model that is the object to be measured is manufactured at any height using dental plaster, the optical system automatically optimizes the optimum three-dimensional shape. It can be moved and adjusted to the coordinate position. Leads to excellent effect of that.

According to the fifteenth aspect of the present invention, when the multi-axis moving means for moving the optical system is also applied, the degree of freedom of the measuring range and the measuring direction can be further expanded. Further, there is an excellent effect that it becomes possible to scan the object to be measured with the laser beam similarly to the multi-axis moving means or the like without applying the multi-axis moving means or the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a configuration example of an optical system in a three-dimensional shape measuring apparatus according to the present invention.

FIG. 2 is an explanatory cross-sectional view showing an example of how an error occurs due to secondary reflected light.

FIG. 3 is an explanatory cross-sectional view showing a state of measurement of an object to be measured having a concave portion.

FIG. 4 is a cross-sectional explanatory diagram showing another example of how errors are generated by secondary reflected light.

FIG. 5 is an explanatory diagram showing a configuration of an embodiment of a signal processing device in the three-dimensional shape measuring apparatus according to the present invention.

FIG. 6 is a flowchart showing an example of an operation procedure of the three-dimensional shape measuring apparatus according to the present invention.

FIG. 7 is a cross-sectional explanatory view showing another configuration example of the optical system in the three-dimensional shape measuring apparatus according to the present invention.

FIG. 8 is a cross-sectional explanatory view showing still another configuration example of the optical system in the three-dimensional shape measuring apparatus according to the present invention.

FIG. 9 is a cross-sectional explanatory view showing still another configuration example of the optical system in the three-dimensional shape measuring apparatus according to the present invention.

FIG. 10 is an explanatory diagram showing the configuration of another embodiment of the three-dimensional shape measuring apparatus according to the present invention.

FIG. 11 is an explanatory diagram showing the configuration of still another embodiment of the three-dimensional shape measuring apparatus according to the present invention.

FIG. 12 is an explanatory diagram showing a state in which the distance in the height direction of the step of the object to be measured having a shape having a standing wall-shaped step is measured.

FIG. 13 is a flowchart showing an example of an operation procedure of the three-dimensional shape measuring apparatus according to the present invention.

FIG. 14 is an explanatory diagram showing the configuration of still another embodiment of the three-dimensional shape measuring apparatus according to the present invention.

FIG. 15 is an explanatory diagram showing a configuration example of a dental prosthesis design device.

FIG. 16 is an explanatory diagram showing an example of a conventional three-dimensional shape measuring means for an object to be measured.

FIG. 17 is an explanatory diagram showing another example of the conventional three-dimensional shape measuring means for the object to be measured.

[Explanation of symbols]

 1 Laser Light Source 2 Lens 3 PSD (Optical Position Detection Element) 4 A / D Converter 5 Control / Calculator 6 Output Means 21 Optical System 22 Multi-axis Moving Means 23 Positioning Control Means 24 Distance Calculating Means 25 Error Correcting Means 26 Three-Dimensional Shape calculation means 27 Output means 28 Object moving means 41 Irradiation movable reflecting mirror 41b Angle detecting reflecting mirror 42, 43 Reflected light movable reflecting mirror 44 Angle detecting sensor 45 Angle detecting light source V Signal processing device M Measured Object P Measuring point L Laser light Ra to Rd Primary reflected light Ga to Gc Virtual image point X Step height

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuo Ishiwaka 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd.

Claims (15)

[Claims] 1. A three-dimensional shape measuring apparatus used for non-contact measurement of a three-dimensional shape of an object to be measured such as a tooth model necessary for designing and manufacturing a dental prosthesis. A laser light source that irradiates a measurement point of a measurement object with a laser beam, a lens that condenses reflected light from the measurement point, and light that receives the condensed reflected light and outputs light receiving position information on the light receiving surface. A position detecting element is provided, a distance to a measurement point of the measured object is calculated based on the output of the optical position detection element, and a three-dimensional shape that specifies the three-dimensional shape of the measured object from the three-dimensional coordinates of a plurality of measurement points A three-dimensional shape measuring apparatus, characterized in that the original shape measuring apparatus is provided with at least two or more combinations of lenses and optical position detecting elements. 2. When measuring the three-dimensional shape of an object to be measured using the three-dimensional shape measuring apparatus according to claim 1, the object is measured from the reference position in the laser light source based on the signal of each optical position detecting element. Calculates the distance to the measurement point of the measured object, corrects the error included in the calculated distance from the calculated reference position of the laser light source to the measured point of the DUT, and creates a new distance. A three-dimensional shape measuring method, characterized in that a three-dimensional shape of an object to be measured is specified by obtaining a specific distance. 3. The distance from the reference position in the laser light source to the measurement point of the object to be measured is calculated based on the signal of each optical position detection element, and two calculations are appropriately selected from the calculated plurality of calculated distances. The difference between the distances is calculated, the error included in the calculated distance is estimated by a function that correlates the calculated difference and the error included in the calculated distance, and the error estimated from the calculated distance is calculated. The three-dimensional shape measuring method according to claim 2, wherein the three-dimensional shape measuring method removes a new distance. 4. The distance from the reference position in the laser light source to the measurement point of the object to be measured is calculated based on the signal of each optical position detection element, and two calculations are appropriately selected from the calculated plurality of calculated distances. The distance is appropriately weighted and the average value of the two is set as a new distance.
The three-dimensional shape measuring method described in. 5. The three-dimensional shape measuring method according to claim 3 and the three-dimensional shape measuring method according to claim 4 are appropriately selected according to the positional relationship of the optical position detection element on which the primary reflected light is incident. The three-dimensional shape measuring method according to claim 2, wherein the three-dimensional shape of the object to be measured is specified. 6. A combination of at least two or more of a plurality of lenses and an optical position detection element is arranged so that primary reflected light from a measurement point irradiated with laser light is directly incident. The three-dimensional shape measuring device according to claim 1, which is characterized in that. 7. A distance calculation means for calculating a distance from a reference position in the laser light source to a measurement point of the object to be measured based on a signal of each optical position detection element, and a reference in the laser light source calculated by the distance calculation means. The three-dimensional shape measuring apparatus according to claim 1 or 6, further comprising an error correcting unit that corrects an error included in a calculated distance from the position to the measurement point of the object to be measured to obtain a new distance. 8. The error correction means calculates a difference between two calculated distances appropriately selected from the plurality of calculated distances calculated by the distance calculation means, and the difference is included in the calculated difference and the calculated distance. The third-order according to claim 7, wherein an error included in the calculated distance is estimated by a function that correlates with the error, and the estimated error is removed from the calculated distance to obtain a new distance. Original shape measuring device. 9. The error correction means appropriately weights two calculated distances selected appropriately from the plurality of calculated distances calculated by the distance calculation means, and sets the average value of the two as a new distance. The three-dimensional shape measuring device according to claim 7. 10. The error correction means according to claim 8 and the error correction means according to claim 9, wherein the two error corrections are made in accordance with a positional relationship of the optical position detection element on which the primary reflected light is incident. The three-dimensional shape measuring apparatus according to claim 7, further comprising an error correction selecting unit that appropriately selects a unit. 11. A multi-axis moving means for moving an optical system including a laser light source, a lens and an optical position detecting element to an arbitrary three-dimensional coordinate position, and a positioning control means for positioning the multi-axis moving means. Claims 1 and 6
The three-dimensional shape measuring device as described in any one of 10 to 10. 12. A plurality of measurement points of an object measured while moving an optical system including a laser light source, a lens and an optical position detecting element by a multi-axis moving means, and the optical corresponding to each of the plurality of measurement points. From the three-dimensional coordinate position of the system,
Characterized in that it comprises a three-dimensional shape calculation means for calculating the three-dimensional coordinate position of each measurement point and calculating the three-dimensional shape of the measured object from the calculated three-dimensional coordinate data group of the plurality of measurement points. The three-dimensional shape measuring device according to claim 11. 13. The three-dimensional shape measuring apparatus according to claim 11, further comprising an object moving means for moving the object to be measured to an arbitrary three-dimensional coordinate position. 14. An optical system including a laser light source, a lens, and an optical position detecting element, and the step when measuring a distance in a height direction of a step of an object to be measured having a shape of a standing wall or a steep step. When measuring the distance between the reference point of the laser light source and the object to be measured while the object to be measured is moved by the optical system and / or the object to be measured moving means by the multi-axis moving means in the direction in which the parts approach each other, a step The height of the stepped portion is calculated by detecting the position of each optical system when the primary reflected light is blocked from entering the respective optical position detection elements by the section and calculating the height of the stepped portion based on this information. Means for providing the means are provided.
The three-dimensional shape measuring device according to any one of 1. 15. A movable reflecting mirror for irradiation that changes the direction of laser light emitted from a laser light source and / or a movable reflecting mirror for reflected light that changes the direction of reflected light from an object to be measured. 15. The three-dimensional shape measuring device according to claim 1, wherein