WO2012057284A1

WO2012057284A1 - Three-dimensional shape measurement device, three-dimensional shape measurement method, manufacturing method of structure, and structure manufacturing system

Info

Publication number: WO2012057284A1
Application number: PCT/JP2011/074856
Authority: WO
Inventors: 青木　洋
Original assignee: 株式会社ニコン
Priority date: 2010-10-27
Filing date: 2011-10-27
Publication date: 2012-05-03
Also published as: JP2014013144A

Abstract

[Problem] To measure a three-dimensional shape of an object to be measured with good accuracy. [Solution] A measurement unit (20) which obtains, by repeatedly taking images of an object to be measured while changing a phase of a stripe pattern with which an object to be measured (11) is irradiated, data of light intensity changes from positions on the object to be measured (11), a focus position change unit (30) which changes a focus position when taking the images by the measurement unit (20), a control unit (101) which controls the measurement unit (20) and the focus position change unit (30) to obtain the data of the light intensity changes each time a focus position is changed, and a coordinate measurement unit (32) which measures the coordinates of positions on the object to be measured (11) on the basis of the data of the light intensity changes of the respective focus positions.

Description

Three-dimensional shape measuring apparatus, three-dimensional shape measuring method, structure manufacturing method, and structure manufacturing system

The present invention relates to a three-dimensional shape measuring apparatus, a three-dimensional shape measuring method, a structure manufacturing method, and a structure manufacturing system.

As a method for measuring the surface shape (three-dimensional shape) of a measurement object in a non-contact manner, a pattern projection type three-dimensional shape measuring apparatus using a phase shift method is known. In this three-dimensional shape measuring device, a fringe pattern having a sinusoidal intensity distribution is projected onto the measurement object, and the measurement object is repeatedly imaged while the phase of the fringe pattern is changed at a constant pitch, and thereby obtained. By applying a plurality of images (light intensity change data) to a predetermined calculation formula, the phase distribution (phase image) of the stripes deformed according to the surface shape of the measurement object is obtained, and the phase image is unwrapped (phase Connection) and then converted into a height distribution (height image) of the measurement object.

For example, in Patent Document 1, a three-dimensional shape measurement apparatus acquires light intensity change data under two types of imaging conditions with different amounts of projected light, evaluates the contrast value of the two types of light intensity change data for each pixel, It is shown that the light intensity change data having a low contrast value is excluded from the calculation target.

JP 2005-214653 A

Since the conventional three-dimensional shape measuring apparatus is in focus on the focus surface, the coordinates of the measurement object can be accurately measured. On the other hand, the conventional three-dimensional shape measuring apparatus cannot accurately measure the coordinates of the measurement object on the out-of-focus (defocused) surface. That is, the conventional three-dimensional shape measuring apparatus has a problem that each position of the measurement object cannot be measured with high accuracy.

Therefore, the present invention has been made in view of the above problems, and a three-dimensional shape measuring apparatus, a three-dimensional shape measuring method, a structure manufacturing method, and a structure that can accurately measure each position of a measurement object, and It is an object to provide a structure manufacturing system.

In order to solve the above problems, the three-dimensional shape measuring apparatus according to one aspect of the present invention repeatedly images the measurement object while changing the phase of the fringe pattern irradiated on the measurement object. , A measurement unit that acquires light intensity change data from each position on the measurement object, a focus position change unit that changes a distance between the measurement unit and the measurement object, and the distance is changed. A control unit that controls the measurement unit and the in-focus position changing unit to acquire the light intensity change data, and on the measurement object based on the light intensity change data of the respective distances. And a coordinate measuring unit that measures the coordinates of each position.

Further, the three-dimensional shape measuring method according to one aspect of the present invention is a three-dimensional shape measuring method executed by the three-dimensional shape measuring apparatus, and changing the phase of the fringe pattern irradiated on the measurement object, By repeatedly imaging the measurement object, obtaining light intensity change data from each position on the measurement object, and changing a focus position at the time of imaging (a measurement unit and a measurement object) Measuring the coordinates of each position on the measurement object based on the light intensity change data of the respective in-focus positions (distances). Each time the focus position is changed, the light intensity change data is acquired by adjusting the focus position.

Further, the structure manufacturing method according to one embodiment of the present invention includes producing design information related to the shape of the structure, producing the structure based on the design information, and the produced structure. Measuring the shape using a three-dimensional shape measurement method according to another aspect of the present invention, and comparing the shape information obtained by the measurement with the design information. It is characterized by that.

In addition, a structure manufacturing system that is one embodiment of the present invention includes a design device that generates design information related to the shape of a structure, a molding device that generates the structure based on the design information, and another device of the present invention. A three-dimensional shape measuring device according to one aspect, and an inspection device that compares the design information with shape information indicating coordinates at which the three-dimensional shape measuring device measures the structure.

According to the present invention, each position of the measurement object can be measured with high accuracy.

It is a perspective view which shows the mechanical structure of the three-dimensional shape measuring apparatus in 1st Embodiment. It is a whole block diagram of the three-dimensional shape measuring apparatus in 1st Embodiment. It is the figure which showed an example of the shape measuring method by the three-dimensional shape measuring apparatus in 1st Embodiment. It is the flowchart which showed the flow of the process by the three-dimensional shape measuring apparatus in 1st Embodiment. It is a whole block diagram of the three-dimensional shape measuring apparatus in 2nd Embodiment. It is an example of the table memorize | stored in the memory | storage part. It is the flowchart which showed the flow of the process by the three-dimensional shape measuring apparatus in 2nd Embodiment. It is a block block diagram of a structure manufacturing system. It is the flowchart which showed the flow of the process by a structure manufacturing system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 is a perspective view showing a mechanical configuration of the three-dimensional shape measuring apparatus according to the first embodiment. As shown in FIG. 1, the three-dimensional shape measuring apparatus includes a stage 12 on which a measurement object 11 such as an industrial product or a part is placed, and a projection unit 13 and an imaging unit 14 fixed to each other. There is an angle between the optical axis of the projection unit 13 and the optical axis of the imaging unit 14, and the optical axes of both intersect on the reference plane of the stage 12. Among these, the optical axis of the imaging unit 14 is perpendicular to the reference plane of the stage 12. It is possible to make the optical axis of the projection unit 13 vertical instead of making the optical axis of the imaging unit 14 vertical, but here it is assumed that the optical axis of the imaging unit 14 is vertical.

The stage 12 has a θ stage 12θ that rotates the measurement object 11 around an axis parallel to the optical axis of the imaging unit 14, and a measurement object toward a predetermined direction (X direction) perpendicular to the optical axis of the imaging unit 14. X stage 12X that shifts 11 and Y stage 12Y that shifts measurement object 11 in a predetermined direction (Y direction) perpendicular to both the rotational axis of θ stage 12θ and the X direction.

The projection unit 13 is an optical system that illuminates a partial region (illumination region) on the stage 12 from an oblique direction, and includes an illumination element 22, a pattern formation unit (stripe pattern generation unit) 23, and a projection optical system 24. Are arranged in this order. It is assumed that the size of the measurement object 11 of the present embodiment is small enough to fit the entire measurement object 11 in the illumination area of the projection unit 13.

The pattern forming unit 23 of the projection unit 13 is a panel (transmission type liquid crystal element, reflection type liquid crystal element, DMD (Digital Mirror Device, digital mirror device, etc.)) having a variable transmittance distribution, and a striped pattern ( By displaying (sine lattice pattern), the cross-sectional intensity distribution of the illumination light flux from the projection unit 13 toward the illumination area is made sinusoidal. Note that the cross-sectional intensity distribution of the illumination light beam does not necessarily have a sine wave shape, but in this specification, the case where the cross-sectional intensity distribution of the illumination light beam is a sine wave shape will be described as an example. The lattice direction of the sine lattice pattern displayed on the pattern forming unit 23 is perpendicular to the plane on which both the optical axis of the projection unit 13 and the optical axis of the imaging unit 14 exist. The reference point located near the center on the display surface of the pattern forming unit 23 is relative to the reference point on the reference surface of the stage 12 (intersection of the optical axis of the imaging unit 14 and the optical axis of the projection unit 13). As a result, the projection destination of the sine lattice pattern is set on the surface of the measurement object 11 (hereinafter referred to as “test surface”) arranged in the illumination area of the stage 12. . Note that the reference point of the pattern forming unit 23 and the reference point of the stage 12 do not have to be completely conjugate as long as a sine lattice pattern can be projected on the surface to be measured.

The imaging unit 14 is an optical system that detects an image (luminance distribution) of an illumination area on the stage 12. The imaging optical system 25 forms an image of reflected light generated in the illumination area, and the imaging optical system 25. An image pickup element 26 that picks up an image formed by the image pickup device and acquires the image is sequentially arranged. The reference point located in the vicinity of the center on the imaging surface of the image sensor 26 is optically conjugate with the above-described reference point of the stage 12, and the image sensor 26 is a measurement object arranged in the illumination area of the stage 12. Eleven images (images of the test surface) can be acquired. Note that the reference point of the image sensor 26 and the reference point of the stage 12 do not have to be completely conjugate as long as an image of the test surface can be acquired with sufficient contrast.

Here, when the light source (reference numeral 21 in FIG. 2) of the projection unit 13 is turned on and the image sensor 26 is driven in this state, an image of the test surface on which the sine lattice pattern is projected (= surface shape information of the test surface) Can be acquired. Hereinafter, this image is referred to as a “stripe image”. Furthermore, if the acquisition of the fringe image is repeated while shifting the phase of the sine lattice pattern, information for making the surface shape data D of the test surface known is gathered.

FIG. 2 is an overall configuration diagram of the three-dimensional shape measuring apparatus according to the first embodiment. 2, the same elements as those shown in FIG. 1 are denoted by the same reference numerals. The three-dimensional shape measuring apparatus 1 includes a stage 12, a measuring unit 20, a focusing position changing unit 30, and a computer 100. The measurement unit 20 includes a main light source (light source unit) 21, an optical fiber 21 ′, a projection unit 13, and an imaging unit 14. The projection unit 13 includes an illumination element 22, a pattern formation unit (stripe pattern generation unit) 23, and a projection optical system 24.

2, a main light source 21 that is a light source of the projection unit 13 is connected to the projection unit 13. Since the main light source 21 is used for pattern projection type surface shape measurement, for example, a general light source such as an LED, a halogen lamp, or a metal halide lamp can be applied. The light emitted from the main light source 21 is introduced into the illumination element 22 through the optical fiber 21 '. Although an example in which the optical fiber 21 ′ is used is shown here, a small light source such as an LED may be arranged at a position indicated by reference numeral 22 in FIG. 1 without using the optical fiber. Moreover, although the illumination element 22 is illustrated as one element, the illumination element 22 may be configured by an illumination optical system including a plurality of optical elements. In that case, for example, an illumination optical system using a fly-eye lens, a rod integrator, or the like for performing uniform illumination is provided.

The illumination element 22 guides the light incident from the optical fiber 21 ′ to the pattern forming unit 23. The pattern forming unit 23 changes the light guided from the pattern forming unit 23 using a sine lattice pattern into a fringe pattern, and irradiates the measurement object 11 with the light changed into the fringe pattern via the projection optical system 24. To do.

The imaging unit 14 images light reflected from the measurement object. The imaging unit 14 includes an imaging optical system 25 and an imaging element 26. The imaging optical system 25 collects the light reflected from the measurement object and guides the collected light to the image sensor 26. The imaging device 26 images light guided to the imaging optical system 25 and outputs an analog voltage value of each pixel generated by the imaging to an AD conversion unit 19 described later of the computer 100. The imaging device 26 performs the above process every time the distance from the measurement unit 20 to the measurement object 11 is changed by the focus position changing unit 30.

The AD conversion unit 19 converts the analog voltage value of each pixel input from the image sensor 26 into light intensity change data indicating the luminance value of each pixel, and outputs the converted light intensity change data to the data extraction unit 31. . The AD conversion unit 19 performs the above process every time the distance from the measurement unit 20 to the measurement object 11 is changed by the focus position changing unit 30.

The computer 100 includes a storage unit 16, a display unit 17, an input unit 18, an AD conversion unit 19, and a control unit 101. The control unit 101 controls the entire three-dimensional shape measuring apparatus 1. The storage unit 16 stores an operation program for the control unit 101 in advance. The control unit 101 reads the operation program and operates according to the read operation program. For example, the control unit 101 drives and controls each unit of the three-dimensional shape measuring apparatus 1 by giving various instructions to the control unit 101. In addition to the above-described operation program, various types of information necessary for the operation of the control unit 101 are stored in the storage unit 16 in advance.

The control unit 101 causes the display unit 17 to display the coordinates of the measurement object according to the operation program read from the storage unit 16. The input unit 18 receives an external input signal and outputs the input information to the control unit 101. The input unit 18 is, for example, a keyboard or a mouse. The control unit 101 starts or ends coordinate measurement based on the input information input from the input unit 18.

The data extraction unit 31 is an area determined by the imaging optical system 25 of the measurement unit 20 in the light intensity change data generated for each distance from the measurement unit 20 to the measurement object 11 and is in focus. Data in the effective area that is the area is extracted. The data extraction unit 31 outputs the data in the extracted effective area to the coordinate measurement unit 32. The data in the effective area may be any data as long as it is within the depth of field. Further, a person may determine an area to be extracted from the generated light intensity change data as an effective area.

The coordinate measurement unit 32 measures the coordinates of each position on the measurement object based on the light intensity change data for each distance from the measurement unit 20 to the measurement object 11. Specifically, each time the distance from the measurement unit 20 to the measurement object 11 is changed by the focus position changing unit 30, the coordinate measuring unit 32 is in the effective area extracted by the data extracting unit 31. The coordinates corresponding to are calculated.

The coordinate measuring unit 32 stores information indicating the calculated coordinates in the storage unit 16 sequentially after the calculation. The control unit 101 reads information indicating coordinates from the storage unit 16 and causes the display unit 17 to display information indicating the read coordinates in a predetermined display format. The control unit 101 is connected to the stage 12, the main light source 21, the pattern forming unit 23 of the projection unit 13, the imaging element 26 of the imaging unit 14, and the focus position changing unit 30.

The control unit 101 includes coordinates of the stage 12, timing for turning on / off the main light source 21, emission intensity of the main light source 21, phase of a sine lattice pattern displayed on the pattern forming unit 23, timing for acquiring an image by the image sensor 26, A charge accumulation time (hereinafter referred to as shutter speed) at the time of image acquisition by the image sensor 26 is controlled.

Further, the control unit 101 causes the in-focus position changing unit 30 to control the distance from the measuring unit 20 to the measuring object 11. And the control part 101 controls the measurement part 20 and the focus position change part 30 so that the said light intensity change data may be acquired whenever the distance from the measurement part 20 to the measurement object 11 is changed. Note that the control unit 101 can also set the pattern displayed on the pattern forming unit 23 to a uniform pattern.

The focus position changing unit 30 drives the measuring unit 20 to change the distance from the measuring unit 20 to the measurement object 11. The in-focus position changing unit 30 may drive the stage 12 and change the distance from the measuring unit 20 to the measurement object 11.

FIG. 3 is a diagram showing an example of a shape measuring method by the three-dimensional shape measuring apparatus in the first embodiment. On the left side and right side of the figure, when the measuring unit 20 takes an image every time the height of the measuring unit 20 is reduced by 1 mm with respect to the measuring object 11, the area of the measuring object at each depth of field is shown. A certain measurement band (measurement band 40 to measurement band 46) is shown.

In the center of the figure, a region 47 is shown in which measurement bands at respective depths of field are connected when the measurement unit 20 images at each height. The control unit 101 can measure the coordinates of the entire measurement object by integrating the coordinates of the measurement object at each depth of field measured by the measurement unit 20 at each height. Thereby, since the three-dimensional shape measuring apparatus 1 calculates the coordinates of the region in good focus, it is possible to measure the coordinates of the measurement object with high accuracy.

In particular, the measurement method of the three-dimensional shape measuring apparatus 1 in this embodiment measures an object whose surface is finely uneven, such as a forged product or a cast product, and the reflectance changes finely corresponding to the unevenness. Effective when used as a target. When a forged product or a cast product is used as a measurement target, the surface is finely uneven and rough, and when light is irradiated, portions with high reflected light intensity are generated discretely and irregularly. If the in-focus state deteriorates, the light intensity at each point blurs and spreads, and the part where the light intensity is inherently low becomes high, resulting in a measurement error. It is difficult to reduce the impact.

When a conventional three-dimensional shape measuring device is forged or cast, the bright spot will spread if the focus state is not good, and the intensity of the portion where the reflected light intensity is low will increase, resulting in the original There is a problem that coordinates different from the coordinates are calculated. On the other hand, the three-dimensional shape measuring apparatus 1 according to the present embodiment calculates coordinates of a region having a good in-focus state even when a forged product or a cast product is used as a measurement target. Therefore, the coordinates of the measurement object can be accurately calculated.

FIG. 4 is a flowchart showing the flow of processing by the three-dimensional shape measuring apparatus 1 in the first embodiment. First, the projection unit 13 converts light incident from the main light source into a fringe pattern, and irradiates the measurement object with the converted fringe pattern (step S101). Next, the imaging unit 14 images light reflected from the measurement object (step S102). Next, the AD conversion unit 19 acquires the light intensity change data by converting the analog voltage value of each pixel input from the imaging unit 14 into light intensity change data indicating the luminance value of each pixel (step) S103).

Next, the data extraction unit 31 extracts effective area data corresponding to the depth of field from the light intensity change data (step S104). Next, the coordinate measuring unit 32 calculates the coordinates of the effective area from the extracted data of the effective area (step S105). Next, the control unit 101 determines whether or not the distance from the measurement unit 20 to the measurement object 11 is captured at all predetermined distances (step S106).

When imaging is not performed at all predetermined distances (NO in step S106), the focus position changing unit 30 reduces the distance from the measurement unit 20 to the measurement object 11 by a predetermined distance (step S107), and step S101. Return to the process. On the other hand, when images are captured at all predetermined distances (NO in step S106), the control unit 101 integrates the calculated coordinates and acquires the coordinates of the entire measurement object (step S108). Above, the process of this flowchart is complete | finished.

As described above, the measurement unit 20 of the three-dimensional shape measuring apparatus 1 repeatedly images the measurement object 11 while changing the phase of the fringe pattern irradiated on the measurement object 11, whereby each measurement object 11 on the measurement object 11 is imaged. Light intensity change data is acquired from the position, and the focus position changing unit 30 changes the focus position when the measurement unit 20 captures an image. The control unit 101 controls the measurement unit 11 and the focus position changing unit 30 so as to obtain the light intensity change data every time the focus position is changed, and the coordinate measurement unit 32 performs the respective focusing. Based on the light intensity change data of the position, the coordinates of each position on the measurement object 11 are measured.

Further, the data extraction unit 31 extracts data within the effective area from the respective light intensity change data acquired each time the in-focus position is changed, and the coordinate measurement unit 32 is based on the extracted data. Thus, the coordinates of each position on the measurement object 11 can be measured.

Thereby, the 3D shape measuring apparatus 1 calculates the coordinates from the light intensity change data of the effective area every time the distance from the measuring unit 20 to the measuring object 11 is changed, so that the measuring object is accurately obtained for each effective area. The coordinates of the object 11 can be calculated. Since the three-dimensional shape measuring apparatus 1 calculates the coordinates of the entire measurement object 11 by connecting the highly accurate coordinates measured in each measurement zone, it is possible to measure each position of the entire measurement object with high accuracy. it can.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the first embodiment, the three-dimensional shape measurement apparatus integrates the coordinates calculated using the light intensity change data within the focal depth measured at each distance, and calculates the coordinates of the entire measurement object. In the second embodiment, the three-dimensional shape measurement apparatus once acquires light intensity change data under predetermined exposure conditions and calculates the coordinates of the measurement object. Then, the three-dimensional shape measurement apparatus narrows the depth of field so that the resolution in the height direction is increased with respect to the measurement zone in which the gradient of the measurement object measured from the calculated coordinates exceeds a predetermined threshold. Change the exposure conditions.

Then, the three-dimensional shape measuring apparatus calculates coordinates by imaging again a measurement zone in which the gradient exceeds a predetermined threshold value under changed exposure conditions. Then, the three-dimensional shape measuring apparatus replaces the coordinates of the measurement zone in which the gradient of the measurement object exceeds a predetermined threshold among the coordinates calculated from the first imaging with the coordinates calculated from the second imaging. To do. Thus, the three-dimensional shape measuring apparatus can accurately measure coordinates even in a region where the gradient of the measurement object is steep.

FIG. 5 is an overall configuration diagram of the three-dimensional shape measuring apparatus 1b according to the second embodiment. In addition,
Elements common to those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. The configuration of the three-dimensional shape measuring apparatus 1b in FIG. 5 is different from that of the three-dimensional shape measuring apparatus 1 in FIG. 2 in that the computer 100 is the computer 100b, the storage unit 16 is the storage unit 16b, and the data extraction unit 31 is the data. In the extraction unit 31b, the coordinate measurement unit 32 is changed to the coordinate measurement unit 32b, the control unit 101 is changed to the control unit 101b, the measurement unit 20 is changed to the measurement unit 20b, and the aperture unit 27 is added. In addition, the direction from the measurement object 11 to the measurement unit 20b is the z-axis direction, the direction perpendicular to the z-axis, and the width direction of the measurement object 11 is the x-axis direction.

In the storage unit 16b, a rate of change in the direction from the measuring unit 20b to the measuring object 11 with respect to a direction perpendicular to the direction from the measuring unit 20b to the measuring object 11 (hereinafter referred to as a rate of change in the vertical direction). A table T1 is stored that associates the aperture value, which is the brightness of an image that appears on the image sensor through the lens, with the shutter speed. The change rate in the vertical direction is, for example, the change rate of the distance in the z-axis direction with respect to the x-axis direction. Here, the aperture value and the shutter speed are collectively referred to as an exposure condition. The storage unit 16b stores a predetermined exposure condition used for the first imaging.

The diaphragm unit 27 adjusts the amount of light that is reflected from the measurement object 11 and guided to the imaging element 26 of the imaging unit 14 in accordance with a control signal from the control unit 101b. The control unit 101b generates a control signal for controlling the aperture unit 27 according to the aperture value read from the storage unit 16b, and outputs the control signal to the aperture unit 27 to control the aperture amount of light. . For example, when the aperture value becomes small, the control unit 101b controls to open the aperture unit 27. On the other hand, when the aperture value becomes large, the control unit 101b controls the aperture unit 27 to stop.

The control unit 101b reads a predetermined exposure condition used at the time of the first imaging from the storage unit 16b in order to obtain the first light intensity change data. And the control part 101b controls the image pick-up element 26 so that it may image, whenever the focus position change part 30 changes the height of the measurement part 20b. The AD conversion unit 19 converts the analog voltage value of each pixel input from the image sensor 26 into light intensity change data indicating the luminance value of each pixel, and outputs the converted light intensity change data to the data extraction unit 31b. .

The data extraction unit 31b extracts effective area data from the light intensity change data input from the AD conversion unit 19, and outputs the extracted effective area data to the coordinate measurement unit 32b. The coordinate measuring unit 32b calculates coordinates from the extracted effective area data, and stores the calculated coordinates in the storage unit 16b as the first coordinate.

The control unit 101b obtains the light intensity change data, extracts the effective area data, and calculates the effective area coordinates as a distance between the measurement unit 20 and the measurement object 11 and a predetermined range. At all distances. Thereby, the three-dimensional shape measuring apparatus 1b can calculate the coordinates of the measurement object with a predetermined resolution.

The control unit 101b calculates, from the calculated coordinates, the rate of change in the direction from the measurement unit 20b to the measurement object 11 in the direction perpendicular to the direction from the measurement unit 20b to the measurement object 11. In other words, the control unit 101b calculates the gradient of the measurement object from the calculated coordinates. Specifically, for example, the control unit 101b extracts two points adjacent to each other in the x-axis direction at a certain coordinate, and calculates the inclination in the z-axis direction with respect to the x-axis direction on the xz plane from the certain coordinate and the two extracted points. Calculate with the least squares method. Alternatively, the control unit 101b may simply calculate the difference to obtain the inclination (that is, the differential value at the coordinates).

The control unit 101b sets the calculated inclination as the inclination of the measurement object at a certain coordinate. The control unit 101b calculates the gradient of the measurement object at each coordinate by performing the above process on all the calculated coordinates. The control unit 101b calculates, for each effective area determined for each height of the measuring unit 20, a maximum change rate that is the maximum value of the change rate in the vertical direction in the effective area.

Further, the control unit 101b determines whether or not the calculated maximum change rate exceeds a predetermined threshold value. When the predetermined threshold value is exceeded, the control unit 101b reads the exposure condition corresponding to the maximum change rate from the storage unit 16b. The control unit 101b controls the image sensor 26 and the diaphragm unit 27 so as to change to the read exposure condition when the region where the maximum change rate exceeds the predetermined threshold is imaged again.

The control unit 101b reads the aperture value and shutter speed corresponding to the maximum change rate in the vertical direction from the storage unit 16b, thereby selecting the optimum aperture value and shutter speed corresponding to the maximum change rate in the vertical direction. it can. As a result, when the maximum rate of change in the vertical direction is greater than a predetermined threshold, by reducing the aperture value, the depth of the subject can be reduced and the distance in the vertical direction of the effective area can be reduced.

The control unit 101b changes the distance from the measurement unit 20 to the measurement object 11 that is changed at a time by the focus position changing unit 30 according to the aperture value read from the storage unit 16b. For example, the control unit 101 changes the distance from the measurement unit 20 to the measurement object 11 at a time by the same distance as the depth of field determined according to the aperture value read from the storage unit 16b. Each time the distance is changed, the control unit 101 causes the measurement unit 20 to image again the region where the maximum change rate exceeds a predetermined threshold under the changed exposure condition, and obtains light intensity change data by imaging.

The data extraction unit 31b extracts effective area data from the acquired light intensity change data, and outputs the extracted effective area data to the coordinate measurement unit 32b. The coordinate measuring unit 32b calculates coordinates from the extracted data of the effective area. The coordinate measuring unit 32b reads the coordinates calculated from the first imaging from the storage unit 16b.

The coordinate measuring unit 32b replaces the coordinates of the measurement band in which the maximum change rate exceeds a predetermined threshold among the coordinates calculated from the first imaging with the coordinates calculated from the second imaging. Then, the coordinate measurement unit 32b stores the replaced coordinates in the storage unit 16b.

FIG. 6 is an example of the table T1 stored in the storage unit 16b. In the table of FIG. 5, the maximum change rate in the vertical direction, the aperture value, and the shutter speed are associated with each other. Since the vertical resolution needs to be increased as the maximum vertical change rate is higher, the depth of field is set to be shallow (the aperture value is reduced). Further, since the amount of light taken into the image sensor 26 increases when the aperture value is small, the shutter speed is set in advance so that the shutter speed is increased as the aperture value is decreased.

FIG. 7 is a flowchart showing a flow of processing by the three-dimensional shape measuring apparatus 1b in the second embodiment. The control unit 101b reads the first exposure condition from the storage unit 16b (step S201). Next, the control unit 101b performs control so as to measure the coordinates of the measurement object along the processing flow shown in FIG. 4 (step S202). Next, the control unit 101b calculates the rate of change in the vertical direction at each coordinate from the measured coordinates (step S203).

Next, the control unit 101b calculates the maximum rate of change that maximizes the rate of change in the vertical direction for each measurement zone (step S204). Next, the control unit 101b extracts a measurement band in which the maximum change rate is greater than a predetermined threshold (step S205). Next, the control unit 101b reads the exposure condition from the storage unit 16b for each extracted measurement band (step S206). Next, the control unit 101b again sets the coordinates of the measurement bands for the measurement bands in which the calculated maximum change rate is larger than a predetermined threshold, under the exposure conditions read according to the measurement bands. Measurement is performed (step S207). Next, the control unit 101b replaces the coordinates of the measurement band in which the maximum change rate exceeds a predetermined threshold among the coordinates calculated from the first imaging with the coordinates calculated from the second imaging (step S208). ). Above, the process of this flowchart is complete | finished.

As described above, the control unit 101b changes the exposure condition when the image of the region included in the measured coordinate range is imaged again after the coordinate measurement unit 32b measures the coordinates of the measurement object 11, and the changed exposure. Under the condition, the measurement unit 20b causes the region included in the range of the measured coordinates to be imaged again, and the coordinate measurement unit 32b obtains the light intensity change data and the light intensity change data acquired by being imaged under the changed exposure condition. Based on the above, the coordinates of each position on the measurement object 11 can be measured.

In addition, the control unit 101b is configured such that the rate of change in the direction from the measuring unit 20b to the measuring object 11 in the direction perpendicular to the direction from the measuring unit 20b to the measuring object 11 (the rate of change in the vertical direction) is a predetermined threshold value. Is extracted, the exposure condition when the extracted area is imaged again is changed, the extracted area is imaged again by the measurement unit 20b under the changed exposure condition, and the coordinate measurement unit 20b Based on the change data and the light intensity change data acquired by imaging under the changed exposure condition, the coordinates of each position on the measurement object 11 can be measured.

Further, the control unit 101b adjusts the depth of field when the measurement unit 20b captures an image according to the measurement region of the measurement object 11, and causes the measurement unit 20b to capture an image with the adjusted depth of field. it can.

Thereby, the three-dimensional shape measuring apparatus 1b once again reduces the depth of field in order to increase the resolution in the height direction of the measurement object for the measurement zone in which the gradient of the measurement object is larger than a predetermined threshold. Coordinates are acquired by imaging. Then, the coordinates of the measurement zone in which the gradient of the measurement object is greater than a predetermined threshold among the coordinates calculated from the first imaging are replaced with the coordinates calculated from the second imaging, so that the gradient of the measurement object is Even in a steep place, the coordinates can be measured with high accuracy.

Further, the three-dimensional shape measuring apparatus 1b does not need to change the aperture amount and perform imaging again in the measurement zone where the maximum change rate is equal to or less than the predetermined threshold. Compared to the case, the overall time required for measurement can be shortened.

In the present embodiment, the three-dimensional shape measuring apparatus 1b once measures the coordinates of the entire measurement object 11, and then again measures the coordinates of the measurement zone in which the maximum change rate is greater than a predetermined threshold. Not limited to. When the three-dimensional shape measuring apparatus 1b measures the coordinates of the measurement object 11 and determines that the maximum rate of change in the vertical direction is larger than a predetermined threshold value, the exposure condition is changed to control the imaging. Also good.

In the present embodiment, the control unit 101b changes the exposure condition when the measurement unit 20b captures an image according to the maximum change rate in the vertical direction. However, the present invention is not limited to this. The control unit 101b changes the exposure condition at the time of imaging according to the in-focus position or the measurement area of the measurement object 11, causes the measurement unit 20b to capture an image under the changed exposure condition, and the coordinate measurement unit 32b The coordinates of each position on the measurement object 11 may be measured based on the intensity change data and the light intensity change data acquired by imaging under the changed exposure condition.

In addition, the control unit 101b causes the coordinate measurement unit 32 or the coordinate measurement unit 32b to measure the coordinates of the measurement object 11 under the first exposure condition, and then, based on the first exposure condition and the measured coordinates, A second exposure condition that is an exposure condition for the next measurement may be calculated using a predetermined arithmetic expression, and the measurement unit 20 may be caused to capture an image under the calculated second exposure condition.

Further, in the first embodiment or the second embodiment, the focusing position changing unit 30 changes the distance between the measuring unit 20 or the measuring unit 20b and the measurement object 11, and thereby the measuring unit 20 takes an image. Although the focus position has been changed, the present invention is not limited to this, and the focus position of the measurement unit 20 or the measurement unit 20b may be changed using a zoom function by an optical system.

<Structure manufacturing system>
Next, the structure manufacturing system provided with the three-dimensional shape measuring apparatus 1 in the first embodiment will be described. FIG. 8 is a block configuration diagram of the structure manufacturing system 200. The structure manufacturing system 200 includes the three-dimensional shape measuring apparatus 1 according to the first embodiment, a design apparatus 210, a molding apparatus 220, a control apparatus (inspection apparatus) 230, and a repair apparatus 240.

The design device 210 creates design information related to the shape of the structure, and transmits the created design information to the molding device 220. In addition, the design device 210 stores the created design information in a coordinate storage unit 231 described later of the control device 230. Here, the design information is information indicating the coordinates of each position of the structure. The molding apparatus 220 produces the structure based on the design information input from the design apparatus 210. The molding process of the molding apparatus 220 includes casting, forging, cutting, or the like. The three-dimensional shape measuring apparatus 1 measures the coordinates of the structure manufactured as described in the first embodiment, and transmits information (shape information) indicating the measured coordinates to the control device 230.

The control device 230 includes a coordinate storage unit 231 and an inspection unit 232. As described above, design information is stored in the coordinate storage unit 231 by the design apparatus 210. The inspection unit 232 reads design information from the coordinate storage unit 231. The inspection unit 232 compares information (shape information) indicating coordinates received from the three-dimensional shape measuring apparatus 1 with design information read from the coordinate storage unit 231.

The inspection unit 232 determines whether or not the structure is molded according to the design information based on the comparison result. In other words, the inspection unit 232 determines whether or not the created structure is a non-defective product. The inspection unit 232 determines whether or not the structure can be repaired when the structure is not molded according to the design information. If repair is possible, the inspection unit 232 calculates a defective part and a repair amount based on the comparison result, and transmits information indicating the defective part and information indicating the repair amount to the repair device 240.

The repair device 240 processes the defective portion of the structure based on the information indicating the defective portion received from the control device 230 and the information indicating the repair amount.

FIG. 9 is a flowchart showing the flow of processing by the structure manufacturing system 200. First, the design apparatus 210 creates design information related to the shape of the structure (step S301). Next, the molding apparatus 220 produces the structure based on the design information (step S302). Next, the three-dimensional shape measuring apparatus 1 measures the shape of the manufactured structure (step S303). Next, the inspection unit 232 of the control device 230 inspects whether or not the structure is created according to the sincerity design information by comparing the shape information obtained by the three-dimensional shape measuring device 1 with the design information. (Step S304).

Next, the inspection unit 232 of the control device 230 determines whether or not the created structure is a good product (step S305). When the created structure is a non-defective product (step S305: YES), the structure manufacturing system 200 ends the process. On the other hand, when the created structure is not a non-defective product (step S305, NO), the inspection unit 232 of the control device 230 determines whether the created structure can be repaired (step S306).

If the created structure can be repaired (step S306: YES), the repair device 240 reprocesses the structure (step S307) and returns to the process of step S303. On the other hand, when the created structure cannot be repaired (YES in step S306), the structure manufacturing system 200 ends the process. Above, the process of this flowchart is complete | finished.

As described above, since the three-dimensional shape measuring apparatus 1 in the first embodiment can accurately measure the coordinates of the structure, the structure manufacturing system 200 determines whether or not the created structure is a non-defective product. can do. In addition, the structure manufacturing system 200 can repair the structure by reworking the structure when the structure is not a good product.

In addition, the repair process which the repair apparatus 240 in this embodiment performs may be replaced with the process in which the shaping | molding apparatus 220 re-executes a shaping | molding process. In that case, when it determines with the test | inspection part 232 of the control apparatus 230 being able to repair, the shaping | molding apparatus 220 re-executes a shaping | molding process (forging, cutting, etc.). Specifically, for example, the molding apparatus 220 cuts a portion that is originally to be cut and is not cut in the structure. Thereby, the structure manufacturing system 200 can create a structure correctly.

Further, in the present embodiment, the structure manufacturing system 200 has been described as including the three-dimensional shape measuring apparatus 1, but the three-dimensional shape measuring apparatus 1 may be replaced with the three-dimensional shape measuring apparatus 1b in the second embodiment. Good.

As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within a scope not departing from the gist of the present invention. For example, the three-dimensional shape measuring apparatus according to the present invention does not necessarily have all the configurations of the three-dimensional

shape measuring apparatuses

1 and 1b. The three-dimensional shape measuring apparatus according to the present invention has a configuration corresponding to at least the measuring unit 20 (20b), the focus position changing unit 30, the control unit 101 (101b), and the coordinate measuring unit 32 (32b). Other configurations may be appropriately combined as necessary.

The present invention can be applied to a structure manufacturing system that can determine whether or not a manufactured structure is a non-defective product.

1, 1b Three-dimensional shape measuring device 20 Measuring unit 21 Main light source (light source unit)
23 Pattern formation part (stripe pattern generation part)
14 Imaging unit 30 Focus position changing unit 31 Data extracting unit 32 Coordinate measuring unit 101 Control unit 200 Structure manufacturing system 210 Design device 220 Molding device 230 Control device (inspection device)
240 Repair device

Claims

A three-dimensional shape measuring apparatus for measuring a three-dimensional shape of a measurement object,
A measurement unit that obtains light intensity change data from each position on the measurement object by repeatedly imaging the measurement object while changing the phase of the fringe pattern irradiated on the measurement object;
An in-focus position changing unit for changing an in-focus position when the measurement unit captures an image;
A control unit that controls the measurement unit and the focusing position changing unit so as to obtain the light intensity change data each time the focusing position is changed;
A coordinate measuring unit that measures the coordinates of each position on the measurement object based on the light intensity change data of the respective in-focus positions;
A three-dimensional shape measuring apparatus comprising:
A data extraction unit for extracting data in an effective area from the respective light intensity change data acquired each time the in-focus position is changed;
The three-dimensional shape measuring apparatus according to claim 1, wherein the coordinate measuring unit measures the coordinates of each position on the measurement object based on the extracted data.
The control unit changes an exposure condition at the time of imaging according to the in-focus position or a measurement area of the measurement object, and causes the measurement unit to image at the changed exposure condition,
The coordinate measuring unit measures the coordinates of each position on the measurement object based on the light intensity change data and the light intensity change data acquired by imaging under the changed exposure condition. The three-dimensional shape measuring apparatus according to claim 1 or 2, wherein
The control unit changes the exposure condition when the region included in the range of the measured coordinate is imaged again after the coordinates of the measurement object are measured by the coordinate measurement unit, and the changed exposure condition Then, the measurement unit again images the area included in the range of the measured coordinates,
The coordinate measuring unit measures the coordinates of each position on the measurement object based on the light intensity change data and the light intensity change data acquired by imaging under the changed exposure condition. The three-dimensional shape measuring apparatus according to any one of claims 1 to 3, wherein
The control unit extracts a region where the rate of change of the direction from the measurement unit to the measurement target of the coordinates with respect to a direction perpendicular to the direction from the measurement unit to the measurement target exceeds a predetermined threshold, Change the exposure condition when imaging the extracted region again, and let the measurement unit image the extracted region again under the changed exposure condition,
The coordinate measuring unit measures the coordinates of each position on the measurement object based on the light intensity change data and the light intensity change data acquired by imaging under the changed exposure condition. The three-dimensional shape measuring apparatus according to any one of claims 1 to 4, wherein
The control unit adjusts a depth of field when the measurement unit captures an image according to a measurement region of the measurement object, and causes the measurement unit to capture an image with the adjusted depth of field. The three-dimensional shape measuring apparatus according to any one of claims 1 to 5.
The control unit causes the coordinate measurement unit to measure the coordinates of the measurement object under a first exposure condition, and then performs an exposure for a next measurement based on the first exposure condition and the measured coordinates. The three-dimensional shape according to any one of claims 1 to 6, wherein a second exposure condition that is a condition is calculated, and the measurement unit is caused to capture an image under the calculated second exposure condition. measuring device.
The measuring unit is
A light source that emits light;
A fringe pattern generating unit that changes the emitted light into the fringe pattern, and irradiates the measurement object with the light changed into the fringe pattern;
An imaging unit for imaging light reflected from the measurement object;
The three-dimensional shape measuring apparatus according to any one of claims 1 to 7, further comprising:
A three-dimensional shape measuring method executed by the three-dimensional shape measuring apparatus,
Acquiring light intensity change data from each position on the measurement object by repeatedly imaging the measurement object while changing the phase of the fringe pattern irradiated on the measurement object;
Changing the in-focus position when imaging,
Measuring the coordinates of each position on the measurement object based on the light intensity change data of the respective in-focus positions;
Have
Each time the focus position is changed, the light intensity change data is acquired by adjusting the focus position.
Creating design information on the shape of the structure;
Producing the structure based on the design information;
Measuring the shape of the fabricated structure using the three-dimensional shape measurement method according to claim 9;
Inspecting by comparing the shape information obtained by measuring the design information;
A method for producing a structure characterized by comprising:
The method for manufacturing a structure according to claim 10, further comprising reworking the structure based on a result of comparing the shape information and the design information.
12. The method of manufacturing a structure according to claim 11, wherein the reworking is re-execution of manufacturing the structure.
The structure according to claim 11, wherein the rework is to process a defective portion of the structure based on a result of comparing the shape information and the design information. Manufacturing method.
A design device for creating design information on the shape of the structure;
A molding apparatus for producing the structure based on the design information;
The three-dimensional shape measuring apparatus according to any one of claims 1 to 8,
An inspection device that compares the design information with shape information indicating coordinates at which the three-dimensional measuring device measures the structure;
A structure manufacturing system comprising:
15. The structure manufacturing system according to claim 14, further comprising a repair device that performs reworking of the structure based on a comparison result in the inspection device.