KR20040071532A - Three-dimensional image measuring apparatus - Google Patents

Abstract

PURPOSE: A three-dimensional image measuring apparatus is provided to more precisely measure three-dimensional image by removing a shadow by means of a projection part having one or more mirrors, which is capable of conveying an image. CONSTITUTION: A three-dimensional image measuring apparatus includes a work stage(20), a light source(31), a diffraction grating(33), a projection optical system(34), a projection part, a viewing optical system, detector arrays, a frame grabber(53), an image processor(54), and a control part(53). An object(22) to be measured is installed on the work stage(20). The light source(31) emits light. The diffraction grating(33) passes light delivered. The projection part includes appliances having mirrors(36) for reflecting light. The detector arrays detect light. The frame grabber(53) image-processes light and stores the light. The image processor calculates phase of a processed image. The three-dimensional image measuring apparatus includes a plurality of projection parts.

Description

Three-dimensional image measuring apparatus

The present invention eliminates the shadow area, which is a disadvantage of the optical triangulation method, by a projection unit having one or more mirrors capable of transferring an image of a diffraction grating, thereby measuring a more precise three-dimensional shape. It relates to a shape measuring device.

In general, the technique of measuring the three-dimensional shape of the free-form surface is largely divided into contact and non-contact.

First, a method of measuring the entire curved shape by measuring one point on the curved surface by a three-dimensional measuring device has been widely used for a long time. However, this method has a disadvantage in that excessive measurement time is required.

On the other hand, non-contact three-dimensional measuring method is being studied, and the application field plays an important role in the fields of automation, quality control, medicine, robotics, three-dimensional modeling, etc. The non-contact three-dimensional measuring method largely depends on the optical interference method, It is divided into phototriangulation.

Optical interference method includes optical phase interference method using monochromatic light such as laser and optical scanning interference method using light, and precise measurement of nm (nano meter) is possible, but it is difficult to measure large area quickly and expensive and accurate stage There is a problem that is required.

In addition, the optical triangulation method is a method of analyzing the shape information of the surface by projecting a predetermined constant light on the measurement surface at any predetermined angle and extracting the brightness of the light modified according to the shape of the surface at another angle.

According to the projection method in the optical triangulation method, it may be divided into a device using a laser pointer or a laser slit beam, and a device using a moire fringe. An apparatus for scanning using a laser pointer or a laser slit beam has a problem in that the measurement unit is simple, but a mechanism configuration for scanning is required, and the higher the accuracy, the longer the scan time.

In recent years, a lot of non-contact optical measurement method called the moire method is used, which greatly reduces the measurement time compared to the contact method using a three-dimensional measuring instrument.

In order to obtain moire patterns with three-dimensional shape information of the measurement object, the moiré method should form a straight line of uniform intervals on the measurement object and transfer it precisely.

In the conventional method for this purpose, a linear glass grating in which a uniformly spaced linear pattern is engraved on one surface of the glass is projected onto the measurement object using a projection optical system.

In addition, in order to transfer the straight stripes formed on the measurement object at regular intervals, a linear glass grid transfer device is used.

Projecting a straight glass grid composed of a plurality of straight stripes at regular intervals onto the measurement object causes a plurality of stripes to be formed on the surface of the measurement object, and the stripes are curved according to the height of the measurement object.

When a measurement object with stripes is overlapped with a straight glass grid, the shape of a wave pattern composed of a plurality of curves can be seen. This pattern is called a 'moire pattern'. Since the moiré pattern is a contour line formed according to the height of the measurement object, the shape of the measurement object is measured by analyzing the moire pattern.

Hereinafter, a conventional phase shift moire method measuring device will be described with reference to the drawings.

As shown in FIG. 1, a light source 1, a condenser lens 2 provided at one side of the light source 1 at predetermined intervals, a projection grid 3 provided at one side of the condenser lens 2, A projection lattice transfer device 4 provided on one side of the projection lattice 3, a projection lens 5 provided on one side of the projection lattice transfer device 4, and a measurement object at a predetermined distance from the projection lens 5; 6) is located.

An imaging lens 7 is provided at one side of the projection lens 5, and a reference grid 8 is provided at one side of the imaging lens 7, and a relay is provided at one side of the reference lens 8. The lens 9 is provided, and the relay lens 9 CCD camera 10 is provided.

The conventional phase shift moiré measuring device configured as described above may obtain an image by the following operation.

First, the light scanned from the light source 1 passes through the condenser lens 2 and the projection lattice 3 provided on one side of the condenser lens 2. In this case, the projection grid 3 may be transported at equal intervals by about 3 to 5 steps by the projection grid transfer device 4 installed at one side thereof.

When the light 11 passes through the projection lattice 3 and is projected onto the measurement object 6 through the projection lens 5, a deformed stripe is formed on the measurement object 6. The deformed stripe formed on the measurement object 6 passes through the imaging lens 7 and passes through the relay lens 9 through the reference lattice 8 to form a wavy pattern, that is, a moire pattern, in the CCD camera 10. This bears.

However, in the image obtained by the moiré measuring device configured and operated as described above, the moiré pattern representing the height information of the measurement object and the pattern of the reference grid placed in front of the CCD camera 10 are simultaneously displayed.

Therefore, a separate means for removing the image of the reference lattice is required, which leads to a complicated structure.

In addition, all the measurement methods using the optical triangulation method has a problem in that the shadow area is impossible to measure in principle.

The present invention has been invented to solve the above problems, an object of the present invention is a disadvantage of the optical triangulation method by the projection that can be composed of one or more having a mirror capable of transferring the grating image of the diffraction grating The object of the present invention is to provide a three-dimensional shape measuring apparatus capable of measuring a more precise three-dimensional shape by removing a shadow area.

1 is a view showing the structure of a conventional moiré measuring device,

Figure 2a is a view showing a three-dimensional shape measuring apparatus of the present invention,

Figure 2b is a view showing the rotation direction of the projection,

3A is a view showing first and second projection parts of another embodiment;

3B is a view showing a setting state of the first and second projection parts,

4 is a view showing a mirror applied to the present invention.

<Description of the symbols for the main parts of the drawings>

20: work stage 22: measuring object

30, 130, 140: first and second projection parts

31, 131, and 141: light source, first and second light sources

32, 132, 142: fiber bundle, first second fiber bundle

33, 133, 143: diffraction gratings, first and second diffraction gratings

34, 134, 144: projection optical system, first and second projection optical system

35, 135, 145: fine rotating mechanism, first and second fine rotating mechanism

36, 136, 146: mirrors, first and second mirror

37, 137, 147: shutter, first and second shutters

50: image forming unit 51: viewing optical system

52: detector array 53: frame grabber

54: image processor 53: control unit

The three-dimensional shape measuring apparatus according to the present invention for achieving the above object is a work stage on which the measurement object can be installed; A light source disposed above the work stage and emitting light, a fiber bundle through which the light is transmitted, a diffraction grating through which the transmitted light passes, a projection optical system through which the transmitted light passes, and the transmitted light A projection portion formed of a fine rotating mechanism having a mirror on which light is reflected; A projection optical system installed at one side of the projection unit to receive light reflected from a measurement object, a detector array to sense the received light, a frame grabber to image and store the detected light, and the processed image An image processor for calculating a phase of the image and the image forming unit consisting of a control unit, the projection unit may be composed of one or more, the projection unit is controlled by the control unit is rotated around the measurement object at a predetermined angle to emit light Can be injected.

The micro rotating mechanism may change the optical path of the light by rotating the mirror provided on one side thereof.

A work stage on which the measurement object can be installed; A first and second light sources disposed above the work stage and emitting light, first and second fiber bundles through which the light is transmitted, and first and second diffraction gratings through which the transmitted light passes; First and second projection parts including first and second projection optical systems through which the transmitted light is transmitted, and first and second fine rotating mechanisms having first and second mirrors through which the transmitted light is reflected; ; Installed on one side of the first and second projection units, a viewing optical system for receiving light reflected from a measurement object, a detector array for sensing the received light, a frame grabber for image processing the stored light, and And an image processor for calculating a phase of the processed image and an image forming unit including a control unit. The first and second projection units are symmetrically installed at a predetermined angle on a vertical line of an upper portion of the measurement object. And a second projection unit controlled by the controller to alternately scan the light to the measurement object.

The first and second fine rotating mechanisms may rotate the first and second mirrors provided at one side thereof to change the optical path.

The first and second projection units may alternately scan the light to the measurement object by the first and second shutters controlled by the controller.

Hereinafter, a three-dimensional shape measuring apparatus of the present invention will be described with reference to the drawings.

Figure 2a is a view showing a three-dimensional shape measuring apparatus of the present invention, Figure 2b is a view showing the rotation direction of the projection unit.

First, as shown in FIG. 2A, the three-dimensional shape measuring apparatus of the present invention includes a work stage 20, a projection unit 30 installed on an upper side of the work stage 20, and the projection unit ( It consists of an imaging part 50 provided in the other side of 30).

The work stage 20 may have a measurement object 22 installed on an upper surface thereof.

The projection unit 30 is installed on the work stage 20, the light source 31 for emitting light and the light source 31 is provided on one side of the light source 31 freely emitted from the light source 31 A fiber bundle 32 capable of transmitting, a diffraction grating 33 installed at one side of the fiber bundle 32 to transmit light, and installed at one side of the diffraction grating 33 to project the transmitted light A projection optical system 34, a microrotation mechanism 35 provided on one side of the projection optical system 34, and a mirror capable of angle adjustment of an optical path of light provided and projected on the microrotation mechanism 35 ( 36).

The diffraction grating 33 generates a grid image while light is transmitted, and the generated grid image is transmitted to the mirror 36 of the micro rotating mechanism 35 through the projection optical system 34.

The micro-rotation mechanism 35 finely converts the angle of the mirror 36 installed on one side four times so that the grid image can be scanned four times on the measurement object 22.

The imaging unit 50 is installed on the upper side of the work stage 20 of the projection unit 30, the viewing optical system 51 for receiving a grid image reflected from the measurement object 22, and the viewing optical system ( A detector array 52 for detecting an image formed by the grid image transmitted from 51), a frame grabber 53 for storing the detected image in units of frames, and an image for phase calculation using the detected image. It consists of a processor 54 and a control part 55.

The diffraction grating 33 or the fine rotating mechanism 35 moves finely four times, thereby changing the optical path four times. As a result, the detector array 52 detects four images and thereby the frame. The grabber 53 stores four images, and the image processor 54 installed on one side of the frame grabber 53 calculates a phase by using the sensed image. As a result, three of the measurement objects 22 The dimensional shape can be acquired.

In addition, as shown in FIG. 2B, the projection unit 30 is rotated at a predetermined angle around the measurement object 22 by the control unit 55, and then the light is measured at a predetermined position. Can be injected.

When the light is scanned using the present invention as described above, the shadow area 23 is not generated in the measurement object 22, and as a result, a precise three-dimensional shape can be measured with respect to the measurement object 22.

Meanwhile, another embodiment of the present invention is as follows. Figure 3a is a view showing the first and second projection portion of another embodiment of the present invention, Figure 3b is a view showing the setting state of the first and second projection portion.

First, as shown in Figure 3a, the three-dimensional shape measuring apparatus of the present invention largely the work stage 20, the first and the second is installed symmetrically at a predetermined angle on the upper side of the work stage 20 It consists of the projection part 130,140, and the imaging part 50 provided between the said 1st and 2nd projection part 130,140.

The work stage 20 may have a measurement object 22 installed on an upper surface thereof.

The first and second projection units 30 are installed on the work stage 20, and emit light of the first and second light sources 131 and 141 and the first and second light sources 131 and 141. First and second fiber bundles 132 and 142 installed on one side and capable of freely transmitting light emitted from the first and second light sources 131 and 141, and on one side of the first and second fiber bundles 132 and 142. First and second diffraction gratings 133 and 143 installed at one side of the first and second diffraction gratings 133 and 143 and provided to one side of the first and second diffraction gratings 133 and 143 to project the transmitted grating image. On the second projection optical system (134,143), the first and second micro-rotation mechanism (135,145) installed on one side of the first and second projection optical system (134,144), and the first and second micro-rotation mechanism (135,145) First and second mirrors 136 and 146 which can adjust the angle of the grid image to be installed and projected, and are installed on one side of the first and second mirrors 136 and 146 It consists of the first and second shutters (137 147) that pass for the reflected image of the grid or can be blocked.

The first and second diffraction gratings 133 and 143 are grid images are generated by the transmitted light, and the generated grid images are first and second projection optical systems 134 and 144, and the first and second fine rotating mechanisms 135 and 145. Are transmitted to the first and second mirrors 136 and 146.

The first and second fine rotating mechanisms 135 and 145 convert the angles of the first and second mirrors 136 and 146 on one side four times to finely scan the grid image four times.

The imaging unit 50 is installed on the upper side of the work stage 20 of the projection unit 30, the viewing optical system 51 for receiving a grid image reflected from the measurement object 22, and the viewing optical system ( A detector array 52 for detecting an image formed by the grid image transmitted from 51), a frame grabber 53 for storing the detected image in units of frames, and an image for phase calculation using the detected image. It consists of a processor 54 and a control part 55.

The controller 55 drives the first and second fine rotating mechanisms 135 and 145, and the first and second mirrors 135 and 145 are predetermined four times by the first and second fine rotating mechanisms 135 and 145. Can be rotated at an angle of

The first and second mirrors 135 and 145 of the first and second fine rotating mechanisms 35 are moved finely four times, respectively, and the grid image is scanned on the measurement object 22 four times, and the measurement object 22 The detector array 52 detects four images of the grid image reflected on the image.

By detecting four images of the detector array 52, the frame grabber 53 stores four images, and the image processor 54 installed at one side of the frame grabber 53 uses the detected image. By calculating the phase, the three-dimensional shape of the measurement object 22 can be obtained as a result.

In addition, as shown in FIG. 3B, the first and second projection parts 130 and 140, which are symmetrically installed at a predetermined angle with respect to the measurement object 22, are installed in the first and second shutters 137 and 147. ) Is controlled by the control unit 55, the first and second projection unit 130, 140 may alternately scan the light to the measurement object (22).

In the same manner as described above, scanning the grid image generated by the light prevents the shadow area 23 from being generated in the measurement object 22, so that a precise three-dimensional shape can be measured with respect to the measurement object 22. Will be.

4 is a view showing a mirror applied to the present invention. As shown in FIG. 4, the mirror 36 is rotatably installed at one side of the microrotation mechanism 35, and the microrotation mechanism 35 and the mirror 36 are first and first. It may be applied to the two projection parts 130 and 140 to be used as the first and second fine rotating mechanisms 135 and 145 and the first and second mirrors 136 and 146.

Operation of the three-dimensional shape measuring apparatus of the present invention configured as described above is as follows.

First, as illustrated in FIGS. 2A and 2B, light is generated from a light source 31 installed in the projection unit 30, and the light is generated through the fiber bundles 32 installed on one side of the light source 31. Pass through the diffraction grating 33 is installed on one side of the fiber bundle (32).

At this time, the diffraction grating 33 is reflected by the mirror 36 of the fine rotating mechanism 35 after the grating image generated by the transmitted light passes through the projection optical system 34, the mirror 36 is It rotates finely four times, whereby the grid image is scanned four times on the measurement object 22.

The projection unit 30 is driven by the controller 55 to rotate the light around the measurement object 22 at a predetermined angle so that the shadow area 23 is not generated in the measurement object 22. Can be injected.

The grating image reflected by the measurement object 22 is received by the viewing optical system 51 of the imaging unit 50, and the grating image received by the viewing optical system 51 is a detector installed at one side of the viewing optical system 51. The image formed by the grid image in the detector array 52 that is delivered to the array 52 is sensed.

In this case, four images detected by the detector array 52 by four movements of the diffraction grating 33 or the mirror 36 are stored in the frame grabber 53 in units of four frames, and the stored four frames. The phase is calculated by the image processor 54 to obtain a three-dimensional shape.

As such, the present invention configured can eliminate the shadow area that can be generated on the measurement object by the projection part which can be constituted by one or more.

Operation of the three-dimensional shape measuring apparatus of another embodiment of the present invention is as follows.

First, light is generated from the first and second light sources 131 and 141 installed in the first and second projection parts 130 and 140, and the light is provided on one side of the first and second light sources 131 and 141. A grid image is generated while passing through first and second diffraction gratings 133 and 143 installed on one side of the first and second fiber bundles 132 and 142 through second fiber bundles 132 and 142, and the generated grid image is projected. After passing through the optical systems 134 and 144, the first and second mirrors 136 and 146 of the first and second fine rotating mechanisms 135 and 145 are reflected to pass through the first and second shutters 137 and 147.

The grid images generated by the first and second diffraction gratings 133 and 143 are clearly scanned on the measurement object 22 while passing through the first and second projection optical systems 134 and 144.

In this case, the first and second shutters 137 and 147 installed in the first and second projection units 130 and 140 are controlled by the controller 55 to alternately block the grid images so that the grid images are alternately placed on the measurement object 22. To be injected.

The grating image reflected by the measurement object 22 is received by the viewing optical system 51 of the imaging unit 50, and the grating image received by the viewing optical system 51 is a detector installed at one side of the viewing optical system 51. The image formed by the grid image in the detector array 52 that is delivered to the array 52 is sensed.

In this case, four images detected by the detector array 52 by four movements of the first and second diffraction gratings 133 and 143 are stored in the frame grabber 53 in units of four frames, and the stored four frames are stored. The phase is calculated by the image processor 54 to obtain a three-dimensional shape.

As described above, the three-dimensional shape measuring apparatus of another embodiment according to the present invention may be configured such that the first and second projection parts are symmetrical, thereby scanning light so that no shadow area is generated on the measurement object.

As described above, the three-dimensional shape measuring apparatus according to the present invention can measure the precise three-dimensional shape by preventing the shadow area from occurring on the measurement object by using the projection unit, which may be composed of one or more mirrors. There is an advantage to that.

Claims (7)

A work stage on which the measurement object can be installed; A light source installed on the work stage, a light source emitting light, a fiber bundle to which the light is transmitted, a diffraction grating to generate a grid image using the transmitted light, and a projection through which the passed grid image is transmitted A projection unit comprising an optical system and a fine rotating mechanism having a mirror on which the transmitted grating image is reflected; A perspective optical system installed at one side of the projection unit to receive a grid image reflected from a measurement object, a detector array for sensing the received grid image, a frame grabber for image processing the stored grid image, and the It is composed of an image processor for calculating the phase of the processed image, and an image forming unit consisting of a control unit, The projection unit may be composed of one or more, wherein the projection unit is controlled by a control unit is a three-dimensional shape measuring apparatus, characterized in that for rotating the light around the measurement object at a predetermined angle to scan the light. The method of claim 1, The micro-rotation mechanism is controlled by a control unit, characterized in that the rotatable mirror is installed on one side thereof. The method according to claim 1 and 2, The micro-rotation mechanism is a three-dimensional shape measuring apparatus, characterized in that to rotate the mirror installed on one side finely four times to scan the grid image to the measurement object four times. A work stage on which the measurement object can be installed; A first and second light sources disposed above the work stage and emitting light, first and second fiber bundles through which the light is transmitted, and first and second diffraction gratings through which the transmitted light passes; First and second projection parts including first and second projection optical systems through which the transmitted light is transmitted, and first and second fine rotating mechanisms having first and second mirrors through which the transmitted light is reflected; ; Installed on one side of the first and second projection units, a viewing optical system for receiving light reflected from a measurement object, a detector array for sensing the received light, a frame grabber for image processing the stored light, and And an image processor for calculating a phase of the processed image and an image forming unit including a control unit. The first and second projection parts are installed symmetrically at a predetermined angle on a vertical line of the upper portion of the measurement object, and the first and second projection parts are controlled by a controller to alternately scan light to the measurement object. Three-dimensional shape measuring device characterized in that. The method of claim 4, wherein The first and second fine rotating mechanism is controlled by a control unit, the three-dimensional shape measuring apparatus, characterized in that the first and second mirrors are installed on one side thereof. The method according to claim 4 and 5, The first and second micro-rotation mechanism is a three-dimensional shape measuring device, characterized in that to rotate the first and second mirrors provided on each side of the fine four times to scan the grid image to the measurement object four times. The method of claim 4, wherein The first and second projection unit is a three-dimensional shape measuring apparatus, characterized in that for scanning the light to the measurement object by the first and second shutter controlled by the control unit.