JP2004333367A - Apparatus and method for measuring three-dimensional shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and visually recognize a standby state used for determining a measuring section in a three-dimensional shape measuring apparatus. <P>SOLUTION: Laser light emergent from a laser light source 12 forms an irradiation spot in the surface of an object OB via a collimator lens 13 and a galvano mirror 14. The surface of the object OB is linearly scanned with the irradiation spot by the rotation of the galvano mirror 14. Reflected light from the irradiation spot is guided to a line sensor 16 via the galvano mirror 14 and an image forming lens 15 to measure the surface shape of the object OB through the use of the principle of triangulation. The laser light source 12 is intermittently excited at standby mode to make a scanning track by the laser light of a plurality of discrete irradiation spots. The laser light source 12 is continuously excited at measurement to make the scanning track by the laser light of a continuous line. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a three-dimensional shape measuring apparatus and a three-dimensional shape measuring device for irradiating a laser beam on a surface of an object while scanning the same, receiving the laser light reflected on the surface of the object, and measuring the three-dimensional shape of the surface of the object. Related to the measurement method.
[0002]
[Prior art]
Conventionally, an irradiation spot is formed on the surface of an object by irradiating the object with laser light from a laser light irradiator including a laser light source and a collimating lens, and the irradiation spot is scanned on the surface of the object, and the object is scanned. The laser light reflected from the surface is received by a light receiver consisting of a line sensor in which an imaging lens and a CCD are linearly arranged, and the received reflected light is used to detect a target object based on the principle of triangulation. A three-dimensional shape measuring apparatus for measuring a three-dimensional shape is well known (for example, see Patent Documents 1 and 2 below).
[0003]
[Patent Document 1]
JP 2002-243421 A [Patent Document 2]
JP-A-2002-139311
[Problems to be solved by the invention]
In such a three-dimensional shape measurement of an object, before the measurement, the position of the three-dimensional shape measurement device or the object is moved, and a scanning trace of the surface of the object by laser light is visually confirmed to check the object. It is usual to determine the measurement site. In this specification, a state in which the measurement site of the object is determined is referred to as a standby state, and a state in which the three-dimensional shape of the surface of the object is actually measured is referred to as a measurement state. In this standby state, the intensity of the laser beam is usually maintained at a small value to some extent due to the effect on the eyes of the worker.
[0005]
However, in the above-described conventional apparatus, the scanning trace by the laser beam in the standby state and the scanning trace by the laser beam in the measurement state are the same continuous line. Since the worker is gazing at the scanning trace by the laser beam in specifying the measurement site in the standby state, the worker switches the three-dimensional shape measuring apparatus to the measurement state by mistake, or another worker mistakenly switches the three-dimensional shape measurement apparatus to the measurement state. Even when the shape measuring device is switched to the measurement state, the switching is often not noticed. As described above, not knowing whether the three-dimensional shape measuring apparatus is in the standby state or the measurement state deteriorates the work efficiency in measuring the three-dimensional shape of the object.
[0006]
In a typical three-dimensional shape measuring device, the reflected light from the object surface is received by a photodetector independent of the line sensor, and the output power of the laser light source is controlled so that the amount of received light is always constant. Thus, it is possible to measure a good three-dimensional shape even in a portion of the object surface where the reflectance of the laser beam is low. However, as described above, the worker may mistakenly consider the three-dimensional shape measuring apparatus in the measurement state to be in the standby state, and in this case, the worker has not taken protective measures for eyes. Is not preferred.
[0007]
Summary of the Invention
SUMMARY OF THE INVENTION The present invention has been made to address the above problems, and an object of the present invention is to provide a three-dimensional shape measuring apparatus and a three-dimensional shape measuring method capable of easily visually confirming a standby state of the three-dimensional shape measuring apparatus. To provide.
[0008]
In order to achieve the above object, a structural feature of the present invention resides in that a visual aspect of a scanning trace by a laser beam is made different between a measurement state and a standby state. In this case, for example, it is preferable that the scanning trace of the laser beam visually observed in the measurement state is a continuous line, and the scanning trace of the laser beam visually observed in the standby state is formed of a plurality of discrete irradiation spots.
[0009]
According to this, the operator can easily grasp that the three-dimensional shape measuring apparatus is in the standby state by visually observing the scanning trace of the laser light composed of a plurality of discrete irradiation spots. As a result, the work efficiency of the three-dimensional shape measurement of the object can be improved. In addition, in the measurement state of the three-dimensional shape measuring device, it is possible to appropriately take protective measures for the worker.
[0010]
Further, another configuration feature of the present invention is that the laser light is continuously irradiated on the surface of the object in the measurement state, and the laser light is intermittently irradiated on the surface of the object in the standby state. is there. Specifically, it is preferable to excite the laser light irradiator continuously in the measurement state and to intermittently excite the laser light irradiator in the standby state. In order to intermittently excite the laser beam irradiator, the laser beam irradiator may be excited with a pulse train signal having a predetermined period.
[0011]
According to this, the scanning trace by the laser beam in the standby state can be made different from the scanning trace by the laser beam in the measurement state by a simple method.
[0012]
Embodiment
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a three-dimensional shape measuring system including a three-dimensional shape measuring apparatus 10 according to the embodiment.
[0013]
This three-dimensional shape measurement system includes a support mechanism 40 that is fixed on the base 30 and that displaces the distal end portion freely in the space to be measured. The support mechanism 40 includes a fixed pole 41, a rotating rod 42, a first arm 43, a second arm 44, and a third arm 45. The three-dimensional shape measuring device 10 is assembled to the tip of the third arm 45.
[0014]
The fixed pole 41 is formed in a cylindrical shape, and is vertically fixed on the base 30 at a lower end thereof. The rotating rod 42 is formed in a columnar shape, and is rotatably supported at its lower end by the fixed pole 41 around the axis, and protrudes upward from the fixed pole 41. The first arm 43 is attached to a connecting portion 42a provided at the distal end of the rotating rod 42 at a connecting portion 43a provided at the base end thereof so as to be rotatable around an axis orthogonal to the axial direction of the rotating rod 42. . The second arm 44 is rotatably assembled to a connecting portion 43b provided at a distal end of the first arm 43 at a connecting portion 44a provided at a base end thereof so as to be rotatable around an axis orthogonal to the axial direction of the first arm 43. ing. The third arm 45 is attached to a connecting portion 44b provided at the distal end of the second arm 44 at a connecting portion 45a provided at the base end thereof so as to be rotatable around an axis orthogonal to the axial direction of the second arm 44. ing.
[0015]
The three-dimensional shape measuring apparatus 10 is attached to the distal end of the third arm 45 so as to be rotatable around the axis of the third arm 45 by a coupler 11 a fixed to the housing 11.
[0016]
In the support mechanism 40, rotation angle sensors 46a, 46b, 46c, 46d, and 46e are provided. The rotation angle sensor 46 a is incorporated in the fixed pole 41 and detects a rotation angle of the rotation rod 42 about the axis with respect to the fixed pole 41. The rotation angle sensor 46b is incorporated in the connection portion 43a of the first arm 43, and detects a rotation angle of the connection portion 43a of the first arm 43 with respect to the connection portion 42a of the rotation rod 42 around one axis. The rotation angle sensor 46c is incorporated in the connection portion 44a of the second arm 44, and detects a rotation angle of the connection portion 44a of the second arm 44 with respect to the connection portion 43b of the first arm 43 around one axis. The rotation angle sensor 46d is incorporated in the connection portion 45a of the third arm 45, and detects the rotation angle of the connection portion 45a of the third arm 45 with respect to the connection portion 44b of the second arm 44 about one axis. The rotation angle sensor 46e is incorporated in the distal end of the third arm 45, and the rotation angle of the third arm 45 with respect to the third arm 45 about one axis of the third arm 45, that is, the rotation angle sensor 46e of the three-dimensional shape measurement device 10. The rotation angle of the third arm 45 with respect to the tip is detected.
[0017]
As shown in FIG. 2, the three-dimensional shape measuring apparatus 10 houses a laser light source 12, a collimating lens 13, a galvano mirror 14, an imaging lens 15, a line sensor 16, and a photodetector 17 in a housing 11 thereof.
[0018]
The laser light source 12 is composed of a semiconductor laser or the like, and emits laser light toward the collimator lens 13. The collimator lens 13 converts the laser light emitted from the laser light source 12 into parallel light. The laser light source 12 and the collimating lens 13 constitute a laser light irradiator.
[0019]
The galvanomirror 14 changes the path of the laser light collimated by the collimating lens 13 and emits the laser light to the object OB, and changes the path of the laser light reflected on the surface of the object OB to form an image. Guide to the lens 15. The galvanomirror 14 is driven by an electric motor 21 to scan the surface of the object OB with an irradiation spot, and rotates by a predetermined angle around the vertical axis of the drawing. A rotation angle sensor 22 that detects the rotation angle of the electric motor 21, that is, the rotation angle of the galvanometer mirror 14 is attached to the electric motor 21.
[0020]
The imaging lens 15 forms an image of the reflected light from the object OB on the line sensor 16. The line sensor 16 is configured in a long shape by arranging a plurality of light receiving elements such as CCDs in a line, and measures a distance from the laser light source 12 to an irradiation spot of the object OB among the plurality of light receiving elements. The detection is performed based on the position of the light receiving element that receives the reflected light from the object OB. The imaging lens 15 and the line sensor 16 constitute a light receiver that receives reflected light. The photodetector 17 receives the laser light reflected by the line sensor 16 and outputs a detection signal indicating the amount of the received light.
[0021]
Further, an electric control circuit 23 is also built in the housing 11. The electric control circuit 23 controls the operation of the laser light source 12 and the electric motor 21 according to an external instruction. The electric control circuit 23 inputs a detection signal indicating the amount of received light detected by the photodetector 17 and outputs the detection signal to the outside, and inputs a detection signal indicating the rotation angle detected by the rotation angle sensor 22 to input an external signal. Output to
[0022]
Further, based on the principle of triangulation, the electric control circuit 23 uses a detection signal from the line sensor 16 to generate a reference point in the three-dimensional shape measuring apparatus 10 (for example, a reflection position of a laser beam on the galvanomirror 14). From the object to the irradiation spot of the object OB is calculated. Hereinafter, this distance is referred to as a Z-direction distance. The electric control circuit 23 receives the detection signal from the rotation angle sensor 22 and also calculates the tilt angle of the laser beam along the X-axis with respect to the reference direction extending from the reference point. Hereinafter, this inclination angle is referred to as an X-direction inclination angle. Then, the electric control circuit 23 outputs, as the surface shape information of the target object OB, a pair of the distance in the Z direction and the inclination angle in the X direction for each irradiation spot. The X, Y, and Z axis directions are as shown in FIG.
[0023]
Returning to the description of FIG. 1 again, the three-dimensional shape measuring apparatus 10 has an input device 50 and a controller 60 attached. The input device 50 includes a keyboard including a plurality of operators, and instructs operation of the three-dimensional shape measurement system. The controller 60 controls the operation of the three-dimensional shape measuring device 10 in accordance with an instruction from the input device 50 and controls the operation of the image processing device 70 that forms a three-dimensional shape measuring system together with the three-dimensional shape measuring device 10. .
[0024]
As shown in FIG. 3 in detail, the controller 60 has a control circuit 61 mainly including a CPU, a ROM, a RAM, and the like. The control circuit 61 controls a pulse train signal generation circuit 62, a laser power adjustment circuit 63, a selection circuit 64, and a motor drive circuit 65 according to various modes such as a standby mode and a measurement mode by executing a program (not shown).
[0025]
Specifically, when the standby mode is designated by operating the input device 50, the control circuit 61 activates the pulse train signal generation circuit 62 and controls the selection circuit 64 to output the pulse train signal from the pulse train signal generation circuit 62. The signal is selectively output to the laser drive circuit 66. At the time of its operation, the pulse train signal generation circuit 62 generates a cycle obtained by dividing the rotation cycle of the galvanomirror 14 by the electric motor 21 by an integer of 10 to 30 (for example, if the rotation cycle of the galvanomirror 14 is 1/30 Hz, 1.67). (Milliseconds) and a pulse train signal of a predetermined amplitude level having a duty ratio of 1/10 to 1/3. In this case, in response to the pulse train signal, the laser drive circuit 66 intermittently excites the laser light source 12 at the above-described cycle, and emits laser light to the collimator lens 13 at the same cycle. In this case, the intensity of the laser light emitted from the laser light source 12 can be suppressed to a certain extent.
[0026]
When the measurement mode is designated by operating the input device 50, the control circuit 61 activates the laser power adjustment circuit 63 and controls the selection circuit 64 to output the output signal from the laser power adjustment circuit 63 to the laser. Selectively output to the drive circuit 66. The laser power adjustment circuit 63 outputs a continuous signal having a level corresponding to the signal indicating the amount of reflected light from the reflected light amount detection circuit 67. The reflected light amount detection circuit 67 receives the detection signal from the photodetector 17, detects the intensity of the light reflected by the irradiation spot from the surface of the object OB, and outputs a signal representing the detected intensity. Then, in response to this signal, the laser power adjustment circuit 63 outputs a continuous signal whose level increases as the intensity of the reflected light decreases, to the laser drive circuit 66. In this case, the laser drive circuit 66 continuously excites the laser light source 12, and controls the laser light source 12 so that the intensity of the emitted laser light increases as the level of the supplied continuous signal increases. Therefore, the intensity of the reflected light reflected by the surface of the target object OB and reaching the line sensor 16 is always kept constant.
[0027]
Further, the control circuit 61 operates the motor drive circuit 65 in both the standby mode and the measurement mode. The motor drive circuit 65 receives the detection signal from the rotation angle sensor 22 and inverts the electric motor 21 every time the electric motor 21 (that is, the galvanometer mirror 14) rotates by a predetermined angle from the reference rotation position. Thus, in the standby mode and the measurement mode, the galvanomirror 14 reciprocates within a predetermined angle range from the reference rotation position.
[0028]
The image processing device 70 is configured by a computer device (for example, a personal computer) including a CPU, a ROM, a RAM, and a storage device. It has a function of generating three-dimensional image data representing the surface shape of the target object OB using the surface shape information of the target object OB paired with the direction inclination angle and the detected rotation angles from the rotation angle sensors 46a to 46e. In the generation of the three-dimensional image data, the detected rotation angles are input from the rotation angle sensors 46a to 46e, and the surface shape of the object OB obtained by pairing the distance in the Z direction and the tilt angle in the X direction from the three-dimensional shape measuring device 10 is used. Enter information. Then, the image processing device 70 calculates the three-dimensional image data of the target OB in the coordinate system of the three-dimensional shape measuring device 10 using the input surface shape information of the target OB for each irradiation spot. Next, the calculated three-dimensional image data is calculated using the previously stored heights of the fixed pole 41 and the rotating rod 42, the lengths of the first to third arms 43 to 45, and the input detected rotation angle. And coordinate conversion into three-dimensional image data in a reference coordinate system (for example, coordinates based on a predetermined specific position of the base 30).
[0029]
A display device 80 is also connected to the image processing device 70. The display device 80 includes a liquid crystal display, a plasma display, a CRT display, and the like, and displays a three-dimensional image of the object OB based on three-dimensional image data from the image processing device 70.
[0030]
Next, the operation of the embodiment configured as described above will be described. First, the operator places the object OB on the base 30 and operates the input device 50 to set the three-dimensional shape measuring device 10 to the standby mode and hold the three-dimensional shape measuring device 10 by hand. To the part of the object OB to be measured. It is not always necessary to place the object OB on the base 30. In the standby mode, the laser light source 12 is intermittently excited by the operation of the pulse train signal generation circuit 62, the selection circuit 64, and the laser drive circuit 66 in the controller 60, and the laser light source 12 emits laser light intermittently. . The intermittent laser light emitted from the laser light source 12 irradiates the surface of the object OB via the collimator lens 13 and the galvanometer mirror 14, and forms an irradiation spot intermittently on the surface of the object OB.
[0031]
On the other hand, in this standby mode, the electric motor 21 is also operating, and the galvanomirror 14 reciprocates within a predetermined angle range, so that the scanning trace of the laser beam on the surface of the object OB in the X-axis direction shown in FIG. And the scanning trace is visually observed. In this case, since the irradiation with the laser beam is intermittent as described above, the scanning trace is composed of a plurality of discrete irradiation spots as shown in FIG. In this case, the intensity of the laser light emitted from the laser light source 12 is suppressed to a certain small intensity.
[0032]
In this state, the operator determines the measurement site of the target object OB by moving the three-dimensional shape measurement device 10 while holding it while observing the scanning trace formed of the intermittent irradiation spot. Thereafter, the operator operates the input device 50 to switch the three-dimensional shape measuring device 10 to the measurement mode.
[0033]
In the measurement mode, the laser light source 12 is continuously excited by the operation of the laser power adjustment circuit 63, the selection circuit 64, and the laser drive circuit 66 in the controller 60, and the laser light source 12 continuously emits laser light. The continuous laser light emitted from the laser light source 12 irradiates the surface of the object OB via the collimator lens 13 and the galvanometer mirror 14, and continuously forms an irradiation spot on the surface of the object OB. The laser light reflected from the irradiation spot forms an image on the line sensor 16 via the galvanometer mirror 14 and the imaging lens 15.
[0034]
Also in this measurement mode, the electric motor 21 is operating and the galvanomirror 14 reciprocates within a predetermined angle range, so that the scanning trace by the laser light on the surface of the object OB in the X-axis direction shown in FIG. Is formed along. In this case, since the irradiation with the laser beam is continuous as described above, the scanning trace is continuous as shown in FIG.
[0035]
Then, if the worker holds the three-dimensional shape measuring device 10 at the measurement position, the image processing device 70 indicates the surface shape of the object OB in the scanning line direction (X-axis direction) of the measurement laser light. Surface shape information in which the Z-direction distance and the X-direction tilt angle are paired is sequentially supplied from the three-dimensional shape measurement device 10. Then, the image processing device 70 generates three-dimensional image data representing the surface shape of the target object OB based on the rotation angles detected by the rotation angle sensors 46a to 46e in addition to the surface shape information, and supplies the data to the display device 80. . Therefore, the display device 80 displays the surface shape of the object OB along the scanning line of the laser beam.
[0036]
Further, if the operator moves the three-dimensional shape measuring device 10 in the Y-axis direction, the surface shape information along the scanning line of the laser beam at a different Y-axis direction position on the object OB is also input to the image processing device 70. Is done. Therefore, according to this, the surface shape of the predetermined area of the target object OB is displayed on the display device 80.
[0037]
Further, in this measurement mode, when the amount of laser light reaching the line sensor 16 from the surface of the object OB is insufficient, the photodetector 17, the reflected light amount detection circuit 67 and the laser power adjustment circuit 63 use the line sensor. 16 is controlled such that the amount of laser light received by the laser beam 16 is always constant. As a result, it is possible to measure a good three-dimensional shape even in a portion where the reflectance of the laser light on the surface of the object OB is low.
[0038]
As can be understood from the above description of the operation, according to the above embodiment, the operator views the scanning trace of the laser light composed of a plurality of discrete irradiation spots, and thereby places the three-dimensional shape measuring apparatus 10 in the standby state. You can easily understand that there is something. As a result, the work efficiency of the three-dimensional shape measurement of the object OB can be improved. Further, in the measurement state of the three-dimensional shape measuring apparatus 10, even if the intensity of the laser light emitted from the laser light source 12 is increased, it is possible to appropriately take protective measures for the worker.
[0039]
As mentioned above, although one Embodiment of this invention was described, in implementing this invention, it is not limited to the said Embodiment, A various deformation | transformation is possible unless it deviates from the objective of this invention.
[0040]
For example, in the above embodiment, the standby mode and the measurement mode of the three-dimensional shape measuring apparatus 10 are selected by operating the input device 50. However, instead of this, if the operation switches for selecting these modes are arranged on the housing 11 of the three-dimensional shape measuring device 10, the operator can hold the three-dimensional shape measuring device 10 with his / her hand, By operating the operation switch, it is possible to set the standby mode and the measurement mode.
[0041]
Further, in addition to scanning in the X-axis direction, by scanning the surface of the object OB also in the Y-axis direction with laser light, the surface of the object OB is scanned in both the X-axis and Y-axis directions, that is, in a matrix. Alternatively, the three-dimensional surface shape of the object OB in both the X-axis and Y-axis directions may be automatically measured without moving the three-dimensional shape measuring apparatus 10 in the Y-axis direction. In this case, the entire optical system including the laser light source 12, the collimating lens 13, the galvanometer mirror 14, the imaging lens 15, the line sensor 16, and the photodetector 17 is incorporated into a case movably assembled in the housing 11, and the entire case is assembled. The housing 11 may be rotated by an electric motor or the like along the Y-axis direction.
[0042]
Furthermore, in the above-described embodiment, the measurement position is determined by moving the three-dimensional shape measuring apparatus 10 with respect to the object OB. Conversely, the measurement of the three-dimensional shape measuring apparatus 10 is performed by moving the object OB. The position may be determined. Instead of manually moving the three-dimensional shape measuring device 10, the three-dimensional shape measuring device 10 may be moved by the moving device by assembling it with the moving device.
[Brief description of the drawings]
FIG. 1 is an overall schematic diagram of a three-dimensional shape measuring system including a three-dimensional shape measuring device according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing a configuration of the three-dimensional shape measuring apparatus of FIG.
FIG. 3 is a detailed block diagram of a controller attached to the three-dimensional shape measuring apparatus of FIG.
FIG. 4A is a diagram showing scanning traces of laser light in a standby mode, and FIG. 4B is a diagram showing scanning traces of laser light in a measurement mode.
[Explanation of symbols]
OB: object, 10: three-dimensional shape measuring device, 12: laser light source, 13: collimating lens, 14: galvanometer mirror, 15: imaging lens, 16: line sensor, 17: photodetector, 21: electric motor, 50 ... Input device, 60: controller, 61: control circuit, 62: pulse train signal generation circuit, 63: laser power adjustment circuit, 64: selection circuit, 70: image processing device, 80: display device.

Claims (6)

A laser light irradiator for irradiating the surface of the object with the laser light while scanning the laser light; and a light receiver for receiving the laser light reflected on the surface of the object. In a three-dimensional shape measuring device for measuring
A three-dimensional shape measuring apparatus, further comprising control means for controlling the laser beam irradiator so that a visual state of a scanning trace by the laser beam is different between a measurement state and a standby state. The three-dimensional shape measuring apparatus according to claim 1, wherein the scanning trace of the laser beam visually observed in the measurement state is a continuous line, and the scanning trace of the laser beam visually observed in the standby state is formed of a plurality of discrete irradiation spots. . 3. The laser beam irradiator according to claim 2, wherein the control unit controls the laser beam irradiator so as to continuously excite the laser beam irradiator in the measurement state and intermittently excite the laser beam irradiator in the standby state. 3D shape measuring device. A three-dimensional shape measuring method for irradiating an object surface with a laser beam while scanning the same, receiving the laser beam reflected on the object surface, and measuring the three-dimensional shape of the object surface with the received laser beam. ,
A three-dimensional shape measuring method, wherein a visual aspect of a scanning trace by the laser light is made different between a measurement state and a standby state. 5. The three-dimensional shape measuring method according to claim 4, wherein the scanning trace of the laser beam visually observed in the measurement state is a continuous line, and the scanning trace of the laser beam visually observed in the standby state includes a plurality of discrete irradiation spots. . 6. The three-dimensional shape measuring method according to claim 5, wherein the surface of the object is continuously irradiated with the laser light in the measurement state, and the surface of the object is intermittently irradiated with the laser light in the standby state.

Images