JP3727513B2 - Distance measuring method and distance measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distance measuring method and a distance measuring device, and more particularly, irradiates a target with light such as a laser beam and measures the distance to the target based on reflected light from the target. The present invention relates to a distance measuring method and a distance measuring apparatus suitable for distance measurement using a triangulation method.
[0002]
[Prior art]
Conventionally, as a device for measuring the amount of movement of an object as an object to be measured, the size of the object, or the shape of the object, for example, a distance measuring device using a laser beam applying a triangulation method is known. Some of these distance measuring devices can measure the three-dimensional shape of an object.
[0003]
Here, as a distance measuring device capable of measuring a three-dimensional shape of an object, for example, it is arranged on an XY plane of an orthogonal coordinate system defined by an X axis, a Y axis, and a Z axis orthogonal to each other. And a rotatable turntable and a head that is fixed in the direction toward the rotation center of the turntable and that can move up and down in the Z-axis direction (height direction). Things are known.
[0004]
The above-described head irradiates the object placed on the turn table with a laser beam, and the irradiation direction of the laser beam passes through the rotation axis of the turn table. A laser diode fixed in direction and an image sensor for forming an image of reflected light from an object irradiated with a laser beam from the laser diode are provided.
[0005]
In the above configuration, in order to measure the distance between the three-dimensional object and the head using the distance measuring device described above, the turntable on which the object is placed is rotated and the head is moved in the Z-axis direction ( The object is irradiated with a laser beam from the laser diode of the head at each repetition, and the reflection from the object accompanying the irradiation of the laser beam. A light image is formed on an image sensor, and the distance between the object and the head is measured in accordance with the image formation position.
[0006]
However, in the conventional distance measuring apparatus as described above, since the irradiation direction of the laser beam is fixed in such a direction as to pass through the rotation axis of the turntable, for example, the object is a coffee cup. In such a case, the area where the laser beam cannot be irradiated, such as the inside of the handle of the coffee cup (hereinafter referred to as “the area where the laser beam cannot be irradiated”) is appropriately referred to as “blind spot”. There was a problem that the accuracy of measurement was reduced.
[0007]
Further, it is known that it is preferable to irradiate a laser beam so as to be orthogonal to the measurement surface of the object in order to perform measurement with high accuracy using the conventional distance measuring apparatus as described above.
[0008]
However, in the conventional distance measuring apparatus as described above, since the irradiation direction of the laser beam irradiated to the object is fixed in a certain direction, the measurement surface of the object is compared with the measurement surface. The region where the laser beam cannot be irradiated so as to be orthogonal (hereinafter, “the region where the laser beam cannot be irradiated so as to be orthogonal to the measurement surface” will also be appropriately referred to as “dead angle”. ) Increased, and there was a problem that high-precision measurement could not be performed.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the problems of the prior art as described above, and the object of the present invention is to improve the accuracy of measurement by reducing the blind spot when irradiating the object with light. It is an object of the present invention to provide a distance measuring method and a distance measuring apparatus that can achieve the above.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a distance measuring method and a distance measuring device according to the present invention are arranged around the Z-axis direction on the XY plane of the orthogonal coordinate system defined by the mutually orthogonal X-axis, Y-axis, and Z-axis. Synchronizing with the rotation of the object to be rotated, by rotating the optical axis of the light irradiated to the object at the same angle in the same direction as the rotation, the region irradiated with light as the object rotates The pseudo coordinate system is constructed in a pseudo manner.
[0011]
That is, according to the first aspect of the present invention, the object is irradiated with light by the light irradiation means, and an image of the reflected light from the object is formed on the image sensor, and the image Orthogonal coordinates defined by mutually orthogonal X-axis, Y-axis, and Z-axis in a distance measurement method for performing distance measurement processing for measuring the distance to the object based on the imaging position of the reflected light image on the sensor The object is rotated in the predetermined direction at a predetermined angle from the initial position on the XY plane of the system in the predetermined direction, and the optical axis of the light irradiation means is set to the initial position in synchronization with the rotation of the target object. The distance is measured according to the rotation of the object and the optical axis of the light irradiation means by rotating around the Z-axis direction so as to maintain the same direction and the same rotation angle as the rotation direction of the object. It is something to be processed
[0012]
Therefore, according to the first aspect of the present invention, in synchronization with the rotation of the object around the Z-axis direction, the optical axis of the light irradiation means is the same direction and the same as the rotation direction of the object. It rotates around the Z-axis direction so as to maintain the rotation angle. As a result, it becomes possible to change the optical axis of the light irradiated to the object from the light irradiating means, so that it is possible to reduce a blind spot that is an area where the light irradiating means cannot irradiate light, and to measure It is possible to improve the accuracy.
[0013]
In other words, since the region of the measurement surface of the object irradiated with light from the light irradiation means can be orthogonal to the optical axis of the light irradiated by the light irradiation means, the measurement of the object is performed. This makes it possible to reduce blind spots, which are regions where light cannot be irradiated so as to be orthogonal to the surface.
[0014]
Moreover, the optical axis of the light irradiation means in the invention described in claim 1 of the present invention is independent of rotation around the Z-axis direction as in the invention described in claim 2 of the present invention. It can move along the axial direction.
[0015]
The invention according to claim 3 of the present invention forms an image of light irradiation means for irradiating the object with light and reflected light from the object irradiated with light from the light irradiation means. An X-axis orthogonal to each other in a distance measurement device that performs a distance measurement process that measures a distance from the object based on an imaging position of an image of reflected light on the image sensor, A first object that arranges an object on an XY plane of an orthogonal coordinate system defined by the Y axis and the Z axis, and rotates the object in a predetermined direction at a predetermined angle from an initial position around the Z axis direction. In synchronization with the rotation of the object by the rotation means and the first rotation means, the optical axis of the light irradiation means is maintained in the same direction as the rotation direction of the object and the same rotation angle from the initial position. Rotate around the Z-axis To is obtained so as to have a second rotary means.
[0016]
Therefore, according to the third aspect of the present invention, the optical axis of the light irradiating means is adjusted by the second rotating means in synchronization with the rotation of the object around the Z-axis direction by the first rotating means. It is rotated around the Z-axis direction so as to maintain the same direction and the same rotation angle as the rotation direction of the object. As a result, the optical axis of the light applied to the object from the light irradiating means changes, so that it is possible to reduce the blind spots that are areas where the light irradiating means cannot irradiate light, thereby improving the measurement accuracy. Will be able to.
[0017]
In other words, the area of the measurement surface of the object irradiated with light from the light irradiation means becomes orthogonal to the optical axis of the light irradiated by the light irradiation means, and the measurement surface of the object is This makes it possible to reduce blind spots, which are regions where light cannot be irradiated so as to be orthogonal.
[0018]
Further, as in the invention described in claim 4 of the present invention, in the invention described in claim 3 of the present invention, the optical axis of the light irradiation means is further independent of rotation around the Z-axis direction. A moving means that moves along the Z-axis direction may be provided.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a distance measuring method and a distance measuring device according to the present invention will be described in detail with reference to the accompanying drawings.
[0020]
Here, FIGS. 1 and 2 are schematic configuration perspective views showing an example of the embodiment of the distance measuring device according to the present invention. 1 is a schematic perspective view of the distance measuring device as viewed from above, and FIG. 2 is a schematic perspective view of the distance measuring device as viewed from below (note that the first column member 14 (described later). ) Is omitted for ease of understanding.)
[0021]
The distance measuring device 10 includes a rectangular base 12 and a first column member 14 and a first column member 14 erected facing each other at a predetermined interval on one end of the base 12 on the upper surface 12a side. A two-column member 16, an upper surface member 18 that bridges the upper surface of the first column member 14 and the upper surface of the second column member 16, and a turntable base 20 disposed on the upper surface 12 a side of the base 12. 1 is formed on an upper surface 20a side of the turntable base 20 to form an XY plane in an orthogonal coordinate system defined by an X axis, a Y axis, and a Z axis orthogonal to each other and around the Z axis direction. Turn table 22 as the first rotating means, and the first column member 14 and the second column, which are rotatably arranged in the arrow A direction (clockwise direction) and the arrow B direction (counterclockwise direction), respectively. Between the member 16 1 are arranged along the axial direction (Z-axis direction) of the first pillar member 14 and the second pillar member 16, and the arrow C direction (clockwise direction) and the arrow D direction (counterclockwise direction) in FIG. A rotating support column 24 as a second rotating means that can be rotated in each direction, and a rotary support column 24 that is movably arranged in the vertical direction along the Z-axis direction via a linear motion bearing 26. And a head 28 that rotates with the rotation of the rotating column 24 around the Z-axis direction.
[0022]
The head 28 is irradiated with a laser diode 30 as an irradiating means for irradiating an object to be measured arranged on the turntable 22 as light and a laser beam from the laser diode 30. A CCD 32 as an image sensor that forms an image of reflected light from the target object is fixedly arranged in a predetermined direction.
[0023]
Reference numeral 34 denotes a bearing for rotatably supporting the upper end portion of the rotating column 24 on the upper surface member 18, and reference numeral 36 denotes a bearing for rotatably supporting the lower end portion of the rotating column 24 on the base 12. .
[0024]
Next, the rotation mechanism of the turn table 22 and the rotating column 24 of the distance measuring device 10 will be described with reference to FIGS. 1 and 2 and the conceptual view of the rotating mechanism of the distance measuring device 10 shown in FIG.
[0025]
The initial positions of the turntable 22 and the rotary column 24 can be set as arbitrary positions. The rotary column 24 is attached to the rotary column 24, for example. The position of the optical axis of the laser beam emitted from the laser diode 30 of the head 28 passes through the center of rotation of the turntable 22, or the laser beam of the head 28 attached to the rotary column 24 For example, the optical axis of the laser beam emitted from the diode 30 may pass through the center of rotation of the object disposed on the turntable 22.
[0026]
On the lower surface 12 b side of the base 12, a pulley 38 fixed to a rotation shaft disposed at the center of the turn table 22, a turn table motor 40 for rotating the turn table 22, A pulley 42 fixed to the rotating shaft of the table motor 40, a pulley 44 fixed to the lower end of the rotating column 24, a rotating column motor 46 for rotating the rotating column 24, and a rotating column motor 46 And a pulley 48 fixed to the rotary shaft.
[0027]
An endless belt 50 is stretched between the pulley 38 and the pulley 42, and the rotation of the rotating shaft of the turntable motor 40 is transmitted to the turntable 22. The rotation of the rotary shaft causes the turntable 22 to rotate in the direction of arrow A (clockwise direction) and in the direction of arrow B (counterclockwise direction) around the Z-axis direction.
[0028]
Further, an endless belt 52 is stretched between the pulley 44 and the pulley 48, and the rotation of the rotating shaft of the rotating column motor 46 is transmitted to the rotating column 24, and the rotating shaft of the rotating column motor 46 is rotated. The rotation support 24 rotates around the Z-axis direction in the direction of arrow C (clockwise direction) and in the direction of arrow D (counterclockwise direction).
[0029]
Here, the turn table motor 40 and the rotary column motor 46 are configured such that the turn table 22 and the rotary column 24 rotate in the same direction around the Z axis in the same direction, that is, the turn table 22 has the Z axis. When rotating in the direction of arrow A (clockwise direction) in FIG. 1 around the direction, the rotary support 24 rotates in the direction of arrow C (clockwise direction) in FIG. 1 rotates in the direction of arrow B (counterclockwise direction) in FIG. 1 around the Z-axis direction, the rotating column 24 rotates in the direction of arrow D (counterclockwise direction) in FIG. 1 around the Z-axis direction. As described above, the rotation direction and the rotation angle are controlled by the microcomputer 100.
[0030]
Further, a motor 54 that drives the head 28 in the vertical direction along the Z-axis direction is disposed on the second column member 16. A pulley 56 is fixed to the rotating shaft of the motor 54.
[0031]
On the other hand, a pulley 58 is rotatably disposed below the second column member 16 so as to face the pulley 56.
[0032]
An endless belt 60 that fixes a mounting portion 28a formed on the head 28 is stretched between the pulley 56 and the pulley 58, and the endless belt 60 is moved by the rotation of the rotating shaft of the motor 54. Thus, the head 28 is configured to move in the vertical direction.
[0033]
In the above configuration, the distance measuring device 10 also irradiates the object placed on the turntable 22 with the laser beam from the laser diode 30 of the head 28, as in the conventional distance measuring device. An image of the reflected light from the object is formed on the CCD 32, and the distance between the object and the head 28 is measured according to the image forming position.
[0034]
Next, the rotation around the Z-axis direction of the turn table 22 and the rotation of the rotary support 24 around the Z-axis direction, that is, the rotation of the head 28 around the Z-axis direction, that is, the Z of the laser diode. The rotation around the axial direction will be described with reference to the explanatory view showing the positional relationship between the turntable 22 and the head 28 as viewed from above shown in FIG.
[0035]
In the following description, a case where the distance between the cube-shaped object 200 and the head 28 is measured will be described.
[0036]
Here, the object 200 is arranged on the turn table 22 so that the center position C in the XY plane coincides with the rotation center of the turn table 22.
[0037]
The initial position of the optical axis of the laser beam emitted from the laser diode 30 is set to a position that passes through the rotation center of the turntable 22.
[0038]
On the other hand, the initial position of the object 200 arranged on the turntable 22 is such that the surface (measurement surface) located closest to the laser diode 30 of the object 200 is irradiated from the laser diode 30 at the initial position. It is set at a position perpendicular to the optical axis of the laser beam.
[0039]
A surface parallel to the measurement surface and passing through the center position C is referred to as a quasi-orthogonal surface.
[0040]
By the way, when measuring the measurement point P on the measurement surface of the object 200 arranged on the turn table 22 by the triangulation method using the conventional distance measurement method, the laser diode 30 of the head 28 irradiates. It is preferable to move the laser diode 30 to the laser position 2 in FIG. 4 because it is possible to perform measurement with high accuracy when the laser beam is measured in a state orthogonal to the measurement surface.
[0041]
However, in the distance measuring device 10 according to the present invention, the turntable motor 40 and the rotary column motor 46 are controlled by the micro computer 100 so that the turntable 22 and the head 28 are the same in the Z-axis direction. It is set so that the laser beam irradiated from the laser diode 30 of the head 28 passes through the measurement point P orthogonally by rotating in the same direction (in the direction of arrow E in FIG. 4) by the angle θ. . At this time, the measurement distance 2 in FIG.
[0042]
Here, the measurement distance 2 is “distance L1−distance L2.” That is, the measurement distance 2 is obtained by the calculation shown in Expression (1).
[0043]
Measurement distance 2 = distance L1-distance L2 (1)
Here, the distance L1 can be derived from the following equation (2) using the angle θ and the head distance.
[0044]
Distance L1 = Head distance × cos θ (2)
Therefore, by substituting Equation (2) into Equation (1), Equation (1) can be modified as shown in Equation (3).
[0045]
Measurement distance 2 = (head distance × cos θ) −L2 (3)
The distance L2 can be obtained from the measurement result obtained by the distance measuring device 10.
[0046]
That is, as described above, the turn table 22 and the head 28 are synchronously rotated by the same angle in the same direction around the Z axis direction, so that the X axis and the Y axis that are quasi-orthogonal to each other on the turn table 22 And an orthogonal coordinate system defined by the Z axis can be constructed, and a laser beam can be emitted from the laser diode 30 of the head 28 so as to be orthogonal to the quasi-orthogonal plane.
[0047]
Therefore, according to the distance measuring device 10, the optical axis of the laser beam emitted from the laser diode 30 is the same as the rotation direction of the object 200 in synchronization with the rotation of the object 200 around the Z-axis direction. Since the rotation is performed around the Z-axis direction while maintaining the same direction and the same rotation angle, the optical axis of the laser beam irradiated from the laser diode 30 onto the object 200 can be changed. Therefore, it is possible to reduce the blind spot, which is an area where the laser diode 30 cannot irradiate the laser beam, and to improve the measurement accuracy.
[0048]
Further, according to the distance measuring device 10, the optical axis of the laser beam emitted from the laser diode 30 is the same as the rotation direction of the object 200 in synchronization with the rotation of the object 200 around the Z-axis direction. And rotating around the Z-axis direction so as to maintain the same rotation angle, the laser diode 30 irradiates the region of the measurement surface of the object 200 irradiated with the laser beam from the laser diode 30. Since the laser beam can be orthogonal to the optical axis of the laser beam, the blind spot, which is a region where the laser beam cannot be irradiated so as to be orthogonal to the measurement surface of the object 200, can be reduced. Thus, the accuracy of measurement can be improved.
[0049]
In the example shown in FIG. 4, for example, when the measurement surface is to be measured from the measurement point P to the measurement point Pn, if “angle θ = 1 °” is set, the measurement point P to the measurement point The distance can be measured at each measurement point where the angle on the measurement surface up to Pn is changed by 1 °.
[0050]
The distance measurement performed while changing the turn table 22 and the head 28 by a predetermined angle θ as described above is repeated while changing the vertical height of the head 28 in the Z-axis direction. On the other hand, since the distance of the measurement surface of the object 200 located in front of the pseudo orthogonal surface can be measured, it is possible to obtain a three-dimensional shape of the measurement surface.
[0051]
In the conventional distance measuring apparatus, the laser beam irradiation direction is fixed in a direction passing through the rotation center of the turntable 22, and the laser beam is sequentially applied to the measurement target surface of the coffee cup 300 as shown in FIG. , The inner surface 300b of the handle 300a of the coffee cup 300 becomes a blind spot, making it impossible to irradiate a laser beam.
[0052]
However, in the distance measuring device 10 according to the present invention, the turntable 22 and the laser diode 30 are rotated around the Z-axis direction to a position where the laser beam reaches the inner surface 300b of the handle 300a and can be measured (laser).・ Rotation of the diode 30 around the Z-axis direction is realized by rotating the rotary support column 24 around the Z-axis direction and rotating the head 28 around the Z-axis direction as the rotary support column 24 rotates around the Z-axis direction. By irradiating a laser beam to the quasi-orthogonal plane obtained thereby, it is possible to measure by irradiating a laser beam to a part that cannot be measured because it becomes a blind spot in a conventional distance measuring device. become able to.
[0053]
Moreover, the preferable procedure in the case of measuring the three-dimensional shape of a target object using this distance measuring device 10 is as follows, for example.
[0054]
That is, by using the vertical movement of the head 28 along the Z-axis direction and the rotation of the turn table 22, an image of reflected light (distance image) is obtained radially with respect to the object to be measured and formed on the CCD. The distance is measured (first measurement process).
[0055]
Next, a plane that can be accurately measured, that is, a pseudo-orthogonal plane, is set in a pseudo manner with respect to the part that becomes the blind spot of the measurement object, and a distance is measured with respect to the pseudo-orthogonal plane using an orthogonal coordinate system. (Second measurement process).
[0056]
What is necessary is just to perform the process which synthesize | combines the data obtained by the above-mentioned 1st measurement process and 2nd measurement process, and obtains the distance image of the whole target object.
[0057]
As described above, according to the distance measuring device 10 of the present invention, it is possible to perform highly accurate measurement with a small blind spot on an object.
[0058]
Further, according to the distance measuring device 10 of the present invention, even if distance images from various directions are obtained, the data of these distance images can be easily synthesized.
[0059]
Furthermore, according to the distance measuring device 10 of the present invention, it is easy to set conditions for repeated measurements.
[0060]
The embodiment described above may be modified as described in the following (1) to (6).
[0061]
(1) In the above-described embodiment, the laser diode 30 is used as the light irradiating means. However, the present invention is not limited to this, and various types such as, for example, a multi-mode laser oscillator are used. A laser oscillator, a lamp, or the like may be used.
[0062]
(2) In the above-described embodiment, the CCD 32 is used as the image sensor. However, the present invention is not limited to this, and various image sensors may be used as appropriate.
[0063]
(3) In the above-described embodiment, the turn table 22 and the rotating column 24 are rotated by transmitting the rotation of the motor through the belt. However, the present invention is not limited to this, and the motor May be directly rotated or may be rotated via a gear, and an appropriate method can be used.
[0064]
(4) In the above-described embodiment, the case of “angle θ = 1 °” has been described. However, the present invention is not limited to this, and an arbitrary angle can be set as the angle θ. .
[0065]
(5) In the above-described embodiment, the cube-shaped object 200 and the coffee cup 300 have been described as the objects to be measured. However, the present invention is not limited to this, and an arbitrary shape may be used. An object may be an object to be measured.
[0066]
(6) You may make it combine the above-mentioned embodiment and the modification shown in said (1) thru | or (5) suitably.
[0067]
【The invention's effect】
Since the present invention is configured as described above, there is provided a distance measuring method and a distance measuring apparatus capable of reducing the blind spot when irradiating light on an object and improving the accuracy of measurement. There is an excellent effect that it can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration perspective view showing an example of an embodiment of a distance measurement device according to the present invention, and is a schematic configuration perspective view when the distance measurement device is viewed from above.
FIG. 2 is a schematic configuration perspective view showing an example of an embodiment of a distance measurement device according to the present invention, and is a schematic configuration perspective view when the distance measurement device is viewed from below. The first pillar member is omitted for easy understanding.
FIG. 3 is a conceptual diagram of a rotation mechanism of the distance measuring device.
FIG. 4 is an explanatory diagram showing a positional relationship between a turntable and a head viewed from above.
FIG. 5 is a perspective view of a coffee cup as an object to be measured.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Distance measuring device 12 Base 12a Base upper surface 12b Base lower surface 14 First column member 16 Second column member 18 Upper surface member 20 Turn table base 20a Turn table base upper surface 22 Turn table 24 Rotating column 26 Direct Dynamic bearing 28 Head 28a Mounting portion 30 Laser diode 32 CCD
34, 36 Bearing 38, 42, 44, 48, 56, 58 Pulley 40 Motor for turntable 46 Motor for rotating column 50, 52, 60 Endless belt 54 Motor 100 Micro computer 200 Object 300 Coffee cup 300a Handle 300b Inside surface of the handle

Claims (4)

The object is irradiated with light by the light irradiating means, and an image of reflected light from the object is formed on an image sensor, and based on the imaging position of the image of reflected light on the image sensor, In a distance measurement method for performing a distance measurement process for measuring a distance to an object,
Rotating an object in a predetermined direction at a predetermined angle from an initial position around the Z-axis direction on an XY plane of an orthogonal coordinate system defined by an X-axis, a Y-axis, and a Z-axis orthogonal to each other;
In synchronization with the rotation of the object, the optical axis of the light irradiation means is rotated around the Z-axis direction from the initial position so as to maintain the same direction and the same rotation angle as the rotation direction of the object,
A distance measuring method for performing the distance measuring process according to the rotation of the object and the optical axis of the light irradiation means. The distance measuring method according to claim 1,
A distance measuring method in which the optical axis of the light irradiation means moves along the Z-axis direction independently of the rotation around the Z-axis direction. A light irradiating means for irradiating the object with light; and an image sensor for forming an image of reflected light from the object irradiated with light from the light irradiating means, and reflection on the image sensor. In a distance measuring device that performs a distance measuring process for measuring a distance from the object based on an imaging position of an image of light,
An object is disposed on an XY plane of an orthogonal coordinate system defined by an X axis, a Y axis, and a Z axis orthogonal to each other, and the object is arranged at a predetermined angle from an initial position around the Z axis direction. First rotating means for rotating in the direction;
Synchronously with the rotation of the object by the first rotating means, the optical axis of the light irradiating means is maintained in the same direction and the same rotation angle as the rotation direction of the object from the initial position. A distance measuring device having a second rotating means that rotates around an axial direction. The distance measuring device according to claim 3, further comprising:
A distance measuring apparatus comprising: a moving unit that moves the optical axis of the light irradiation unit along the Z-axis direction independently of rotation around the Z-axis direction.

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