JP2003232626A - Method and device for measuring distance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for measuring distance inexpensively, capable of measuring the distance precisely with a simple system. <P>SOLUTION: The method for measuring distance comprises a first step, a second step, a third step, a fourth step, and a fifth step. In the first step, light is irradiated by a light irradiating means to a first reference object, and a distance conversion table, in which the image formation position on an image sensor is stored correspondingly to the distance between the light irradiating means and the first reference object, is produced. In the second step, light is irradiated by the light irradiating means under a prescribed condition to a second reference object disposed at a prescribed distance from the light irradiating means, and the reference image formation position is obtained. In the third step, light is irradiated by the light irradiating means to the second reference object, and the difference between the obtained image forming position and the reference image forming position obtained in the second step is calculated. In the fourth step, the distance conversion table is corrected according to the calculated difference. In the fifth step, the distance between the light irradiating means and the object of measurement is calculated based on the distance conversion table corrected in the fourth step according to the image forming position of the image sensor having received the reflected light from the object. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring method and a distance measuring apparatus, and more particularly, it irradiates a measuring object with light such as a laser beam and based on the reflected light from the measuring object. The present invention relates to a distance measuring method and a distance measuring device suitable for distance measurement using a triangulation method for measuring the distance to the measurement object.

In the present specification, the term "measurement object" means, for example, an opaque object having a three-dimensional spatial spread and formed of a predetermined material having a rough surface, and the like. The surface may be provided with a single color or a plurality of colors.

[0003]

2. Description of the Related Art Conventionally, an optical distance measuring device to which a triangulation method is applied is known.

In such a distance measuring device, a laser diode for irradiating a laser beam onto an object, a light receiving lens for receiving reflected light from the object irradiated with the laser beam from the laser diode, and a light receiving lens And an image sensor for forming an image of the reflected light received by the image sensor.

In the above distance measuring device, the light receiving lens receives the reflected light from the object, and the object to be measured is based on the received light waveform output from the image sensor in response to the reflected light from the received object. The distance to the object is measured.

In such a conventional distance measuring device,
There is a problem that it is not possible to perform highly accurate measurement due to temperature changes of optical system components such as the light receiving lens.

Therefore, in the conventional distance measuring device,
In order to perform highly accurate measurement, the temperature at the time of distance measurement is measured and corrected according to the temperature change,
Alternatively, an optical component for performing correction according to a temperature change is separately arranged.

However, like the conventional distance measuring device,
If the temperature is measured and the correction is performed according to the temperature change, a new problem that the whole system of the distance measuring device becomes complicated is brought about, and an optical component is separately added to the distance measuring device. If they are arranged, the structure of the entire apparatus becomes complicated, which causes a new problem that the number of parts and the manufacturing cost increase.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and the purpose thereof is to perform highly accurate measurement with a simple system. It is an object of the present invention to provide a distance measuring method and a distance measuring device that can be performed at low cost.

[0010]

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention irradiates a measuring object with light by means of a light irradiating means, In the distance measuring method, the reflected light is imaged on the image sensor, and the distance measuring process is performed to measure the distance to the object to be measured based on the imaged position of the reflected light on the image sensor. The light irradiation means irradiates the reference object with light, and the image formation position on the image sensor where the reflected light from the first reference object is received is defined by the light irradiation means and the first reference object. The first step of generating a distance conversion table stored in correspondence with the distance, and the second reference object arranged at a predetermined distance from the light irradiation means under the predetermined conditions. Irradiate light with
The second step of acquiring the image formation position on the image sensor, which receives the reflected light from the second reference object, as a reference image formation position, and the light irradiation means for irradiating the second reference object. Calculating the difference between the image formation position on the image sensor that receives the light reflected by the second reference object and the reference image formation position acquired in the second step. The third step, a fourth step of correcting the distance conversion table generated in the first step according to the difference calculated in the third step, and the light irradiation means for measuring the object to be measured. Depending on the image forming position of the image sensor that radiates light and receives the reflected light from the measurement object,
It has a fifth step of calculating the distance between the light irradiation means and the measurement object from the distance conversion table corrected in the fourth step.

Therefore, according to the first aspect of the present invention, the difference between the image forming position on the image sensor receiving the reflected light from the second reference object and the reference image forming position is calculated. Accordingly, the distance conversion table is corrected, so even if a plastic lens is used as the light receiving lens that receives the reflected light from the measurement object, high accuracy measurement can be performed with a simple system. It is possible and can be an inexpensive method.

In the invention according to claim 2 of the present invention, in the invention according to claim 1, the predetermined condition when the reference imaging position is acquired in the second step is This is to match the condition when the distance conversion table is generated in the first stage.

In the invention according to claim 3 of the present invention, there is provided light irradiation means for irradiating the measurement object with light, and reflected light from the measurement object irradiated with light from the light irradiation means. A distance measuring device having an image sensor for forming an image and performing a distance measuring process for measuring a distance from the object to be measured based on an image forming position of reflected light on the image sensor; The light irradiation means irradiates the object with light, and the image formation position on the image sensor which receives the reflected light from the first reference object is defined by the light irradiation means and the first reference object. Distance conversion table generation means for generating a distance conversion table stored corresponding to the distance, and second distance arranged at a predetermined distance from the light irradiation means.
Of the reference object is irradiated with light by the light irradiation means under a predetermined condition, and the image formation position on the image sensor which receives the reflected light from the second reference object is set as a reference image formation position. Image formation on the image sensor, which receives the reference image formation position obtaining means and the second reference object which is irradiated with light by the light irradiation means and receives reflected light from the second reference object. Generated by the distance conversion table generation means according to the difference calculated by the difference calculated between the position and the reference image formation position acquired by the reference image formation position acquisition means, and the difference calculated by the difference calculation means. According to the image forming position of the image sensor that receives the reflected light from the measurement object by irradiating the measurement object with light by the light irradiating means and a correction means for correcting the distance conversion table. Up From the distance conversion table corrected by the correction means it is obtained so as to have a distance calculating means for calculating the distance between the light irradiation means and said object.

Therefore, according to the third aspect of the present invention, the image forming position on the image sensor and the reference image forming position where the reflected light from the second reference object is received by the difference calculating means. When a plastic lens is used as the light receiving lens for receiving the reflected light from the measurement object, the distance conversion table is corrected according to the difference calculated by the correction means. Also in this case, highly accurate measurement can be performed with a simple system, and an inexpensive device can be obtained.

According to a fourth aspect of the present invention, in the invention according to the third aspect, the predetermined condition when the reference image-forming position obtaining means obtains the reference image-forming position is The condition for generating the distance conversion table by the distance conversion table generating means is matched.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of a distance measuring method and a distance measuring device according to the present invention will be described below in detail with reference to the accompanying drawings.

Here, FIGS. 1 and 2 are schematic perspective views showing an example of an embodiment of the distance measuring apparatus according to the present invention. 1 is a schematic configuration perspective view of the distance measuring device as viewed from above, and FIG. 2 is a schematic configuration perspective view of the distance measuring device as viewed from below (first
The pillar member 14 (described later) is omitted for easy understanding. ).

FIG. 3 is an explanatory view of the schematic configuration centering on the laser diode when the distance measuring device is viewed from above, and FIG. 4 is a conceptual diagram of the rotating mechanism of the distance measuring device. FIG. 5 is a block configuration diagram mainly showing a control system for controlling the entire operation of the distance measuring device.

The distance measuring device 10 includes a base 12 having a rectangular parallelepiped shape and a first pillar member which is erected so as to face one end of the base 12 on the upper surface 12a side with a predetermined gap therebetween. 14 and the second pillar member 16, and an upper surface member 18 that bridges between the upper surface of the first pillar member 14 and the upper surface of the second pillar member 16.
And a turn table base 20 disposed on the upper surface 12a side of the base 12, and a turn table base 20.
1 is formed on the upper surface 20a side of the XY plane and forms an XY plane in an orthogonal coordinate system defined by an X axis, a Y axis, and a Z axis that are orthogonal to each other, and the arrow A direction (clockwise direction in FIG. Direction) and the arrow B direction (counterclockwise direction), respectively, between the turn table 22 as the first rotating means and the first pillar member 14 and the second pillar member 16, which are rotatably arranged. The first pillar member 14 and the second pillar member 16 are arranged along the axial direction (Z-axis direction), and the arrow C direction (clockwise direction) and the arrow D direction (counterclockwise) in FIG. And a rotary support 24 as a second rotating means which is rotatable in the rotational direction) and a Z-direction via the linear motion bearing 26 on the rotary support 24.
The head 28 is arranged so as to be movable in the vertical direction along the axial direction, and rotates with the rotation of the rotary column 24 around the Z-axis direction, and the turntable base member 2.
It has a reference object 70 disposed on the upper surface 20a of the reference table 0 close to the turntable 22.

The above-described distance measuring device 10 is controlled by the microcomputer 100 in its entire operation including drive control of a turn table motor 40, a rotating column motor 46, and a head motor 54, which will be described later. It is a thing.

Further, reference numeral 34 is a bearing for rotatably supporting the upper end portion of the rotary support column 24 on the upper surface member 18, and reference numeral 36 is a bearing for rotatably supporting the lower end portion of the rotary support column 24 on the base 12. It is a bearing.

The head 28 is provided with a laser diode 72 as an irradiation means for irradiating a laser beam as light from an emission point 72a, and a projection lens 74 for receiving the laser beam emitted from the laser diode 72. From the laser diode 72 to the laser
As a light receiving lens 76 on which the reflected light from the measuring object 200 irradiated with the beam enters, and an image sensor for receiving the diffuse reflection component of the reflected light received by the light receiving lens 76 and forming an image of the reflected light CCD (charge-
and a coupled device 78 are fixedly arranged in respective predetermined directions. The head 28 includes a laser diode drive circuit 80 for driving the laser diode 72 and a C for driving the CCD 78.
And a CD drive circuit 82.

The light projecting lens 74 and the light receiving lens 76 are plastic lenses. The focal position of the light projecting lens 74 is from the laser diode 72 to the light projecting lens 74 on the measurement surface 70a of the reference object 70.
It is set so that the spot diameter of the laser beam projected through is minimum.

The turntable 22 has a substantially circular upper surface 22a. In the present specification,
The "center of rotation of the turntable 22" will be appropriately referred to as "origin C of the turntable 22 (see FIGS. 1 and 3)". Also, in this embodiment, the radius r of the upper surface 22a of the turntable 22 is 13
It is set to 0 mm (so the diameter 2r is 260 m
m. ). And the origin C of the turntable 22
And the emission point 72 of the laser diode 72 of the head 28
The distance L1 from a is set to 230 mm.

The reference object 70 is a substantially plate-shaped body as a whole, and is formed of, for example, a metal, and the surface thereof is rustproofed. Further, the flat measurement surface 70a side is fixedly disposed on the upper surface 20a of the turn table base member 20 so as to face the head 28.

More specifically, the reference object 70 is arranged such that the distance L2 between the measurement surface 70a of the reference object 70 and the emission point 72a of the laser diode 72 of the head 28 becomes a predetermined distance. In addition, in this embodiment,
The distance L2 between the measurement surface 70a of the reference object 70 and the emission point 72a of the laser diode 72 of the head 28 is 21
It is set to 0 mm. That is, the distance L2 between the measurement surface 70a of the reference object 70 and the emission point 72a of the laser diode 72 of the head 28 is the distance between the origin C of the turntable 22 and the emission point 72a of the laser diode 72 of the head 28. It is set to be 20 mm shorter than L1.

Next, regarding the rotating mechanism of the turn table 22 and the rotating column 24 of the distance measuring device 10,
A distance measuring device 1 shown in FIG. 3 together with FIG. 1 and FIG.
This will be described with reference to the conceptual diagram of the 0 rotation mechanism.

As the initial positions of the turn table 22 and the rotary support column 24, arbitrary positions can be set as the initial positions. For the rotary support column 24, for example, the rotary support column 24 is used. The head 28 mounted on the rotary column 24 is positioned such that the optical axis of the laser beam emitted from the laser diode 72 of the head 28 mounted on the rotary table 24 passes through the origin C of the turntable 22. The optical axis of the laser beam emitted from the laser diode 72 can be set to a position such that the optical axis of the laser beam passes through the position of the center of gravity of the measuring object 200 arranged on the turntable 22.

Then, on the lower surface 12b side of the base 12,
A pulley 38 fixed to a rotary shaft arranged at the center of the turntable 22, a turntable motor 40 for rotating the turntable 22, and a turntable
A pulley 42 fixed to the rotary shaft of the table motor 40 and a pulley 4 fixed to the lower end of the rotary column 24.
4, a rotary strut motor 46 for rotating the rotary strut 24, and a pulley 48 fixed to the rotation shaft of the rotary strut motor 46.

An endless belt 50 is stretched between the pulley 38 and the pulley 42, and the rotation of the rotary shaft of the turn table motor 40 is transmitted to the turn table 22 for the turn table. The turntable 22 rotates around the Z-axis in the arrow A direction (clockwise direction) and the arrow B direction (counterclockwise direction) by the rotation of the rotating shaft of the motor 40.

An endless belt 52 is stretched between the pulley 44 and the pulley 48, and the rotation of the rotation shaft of the rotating strut motor 46 is transmitted to the rotating strut 24.
The rotation column 24 is rotated around the Z axis in the arrow C direction (clockwise direction) and the arrow D direction (counterclockwise direction) by the rotation of the rotation shaft of the rotation column motor 46.

Here, the turntable motor 40
And the rotary strut motor 46, the turntable 22
When the turntable 22 rotates in the same direction around the Z axis in the same direction, that is, when the turntable 22 rotates in the direction of arrow A (clockwise direction) in FIG. The support column 24 rotates around the Z-axis in the direction of arrow C (clockwise direction) in FIG.
When the table 22 rotates in the direction of arrow B (counterclockwise direction) in FIG.
The rotation direction and the rotation angle are controlled by the microcomputer 100 so that is rotated in the arrow D direction (counterclockwise direction) in FIG. 1 around the Z-axis direction.

Further, a head motor 54 for driving the head 28 in the vertical direction along the Z-axis direction is disposed above the second pillar member 16. A pulley 56 is fixed to the rotary shaft of the head motor 54.

On the other hand, a pulley 58 is rotatably disposed below the second pillar member 16 so as to face the pulley 56.

An endless belt 60, to which the mounting portion 28a formed on the head 28 is fixed, is stretched between the pulley 56 and the pulley 58, and the endless belt 60 is rotated by the rotation of the rotating shaft of the motor 54. By moving, the head 28 is configured to move in the vertical direction.

Next, FIG. 5 shows a block diagram mainly showing a control system for controlling the entire operation of the distance measuring device 10. This control system is the microcomputer as described above. 100 controls the overall operation.

The microcomputer 100 includes a central processing unit (CPU) 102 for executing processing according to a program stored in a memory 104, which will be described later, and a CPU 1.
A memory 104 storing a program to be executed by 02.
And a light receiving waveform data storage unit 106-1 that stores light receiving waveform data described below under the control of the CPU 102 and the CPU.
A random access memory (RA) in which an area or the like as a working area when the distance measurement device 10 performs the distance measurement processing is set under the control of 102.
M) 106 and a distance data memory 108 that stores distance data described below under the control of the CPU 102.

Here, the microcomputer 100
There are a timing signal generating circuit 110 for outputting a predetermined timing signal, and an analog / digital (A / D) converter 112 for converting a light receiving waveform signal which is an analog signal output from the CCD 78 into light receiving waveform data which is a digital signal. It is connected. Therefore, the received light waveform data based on the received light waveform signal output from the CCD 78 is input to the microcomputer 100.

Further, the CPU 102 of the distance measuring device 10
Is connected to the external computer 12 via the communication circuit 120.
It is connected to 2. Therefore, various data of the distance measuring device 10 is transmitted to the computer 1 via the communication circuit 120.
22 and is processed by the computer 122.

Then, the CPU 102 outputs the laser beam from the laser diode 72 and the CCD 78.
The measurement control signal for controlling the reception of the reflected light by is output to the timing signal generation circuit 110 at a predetermined timing.

Further, the CPU 102 outputs drive signals for driving the turntable motor 40, the rotary strut motor 46 and the head motor 54 at predetermined timings to the turntable motor 40, the rotary strut motor 46 and the head. It outputs to each of the motor 54 for. The turn table motor 40 and the rotary strut motor 46 have a rotation direction and a rotation angle such that the turn table 22 and the rotation strut 24 rotate in the same direction by the same angle around the Z-axis direction. Are controlled by the CPU 102.

Then, the timing signal generation circuit 110
Outputs a timing signal to each of the laser diode drive circuit 80 and the CCD drive circuit 82 at a predetermined timing according to the measurement control signal from the CPU 102. Further, the timing signal generation circuit 110 controls the RAM 106 and the A / D converter 112.

Therefore, the turntable 22 is rotated around the Z-axis direction as the turntable motor 40 for rotating the turntable 22 is driven by the drive signal from the CPU 102. Has been done. That is, the rotation direction and the rotation angle of the turntable 22 around the Z-axis direction are controlled by the CPU 102.

On the other hand, in the head 28, the rotary strut motor 46 for the rotary strut 24 on which the head 28 is arranged is
It is adapted to rotate in accordance with the rotation of the rotary column 24 around the Z-axis direction when driven by the drive signal from the PU 102. A head motor 54 for moving the head 28 up and down is movable in the vertical direction along the Z-axis direction as it is driven by a drive signal from the CPU 102. Therefore, the head 28
The CPU 102 controls the rotation direction and rotation angle around the Z-axis direction, and the movement direction and movement distance along the Z-axis direction.

Laser diode 72 of head 28
Is driven by the laser diode drive circuit 80 when the timing signal output from the timing signal generation circuit 110 is input to the laser diode drive circuit 80. At this time, the laser diode 72 emits a laser beam at a predetermined timing according to the timing signal for a predetermined time.

The CCD 78 of the head 28 is connected to the light receiving lens 7
A light receiving buffer 78a having an electronic shutter for receiving the diffuse reflection component of the reflected light received by 6 and a transfer buffer 78 for transferring the accumulated charges to the outside of the CCD 78.
and b.

The light receiving buffer 76a of the CCD 78 reflects light from the measuring object 200 or the like (diffuse reflection component of reflected light).
The light receiving time, that is, the exposure time of the CCD 78 is controlled by the exposure time control signal output from the timing signal generating circuit 110.

Then, the transfer buffer 78b of the CCD 78
The light receiving buffer 78a transfers the accumulated charges to the outside by receiving the diffuse reflection component of the reflected light. This causes the CCD 78 to receive the light receiving buffer 78a.
The received light waveform signal which is an analog signal based on the received light at
Output to the / D converter 112.

In the above structure, the operation of the above distance measuring device 10 will be described with reference to FIGS. 6 to 10.

When the user of the distance measuring device 10 uses the distance measuring device 10 to measure the distance with respect to the object 200 to be measured, the distance conversion table and the reference address are set in advance in the memory 104. It is assumed to be stored in the area.

Here, the distance conversion table is for calculating the distance between the measuring object 200 and the head 28 from the received light waveform data obtained in the distance measuring device 10. It is created at the time of factory shipment and stored in a predetermined area of the memory 104.

Specifically, first, the reference object 700 (see FIG. 6) made of gypsum is placed on the turntable 22.
It is placed on the upper surface 22a. Further, a jig (not shown) in which a motor is arranged and whose position can be designated is also placed at a predetermined position on the upper surface 22a of the turn table 22. By driving this jig by the driving force of the motor, the jig can move the reference object 700 to a predetermined position on the upper surface 22a of the turntable 22.

Then, along the diametrical direction passing through the origin C of the turntable 22, from the end of the turntable 22 closest to the head 28 to the end of the turntable 22 farthest from the head 28, the reference object 700 is formed. Is moved by a jig at a predetermined interval (see the interval W shown in FIG. 6), and the address of the CCD 78 for each interval W of the turn table 22 is sequentially stored. The interval W is, for example, 5 mm.

More specifically, each time the reference object 700 moved by the jig is moved to a predetermined position on the upper surface 22a of the turntable 22 at every interval W, it is output from the timing signal generating circuit 110. According to the timing signal, the laser beam from the laser diode 72 of the head 28 is applied to the reference object 700 via the light projecting lens 74.

Then, the reflected light from the reference object 700 irradiated with the laser beam from the laser diode 72 is received by the light receiving lens 76.

In this way, the diffuse reflection component of the reflected light received by the light receiving lens 76 is at a timing according to the timing signal output from the timing signal generating circuit 110, specifically, the laser from the laser diode 72.
The light receiving buffer 7 of the CCD 78 is synchronized with the irradiation of the beam.
The light is received by 8a.

At this time, the CCD drive circuit 82 is driven according to the exposure time control signal according to the preset exposure time, the electronic shutter of the CCD 78 is opened for a predetermined exposure time, and the diffuse reflection component of the reflected light is CCD78. Is received by the light receiving buffer 78a.

When the light receiving buffer 78a receives the diffuse reflection component of the reflected light in this way, the accumulated charge is transferred to the CCD 78.
Is transferred to the outside by the transfer buffer 78b of FIG. 1 and the received light waveform signal is output to the A / D converter 112.

The received light waveform signal is converted into received light waveform data by the A / D converter 112, and the upper surface 22a of the turntable 22 on which the reference object 700 is located.
The received light waveform data at a predetermined position of is stored in the received light waveform data storage unit 106-1. The light reception waveform data obtained in this way indicates the brightness (light reception amount) for each address of the CCD 78.

Here, when the position of the reference object 700 changes on the upper surface 22a of the turntable 22 moved by the jig, that is, when the distance between the reference object 700 and the head 28 changes, the reference object 700 is changed. The position at which the diffuse reflection component of the reflected light is received by the light receiving buffer 78a of the CCD 78 also changes.

Therefore, by the processing of the CPU 102, the center of gravity position of the received light waveform indicated by the received light waveform data is calculated, and the CCD address S1 (see FIG. 7) corresponding to the calculated center of gravity position is set as the image forming position on the CCD 78. It is stored in association with the position of the upper surface 22a of the turntable 22 on which the reference object 700 was located when the received light waveform data was obtained. From this, a distance conversion table in which the CCD address of the CCD 78 is associated with the distance between the reference object 700 and the head 28 is generated.

FIG. 8 shows a graph showing an example of the distance conversion table. In the graph shown in FIG. 7, on the upper surface 22 of the turntable 22 having a diameter of 260 mm, the reference object 700 is moved by 5 mm by a jig along the diameter direction passing through the origin C of the turntable 22. This is an example of the case.

That is, the distance “0” mm shown on the horizontal axis of the graph corresponds to the origin C of the turn table 22, and the range of 0 <distance ≦ 130 is within the range of the turn table 22.
From the origin C of the turntable 22 to the end of the turntable 22 closest to the head 28. The range of −130 ≦ distance <0 is from the origin C of the turntable 22 to the head 28 of the turntable 22. It corresponds to the farthest end. The blank portion between two adjacent points where the received light waveform data is actually obtained is interpolated and generated by linear interpolation.

On the other hand, the reference address is a reference value for distance correction, is acquired under the condition that matches the condition when the distance conversion table is generated, and is stored in the memory 104.
Is stored in a predetermined area. Therefore, for example, when the distance measuring device 10 is shipped from the factory, if the reference address is acquired immediately after the distance converting table is generated, when the environmental temperature of the distance measuring device 10 is 28 ° C., the distance converting table is obtained. Is generated, and the reference address is acquired at the same environmental temperature of 28 ° C.

Specifically, the reference object 7 fixedly arranged on the upper surface 20a of the turntable base member 20.
A laser beam is emitted from the laser diode 72 of the head 28 through the light projecting lens 74 onto the surface 70a of 0. Then, the surface 7 of the reference object 70 irradiated with the laser beam from the laser diode 72.
The reflected light from 0a is received by the light receiving lens 76, and the received light waveform data at the position of the reference object 70 is obtained.

Here, the measurement surface 70a of the reference object 70 and the emission point 72a of the laser diode 72 of the head 28 are measured.
And the distance L2 is 210 mm, and the spot diameter of the laser beam projected from the laser diode 72 via the projection lens 74 is minimized on the measurement surface 70a of the reference object 70. Therefore, the center of gravity position of the received light waveform indicated by the received light waveform data obtained at the position of the reference object 70 is calculated, and the CC corresponding to the calculated center of gravity position is calculated.
With the D address as the imaging position on the CCD 78, the distance from the emission point 72a of the laser diode 72 is 2
It is stored as a reference address indicating the reference in the case of 10 mm. Since this reference address is acquired immediately after the distance conversion table is generated, for example, when the distance conversion table as shown in FIG. 8 is generated, the reference address is the distance +20 in the distance conversion table. (= 230mm
(L1) -210 mm (L2)) CCD address S2
(See FIG. 8).

In addition to the distance conversion table and the reference address, when the distance measuring device 10 is shipped from the factory, for example, the laser beam emitted from the laser diode 72 of the head 28 measures the reference object 70. Face 7
From the position irradiated with 0a to the position where the optical axis of the laser beam passes the origin C of the turntable 22,
The swinging step amount of the head 28 is also stored in advance in a predetermined area of the memory 104.

When the user uses the distance measuring device 10 to measure the object 200 to be measured with the distance conversion table and the reference address as described above stored in the memory 104 in advance, The distance measurement processing of the distance measurement processing routine shown in FIG. 9 is executed. It should be noted that this distance measurement processing routine is started and executed when an instruction from the computer 122 is received while the distance measuring device 10 is powered on.

At the time of distance measurement, the user places the measuring object 200 to be measured on the upper surface 22 of the turntable 22.
Place it near the origin C of a.

On the other hand, the initial position of the optical axis of the laser beam emitted from the laser diode 72 of the head 28 is set so as to pass the origin C of the turntable 22.

When this distance measurement processing routine is activated, first, in step S902, scan parameter input processing is performed. Specifically, when this distance measurement processing routine is started while the distance measuring device 10 is powered on, a user setting screen (not shown) is displayed on the screen of the display device (not shown) of the computer 122. ) Is displayed. A user of the distance measuring device 10 selects each of the fields on the user setting screen by using an input device (not shown) of the computer 122, and various parameters for measurement such as a scan pitch and a scan range. Can be set. Then, various parameters set in the computer 122 are input to the distance measuring device 10 via the communication circuit 120 and stored in a predetermined area of the RAM 106.

When the process of step S902 ends, the process proceeds to step S904, and the scan start instruction information input process is performed. A user who uses the distance measuring device 10 selects the start of measurement by using the input device (not shown) of the computer 122, and the scan start instruction information for instructing the start of the measurement is transmitted to the communication circuit 12.
It is input to the distance measuring device 10 via 0. As a result, in the distance measuring device 10, the measurement according to the scan parameter input in the process of step S902 is started.

Subsequent to the processing of step S904, the reference object 70 is scanned in step S906. That is, when the distance measurement device 10 is instructed to start the measurement, first, according to the swing step amount of the head 28 stored in advance in a predetermined area of the memory 104,
The CPU 102 controls the rotary strut motor 46 to rotate the head 28 facing the origin C of the turntable 22 around the Z-axis direction (direction of arrow C in FIG. 3). As a result, a laser beam is emitted from the laser diode 72 (indicated by a broken line in FIG. 3) of the head 28 facing the reference object 70 via the projection lens 74. Irradiate 70.

Laser diode 72 to laser
The reflected light from the surface 70a of the reference object 70 irradiated with the beam is received by the light receiving lens 76. Light receiving lens 7
The diffuse reflection component of the reflected light received by 6 is received by the light receiving buffer 78a of the CCD 78, and the accumulated charge is CC.
The light is transferred to the outside by the transfer buffer 78b of D78 and the received light waveform signal is output to the A / D converter 112.

The received light waveform signal is converted into received light waveform data by the A / D converter 112, and the received light waveform data at the position of the reference object 70 after the measurement start instruction and before the measurement start is obtained.

When the process of step S906 ends, the process proceeds to step S908, the difference from the reference address is calculated, and the correction value is determined. More specifically, the barycentric position of the received light waveform indicated by the received light waveform data is calculated from the received light waveform data at the position of the reference object 70 after the measurement start instruction obtained by the process of step S906. Then, the difference between the CCD address corresponding to the calculated center of gravity position and the reference address is calculated.

If the CCD address corresponding to the barycentric position of the received light waveform data at the position of the reference object 70 after the measurement start instruction and the reference address match, step S
At 906, the reference address is acquired based on the condition when the received light waveform data is obtained at the position of the reference object 70 after the measurement start instruction, that is, the temperature of the external environment in which the distance measuring device 10 is currently installed. It is consistent with the time and has not changed.

That is, it is not necessary to consider the expansion and contraction of the plastic light-receiving lens 76 due to the temperature change, and the CCD address corresponding to the barycentric position of the light-receiving waveform data at the position of the reference object 70 after the measurement start instruction The difference from the reference address is “0”, and the correction value = 0.

On the other hand, the CC corresponding to the position of the center of gravity of the received light waveform data at the position of the reference object 70 after the measurement start instruction is issued.
If the D address and the reference address do not match, the condition when the received light waveform data at the position of the reference object 70 after the measurement start instruction is obtained in step S906, that is, the distance measuring device 10 is provided. It means that the external environment such as the temperature being changed does not match when the reference address was acquired.

That is, it is necessary to consider the expansion and contraction of the plastic light-receiving lens 76 due to the temperature change, and the address of the center of gravity position of the light-receiving waveform data and the reference address at the position of the reference object 70 after the measurement start instruction is made. The difference is calculated and used as the correction value. In this case, the correction value ≠ 0.

When the process of step S908 is completed, the process proceeds to step S910 and the turntable 22
The measurement object 200 placed on the is scanned.

First, the CPU 102 controls the rotary strut motor 46 in accordance with the swing step amount of the head 28 stored in a predetermined area of the memory 104 in advance, and the head facing the reference object 70. 28 is rotated around the Z-axis direction (direction of arrow D in FIG. 3) to face the origin C of the turntable 22.

Here, the measurement surface of the measuring object 200 (see FIG. 5) arranged on the turntable 22 is measured point P0, measuring point P1, measuring point P3, ...
Measurement point Pm-1, measurement point Pm (however,
“M” is a positive integer indicating the total number of measurement points. )
If it is set to “angle θ = 1 °” for each measurement, the measurement point P0 to the measurement point Pm
The distance is measured at each measurement point where the angle on the measurement surface up to is changed by 1 °.

At this time, by driving the turn table motor 40, the rotating column motor 46, and the head motor 54 in accordance with the drive signal of the CPU 102, the object to be measured around the Z-axis along with the rotation of the turn table 22. Laser diode 72 synchronized with the rotation of 200
The optical axis of the laser beam emitted from the object to be measured 2
The head 28 is rotated around the Z-axis direction so as to maintain the same direction and the same rotation angle as the rotation direction of 00.

Thus, the region of the measurement surface of the measuring object 200 irradiated with the laser beam from the laser diode 72 can be made orthogonal to the optical axis of the laser beam irradiated by the laser diode 72. Therefore, the accuracy of measurement can be improved.

Such a turntable 22 and head 2
8 is repeatedly performed while changing the height of the head 28 in the Z-axis direction while changing the distance between the head 28 and the measuring object 20 by changing the predetermined angle θ.
The distance of the measurement surface of 0 is measured.

Then, a laser beam is emitted from the laser diode 72 of the head 28 at each measurement point on the measurement surface of the measurement object 200 arranged on the turntable 22, and the received light waveform data at each measurement point is obtained. It is stored in the received light waveform data storage unit 106-1.

Subsequent to the processing of step S910, distance data calculation processing is performed in step S912. In this distance data calculation process, step S
In 910, distance data indicating the distance between each measurement point of the measurement object 200 and the head 28 is calculated from the received light waveform data for each measurement point stored in the received light waveform data storage unit 106-1.

The distance data is calculated from such received light waveform data by calculating the peak position of the received light waveform indicated by the received light waveform data and converting the distance using the CCD address corresponding to the calculated peak position as the imaging position on the CCD 78. It is done using a table.

Here, if the correction value = 0 in step S908, that is, the reference object 7 after the measurement start instruction is given.
When the CCD address corresponding to the position of the center of gravity of the received light waveform data at the position of 0 and the reference address match, the memory 1 created at the factory of the distance measuring device 10 is shipped.
The distance data is calculated using the distance conversion table stored in the predetermined area 04.

For example, when the distance conversion table shown in FIG. 8 is created at the time of factory shipment of the distance measuring device 10 and stored in a predetermined area of the memory 104, the CCD address corresponding to the calculated peak position of the received light waveform. Is "410
If it is "00", the distance is +54 mm. That is, the distance between the head 28 and each measurement point of the measurement object 200 from which the received light waveform data is obtained is 176 mm (= 230 mm).
mm (L1) -54 mm).

On the other hand, in step S908, the correction value ≠
If 0, that is, the reference object 70 after the measurement start instruction
C corresponding to the position of the center of gravity of the received light waveform data at the position
If the CD address and the reference address do not match, the memory 1 created when the distance measuring device 10 is shipped from the factory.
The distance conversion table stored in the predetermined area 04 is corrected by the correction value, and the distance data is calculated using the corrected distance conversion table.

Specifically, for example, the CCD address corresponding to the barycentric position of the received light waveform data at the position of the reference object 70 after the measurement start instruction obtained in step S906 is "43281", and the reference address is " 4378
If it is “1”, by the processing of step S908,
The difference between the address "43281" of the center of gravity position of the received light waveform data at the position of the reference object 70 after the measurement start instruction and the reference address "43781" +500 (= 43781)
-43281) is determined as the correction value.

That is, the address of the distance conversion table created at the time of factory shipment of the distance measuring device 10 and stored in the predetermined area of the memory 104 is shifted by the correction value = + 500 (see the broken line in FIG. 10). as a result,
When the CCD address corresponding to the calculated peak position of the received light waveform is "41000", the distance is +58 mm. That is, the distance between the head 28 and each measurement point of the measuring object 200 from which the received light waveform data is obtained is 172.
mm (= 230 mm (L1) -58 mm).

Then, the calculated distance data is stored in the distance data memory 108. Further, the distance data stored in the distance data memory 108 is used as the communication circuit 1
It is output to the computer 122 via 20 and the distance measurement processing routine is ended.

As described above, in the distance measuring device 10 having an example of the embodiment of the distance measuring method and the distance measuring device according to the present invention, the received light waveform data at the position of the reference object 70 after the measurement start instruction is given. When the CCD address corresponding to the position of the center of gravity and the reference address do not match, a correction value is calculated, and the distance conversion table generated using the reference object 700 is corrected. Can be measured, and an inexpensive device can be obtained.

That is, according to the distance measuring method and the distance measuring device of the present invention, the light receiving lens 76 made of plastic is provided in the distance measuring device 10. It is possible to obtain a highly accurate measurement result without performing an appropriate correction or separately disposing an optical component that performs a correction according to a temperature change.

Further, according to the distance measuring method and the distance measuring apparatus of the present invention, an inexpensive plastic light receiving lens 76 can be provided without changing the plastic light receiving lens to expensive glass which is hardly affected by temperature. Since a highly accurate measurement result can be obtained while it is used, the entire device can be made inexpensive.

Furthermore, according to the distance measuring method and the distance measuring device of the present invention, it is not limited to the case where the plastic light receiving lens expands or contracts with the temperature change,
For example, even if the external environment other than temperature such as humidity or various conditions such as temperature change of optical system components such as a light projecting lens and a lens barrel change, highly accurate measurement results can be obtained. .

The above-described embodiment may be modified as described in (1) to (7) below.

(1) In the above embodiment, the laser diode 72 is used as the light irradiating means.
Of course, the present invention is not limited to this. For example, various laser oscillators such as a multi-mode laser oscillator and lamps may be used.

(2) In the above-mentioned embodiment, the CCD 78 is used as the image sensor, but it is needless to say that it is not limited to this, and various image sensors may be appropriately used. Good.

(3) In the above-described embodiment, the case of "angle θ = 1 °" in the scanning of the measuring object 200 has been described, but it is needless to say that the angle θ is not limited to this. Any angle can be set as. Further, it goes without saying that the driving method and driving direction of the head 28 and the turn / tumble 22 are not limited to those in the above-described embodiment, and all the measurement points are measured according to the type of the measuring object 200. You may change suitably as much as possible.

(4) In the above embodiment, the received light waveform data and the distance data are stored in the received light waveform data storage unit 106-1 and the distance data memory 108, respectively, but the present invention is not limited to this. Needless to say, the area for storing various data, whether to process inside or outside the distance measuring device, and the like may be changed as appropriate.

(5) In the above embodiment, the distance conversion table is generated by using the reference object 700 formed of gypsum, and the reference object is formed of metal and the surface of which is subjected to rust prevention processing. Although the reference address is acquired using 70, it goes without saying that the reference address is not limited to this, and the reference object for generating the distance conversion table and the reference object for acquiring the reference address are not limited to this. The material may be changed as appropriate, and the arrangement position and the like may be changed according to the size of the entire apparatus.

(6) In the above embodiment, when the correction value ≠ 0 in the distance measurement processing routine, the address of the distance conversion table is uniformly shifted by the correction value to set the distance conversion table. Although the correction is performed (see FIGS. 9 and 10), it is needless to say that the correction value is not 0, and when the correction value ≠ 0, the distance conversion table is calculated using the correction value and the predetermined coefficient. May be corrected.

For example, the correction value calculated in step S908 and the CCD 78 in the above-described embodiment.
When the distance conversion table is corrected with a value calculated using a coefficient such that the value to be corrected becomes smaller as the address of is closer to 0, and the value to be corrected becomes larger as the address of the CCD 78 is further from 0. It is possible to obtain a more accurate measurement result.

(7) The above-described embodiments and the modifications shown in (1) to (6) may be combined appropriately.

[0109]

Since the present invention is configured as described above, it is possible to provide a highly accurate measurement with a simple system and an inexpensive distance measuring method and distance measuring device. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic configuration perspective view showing an example of an embodiment of a distance measuring device according to the present invention, and is a schematic configuration perspective view of a distance measuring device when 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 of the distance measurement device when viewed from below. The first pillar member is
Omitted for ease of understanding.

FIG. 3 is a schematic configuration explanatory view mainly showing a laser diode when the distance measuring device according to the present invention is viewed from above.

FIG. 4 is a conceptual diagram of a rotation mechanism of the distance measuring device according to the present invention.

FIG. 5 is a block diagram mainly showing a control system for controlling the overall operation of the distance measuring device according to the present invention.

FIG. 6 is an explanatory view mainly showing a laser diode and a CCD of the distance measuring device according to the present invention.

FIG. 7 is a graph showing an example of a received light waveform represented by received light waveform data.

FIG. 8 is a graph showing an example of a distance conversion table.

FIG. 9 is a flowchart of a distance measurement processing routine of the distance measurement device according to the present invention.

FIG. 10 is a graph showing another example of the distance conversion table.

[Explanation of symbols]

10 distance measuring device 12 base 12a upper surface of base 14 first pillar member 16 second pillar member 18 upper surface member 20 turn table base 20a upper surface of turn table base 22 turn table 24 rotating strut 26 linear bearing 28 head 28a mounting portion 34, 36 bearing 38, 42, 44, 48, 56, 58 pulley 40 turn table motor 46 rotating strut motors 50, 52, 60 endless belt 54 motor 70 reference object 70a measuring surface 72 laser diode 72a Emitting point 74 Light emitting lens 76 Light receiving lens 78 CCD 78a Light receiving buffer 78b Transfer buffer 80 Laser diode drive circuit 82 CCD drive circuit 100 Micro computer 102 Central control unit (CPU) 104 Memory 106 Random Access memory (RAM) 106-1 receiving the waveform data storage section 108 the distance data memory 110 the timing signal generating circuit 112 analog / digital (A / D) converter 120 communication circuit 122 computer 200 measurement object 700 reference object

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA06 BB05 DD00 EE02 EE05                       FF09 FF61 GG06 GG12 HH04                       JJ03 JJ26 LL30 NN01 NN11                       PP02 PP05 PP13 QQ00 QQ03                       QQ23 QQ25 QQ28                 2F112 AA09 BA09 CA12 DA26 EA05                       FA03 FA07 FA21 FA45 GA10

Claims (4)

[Claims] 1. A light irradiation means irradiates a measuring object with light to form an image of reflected light from the measuring object on an image sensor, and at an image forming position of the reflected light on the image sensor. In the distance measuring method for performing the distance measuring process for measuring the distance to the measurement object based on the above, the first reference object is irradiated with light by the light irradiating means, and the reflected light from the first reference object is emitted. A first step of generating a distance conversion table in which the received image formation position on the image sensor is stored in association with the distance between the light irradiation means and the first reference object; On the image sensor which has received light reflected by the second reference object by irradiating the second reference object arranged at a predetermined distance with light by the light irradiation means under predetermined conditions. The image forming position of is the reference image forming position A second step of obtaining, and an image forming position on the image sensor, which irradiates the second reference object with light by the light irradiating means and receives reflected light from the second reference object, A third step of calculating a difference from the reference imaging position acquired in the second step, and the distance generated in the first step according to the difference calculated in the third step Fourth to correct the conversion table
And the image forming position of the image sensor which receives the reflected light from the measuring object by irradiating the measuring object with light by the light irradiating means and is corrected in the fourth step. A distance measuring method comprising a fifth step of calculating a distance between the light irradiation means and the measurement object from a distance conversion table. 2. The distance measuring method according to claim 1, wherein the predetermined condition when the reference imaging position is acquired in the second step is that a distance conversion table is generated in the first step. A distance measurement method that matches the conditions for the measurement. 3. A light irradiation means for irradiating the measurement object with light, and an image sensor for forming an image of reflected light from the measurement object irradiated with light from the light irradiation means,
In a distance measuring device that performs a distance measuring process for measuring a distance to the measurement object based on an image formation position of reflected light on the image sensor, the first reference object is irradiated with light by a light irradiation unit. , An image of the reflected light received from the first reference object
A distance conversion table generating means for generating a distance conversion table in which the imaging position on the sensor is stored in correspondence with the distance between the light irradiation means and the first reference object; and a predetermined distance from the light irradiation means. An image is formed on the image sensor, which receives light reflected by the second reference object by irradiating the second reference object arranged in A reference image forming position obtaining unit that obtains a position as a reference image forming position; and the second reference object, which is irradiated with light by the light emitting unit and receives reflected light from the second reference object. Difference calculation means for calculating a difference between the image formation position on the image sensor and the reference image formation position acquired by the reference image formation position acquisition means, and the difference calculation means according to the difference calculated by the difference calculation means Distance conversion table generation Correction means for correcting the distance conversion table generated by the step, and the image forming position of the image sensor which receives the reflected light from the measurement object by irradiating the measurement object with light by the light irradiation means. Accordingly, a distance measuring device having distance calculating means for calculating the distance between the light irradiation means and the object from the distance conversion table corrected by the correcting means. 4. The distance measuring device according to claim 3, wherein the predetermined condition when the reference image formation position acquisition unit acquires the reference image formation position is that the distance conversion table generation unit performs the distance conversion. A distance measuring device that matches the conditions when the table is generated.