JP2014202691A - Three-dimensional measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional measuring system capable of always realizing highly accurate measurement even for changes of environmental temperature.SOLUTION: A three-dimensional measuring system comprises: a movable point light source for measurement movable to an arbitrary position; and a position detector which receives light from the point light source for measurement and detects the position of the point light source for measurement. A transparent substrate for calibration having at least two reference lines which are separate with a gap in a pixel array direction of each line sensor are arranged between a first optical system and a first line sensor and between a second optical system and a second line sensor which constitute the position detector. Further, in a probe calculation section, out of brightness distribution signal detected by each line sensor and reference position signals 82A, 82B based on the two reference lines, a shift amount associated with thermal expansion or movement of the line sensor is calculated from pixel positions of the line sensors corresponding to the reference position signals 82A, 82B, the shift amount is corrected and the coordinates of the point light source for measurement are calculated.

Description

  The present invention relates to a three-dimensional measurement system for optically measuring the position and shape of a workpiece. More specifically, the present invention relates to a three-dimensional measurement system including a measurement point light source that can be moved to an arbitrary position, and a position detection device that receives light from the measurement point light source and detects the position of the measurement point light source. .

  Conventionally, spot light is irradiated onto the workpiece (workpiece), and the reflected light from the irradiation position or the light from the measuring point light source that can be moved to any position is received to detect the irradiation position and measurement of the spot light. A three-dimensional measurement system for obtaining information on the position of a point light source is known.

  For example, in Patent Document 1, first and second optical systems that irradiate a workpiece with spot light and converge reflected light from the irradiation position onto different regions on the X axis, and these optical systems on the X axis. First and second line sensors that receive reflected light converged in different regions and output detection signals representing the luminance distribution on the X axis, and an optical system that converges the reflected light of the spot light on the Y axis. A third line sensor that receives reflected light converged on the Y-axis by this optical system and outputs a detection signal representing a luminance distribution on the Y-axis, and a workpiece based on the detection signal from each line sensor. A three-dimensional measurement system including an arithmetic processing unit that obtains information on the irradiation position of the spot light has been proposed.

  According to such a measurement system, even if it does not have a three-dimensional drive axis such as an X-axis, a Y-axis, or a Z-axis, the information regarding the irradiation position where the spot light is irradiated only by irradiating the workpiece with the spot light. Can be detected optically accurately. Therefore, it is used for measurement of huge structures and measurement in dangerous areas.

JP 2005-233759 A

By the way, since the above-mentioned three-dimensional measurement system is used for measurement of a huge structure or the like, it is often used in an environment with a large temperature change such as outdoors.
When used in an environment with a large temperature change, the pixels that make up the line sensor and the mount plate to which the line sensor is attached undergo thermal expansion as the temperature changes. It will change. As a result, when obtaining the irradiation position of the spot light or the coordinate position of the point light source from the barycentric position of these luminance distribution signals, high-precision measurement cannot be expected.

  An object of the present invention is to provide a three-dimensional measurement system that can always realize highly accurate measurement even when the ambient temperature changes.

  The three-dimensional measurement system of the present invention includes a measurement point light source that can move to an arbitrary position, and a position detection device that receives light from the measurement point light source and detects the position of the measurement point light source. The position detection device is arranged on the first axis by a pair of first optical systems arranged separately from each other and condensing the light from the point light source for measurement on the first axis. A pair of first line sensors that receive the light condensed on the first axis and output a first luminance distribution signal representing the luminance distribution on the first axis, and the light from the measurement point light source is orthogonal to the first axis A second optical system for condensing on the second axis, and a second luminance distribution signal representing the luminance distribution on the second axis by receiving the light condensed on the second axis by the second optical system. Based on the output second line sensor, the first luminance distribution signal and the second luminance distribution signal, In the three-dimensional measurement system configured to include a position calculation unit that calculates the coordinates of the fixed point light source, between the first optical system and the first line sensor, and between the second optical system and the second A transparent calibration substrate having at least two reference lines spaced from each other in the pixel array direction of each line sensor is disposed between the line sensors, and the position calculation unit is a luminance detected by each line sensor. Of the reference position signal based on the distribution signal and the two reference lines, a shift amount accompanying thermal expansion or movement of the line sensor is calculated from the pixel position of the line sensor corresponding to the reference position signal, and the shift amount And the coordinates of the point light source for measurement are calculated.

According to such a configuration, when the measurement point light source is turned on, the light from the measurement point light source is detected as a luminance distribution signal by the first line sensor and the second line sensor.
In the present invention, at least two reference lines that are spaced apart in the pixel array direction of each line sensor between the first optical system and the first line sensor and between the second optical system and the second line sensor. Therefore, the reference position signal based on these reference lines is detected by each line sensor in a state of being superimposed on the luminance distribution signal.

Then, the position calculation unit performs thermal expansion or movement of the line sensor from the pixel position of the line sensor corresponding to the reference position signal, out of the luminance distribution signal detected by each line sensor and the reference position signal based on the two reference lines. The shift amount accompanying the calculation is calculated, the shift amount is corrected, and the coordinates of the measurement point light source are calculated. For example, after correcting the luminance centroid position of the luminance distribution signal detected by each line sensor with the calculated shift amount, the coordinates of the point light source for measurement are calculated from the corrected luminance centroid position.
Therefore, even if the line sensor thermally expands or moves due to a change in the environmental temperature, the coordinates of the point light source for measurement are calculated by correcting the shift amount associated with the thermal expansion or movement. Even with this, high-precision measurements can always be achieved.

  In the three-dimensional measurement system of the present invention, the position calculation unit includes two reference-time pixel positions of the line sensor corresponding to the two reference position signals detected in advance at a reference temperature, and the detection at the time of measurement. Preferably, a shift amount is calculated from a difference between two reference position signals and two pixel positions at the time of measurement of the line sensor, and the coordinates of the measurement point light source are corrected so as to cancel the shift amount. .

  According to such a configuration, the two reference-time pixel positions of the line sensor corresponding to the two reference position signals detected in advance at the reference temperature, and the line sensor corresponding to the two reference position signals detected at the time of measurement. Since the shift amount is calculated from the difference between the two measurement pixel positions and the luminance gravity center position is corrected by this shift amount, the coordinates of the measurement point light source can be calculated with high accuracy.

  In the three-dimensional measurement system of the present invention, when the position of the two pixel positions at the time of measurement of the line sensor corresponding to the two reference position signals detected at the time of measurement has changed, The shift amount accompanying the thermal expansion of the line sensor is calculated from the difference between the two reference pixel positions and the two measurement pixel positions, and 2 of the line sensor corresponding to the two reference position signals detected at the time of measurement. When the interval between two measurement pixel positions does not change, it is preferable to calculate a certain amount of shift amount accompanying the movement of the line sensor from the difference between the reference pixel position and the measurement pixel position.

According to such a configuration, when the interval between two measurement pixel positions of the line sensor corresponding to the two reference position signals detected at the time of measurement changes, the thermal expansion of the line sensor occurs. Since the shift amount associated with the thermal expansion of the line sensor is calculated from the difference between the two reference pixel positions and the two measurement pixel positions, the shift amount associated with the thermal expansion of the line sensor can be accurately calculated.
Further, when the interval between two measurement pixel positions of the line sensor corresponding to the two reference position signals detected at the time of measurement does not change, the line sensor is regarded as moving, and the reference pixel position and the measurement are measured. Since a certain amount of shift according to the difference from the time pixel position is calculated, the amount of shift accompanying the movement of the line sensor can be accurately calculated.

In the three-dimensional measurement system of the present invention, it is preferable that the calibration substrate is formed by etching the reference line on a glass substrate.
According to such a configuration, the calibration substrate has a configuration in which the reference line is formed on the glass by etching, so that there is an advantage that it is less affected by heat and can be easily manufactured.

The figure which shows the whole structure of 1st Embodiment of this invention. The block diagram of embodiment same as the above. The perspective view which shows a contact-type probe in embodiment same as the above. The perspective view which shows the structure of a detection part in embodiment same as the above. The figure which shows the state which incorporates the board | substrate for calibration in embodiment same as the above. The figure which shows the board | substrate for a calibration in embodiment same as the above. The figure which shows the relationship between the luminance distribution signal detected by a line sensor, and a reference position signal in embodiment same as the above. The figure for demonstrating the correction method by the thermal expansion of a line sensor in embodiment same as the above. The figure for demonstrating the correction method by the movement of a line sensor in embodiment same as the above. The figure for demonstrating the correction method by thermal expansion and a movement of a line sensor in embodiment same as the above. The figure which shows a non-contact-type probe.

<First Embodiment>
As shown in FIGS. 1 and 2, the three-dimensional measurement system of the present embodiment controls the probe 10, the imaging unit 20, the probe 10 and the imaging unit 20, and based on the detection signal from the imaging unit 20. A calculation control device 30 that calculates the position of the probe 10 and the position of the contact 17 of the probe 10 and a display device 40 are provided. Here, the imaging unit 20 and the calculation control device 30 constitute a position detection device.

As shown in detail in FIG. 3, the probe 10 includes a probe main body 11 having a size that can be moved by a measurer to an arbitrary position by hand, and a stylus 16 provided integrally with the probe main body 11. It is configured.
The probe main body 11 is formed in a shape having two arms 12 and 13 which are joined at one end, bent in an arc shape so that the other end is gradually separated, and then joined again so that the measurer can grasp with both hands. . In addition, on the front surface of the probe main body 11, there are three LEDs (point light sources for measurement) on one end coupling portion 14 of the arms 12 and 13 and both sides sandwiching the other end coupling portion 15 of the arms 12 and 13 ( Light emitting diodes 1 to 3, 4 to 6, and 7 to 9 are arranged, respectively. That is, a total of nine LEDs 1 to 9 are arranged on the probe main body 11. These LEDs 1 to 9 are configured to be lit in a preset order in synchronization with a pulse signal from the arithmetic and control unit 30.
The stylus 16 is provided so as to protrude from the other end coupling portion 15 of the arms 12 and 13 of the probe main body 11 to the side opposite to the one end coupling portion 14, and has a spherical contact 17 at the tip. Accordingly, since the LEDs 1 to 9 and the contact 17 are arranged in a predetermined positional relationship with respect to the probe main body 11, the coordinates of the contact 17 are obtained from these coordinates by obtaining the coordinates of the LEDs 1 to 9. Can do.

The imaging unit 20 includes a tripod 21, a horizontally long box-like case 22 supported substantially horizontally by the tripod 21, and three detection units 23 </ b> A disposed at three positions on the front side of the case 22, that is, left and right and the center. 23B and 23C, and a frame grabber 26 and a control board 27 arranged in the case 22.
As shown in FIG. 4, the detection units 23 </ b> A to 23 </ b> C collect cylindrical light 24 </ b> A to 24 </ b> C that collects light incident from the light collecting region 28 on one axis, and light collected by the cylindrical lenses 24 </ b> A to 24 </ b> C. The line sensors 25A to 25C are configured to receive light and output a luminance distribution signal representing a luminance distribution on one axis. The line sensors 25A to 25C have a configuration in which, for example, CCDs (charge coupled devices) are arranged in a line.

Here, in the detection units 23A and 23C, the line sensors 25A and 25C constitute a first line sensor that is arranged apart from each other, and Y that is orthogonal to the X axis (first axis) of the light collection region 28. It is orthogonal to the axis (second axis) and is inclined slightly inward with respect to the X axis. The cylindrical lenses 24A and 24C constitute a first optical system, and are arranged orthogonal to the line sensors 25A and 25C (parallel to the Y axis) at substantially the center positions of the line sensors 25A and 25C. In other words, the detectors 23A and 23C are arranged to be inclined inward so that the direction of the detectors 23A and 23C slightly faces the center detector 23B. Accordingly, the light incident from the condensing region 28 is detected as a luminance distribution on the X axis by the line sensors 25A and 25C.
In the detection unit 23 </ b> B, the line sensor 25 </ b> B constitutes a second line sensor and is arranged in parallel with the Y axis of the light collection region 28. The cylindrical lens 24B constitutes the second optical system, and is disposed at a substantially central position of the line sensor 25B and orthogonal to the line sensor 25B (in parallel with the X axis). Therefore, the light incident from the condensing region 28 is detected as a luminance distribution on the Y axis by the line sensor 25B.

  The control board 27 captures the images of the line sensors 25A to 25C of the detection units 23A to 23C via the frame grabber 26 in synchronization with the pulse signal from the arithmetic control device 30, and sends them to the arithmetic control device 30 as luminance distribution signals. send.

The calculation control device 30 includes a timing control unit 31, a probe calculation unit 32 that calculates a position of the probe 10 by processing a signal from the imaging unit 20, and a measurement point calculation unit 33 that calculates a workpiece measurement point. It consists of
The timing control unit 31 constantly transmits a pulse signal that sequentially turns on the LEDs 1 to 9 of the probe 10, and simultaneously captures the luminance distribution signals of the line sensors 25 </ b> A to 25 </ b> C to the imaging unit 20 in synchronization with this. A pulse signal to be controlled is always transmitted.
The probe calculation unit 32 takes in the luminance distribution signal from the imaging unit 20, obtains the luminance centroid position of the luminance distribution signal, and calculates the position of the probe 10 from the luminance centroid position. That is, the coordinates of the LEDs 1 to 9 are calculated.
The measurement point calculation unit 33 calculates the contact in the three-dimensional measurement system from the position of the probe 10 (the coordinates of the LEDs 1 to 9) calculated by the probe calculation unit 32 and the position of the contact 17 with respect to the LEDs 1 to 9 of the probe 10. 17 coordinates are calculated.

In the above configuration, in the present embodiment, as shown in FIG. 5, in each of the detection units 23 </ b> A to 23 </ b> C, the calibration substrate 80 is incorporated between the cylindrical lenses 24 </ b> A to 24 </ b> C and the line sensors 25 </ b> A to 25 </ b> C. .
Specifically, as shown in FIG. 5, line sensors 25 </ b> A to 25 </ b> C are fitted and attached to a signal processing board 70 as a mount plate. The signal processing board 70 in this state is fixed by a screw 72 to a lens barrel 74 in which the cylindrical lenses 24A to 24C are housed. A calibration substrate 80 is incorporated in the lens barrel 74. That is, the calibration substrate 80 is incorporated between the cylindrical lenses 24A to 24C and the line sensors 25A to 25C.

  As shown in FIG. 6, the calibration substrate 80 has two reference lines 81A and 81B formed by etching or the like on a substrate made of a material having a small linear expansion coefficient such as glass. When the calibration substrate 80 is assembled between the cylindrical lenses 24A to 24C and the line sensors 25A to 25C, the two reference lines 81A and 81B are arranged at intervals in the pixel array direction of the line sensors 25A to 25C. Embedded in.

Therefore, at the time of measurement, when the LEDs 1 to 9 that are measurement point light sources are turned on, the light from these LEDs 1 to 9 is detected as luminance distribution signals by the line sensors 25A to 25C.
At the same time, the reference position signals based on the two reference lines 81A and 81B of the calibration substrate 80 are detected by the line sensors 25A to 25C while being superimposed on the luminance distribution signal.

<Work measurement work>
(A) To perform the workpiece measurement operation, a measurement switch (not shown) provided on the probe 10 is pressed in a state where the contact 17 of the probe 10 is in contact with the measurement site of the workpiece. Then, using the signal as a trigger, the LEDs 1 to 9 provided in the probe 10 are sequentially turned on in synchronization with the pulse signal transmitted from the timing control unit 31, and the lights from the LEDs 1 to 9 are emitted. It detects in each detection part 23A-23C. That is, the light from the LEDs 1 to 9 is detected as a luminance distribution signal in the line sensors 25A to 25C.

  At this time, in each of the detection units 23A to 23C, at least two reference lines 81A that are spaced in the pixel array direction of the line sensors 25A to 25C between the cylindrical lenses 24A to 24C and the line sensors 25A to 25C. , 81B, the transparent calibration substrate 80 is arranged, so that the signal of the pixel portion corresponding to the reference lines 81A, 81B with respect to the luminance distribution signal 83, as shown in FIG. Are detected by the line sensors 25A to 25C as the reference position signals 82A and 82B which become edges by blocking the light from .about.9. Then, the control board 27 takes in the data of the line sensors 25 </ b> A to 25 </ b> C via the frame grabber 26, calculates the pixel positions corresponding to the reference position signals 82 </ b> A and 82 </ b> B, and sends these data to the probe calculation unit 32. FIG. 7B shows a state in which the reference position signals 82A and 82B are detected in a state where the luminance of all the pixels is maximized. In the description of the correction method to be described later, in order to make the description easier to understand, the description will be made with reference to the state diagram of FIG.

In the probe calculation unit 32, the luminance center-of-gravity positions G1 and G2 from the luminance distribution signal 83 among the luminance distribution signal 83 detected by each line sensor 25A to 25C and the reference position signals 82A and 82B based on the two reference lines 81A and 81B. , G3.
Further, the shift amount accompanying thermal expansion and movement of the line sensors 25A to 25C is calculated from the pixel positions of the line sensors 25A to 25C corresponding to the reference position signals 82A and 82B, and the shift amount accompanying the thermal expansion and movement is corrected. Then, the luminance gravity center positions G1, G2, and G3 are corrected.

Therefore, these correction methods will be described.
(I) Method for correcting shift amount due to thermal expansion of line sensor As shown in FIG. 8A, reference position signals 82A and 82B are applied to pixels of line sensors 25A to 25C at a reference temperature (for example, 20 ° C.) in advance. Is detected and stored in the control board 27 as a reference pixel position.
As shown in FIG. 8B, at the time of measurement, when the line sensors 25A to 25C are extended, for example, when the maximum pixel value side is extended as a fulcrum, the reference position signals 82A and 82B are displaced in the positive direction. Since the displacement amount is larger as the reference position signal 82A is farther from the fulcrum, the shift amount is basically a straight line descending to the right. Specifically, the shift amount is calculated from the difference between the two reference pixel positions and the two reference position signals 82A and 82B detected at the time of measurement and the two measurement pixel positions of the corresponding line sensors 25A to 25C. . Then, correction is performed so as to cancel out this shift amount. That is, the shift amount corresponding to the pixel position of the luminance centroid position of the luminance distribution signal is corrected from the luminance centroid position.
As shown in FIG. 8C, when the line sensors 25A to 25C contract during measurement, for example, when the maximum pixel value side contracts as a fulcrum, the reference position signals 82A and 82B shift in the negative direction. Since the displacement amount is larger as the reference position signal 82A is farther from the fulcrum, the shift amount is basically a straight line rising to the right. Specifically, the shift amount is calculated from the difference between the two reference pixel positions and the two reference position signals 82A and 82B detected at the time of measurement and the two measurement pixel positions of the corresponding line sensors 25A to 25C. . Then, correction is performed so as to cancel out this shift amount. That is, the shift amount corresponding to the pixel position of the luminance centroid position of the luminance distribution signal is corrected from the luminance centroid position.

(Ii) Method for correcting shift amount by movement of line sensor As shown in FIG. 9A, at which position of the line sensors 25A to 25C the reference position signals 82A and 82B are previously set at a reference temperature (for example, 20 ° C.). Whether it appears is stored in the control board 27 as a reference pixel position.
As shown in FIG. 9B, when the line sensors 25A to 25C move to the maximum pixel value side during measurement, the reference position signals 82A and 82B shift in the negative direction. In this case, since the interval between the pixel positions of the line sensors 25A to 25C corresponding to the reference position signals 82A and 82B does not change, the shift amount is a straight line having the same value for every pixel. Therefore, correction is performed so as to cancel out the shift amount. That is, the fixed shift amount is corrected from the luminance gravity center position.
As shown in FIG. 9C, when the line sensors 25A to 25C move to the minimum pixel value side during measurement, the reference position signals 82A and 82B shift in the positive direction. In this case, since the interval between the pixel positions of the line sensors 25A to 25C corresponding to the reference position signals 82A and 82B does not change, the shift amount is a straight line having the same value for every pixel. Therefore, correction is performed so as to cancel out the shift amount. That is, the fixed shift amount is corrected from the luminance gravity center position.

(Iii) Correction Method of Shift Amount by Combination of Pixel Thermal Expansion and Movement FIG. 10A shows a case where the line sensors 25A to 25C extend due to thermal expansion (shift amount: solid line) and the line sensors 25A to 25C. This is a correction method in a state in which is moved (shift amount: one-dot chain line). Since the shift amount when the line sensors 25A to 25C extend due to thermal expansion is a straight line that goes downward, the shift amount when the line sensors 25A to 25C move becomes a straight line that is parallel to the straight line that goes down to the right. Make corrections to cancel each other.
FIG. 10B is a correction method for a state in which the line sensors 25A to 25C are contracted (shift amount: solid line) and the line sensors 25A to 25C are moved (shift amount: one-dot chain line). . When the line sensors 25A to 25C are contracted, the shift amount is a straight line rising to the right, and when the line sensors 25A to 25C are moved, the shift amount is a straight line parallel to the straight line rising to the right. Make corrections.

(B) Subsequently, the coordinates of the LEDs 1 to 9 are calculated from the corrected luminance gravity center positions G1, G2, and G3 using a triangulation method. Incidentally, the coordinates of the LEDs 1 to 9 can be obtained by a known method disclosed in JP-A-2005-233759 (Patent Document 1).

(C) Next, from the relationship between the contact 17 and the coordinates of the LEDs 1 to 9 calculated using the triangulation method from the luminance gravity center positions G1, G2, and G3 in the measurement point calculation unit 33, the contact 17 The coordinates are obtained and displayed on the display device 40. Thereby, the coordinate of the measurement site | part of the workpiece | work which the contact 17 of the probe 10 contacted can be calculated | required.

<Effect of embodiment>
According to the present embodiment, in each of the detection units 23A to 23C, the transparent calibration substrate 80 having the two reference lines 81A and 81B is disposed between the cylindrical lenses 24A to 24C and the line sensors 25A to 25C. Therefore, the reference position signals 82A and 82B based on the reference lines 81A and 81B are detected by the line sensors 25A to 25C in a state of being superimposed on the luminance distribution signal, and then sent to the probe calculation unit 32.

The probe calculation unit 32 calculates the luminance barycentric position from the luminance distribution signals detected by the line sensors 25A to 25C, and corresponds to the reference position signals 82A and 82B based on the two reference lines 81A and 81B. A shift amount accompanying thermal expansion and movement of the line sensors 25A to 25C is calculated from the pixel position of 25C, the shift amount is corrected, and the luminance centroid position of the luminance distribution signal is corrected.
Therefore, even if the line sensors 25A to 25C thermally expand or move due to a change in environmental temperature, the shift amount associated with the thermal expansion and movement is corrected, and the luminance gravity center position is calculated. Coordinates can be obtained with high accuracy.

  Also, the two reference position pixel positions of the line sensors 25A to 25C corresponding to the two reference position signals 82A and 82B detected in advance at the reference temperature and the two reference position signals 82A and 82B detected at the time of measurement correspond to the two reference position signals 82A and 82B. Since the shift amount is calculated from the difference between the two pixel positions at the time of measurement of the line sensors 25A to 25C and the shift amount due to the thermal expansion and movement of these line sensors 25A to 25C is corrected, the coordinates of the point light source for measurement Can be calculated with high accuracy.

Further, when the distance between two measurement pixel positions of the line sensors 25A to 25C corresponding to the two reference position signals 82A and 82B detected at the time of measurement is changed, thermal expansion of the line sensors 25A to 25C occurs. Since the shift amount accompanying the thermal expansion of the line sensors 25A to 25C is calculated from the difference between the two reference pixel positions and the two measurement pixel positions, the thermal expansion of the line sensors 25A to 25C is calculated. The shift amount can be calculated accurately.
Further, when the distance between the two pixel positions at the time of measurement of the line sensors 25A to 25C corresponding to the two reference position signals 82A and 82B detected at the time of measurement does not change, the line sensors 25A to 25C are moved. Therefore, since a certain amount of shift is calculated according to the difference between the reference pixel position and the measurement pixel position, the shift amount accompanying the movement of the line sensors 25A to 25C can be accurately calculated.

  In addition, the calibration substrate 80 has a configuration in which the reference lines 81A and 81B are formed on the glass substrate by etching, and thus has an advantage that it is less affected by heat and can be easily manufactured.

Second Embodiment
In the first embodiment, as the environmental temperature changes, the shift amount associated with the thermal expansion or movement of the line sensors 25A to 25C is calculated, and the luminance gravity center position of the luminance distribution signal detected by each line sensor 25A to 25C is calculated. However, the method described in the second embodiment can also be applied to changes in environmental temperature.

Conventionally, in the above-described three-dimensional measurement system, spatial accuracy correction is performed at the time of measurement. However, when the environmental temperature changes from a reference temperature (for example, 20 ° C.) or more by a predetermined temperature (for example, 5 ° C. or more), the length It is necessary to perform spatial accuracy correction again using the calibration standard.
However, this work is time consuming because it is necessary to measure the calibration standard for the length in the entire measurement range, and if the work is installed in the measurement area, the work must be moved temporarily. .

In order to deal with such a problem, in the second embodiment, spatial accuracy correction data is acquired in advance at every predetermined temperature within the operating temperature range, for example, every 5 ° C., for example, in the memory in the probe calculation unit 32. Remember me.
In addition, a temperature sensor is built in the three-dimensional measurement system, for example, the case 22 of the imaging unit 20, and the spatial accuracy correction data corresponding to the environmental temperature detected by the temperature sensor is read from the memory. The brightness gravity center position and the coordinate position of the point light source for measurement are corrected by spatial accuracy correction.
In this way, even in a measurement environment where the environmental temperature is not stable, the measurement can be performed efficiently.

<Modification>
It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.

  In the above embodiment, the two reference lines 81A and 81B are provided on the calibration substrate 80, but three or more reference lines may be provided.

In the above embodiment, the contact type probe 10 having the contact 17 at the tip has been described as an example. However, the present invention is not limited to this, and a non-contact type probe may be used.
For example, as shown in FIG. 11, a light emitter 18A that emits light toward the workpiece, a light receiver 18B that receives reflected light from the workpiece, and a position at which light is received by the light receiver 18B. Alternatively, the probe 10 having a configuration in which a non-contact measuring device 18 provided with an arithmetic unit (not shown) for calculating workpiece position information with respect to the probe main body 11 may be used.
In this case, the measurement point calculation unit 33 uses the position of the probe 10 obtained by the probe calculation unit 32 and the position of the measurement point obtained by the non-contact measurement device 18 to determine the non-contact measurement device 18 for the three-dimensional measurement system. The coordinates of the light irradiation position are obtained.
Note that a non-contact type probe does not need to be in contact with the workpiece, so it is possible to measure a workpiece with a more complicated shape.To this end, more probes can be detected so that various postures can be detected. LEDs, for example, 40 LEDs 1, 2, 3,... Are mounted. However, in order to detect the attitude of the probe, not all LEDs need to be detected, and the attitude of the probe can be obtained even if at least three LEDs can be detected.

  In the said embodiment, although nine LED1-9 was arrange | positioned as the point light source for a measurement at the probe 10, it does not necessarily need to be plural and there should just be at least one. For example, if the measurement point light source is moved to the measurement position of the workpiece without providing the LEDs 1 to 9 on the probe 10, the number of measurement point light sources may be one.

  In the above-described embodiment, the detection units 23A to 23C are configured from the cylindrical lenses 24A to 24C and the line sensors 25A to 25C. However, the detection units 23A to 23C may be optical elements that can collect the light from the light collection region 28 in one axis direction. For example, it may not be a cylindrical lens.

  The present invention can be used for measurement of a huge structure or measurement in a dangerous area.

1-9 ... LED (point light source for measurement),
20 ... Imaging unit (position detecting device),
23A, 23B, 23C ... detection part,
24A, 24C ... cylindrical lens (first optical system),
24B ... Cylindrical lens (second optical system),
25A, 25C ... line sensor (first line sensor),
25B ... Line sensor (second line sensor),
30 ... arithmetic control device (position detection device),
32... Probe calculation unit (position calculation unit),
70: Signal processing board (mounting plate)
80 ... Calibration substrate,
81A, 81B ... reference line,
82A, 82B ... reference position signals.

Claims (4)

A measurement point light source movable to an arbitrary position, and a position detection device that receives light from the measurement point light source and detects the position of the measurement point light source,
The position detection device is disposed on a first axis by a pair of first optical systems arranged separately from each other and collecting light from the measurement point light source on a first axis, and the first optical systems. A pair of first line sensors that receive the collected light and output a first luminance distribution signal representing the luminance distribution on the first axis, and the light from the measurement point light source are orthogonal to the first axis A second optical system that condenses on the second axis, and receives light collected on the second axis by the second optical system and outputs a second luminance distribution signal that represents the luminance distribution on the second axis A three-dimensional measurement system configured to include a position calculator that calculates the coordinates of the measurement point light source based on the second line sensor, the first luminance distribution signal, and the second luminance distribution signal;
At least two reference lines that are spaced apart in the pixel array direction of each line sensor between the first optical system and the first line sensor and between the second optical system and the second line sensor. A transparent calibration substrate having
The position calculation unit is configured to calculate, based on a luminance distribution signal detected by each line sensor and a reference position signal based on the two reference lines, from a pixel position of the line sensor corresponding to the reference position signal. Calculating the shift amount accompanying thermal expansion or movement, correcting the shift amount, and calculating the coordinates of the point light source for measurement,
A three-dimensional measurement system. The three-dimensional measurement system according to claim 1,
The position calculation unit corresponds to the two reference-time pixel positions of the line sensor corresponding to the two reference position signals detected in advance at a reference temperature, and the two reference position signals detected at the time of measurement. A shift amount is calculated from a difference between two measurement pixel positions of the line sensor, and the coordinates of the measurement point light source are corrected so as to cancel the shift amount.
A three-dimensional measurement system. The three-dimensional measurement system according to claim 2,
When the interval between the two measurement pixel positions of the line sensor corresponding to the two reference position signals detected at the time of measurement has changed, the position calculation unit may change the two reference pixel positions and two The shift amount accompanying the thermal expansion of the line sensor is calculated from the difference from the pixel position at the time of measurement, and the interval between the two pixel positions at the time of measurement of the line sensor corresponding to the two reference position signals detected at the time of measurement changes. If not, calculate a certain amount of shift amount with the movement of the line sensor from the difference between the reference pixel position and the measurement pixel position,
A three-dimensional measurement system. In the three-dimensional measurement system in any one of Claims 1-3,
The calibration substrate is formed by etching the reference line on a glass substrate.
A three-dimensional measurement system.

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