JPH0484707A - Three-dimensional size measuring apparatus - Google Patents

Abstract

PURPOSE:To shorten the measuring time, to eliminate dispersion in measured values and to improve measuring work efficiency by photographing a light cutting line which is displayed on the surface of an object to be measured, and computing the three-dimensional coordinate values based on the image of the cutting line. CONSTITUTION:Emitted slit light L is displayed as a light cutting line on the surfaces of an object to be measured 11 and 12. The image is picked up with an image sensing means 14. Then, a coordinate operating means 31 computes th three-dimensional coordinate values based on the light cutting line. The result of the operation is processed with a characteristic- point detecting means 41. Namely, in an end-point detecting circuit 43a of a shape determining part 43, the end point is detected based on the change in three-dimensional coordinate values in the height direction. In a round-part-start detecting circuit 43b, the starting point of the curved part is detected. The change in shape in the region which is specified with the shape determining part 43 is extracted with a curve approximation circuit (roundness) 44a and a straight-line approximation circuit (straight line) 44b of a shape-function approximation part 44. The shape changing part in the specified region is extracted as at least one characteris tic point. Then the relative position relationship between the approximate function and the extracted characteristic point is obtained, and the gap and the step of the object to be mea sured is operated in a size operating means.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a three-dimensional dimension measuring device used to measure steps and gaps at seams of panels and the like.

[Prior Art] Conventionally, steps and gaps at joints of thin steel plates have been measured by the method shown in FIGS. 9 and 10. FIG. 9 shows the state of level difference measurement, and a caliper 1 dedicated to level difference measurement is used for this measurement. The dedicated caliper 1 is fixed to one panel 2, and the contact 1a of the dedicated caliper 1 is brought into contact with the other panel 3, and the bent portion 3a
The bending start point Ps of is measured. FIG. 10 shows the state of gap measurement, and a gap gauge (thickness gauge) 5 is used for this measurement. The gap gauge 5 is used by stacking metal plates of different thicknesses, and by inserting the gap gauge 5 into the gap, the gap recess, that is, the bending end point PE of the bent portion is measured.

The measurements of these steps and gaps are directly performed by the measurer, and the measurement results are also recorded in the accuracy table by the measurer.

Note that a method of detecting a level difference using an optical scanning displacement sensor is disclosed in, for example, Japanese Patent Laid-Open No. 1-24501@.

[Problems to be Solved by the Invention] However, in the case of the measurement methods shown in Figs. 9 and 10, a dedicated caliper is used to measure the level difference, and a gap gauge is used to measure the gap. Therefore, two measurements must be taken. Therefore, there was a problem that measurement took a lot of time.

Furthermore, since the operator visually recognizes the bending start point and bending end point and reads the scale, there is a drawback that the measurement values vary widely.

Furthermore, the measured data must be saved;
In this case, an operator has to copy the measured data into an accuracy chart, and an improvement has been desired.

The present invention focuses on the above-mentioned problems, and in measuring steps and gaps at joints of panels, etc., it is possible to shorten the measurement time, eliminate variations in measured values, and eliminate the need to copy measurement data. Another object of the present invention is to provide a three-dimensional dimension measuring device that can improve the efficiency of measurement work.

[Means for Solving the Problems] A three-dimensional dimension measuring device according to the present invention that meets this objective includes: a slit light irradiation unit that irradiates a slit light toward the surface of the object to be measured; an imaging means for capturing an image of a light section line projected on the image; a coordinate calculation means for calculating a three-dimensional coordinate value based on the light section line image from the imaging means; a shape determining unit that determines the shape of the measurement target based on the shape determining unit; and a shape function approximating unit that approximates a change in shape in the region specified by the shape determining unit with a function corresponding to a change in three-dimensional coordinate values,
The shape determining section includes an end point detection circuit that detects the end points of the object to be measured and a rounded part start detection circuit that detects the starting point of a curved part, and the shape function approximation section uses the shape information from the shape determining section. Feature point detection means is comprised of a curve approximation circuit for approximating to a preset curve function and a straight line approximation circuit for approximating to a straight line, and extracts a shape changing part in a specific area as at least one feature point based on the approximation function. and a dimension calculation means for calculating the relative positional relationship between the approximated approximation function and the extracted feature point to calculate gaps and steps of the measurement object, and a gap value calculated by the dimension calculation means. and a storage means for storing the step value; an output means for outputting the data stored in the storage means as information that can be determined by the measurer; It consists of a remote control means capable of remote control, and a device equipped with the following.

[Function] In the three-dimensional dimension measuring device configured in this way,
Slit light is irradiated from the slit light irradiation means toward the surface of the object to be measured. The irradiated slit light is projected onto the surface of the measurement object as a light section line, and the light section line is imaged by the imaging means.

When the optical section line is imaged, the coordinate calculation means calculates three-dimensional coordinate values based on the optical section line.

The calculation results of the coordinate calculation means are processed by the feature point detection means. That is, the end point detection circuit of the shape determining section in the feature inspection means detects the end point based on the change in the three-dimensional coordinate value in the height direction, and the rounded part start detection circuit detects the start point of the curved part. The shape change in the region specified by the shape determination section is approximated by a function corresponding to the change in three-dimensional coordinate values by the curve approximation circuit and straight line approximation circuit of the shape function approximation section. , is extracted as at least one feature point.

When the processing in the feature point detection means is completed, the relative positional relationship between the approximate function and the extracted feature points is determined by the dimension calculation means, and gaps and steps of the object to be measured are calculated.

In this way, the optical section line projected on the object to be measured is imaged and three-dimensional coordinate values are calculated based on the optical section line image, so there is no need to measure steps and gaps separately as in the conventional method. The measurement time can be shortened.

Furthermore, since there is no need for the measurer to recognize the bending start point and bending end point, variations in measurement values are eliminated and measurement accuracy is improved.

The gap and step data calculated by the dimension calculation means can be electrically stored in the storage means, and the data stored in the storage means is outputted by the output means as information that can be determined by the measurer. . Therefore, the conventional work of copying measurement results is also eliminated.

Furthermore, since the remote control means moves together with the slit light irradiation means and the imaging means, even if the imaging position is changed, the imaging means can be easily controlled, improving the efficiency of measurement work.

[Embodiments] Below, preferred embodiments of the three-dimensional dimension measuring device according to the present invention will be described with reference to the drawings.

1 to 8 show one embodiment of the present invention. In the figure, numeral 11 indicates a thin steel plate as an object to be measured having a bent portion, and numeral 12 indicates a thin steel plate as an object to be measured having a bent portion. One thin steel plate 11 and the other thin steel plate 12 are set to face each other with an interval. A slit light irradiation means 13 is arranged above each thin steel plate 11.12 for irradiating slit light onto the surfaces of both thin steel plates 11.12. The slit light irradiation means 13 is composed of, for example, a laser light irradiation device that irradiates laser light. In the vicinity of the slit light irradiation means 13, a TV camera (television camera) 14 is provided as an imaging means for taking an image of the light cutting line projected on the surface of the thin steel plate 11, 12 by the slit light. .

The slit light irradiation means 13 and the TV camera 14 are connected to a multi-axis support 1 which has a function of moving and positioning to the measurement site.
It is supported by 5. The multi-axis support body 15 is composed of, for example, a layout machine (dimension measuring device), an industrial robot, or the like. In this embodiment, the multi-axis support 15 is comprised of a manual layout machine. As shown in FIGS. 1 and 3, the slit light irradiation means 13 and the TV camera 14 are housed in a case 16, and are attached to the arm 15a of the layout machine, which is a multi-axis support 15, through the case 16. installed. In addition, case 1
Slit light irradiation means 13 and TV camera 1 housed in 6
4 is a coordinate calculating means 31 which will be described later via a cable 17.
It is connected to the. The slit light irradiation means 13 and the TV camera 14 must change their positions each time the measurement target position changes. In this case, the positioning is done either directly by the measurer or by using NC data or teaching data. There are cases where this is done on the basis of

3 and 4, the case 16 is directly removed by the operator.
In FIG. 4, the case 16 is suspended via a constant load reel (balancer) 18. This is to significantly reduce the force required to raise and lower the slit light irradiation means 13 and the TV camera 14 as the case 16 moves.

Moreover, FIG. 5 shows a device in which the measurer directly positions the device to perform measurement work, and in this case, case 16
A setting jig 19 is attached to. The setting jig 19 is provided with a remote control means 20. The remote control means 20 has a switch function to start measurement, a measurement data discrimination function, and a data display function. The remote control means 20 includes a measurement switch 20a.
, a display section 20b that displays measurement results, and lamps 20C, 20d, and 20e that display various information are provided.

As shown in FIG. 1, the slit light irradiation means 13 and the TV camera 14 are connected to a coordinate calculation means 31. The coordinate calculating means 31 includes a slit light center detection circuit 32, a YZ coordinate lookup table 33, a slit light reflection intensity detection circuit 34, and a slit light projection intensity setting circuit 35. The slit light center detection circuit 32 has a function of detecting the center of the slit light for each scanning line in a light cut image obtained by imaging with the TV camera 14. Also, YZ
The coordinate lookup table 33 has a function of detecting three-dimensional coordinates (Y, Z) from the data from the slit light center detection circuit 31 using the principle of triangulation. The slit light reflection intensity detection circuit 34 has a function of detecting the intensity of the slit light irradiated onto the surface of the object to be measured.

Further, the slit light projection intensity setting circuit 35 has a function of setting the intensity of the slit light irradiated onto the surface of the object to be measured.

The coordinate calculation means 31 is connected to the feature point detection means 41. As shown in FIG. 2, the feature point detection means 41 includes a filter circuit 42, a shape determination section 43, and a shape function approximation section 44.
, and a vertex detection circuit 45.

The shape determining section 43 roughly consists of an end point detection circuit 43a and a rounded part start detection circuit 43b. The shape function approximation section 44 includes a curve approximation circuit 44a and a straight line approximation circuit 44b. The filter circuit 42 uses moving average, FFT
It has a function to remove noise components from three-dimensional coordinates using (fast Fourier transform) or the like.

The end point detection circuit 43a calculates the difference between the corresponding Z coordinates of adjacent scanning lines at seven coordinates based on the three-dimensional coordinate data from the filter circuit 42, as shown in characteristic (a) I in FIG. It has a function that sets the point where the difference exceeds a threshold value as an end point. As shown in the characteristic (/) in FIG. 7, the rounded portion start detection circuit 43b detects a change rate of 1△2 in the slope of adjacent scanning lines in the Y and Z coordinates with respect to the corresponding Y and Z coordinates.
It has a function of calculating Z/(ΔY)21 and setting the points where the rate of change exceeds a threshold value as starting points PS1 and PS2 between rounded portions.

The curve approximation circuit 44a, as shown in the characteristic port of FIG.
Based on the previously detected end points and starting points between rounded parts, the section defined by the starting point between rounded parts and end points in three-dimensional coordinates is created using the least squares method to create a curve function such as a circle, ellipse, or involute curve according to the measurement area. It has a function of approximating by ft (y) and f2(y).

In addition, as shown in FIG. 7, the linear approximation circuit section 44b approximates the vicinity of one roundness starting point PSa with a straight line A (Z=aV+b) by the least squares method based on the three-dimensional coordinates. Has a function.

As shown at the beginning of FIG. 7, the vertex detection circuit 45 detects a straight line (Z = a 'V+b'
:a'=-1/a, b'=undefined). Then, by moving this straight line in parallel, a = constant, b' varies), curves f, (V), f 2 (
It has a function of detecting contact points PE1 (YEl, ZEl) and PE2 with V).

The feature point detection means 41 described above is connected to the dimension calculation means 51. As shown in FIG. 2, the dimension calculation means 51 includes a step calculation circuit 52 and a gap calculation circuit 53. As shown in the characteristic (E) of FIG. 7, the step calculation circuit 52 calculates the distance (aYs
It has the function of calculating 1-Zs, +b)/Jzo = Td1-. The gap calculation circuit 53 calculates a straight line J-12 (z=a-y+b-:
a=-a/1) and detect the vertex PE, (YE,, ZEl
) and the straight line 1-T2 which distance fist ((-a/1)
YE, -ZE, +b-)/J-℃==1007T
It has a function to calculate T''10(-1)2.

A determining means 61 is connected to the dimension calculating means 51, as shown in FIG. The determining means 61 has a function of calculating the difference between the gap value and step value calculated by the dimension calculating means 51 and a preset correct value, and performs a pass/fail determination and statistical calculations such as variations in measurement results. are doing.

A storage means 71 is connected to the determination means 61 .

The storage means 71 has a function of storing the gap value and step value calculated by the dimension calculation means 51, the measured cross-sectional shape, and the determination result by the determination means 61.

An output means 81 is connected to the storage means 71 .

The output means 81 outputs the data stored in the storage means 71 as information that can be determined by the measurer.
For example, it consists of graphics, printers, plotters, etc.

Note that the coordinate calculation means 31, the feature point detection means 41, the dimension calculation means 51, the determination means 61, the storage means 71, and the output means 8
1 are stored together in one storage case, as shown in FIG.

Next, the operation of the above three-dimensional dimension measuring device will be explained.

When the thin steel plates 11 and 12 to be measured are set, the protective case 16 in which the slit light irradiation means 13 and the TV camera 14 are housed is moved to a predetermined position and fixed. If the multi-axis support 15 is a robot, this movement of the protective case 16 is performed based on preset positioning data, or if it is a manual layout machine, it is moved directly by the measurer. When the protective case 16 is positioned at a predetermined position, the slit light irradiation means 13
The slit light is irradiated from the thin steel plate 11, 12 toward the thin steel plate 11, 12. As a result, a light cutting line is projected onto the thin steel plates 11 and 12.

When the optical cutting line is projected onto both thin steel plates 11 and 12, the optical cutting line is imaged by the TV camera 14.

In the light cutting line image obtained by imaging, the slit center detection circuit 32 of the coordinate calculation means 31 detects the center of the slit light for each scanning line, and uses the principle of triangulation to look up the Y and Z coordinates. Three-dimensional coordinates Y and Z are detected using the table 33.

Next, the feature point detection means 41 detects feature points that define dimensions from the three-dimensional coordinates. That is, the filter circuit 42 removes noise components from the three-dimensional coordinates using a moving average, FFT (Fast Fourier Transform), or the like.

Then, based on the three-dimensional coordinates subjected to the above processing, the end point detection circuit 43a calculates the difference between the corresponding Z coordinates of adjacent scanning lines in the Z coordinate, and the point where the difference exceeds the threshold value is determined. It is considered as an end point. Similarly, in the rounded part start detection circuit 43b, the rate of change in the slope of adjacent scanning lines in Y and Z coordinates with respect to corresponding Y and Z coordinates lΔ2Z/(ΔY)
21 is calculated, and the points where the rate of change exceeds the threshold are defined as starting points P S 1 and P S 2 between rounded portions.

When the starting points P S 1 and P S 2 between rounded portions are obtained, an interval defined by the starting point and end point between rounded portions in three-dimensional coordinates based on the previously detected end points and the starting point between rounded portions is obtained.
Curve functions f, (V) such as circles, ellipses, involute curves, etc.
, ft(V). At the same time, the vicinity of one of the roundness starting points PSa is approximated by a straight line 1 (Z=ay+b) based on the three-dimensional coordinates by the linear approximation circuit 44b.

Next, the vertex detection circuit 45 calculates a straight line A'(z=a'-y+b:a- =-a/1
, b-=indeterminate) is obtained. This straight line E- is translated in parallel, and the contact point PE with the curve f, (V), ft (V),
(YEl, ZE,), PE2 is detected.

When the calculation processing by the feature inspection means 41 is completed, the dimension calculation means 51 calculates gaps and steps based on this information. That is, in the step-change circuit 52, the previously approximated straight line 1 (Z=ay+b) and the roundness starting point PS1
(YSI ZSl ) distance (aYs 1
zsl +b>/a + − is calculated. The gap calculation circuit 53 calculates a straight line 1=Tt (Z=a"y+b-:
a = -a/1) is detected, and the vertex PE1 (YE
,,ZE,) and the distance between straight line tar ■2 ((-a/1)
YE, -ZE, 10b")/-a 10-1
is calculated. The values of the gap and step calculated by these circuits are processed by the determining means 61, and the difference between the correct value and the correct value is calculated, the quality is determined, and the statistical measurement of dispersion and the like is performed.

The values of the gaps and steps, the latitude calculation results obtained by the determination means 51, and the measured cross-sectional shape are stored in the storage means 71 for preservation. The data stored in the storage means 71 is retrieved as needed and output to the output means 81.

Note that since the reflected light does not return to the imaging means at the vertex (PE , , PE 2 of characteristic (a) in Figure 7) which is the end point of R that is the measurement point, it is difficult to capture it as a three-dimensional coordinate due to the characteristic of the figure. Although it is difficult as shown on the side, the characteristics shown in Figure 7 (
As shown in (g), by making the rounded part a function of the curve and calculating the apex, it is possible to define measurement points that are not actually included in three-dimensional coordinates, making highly reliable measurements possible. .

In addition, when detecting the starting point between rounded parts, the rate of change in slope is used, so the slope of the image can be removed (
(See the straight line part in FIG. 8), gaps, and steps are also calculated using a distance meter between the objects to be measured, and the inclination of the image is ignored.

[Effects of the Invention] As explained above, when using the three-dimensional dimension measuring device according to the present invention, the optical section line projected on the surface of the object to be measured is imaged, and three-dimensional coordinate values are determined based on the optical section line image. Since the values of the gap and the difference in level can be calculated at the same time.

Therefore, compared to conventional measurement methods, high-speed measurement is possible, and measurement time can be shortened.

In addition, various measurement points can be automatically recognized from the three-dimensional coordinates calculated based on the optical section line image, and the values of steps and gaps are calculated based on these measurement points, so measurements can be made as usual. This eliminates the dispersion in measured values between different people, making it possible to perform highly accurate measurements.

The gap and step data calculated by the dimension calculation means can be electrically stored in the storage means, and the stored data can be outputted by the output means as information that can be determined by the measurer. Therefore, the conventional work of copying measurement results can be eliminated.

Furthermore, since the remote control means moves together with the slit light irradiation means and the imaging means, even when the imaging position is changed many times, the control operation of the apparatus becomes easy, and the efficiency of measurement work is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a three-dimensional dimension measuring device according to the present invention, FIG. 2 is a block diagram showing a configuration near the feature point detection means in the device shown in FIG. 1, and FIG. 4 is a perspective view showing a modification of FIG. 1, FIG. 5 is a perspective view showing another modification of FIG. 1, and FIG. 6 is a remote control means in FIG. 5. 7 is a characteristic conceptual diagram showing the procedure for determining steps and gaps using the device shown in FIG. 1, and FIG. FIG. 9 is a front view showing a conventional step measurement state; FIG. 10 is a front view showing a conventional step measurement state. 11.12...Measurement object 13...Slit light irradiation means 14...Imaging means 15...Multi-axis support 20... Remote operation means 31...Coordinate calculation means 41...Feature point detection means 43...Shape determination section 44...Shape function approximation section 51... ...Dimension calculating means 61...Judgment means 71...Storage means 81...Output means L...Slit light

Claims (1)

[Scope of Claims] 1. A slit light irradiation means for irradiating slit light toward the surface of the object to be measured; an imaging means for imaging a light section line projected on the surface of the object to be measured by the slit light; and the image pickup device. a coordinate calculating unit that calculates a three-dimensional coordinate value based on a light section line image from the unit; a shape determining unit that determines the shape of the object to be measured based on a rate of change in the height direction of the three-dimensional coordinate value; a shape function approximation unit that approximates a shape change in the region specified by the determination unit with a function corresponding to a change in three-dimensional coordinate values;
The shape determining section includes an end point detection circuit that detects the end points of the object to be measured and a rounded part start detection circuit that detects the starting point of a curved part, and the shape function approximation section uses the shape information from the shape determining section. Feature point detection means is comprised of a curve approximation circuit for approximating to a preset curve function and a straight line approximation circuit for approximating to a straight line, and extracts a shape changing part in a specific area as at least one feature point based on the approximation function. and a dimension calculation means for calculating the relative positional relationship between the approximated approximation function and the extracted feature point to calculate gaps and steps of the measurement object, and a gap value calculated by the dimension calculation means. and a storage means for storing the step value; an output means for outputting the data stored in the storage means as information that can be determined by the measurer; A three-dimensional dimension measuring device comprising: a remote control means capable of remote control; and a three-dimensional dimension measuring device.