JP2783031B2 - Estimation method of virtual point position by measurement with lighthouse sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighthouse type sensor which intermittently scans the surface of an object by gradually changing the direction of measurement light and measures the cross-sectional shape of the surface by the principle of triangulation. From the point sequence of the measurement points obtained as described above, two straight lines are determined by approximation, and when estimating the position of the virtual point by obtaining the intersection of those straight lines, the method relates to a method that can improve the estimation accuracy. is there.

[0002]

2. Description of the Related Art As shown in FIG. 5, a lighthouse type sensor generally reflects a laser beam 2 as a measuring beam emitted from a light source 1 on a scanning mirror 3 and irradiates the laser beam 2 onto a surface of an object 4. After the reflected light from the light source is reflected again by the scanning mirror 3, the light is received by the CCD sensor 5, and the distance between the lighthouse type sensor and the object 4 is measured from the light receiving position by the principle of triangulation, and the scanning mirror is used. The irradiation position is shifted by gradually changing the angle of 3, and the surface of the object 4 is intermittently scanned to obtain point sequence coordinate data of measurement points corresponding to the two-dimensional cross-sectional shape of the surface. In general, the lighthouse type sensor performs feedback control of the operation of the light source 1 based on the amount of light received by the CCD sensor 5 using a light amount adjustment circuit (not shown) so that the amount of light received by the CCD sensor 5 falls within a range suitable for distance measurement. The intensity of the laser light 2 emitted from the light source 1 is adjusted.

[0003] Such a lighthouse type sensor is used, for example, when measuring the assembly accuracy of an automobile body, and the assembly accuracy measurement is conventionally performed, for example, at a plurality of positions of a vehicle body designed in advance, by using a body panel at those positions. A portion having an L-shaped two-dimensional cross-sectional shape is set as a reference portion, and for each of those reference portions, an end of the straight portion corresponding to one side of the L-shape, which is not on the corner portion side of the L-shape. Start point A of measurement
And an end point B of the measurement at an end of the linear portion corresponding to the other side, which is not the corner side of the L-shape, and passes at least one of the start point A and the end point B and the L-shape. One or two reference lines L are set such that the angles with respect to the linear portions corresponding to the respective sides are equal to each other, and the intersection of two straight lines respectively overlapping the linear portions is set as a virtual point P. After that, the measurement is performed by executing a measurement procedure as shown in FIG.

In this measuring procedure, first, in step 101, the above-mentioned starting point A to the ending point are detected by the lighthouse type sensor for each of the reference portions of the vehicle body panel as the object of the first assembled vehicle body. B, the measurement point sequence obtained by the provisional measurement is displayed on the screen. Then, at step 102, at least the start point A and the end point B of the L-shaped measurement point sequence obtained by the provisional measurement are displayed. as one, and the length of the linear single angle such are approximately equal to each other for partial or two of the temporary reference line L _a, for example, such as linear portion shown in FIG. 7 corresponding to the respective sides of the L-shaped equals the measurement point _{P S (s = 1,2,3,.} . .n) point start point a (P ₁₎ in the case of rows of the end point B (P _n) and a single temporary of which connects with a straight line to set the reference line L _a. At this time, and the x-axis and the reference line L _a that extends in the horizontal direction on the screen performs a coordinate transformation of the screen display so as to be parallel.

Next, at step 103, the temporary reference line L
seeking farthest point Q _a provisional is farthest measurement point from _a, in thereafter step 104, a vertical line R _a provisional from the farthest point Q _a of the temporary to the reference line L _a of the temporary, then while L-shape with two straight portions from the measurement point sequence aligned confirmed in the screen display as cut each set the two windows W ₁ and W _2, perpendicular R _a from their window W subsequent the temporary ₁ , distances L ₁ , L ₂ and L ₃ , L to W ₂
Ask for ₄ . In this case, the range of the two windows W _1, W _2, in order to improve the accuracy of linear approximation, which will be described later, does not include a curved portion in L-shaped windows W ₁ thereof from the measurement point sequence arrayed in, W ₂ Is set so that only the linear portion can be cut as long as possible.

Next, in step 105, the main measurement is performed by the lighthouse sensor from the start point A to the end point B. Then, in step 106, the start point A and the end point B of the L-shaped measurement point sequence obtained by the main measurement are measured. One or two reference lines L passing through at least one and having substantially the same angle with respect to the linear portions corresponding to the respective sides of the L-shape, for example, the lengths of the linear portions as shown in FIG. 7 are equal. Measurement point P
_In the point sequence of _S (s = 1, 2, 3,... _N ), one reference line L connecting the start point A (P ₁ ) and the end point B (P _n ) by a straight line is set,
Next, at step 107, the farthest point Q, which is the farthest measurement point from the reference line L, is obtained. Thereafter, at step 108,
A perpendicular line R is drawn from the farthest point Q to a reference line L, and two windows W ₁ and W ₂ are opened based on the distances L ₁ , L ₂ and L ₃ , L ₄ from the perpendicular line R. Is cut out, and the coordinates of the measurement points forming the point sequence are read out.

Next, in step 109, a straight line is approximately obtained by the least square method from the coordinates of the measurement points in the two windows W ₁ and W ₂ , and then in step 110,
The position coordinates of the virtual point P are obtained by calculating the intersection of these straight lines, and then, in step 111, the obtained coordinates of the virtual point P are compared with the coordinate data of the virtual point P in the known design, and The assembly accuracy is determined, and in the next step 112,
Next, the presence or absence of the assembled vehicle body is determined, and if there is the next vehicle body, the process returns to step 105 to repeat the procedure after the main measurement, and the process ends if there is no next vehicle body.

[0008]

In the case where the measurement of the vehicle body assembly accuracy is performed on the vehicle body assembled in an automobile body assembly line, the above-described step 10 is performed.
It is necessary to perform the measurement procedure below the main measurement of 5 within the specified tact time. However, if the angle change of the scanning mirror 3 is increased so that the shape of each of the reference portions can be measured within the predetermined tact time, the change speed of the light receiving amount of the CCD sensor 5 is too fast to keep up with the feedback control. When the laser beam 2 was totally reflected by measuring the corners of the L-shaped cross section of the body panel surface, the amount of received light was excessive and the CCD sensor 5 became saturated, and the measurement was performed in such a saturated state. Measurement point sequence area (saturation area S)
In FIG. 8, the coordinates of the measurement points are shown as being farther from the sensor 7 (located at the lower side in the figure and outside of the figure) than the original position (indicated by the points marked with * in the figure) as shown in FIG. The point that should be the farthest point is not the farthest point, and the measurement point near one or both ends of the saturation region is the farthest point Q
And the position of the farthest point varies.

For this reason, if the main measurement is performed as it is in the above-described conventional method, the two windows W ₁ and W ₂ set in the provisional measurement are greatly displaced from the position with respect to the initially assumed measurement point sequence. Like the window W ₁ , the window may deviate from the linear portion of the substantially linear portion corresponding to one side of the L-shape and include a curved portion near the corner of the L-shaped cross-sectional shape. Therefore, in the above-described conventional estimation method, the position of the virtual point P estimated based on the sequence of points is shifted from the actual position, and there is a problem that the estimation accuracy of the virtual point position and thus the assembly error measurement accuracy cannot be sufficiently improved. Was.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method which advantageously solves the problem of the above-mentioned conventional method of estimating a virtual point position by measurement with a lighthouse type sensor. The method of estimation is to use a lighthouse sensor to scan the surface of the object intermittently by gradually changing the direction of the measurement light, and measure the cross-sectional shape of the surface using the principle of triangulation to obtain the measurement points. From the L-shaped point sequence, two straight lines are determined by approximation, and the position of the virtual point is estimated by finding the intersection of those straight lines. The two windows for defining the portion of the point sequence are arranged so that they pass through at least one of the start point and the end point of the measurement point sequence and have substantially the same angle with respect to the linear portion corresponding to each side of the L-shape. Up to one Whereas two reference lines, as the lower end of the predetermined number-th measurement point from the closest recent reference point sensor saturation region in the measurement point sequence, it is characterized in that set in the predetermined range.

According to a second estimation method of the present invention, a lighthouse-type sensor intermittently scans the surface of an object by changing the direction of measurement light little by little, and cross-sections the surface by the principle of triangulation. From the L-shaped point sequence of the measurement points obtained by measuring the shape, two straight lines are determined by approximation, and when estimating the position of the virtual point by obtaining the intersection of those straight lines, Two windows for defining a point sequence portion of the measurement points each approximated by a straight line are formed by passing through at least one of a start point and an end point of the measurement point sequence and forming an angle with respect to a linear portion corresponding to each side of the L-shape. Is one line or two reference lines that are substantially equal to each other, a straight line parallel to the reference line, which is closer to the reference line by a predetermined distance from the farthest reference point in the measurement point sequence. And the intersection of the measurement point sequence As the lower end, it is characterized in that set in the predetermined range.

[0012]

According to the first virtual point position estimating method of the present invention described above, the surface shape of the object is measured by the lighthouse sensor due to an excessive amount of light received by the lighthouse sensor due to the direction of the surface of the object. Even if a saturated region occurs in the point sequence of the measurement points obtained by the above, the nearest point to the reference line whose position is stable in the saturated region is set as the nearest reference point, and a predetermined number of measurements from the nearest reference point Since the positions of the two windows are determined with the point as the lower end, the linear portions in the L-shaped measurement point sequence can be reliably captured by the two windows, and the estimation accuracy of the virtual point position can be improved. .

According to the second virtual point position estimating method of the present invention described above, the surface shape of the object is measured by the lighthouse sensor due to an excessive amount of light received by the lighthouse sensor due to the direction of the surface of the object. Even if a saturated region occurs in the point sequence of the measurement points obtained as described above, the furthest point with respect to the reference line is set as the furthest reference point, and the reference line which is closer to the predetermined distance reference line from the furthest reference point is With the intersection of the parallel straight line and the measurement point sequence as the lower end,
Since the positions of the two windows are determined, the position of the intersection between the straight line parallel to the reference line and the sequence of measurement points at which the angle to the linear portion corresponding to each side of the L-shape is substantially equal is the original farthest point , The linear portions in the L-shaped sequence of measurement points can be reliably captured by the two windows, and the estimation accuracy of the virtual point position can be improved.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a vehicle body assembly accuracy used in the embodiment of the present invention in which the virtual point position estimating method of the first invention is applied to the measurement of the assembly accuracy of the assembled vehicle body in the assembly line of the vehicle body described above. FIG. 2 is a configuration diagram illustrating a measuring device, and in the method of this embodiment, as in the case of the conventional method,
For a plurality of locations of the vehicle body, a portion having a roughly L-shaped two-dimensional cross-sectional shape of the vehicle body panel at those locations is set as a reference portion, and L is set for each of the reference portions.
The intersection of two straight lines approximating the linear portions corresponding to each side of the character is set as a virtual point, and the body panel 6 of the actually assembled body is set within a predetermined tact time in the assembly line. The lighthouse sensor 7 measures the two-dimensional cross-sectional shape of the surface between the start point and the end point of the measurement set at the ends of the two linear portions, which are not the corners, of the two linear portions for each of the reference portions. From the measurement results, cut out the linear part of the point sequence of the measurement points obtained for each reference part with two windows, determine two straight lines from these cut linear parts by approximation, and determine the intersection of those straight lines. The position of the virtual point P is estimated by calculation, and the position of the plurality of virtual points obtained by the estimation is compared with the position of the virtual point on the designed vehicle body to obtain a position error.
Car body assembly accuracy is measured in the following procedure.

In order to perform such a procedure, the apparatus for measuring the accuracy of assembling the vehicle body in this case comprises, for example, a lighthouse type sensor 7 constructed in the same manner as that shown in FIG. 5 and a control unit comprising, for example, a normal microcomputer. 8, a sensor output signal converter 9 composed of, for example, a normal microcomputer, a point sequence data storage memory 10 composed of, for example, a readable and writable memory, and a process composed of, for example, a general microcomputer. Unit 11 and a set value storage memory 12 composed of, for example, a normal read-only memory
Here, a plurality of lighthouse sensors 7 are provided in a post-process of the vehicle body assembly station of the vehicle body assembly line so as to be able to measure each of the reference portions of the vehicle body panel 6 of the actually assembled vehicle body, The control unit 8 controls the swing angle and the swing speed of the scanning mirror of the lighthouse sensor 7 and feedback-controls the light emission intensity of the light source as described above. The sensor output signal conversion unit 9 outputs the output signal of the lighthouse sensor 7. Is converted into coordinate data of the point sequence of the measurement point, the point sequence data storage memory 10 stores the point sequence coordinate data output by the sensor output signal conversion unit 9, and the processing unit 11 stores the point sequence data storage memory 10 The point sequence coordinate data is read out, and the determination of the point sequence data, the estimation process of the virtual point position, and the determination of the vehicle body assembly accuracy are performed based on the data.

The set value storage memory 12 stores preset measurement points P _S (s is the number of the measurement point; s = 1, 2, 3) on the designed vehicle body panel 6 for each reference portion. ,.
..n) and the coordinates of the virtual point positions based on the measurement points, and at least one of the measurement start point A, ie, the measurement point P ₁ and the end point B, ie, P ₂ , of these measurement points, and is L-shaped With respect to one or two reference lines L whose angles with respect to the linear portions corresponding to the respective sides are substantially equal to each other, each linear The number of measurement points s ₁ and s _{2 up} to the part,
Stores the number of measurement points s ₃ and s ₄ to be included in each window in order to sufficiently increase the accuracy of the linear approximation and cut out only the linear part, and provides them to the processing unit 11 as necessary. I do.

The vehicle body assembling accuracy measuring apparatus having the above-described structure is constructed in accordance with the procedure shown in the flowchart of FIG.
Estimation of the virtual point position based on this embodiment and measurement of the assembly accuracy of the vehicle body based thereon are performed as follows. That is, here, first, in step 121, the control unit 8 scans the lighthouse type sensor 7 corresponding to each reference portion with the lighthouse type sensor 7 by scanning with a laser beam, and the first unit actually assembled at the vehicle body assembly station of the vehicle body assembly line. With respect to each of the reference portions of the vehicle body panel as the target object of the vehicle body, the main measurement for performing the cross-sectional shape measurement for the assembly accuracy measurement from the previously set start point A to the end point B is performed. Normally, a video signal having a sufficiently narrow chevron waveform that only partially exceeds a threshold appropriately set for each measurement point is sequentially output, and the sensor output signal converter 9 first converts the video signal into the threshold. converted to sequential binarized signal using shows the binarized signal is determined orthogonal coordinate values of each measuring point P _S representing the sectional shape from a position of the pixel is 1, in FIG. 3, for example Converting the coordinate data of the feeder point sequence, the point sequence data point sequence data storage memory 10 temporarily stores a table describing the coordinates of each measuring point.

When the vehicle body assembly accuracy measurement is performed on the vehicle body assembled in the assembly line of the vehicle body, it is necessary to perform the measurement procedure following the main measurement in step 121 within a predetermined tact time. . However, if the angle change of the scanning mirror 3 is increased so that the shape of each of the reference portions can be measured within the predetermined tact time, the change speed of the light receiving amount of the CCD sensor 5 is too fast to keep up with the feedback control. The laser beam 2 by measuring the corners of the L-shaped cross section of the body panel surface.
When the light is totally reflected, the amount of received light becomes excessive and the CCD sensor 5 becomes saturated. In such a saturated state, the video signal has a wide mountain-shaped waveform, so that the position where the video signal exceeds the threshold value is shifted. In the area of the measurement point sequence measured in the saturated state (saturation area S), the coordinates of the measurement points are lower than the original position (indicated by the mark * in the figure) as shown in FIG. (Located outside the figure) and far (closer to the reference line L).

The position of the lighthouse type sensor 7 with respect to each reference portion of the vehicle body arranged in the measurement step is determined by an L-shaped design of the vehicle body panel so that a video signal can be reliably obtained over the entire reference portion. Is set so that the portion corresponding to each side of the L-shape is located symmetrically with respect to the straight line connecting the vertex of the corner portion and the lighthouse type sensor 7, so that the CCD sensor 5 always has the L-shaped cross-sectional shape. In this case, the saturation will be highest at the actual measurement point corresponding to the point Q which is originally the farthest point with respect to the reference line L. Therefore, as long as the lighthouse sensor 7 does not have a considerable displacement, the actual measurement point corresponding to the point Q is determined as the closest point to the reference line L, that is, the latest reference point. The position of the reference point is extremely stable.

In view of this fact, in the method of this embodiment, in the next step 122, at least one of the starting point A and the ending point B of the L-shaped measurement point sequence obtained by the main measurement is passed and the L-shaped one such angle relative linear portion are substantially equal to each other corresponding to the sides or two of the reference line L, such as the measurement point is equal to the length of the linear portion as shown in FIG. 3 P _S (s = 1 , 2,3,... N)
One reference line L connecting (P ₁ ) and the end point B (P _n ) with a straight line is set. At this time, the coordinate conversion of the screen display is performed so that the x-axis extending in the horizontal direction on the screen and the reference line L are parallel.

Next, in step 123, the reference line L is set within the sensor saturation region of the L-shaped measurement point sequence obtained by the main measurement.
The closest reference point which is the closest measurement point to the target, for example, a point T in FIG. It should be noted that this latest reference point corresponds to the maximum point between the two minimum points that are normally located near both ends of the sensor saturation region in the measurement point sequence, so that the maximum point is easily and reliably obtained. be able to. Thereafter, in step 124, the previously set numbers s ₁ and s _{2 are} set to the lower end from the latest reference point T, and the previously set numbers s ₃ and s _{4 are} set to the lower end of the measurement points.
Th the upper measurement point, for example, open two windows W ₁ and W ₂ as shown in FIG. 3, read the coordinates of the measurement points constituting the point sequence cut measurement point sequence comes within their windows put out.

Next, at step 125, a straight line is approximately obtained by the least square method from the coordinates of the measurement points in the two windows W ₁ and W ₂ , and then at step 126
By calculating the intersection of these straight lines, the position coordinates of the virtual point P are obtained. Thereafter, in step 127, the obtained coordinates of the virtual point P are compared with the coordinate data of the virtual point P in the known design, and the vehicle body is determined. The assembly accuracy is determined, and in the next step 128,
Next, the presence or absence of the assembled vehicle body is determined, and if there is a next vehicle body, the process returns to step 121 to repeat the procedure after the main measurement, and the process ends if there is no next vehicle body.

As described above, according to the method of this embodiment, the change in the angle of the scanning mirror of the lighthouse sensor 7 is accelerated so that the shape of each of the reference portions can be measured within a predetermined takt time. In addition, the speed of change of the amount of received light of the CCD sensor is too fast to keep up with the feedback control, and a saturated region where the amount of received light of the sensor is excessive at the L-shaped corner of the surface of the vehicle body panel 6 occurs. Even if the position is determined as being farther from the sensor than the actual position, the latest reference point T, which is a point whose position is stable in the sensor saturation region, is determined, and the position of the latest reference point T is used as a reference. One of so opening the window W _1, W _2, only the linear portion, and a sufficient number to become possible to perform linear approximation using the measurement point, the measurement points to the actual cross-sectional shape of the surface of the body panel 6 Column can be reduced the error of cross-section represented by obtained by thus improving the estimation accuracy of the position of the virtual point P, it is possible to improve the measurement accuracy of the vehicle body assembling accuracy.

FIG. 4 shows a window setting in one embodiment in which the virtual point position estimating method according to the second aspect of the present invention is applied to the measurement of the assembly accuracy of the assembled vehicle body in the assembly line of the vehicle body described above. In this method, the vehicle body assembly accuracy measurement is performed on the vehicle body assembled in an automobile body assembly line by using the same vehicle body assembly accuracy measurement device as in the above-described embodiment. In particular, for setting the windows W ₁ and W ₂ , a set value storage memory
12 is a preset position of each measurement point P _S (s is the number of the measurement point; s = 1, 2, 3,... N) on the designed vehicle body panel 6 for each reference portion. In addition to the coordinates of the virtual point position based on the measurement points (in FIG. 4, the points marked with * are included instead of P _{S1 to} P _S4 ), the start point A of measurement among those measurement points, ie, the measurement point P ₁ and through at least one of the end point B i.e. P _2, and with respect to one or two reference lines L as the angle relative to the linear portion corresponding to each side of the L-shaped are substantially equal to each other, the measurement Distance D _G from a point that is originally the farthest point in the sequence of points (point Q marked with * in FIG. 4) to a straight line that passes through the lower ends of both straight portions and is parallel to the reference line L
And the diagonal lengths k ₁ and k _{2 of} the two windows, and provide them to the processing unit 11 as needed. Here, the distance D _G is the radius of the corner portion of the reference part L-shaped r, when the angle of the linear portion corresponding to each side of the L-shaped and theta, the following equation

## EQU1 ## D _G = r · (1−sin θ / 2)

Here, it is assumed that the measurement is performed in a procedure substantially similar to the procedure shown in FIG. 2 in the previous embodiment, and in step 121, the main measurement of each reference portion is performed by the lighthouse sensor 7, and Step 122 of Step 121
One or two lines passing through at least one of the start point A and the end point B of the L-shaped measurement point sequence obtained in the main measurement and having substantially the same angle with respect to a linear portion corresponding to each side of the L-shape. It is not equal to the length measurement point of the reference line L, such as the linear portion as shown in FIG. 4 of this _{P S (s = 1,2,3,.} ..
In the case of the point sequence of n), a straight line passing through the start point A (P ₁ ) and the end point B
Two reference lines L with a straight line passing through (P _n ) are set. At this time, the coordinate conversion of the screen display is performed so that the x-axis extending in the horizontal direction on the screen and the reference line L are parallel.

Next, in step 123, instead of finding the latest reference point T as in the previous embodiment, a series of measurement points obtained by the above main measurement (in FIG. P _S1 including to P _S4) seeking farthest reference point U is the point farthest from the reference line L in its farthest reference point U
From was near cerebrospinal above distance D _G only the reference line L, sets the straight L _G parallel to the reference line L, and the intersection point C _1, C ₂ of the measurement point sequence obtained in this measurement and the straight line L _G Ask. Here, the straight line L _G, because parallel to the reference line L, the position of intersection of the straight line L _G and the measurement point sequence is located approximately equidistant from the original farthest point, yet the farthest reference point U the distance between the reference line L, because the original slightly shorter than the distance between the farthest point and the reference line L, and the straight line L _G was near cerebrospinal its from the farthest reference point U by the distance D _G reference line L The above point C which is the intersection with the measurement point sequence
₁ and C ₂ are located at positions slightly inside the linear portions from the lower ends of both linear portions.

Next, at step 124, the intersections C ₁ and C ₂
Are the inner ends, and their intersections C ₁ , C
_The measurement point D ₁ , which is separated from ₂ by the diagonal lengths k ₁ and k ₂
D ₂ as outer end each, two windows W _1, W
₂ is opened, the measurement point sequence included in those windows is cut out, and the coordinates of the measurement points forming the point sequence are read out. After that, the estimation of the virtual point position and the measurement of the vehicle body assembly accuracy are performed in the same manner as in step 125 and subsequent steps of the previous embodiment.

According to this method, when the angle change of the scanning mirror of the lighthouse sensor 7 is increased so that the shape of each of the reference portions can be measured within a predetermined tact time, the amount of light received by the CCD sensor is reduced. The change speed is too fast to keep up with the feedback control, and a saturated region where the amount of light received by the sensor is excessive at the L-shaped corner of the surface of the vehicle body panel 6, and the position of the measurement point in the saturated region is higher than that of the actual sensor. Even if it is determined that the reference point is far from the reference line L, the farthest reference point U that is the farthest point from the reference line L is determined.
, Two windows W ₁ , W ₂ with the lower end being a position slightly closer to the reference line L than the lower end of the linear portion.
, A straight line approximation is performed using only a straight portion and using a sufficient number of measurement points.
The error of the cross-sectional shape represented by the point sequence of the measurement points with respect to the actual cross-sectional shape of the surface of the surface can be reduced, and thus, the estimation accuracy of the position of the virtual point P can be improved, and the measurement accuracy of the body assembly accuracy can be improved. be able to.

Further, according to this method, the above CC
Since the saturation state of the D sensor is particularly remarkable, for example, P in FIG.
_Even when the measurement points in the saturation area S are missing as shown by _{S1 to} P _S4 , the two windows W ₁ , W are determined based on the farthest reference point U in the obtained measurement point sequence. _Two
Can be opened, the position of the virtual point P can be estimated, and the measurement of the vehicle body assembly accuracy can be reliably performed.

Then, according to the method of any of the embodiments,
Once the above set values are once stored in the set value storage memory 12, the processing unit 11 automatically sets the window.
Unlike the conventional method, since the setting range of the window changes depending on the operator of the measuring device, there is no inconvenience such as a difference in the estimation result of the virtual point position due to a difference in the skill of setting.

In any of the methods, if no saturation region occurs during the measurement by the lighthouse sensor 7, two windows are opened based on the farthest point Q as in the conventional method, and the measurement point sequence is formed. The position of the virtual point P may be estimated by performing a straight line approximation on the cut-out point sequence. In addition, a certain allowable range may be provided for the number of measurement points s ₃ and s ₄ and the diagonal lengths k ₁ and k ₂ that determine the setting range of the window in consideration of the measurement accuracy of the device and the processing accuracy of the panel. good.

Although the present invention has been described with reference to the illustrated examples, the present invention is not limited to the above examples. For example, one microcomputer may be shared by the control unit 8 and the processing unit 11 in the above embodiment. Good to In addition, the method of the present invention can be applied to measurement of body assembly accuracy and shape accuracy of a body panel alone outside a body assembly line, and can also be applied to measurement of an object other than a body panel. .

[0033]

As described above, according to the first aspect of the invention, the measuring point obtained by measuring the surface shape of the object with the lighthouse sensor due to the excessive amount of light received by the lighthouse sensor due to the direction of the surface of the object. Even if a saturated region occurs in the point sequence, the nearest point to the reference line whose position is stable within the saturated region is defined as the nearest reference point, and a predetermined number of measurement points from the nearest reference point is defined as the lower end. Since the positions of the two windows are determined, the linear portion in the L-shaped measurement point sequence can be reliably captured by the two windows, and the estimation accuracy of the virtual point position can be improved.

According to the second aspect of the present invention, the point of the measurement point obtained by measuring the surface shape of the object with the lighthouse sensor due to the excessive amount of light received by the lighthouse sensor due to the direction of the surface of the object. Even if a saturation region occurs in the row, the furthest point with respect to the reference line is set as the farthest reference point, and a straight line parallel to the reference line, which is closer to the reference line from the farthest reference point by a predetermined distance, and a measurement point sequence Since the position of the two windows is determined with the intersection point of as the lower end, the linear portion in the L-shaped measurement point sequence can be reliably captured by the two windows, and the estimation accuracy of the virtual point position can be improved. it can.

[Brief description of the drawings]

FIG. 1 shows an embodiment in which a virtual point position estimating method according to the first invention is applied to measurement of assembly accuracy of an assembled vehicle body in an assembly line of an automobile body, and a virtual point position estimation method according to a second invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram illustrating a body assembly accuracy measuring device used in an embodiment in which the method is applied to measurement of assembly accuracy of an assembled body in an assembly line of an automobile body.

FIG. 2 is a flowchart showing a processing procedure when the vehicle body assembly accuracy measuring device executes a virtual point position estimation and a vehicle body assembly accuracy measurement based on the method of the embodiment of the first invention.

FIG. 3 is a diagram showing a state of a measurement point sequence obtained by measuring the reference portion of the vehicle body panel by the vehicle body assembly accuracy measuring device, and the device is imagined from the measurement point sequence based on the method of the first embodiment of the present invention. It is explanatory drawing which shows the method of estimating the position of a point, respectively.

FIG. 4 is a view showing a state of a measurement point sequence obtained by measuring the reference portion of the vehicle body panel by the vehicle body assembly accuracy measuring device, and the device is imagined from the measurement point sequence based on the method of the second embodiment of the present invention; It is explanatory drawing which shows the method of estimating the position of a point, respectively.

FIG. 5 is an explanatory view showing a configuration of a lighthouse type sensor used in the method of the conventional example and the above-mentioned both examples.

FIG. 6 is a flowchart showing a processing procedure according to a conventional method when estimating a virtual point position and measuring vehicle body assembly accuracy based on a measurement result of a lighthouse type sensor.

FIG. 7 shows an original state of a measurement point sequence obtained by measuring a reference portion of a vehicle body panel by a lighthouse type sensor, and a method of estimating a position of a virtual point based on the conventional method from the measurement point sequence. FIG.

FIG. 8 shows a position of a virtual point based on the state of a failure in a sensor saturation region of a measurement point sequence obtained by measuring a reference portion of a vehicle body panel by a lighthouse type sensor and the measurement point sequence based on the conventional method. It is explanatory drawing which shows the method of estimating respectively.

[Explanation of symbols]

6 body panel 7 Lighthouse formula point sensor 8 control unit 9 sensor output signal converter 10 column data storage memory 11 processor 12 setting value storage memory L reference line L _a straight line P _a measurement point P ₁ starting P _n end points P virtual point Q the farthest point S the saturation region T recent reference point U farthest reference point W _1, W ₂ windows

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01B 11/00-11/30 G06T 7/60

Claims (2)

(57) [Claims] 1. A lighthouse-type sensor intermittently scans the surface of an object by gradually changing the direction of measurement light,
From the L-shaped point sequence of the measurement points obtained by measuring the cross-sectional shape of the surface according to the principle of triangulation, two straight lines are determined by approximation, and the intersection of those straight lines is obtained to obtain the position of the virtual point. When estimating, two windows for defining a point sequence portion of the measurement points that are respectively approximated by the two straight lines pass through at least one of a start point and an end point of the measurement point sequence, and each of the L-shaped With respect to one or two reference lines whose angles with respect to the linear portions corresponding to the sides are substantially equal to each other, a predetermined number of the closest reference points in the sensor saturation region in the measurement point sequence from the closest reference point A method for estimating a virtual point position by measurement with a lighthouse sensor, wherein the measurement point is set in a predetermined range with a lower end as a measurement point. 2. A lighthouse type sensor intermittently scans the surface of an object by gradually changing the direction of measurement light,
From the L-shaped point sequence of the measurement points obtained by measuring the cross-sectional shape of the surface according to the principle of triangulation, two straight lines are determined by approximation, and the intersection of those straight lines is obtained to obtain the position of the virtual point. When estimating, two windows for defining a point sequence portion of the measurement points that are respectively approximated by the two straight lines pass through at least one of a start point and an end point of the measurement point sequence, and each of the L-shaped With respect to one or two reference lines whose angles with respect to the linear portions corresponding to the sides are substantially equal to each other, a predetermined distance from the farthest reference point in the measurement point sequence is not close to the reference line. A method for estimating a virtual point position by measurement with a lighthouse sensor, wherein a predetermined point is set with an intersection of a straight line parallel to the reference line and the sequence of measurement points as a lower end.