JP5438475B2 - Gap step measurement device, gap step measurement method, and program thereof - Google Patents

Description

  The present invention relates to a gap step measuring device that measures a finished dimension of a panel part that forms, for example, an automobile body, and in particular, a gap step measuring device that measures a gap and a step between two panel parts, a gap step measuring method, And the program.

  In the automobile manufacturing process, there is a dimension inspection as an inspection of the finished quality of the automobile body. As one of the dimension inspections, for example, a gap and a step between two panel parts (called workpieces) are measured. Conventionally, when such an inspection is performed, there is a method of measuring dimensions by using a light cutting method (for example, see Patent Document 1).

A conventional measurement method using the light cutting method will be described with reference to FIG. In FIG. 7, when a gap and a step formed by two workpieces W1 and W2 are a measurement object G and the dimensions are measured, the laser slit light is irradiated by the laser irradiation device 50 on the surfaces of the two workpieces W1 and W2. Is done. At this time, the laser irradiation device 50 is arranged so that the laser slit light is irradiated obliquely from above the measurement target G.
The reflected light is imaged by the imaging device 51 including a CCD camera or the like disposed above the measurement target G, and the dimension of the measurement target G (gap and step) is measured based on the captured image.

More specifically, after imaging the reflected light of the laser slit light irradiated to the ends of the workpieces W1 and W2, and binarizing the captured image, as shown in FIG. The plane part height and the tip part position (edge) are obtained, and their intersection coordinates P (x1, z1) and P (x2, z2) are calculated.
Here, since the image acquired by the imaging device 51 is a two-dimensional (XY axis) plan view, the conversion of the workpieces W1 and W2 into the position in the Z direction (height direction) is, for example, the position in the XY direction. A look-up table in which the correspondence with the Z direction position is stored in advance is used. That is, since there is a step between the workpieces, a deviation occurs in the irradiation position of the laser slit light irradiated on the workpiece surface. Using this shift, the intersection position in the Z direction can be obtained by the lookup table.
Then, the gap dimension d1 and the step dimension d2 are obtained from the difference (x1-x2, z1-z2) in the XZ directions of the intersection coordinate P.

Japanese Patent Laid-Open No. 10-232110

  As described above, when obtaining the coordinates of the intersection point P, the reflected light of the irradiated laser slit light is imaged, and the calculation is performed based on the acquired image. That is, in order to obtain the exact position of the intersection point P, it is necessary to irradiate both ends (tip portions) of the workpieces W1, W2 with laser slit light.

However, in order to produce a deviation in the irradiation position of the laser slit light based on the step between the workpieces as described above, it is necessary to irradiate the laser slit light with respect to the measurement target, and in this case, both ends of the workpiece In addition, it has been difficult to reliably irradiate laser slit light.
That is, as shown in the cross-sectional view of FIG. 8, there is a case where the end of one workpiece W1 is irradiated with slit light, but the end E of one workpiece W2 is not irradiated. At this time, as shown in an example in the graph of FIG. 9, the tip E (the tip of 8 to 10 mm) is not detected, and there is a problem that an error occurs in the calculation result of the intersection P.

  The present invention has been made paying attention to the above-described points, and in a gap step measuring apparatus for measuring a gap and a step formed between two workpieces and obtaining a dimension of the measurement target, a measurement posture (a workpiece) It is an object of the present invention to provide a gap level difference measuring apparatus, a gap level difference measuring method, and a program thereof that can easily measure with high accuracy without the need to accurately face the relationship between the sensor and the sensor.

In order to solve the above-described problem, a gap step measuring device according to the present invention is a gap step measuring device for measuring a gap and a step formed between two workpieces and obtaining a dimension of the measurement target, Slit light irradiating means for irradiating the slit light obliquely from above to the measurement target so as to cause a shift in the reflected light of the slit light irradiated on the surfaces of the two workpieces, and disposed immediately above the measurement target. A first planar image including the measurement object in a state where at least the slit light is irradiated; and a second planar image including a pair of workpiece end portions which form the measurement object in a state where the slit light is not irradiated. Imaging means for acquiring the image, and control means for calculating the dimension of the measurement object based on the image acquired by the imaging means, wherein the control means is imaged by the imaging means. The center line of the slit light irradiated on the workpiece surface is extracted from the first plane image, and the edge lines of the pair of workpiece ends are extracted from the second plane image, respectively. It is characterized in that the dimension of the measurement object is calculated based on each intersection of the center line and the edge line of the pair of workpiece ends.
The control unit preferably binarizes the first image and the second image acquired by the imaging unit, respectively, and extracts the center line and the edge line.
Alternatively, it is preferable that the control unit extracts the center line from the barycentric position of the luminance value in the width direction of the slit light in the first image.

  With this configuration, even when the positions of both ends of the workpiece cannot be detected by the slit light as in the conventional case, the edge lines can be accurately extracted, and the gap size and step size of the measurement target can be easily and easily determined. It can be obtained with high accuracy.

The slit light irradiating means irradiates each of the plurality of measurement target parts with independent slit light, and the control means extracts a center line for each of the irradiated slit light, It is desirable to obtain each intersection with the edge line of the workpiece end and calculate the dimension of the measurement object based on the obtained plurality of intersections.
Thus, by obtaining the intersection of the center line of the slit light and the edge line of the workpiece end at a plurality of parts to be measured, the dimension of the measurement target can be obtained with higher accuracy.

In order to solve the above problem, a gap step measuring method according to the present invention is a gap step measuring method for measuring a gap and a step formed between two workpieces and obtaining a dimension of the measurement target. The measurement of the state in which at least the slit light is irradiated while the slit light is irradiated on the measurement object obliquely from above so that the reflected light of the slit light irradiated on the surfaces of the two workpieces is shifted. Obtaining a first planar image including a target, obtaining a second planar image including a pair of workpiece end portions forming the measurement target in a state where the slit light is not irradiated, and the first Extracting a center line of slit light irradiated on the workpiece surface from the planar image of the step, and edge lines of the pair of workpiece ends from the second planar image. Respectively extracting, calculating each intersection of the center line of the slit light and the edge line of the pair of workpiece ends, and calculating a dimension of the measurement object based on each intersection It has a feature in executing.
Note that it is desirable to binarize the first image and the second image, respectively, and extract the center line and the edge line.
Alternatively, in the first image, it is desirable to extract the center line from the barycentric position of the brightness value in the width direction of the slit light.

  By executing such a method, even if the positions of both ends of the workpiece cannot be detected by the slit light as in the conventional case, the edge line can be accurately extracted, and the gap size and step size of the measurement target can be determined. It can be obtained easily and with high accuracy.

In addition, each of the plurality of measurement objects is irradiated with independent slit light, a center line is extracted for each of the irradiated slit light, and an edge line of the pair of workpiece end portions is extracted for each extracted center line. It is desirable to calculate each dimension of the measurement object based on the obtained plurality of intersections.
Thus, by obtaining the intersection of the center line of the slit light and the edge line of the workpiece end at a plurality of parts to be measured, the dimension of the measurement target can be obtained with higher accuracy.

In order to solve the above-described problem, the gap level difference measuring program according to the present invention is a slit light that is irradiated on the surfaces of the two workpieces , with a gap and a step formed between the two workpieces being measured. Slit light irradiating means for irradiating the measurement object obliquely from above with respect to the measurement object so as to cause a deviation in the reflected light of the first, and a first planar image including at least the measurement object in the state irradiated with the slit light; An imaging unit that acquires a second planar image including a pair of workpiece end portions that form the measurement target in a state where the slit light is not irradiated, and the measurement target based on the image acquired by the imaging unit A gap level difference measuring device comprising: a control means for calculating a dimension of the first to second images taken by the imaging means on the workpiece surface. Means for extracting a center line of the projected slit light; means for extracting edge lines of the pair of workpiece ends from the second plane image; and a center line of the slit light and the pair of workpiece ends. It is characterized by functioning as means for calculating each intersection with the edge line and means for calculating the dimension of the measurement object based on each intersection.

  By executing such a program, even if the positions of both ends of the workpiece cannot be detected by the slit light as in the conventional case, the edge lines can be extracted accurately, and the gap size and step size of the measurement target can be determined. It can be obtained easily and with high accuracy.

  According to the present invention, a gap and a step formed between two workpieces are to be measured, and in a gap step measuring apparatus for obtaining a dimension of the measurement target, a measurement posture (a relation between a workpiece and a sensor) is correctly opposed. There is no need, and it is possible to obtain a gap step measuring device, a gap step measuring method, and a program thereof that can easily perform highly accurate measurement.

FIG. 1 is a perspective view schematically showing a configuration of a gap level difference measuring apparatus according to the present invention. FIG. 2 is a flow showing a flow of processing in the gap level difference measuring apparatus of FIG. FIG. 3 is a diagram schematically illustrating a planar image of a measurement target imaged by a CCD camera. FIG. 4 is a diagram schematically showing another planar image of the measurement target imaged by the CCD camera. FIG. 5 is a diagram schematically illustrating the position of the intersection obtained in the control unit. FIG. 6 is a diagram for explaining an intersection obtained in the control unit and a method of calculating the dimension of the measurement target. FIG. 7 is a diagram schematically illustrating a configuration of a measurement apparatus using a conventional light cutting method. FIG. 8 is a diagram for explaining a method for calculating the dimension of the measurement target in the measurement apparatus of FIG. FIG. 9 is a diagram for explaining a problem that the measurement apparatus of FIG. 7 has.

Hereinafter, embodiments of the present invention will be described based on the embodiments shown in the drawings. FIG. 1 is a perspective view schematically showing a configuration of a gap level difference measuring apparatus according to the present invention.
The gap level difference measuring apparatus 1 shown in FIG. 1 uses a gap and a level difference formed between a panel-like workpiece W1 and a workpiece W2 placed on an inspection table 2 as a measurement target G, and obtains the dimensions thereof. It is a device.

As shown in the figure, the gap level difference measuring device 1 includes two laser irradiation devices 4 and 5 (slit light irradiation means) fixed to a frame member 3. These laser irradiation devices 4 and 5 are arranged above the measurement object G, and each irradiates the surface of the workpieces W1 and W2 with laser slit light so as to intersect with the measurement object G formed in a linear shape. It is made like that.
Note that the slit light is irradiated not on the measurement target G but on the measurement target G from obliquely above, so that the slit light (reflected light) applied to the workpieces W1 and W2 is shifted.
In addition, irradiation drive units 7 and 8 are connected to the laser irradiation devices 4 and 5, respectively, and irradiation control can be performed independently. Moreover, each irradiation drive part 7 and 8 is each connected to the control part 10 (control means) which consists of computers.

The laser irradiation devices 4 and 5 will be further described. The irradiation positions of the laser slit light L1 and L2 (slit light) formed by the laser irradiation devices 4 and 5 are preferably irradiated in directions intersecting each other. For example, the irradiation position of the laser slit light L1 is orthogonal to the gap formation direction of the measurement object G (facing position), and the irradiation position of the laser slit light L2 is along the formation direction of the measurement object G ( (Facing position).
However, in the gap level difference measuring apparatus 1 according to the present invention, any one of the laser slit lights L1 and L2 is applied to both the workpieces W1 and W2 from an obliquely upper position with respect to the measurement target G. Thus, the effects according to the present invention can be sufficiently obtained (that is, it is not necessary to accurately face the laser irradiation device 4 (5) to the workpieces W1 and W2).

Further, in this gap level difference measuring apparatus 1, a CCD camera 6, which is an imaging means, is disposed immediately above the measurement target G. As shown in FIG. 3, at least the end W1a of the workpiece W1 and the end W2a of the workpiece W2 in the measurement target G are both acquired as information of one plane image by the CCD camera 6. The inspection table 2 is provided with a non-reflective coating in accordance with the wavelength of the slit light so that the reflected light of the slit light is not imaged by the CCD camera 6.
The CCD camera 6 is connected to the control unit 10 via the A / D conversion unit 9.
In addition, the control unit 10 includes a gap step measurement program P recorded in a storage unit 11 made of, for example, a flash memory, and a calculation unit 12 that performs calculation based on the program.

Next, the flow of processing (gap step measurement method) in the gap step measurement apparatus 1 will be described based on the flowchart of FIG. In addition, the process in the control part 10 is performed based on the gap | interval level | step difference measurement program P. FIG.
First, for example, the whole illumination of white illumination is performed on the workpieces W1 and W2 placed on the inspection table 2 by imaging illumination means (not shown), or laser irradiation is performed by the irradiation driving units 7 and 8. The devices 4 and 5 are driven, and the laser slit lights L1 and L2 are applied to the workpieces W1 and W2, respectively. Then, in a state where each irradiation is performed individually, an image including the measurement object G between the workpieces W1 and W2 is captured by the CCD camera 6 (step S1 in FIG. 2).

Here, the image acquired by the CCD camera 6 includes an image of the measurement target G (second planar image) in a state where only the entire illumination is as shown in FIG. 3, and a laser as shown in FIG. An image (first planar image) irradiated with the slit light L1 from diagonally above the measurement target G and an image (laser slit light L2 as shown in FIG. First plane image). As described above, since the inspection table 2 is coated without reflection, the reflected light of the slit light from the inspection table 2 below the gap of the measurement object G is not imaged.
Each image acquired by the CCD camera 6 is output as digital data in the A / D conversion unit 9 (step S2 in FIG. 2), and binarization processing is performed in the control unit 10. By this binarization processing, the boundary line between the irradiated part and the non-irradiated part is clarified.

In the control unit 10, calculation of intersections P1 and P2 between the laser slit light L1 and the workpiece end shown in FIG. 5A, and intersection P3 between the laser slit light L3 and the workpiece end shown in FIG. 5B. , P4 is calculated.
More specifically, the arithmetic unit 12 first obtains the center line LC of the laser slit light L1 having a predetermined thickness width at the pixel level as shown in the partially enlarged view of FIG. 2 step S3).
Further, the edge lines of the ends W1a and W2a of the workpieces W1 and W2 shown in FIG. 6B are extracted at the pixel level based on the image captured under the overall illumination shown in FIG. 3 (step S4 in FIG. 2). ). FIG. 6B is a cross-sectional view taken along arrow AA in FIG.

  Next, as shown in FIG. 6B, the Z-direction component of the center line LC of the slit light L1 obtained in Steps 3 and 4 and the X-direction component of the edge lines of the workpiece ends W1a and W2a The intersection points P1 and P2 are obtained at the pixel level (step S5 in FIG. 2). Note that the center line LC of the slit light L1 is data on an XY two-dimensional plane orthogonal to the Z direction. For example, the XY direction position and the Z direction position (high A look-up table showing the correspondence with the position) is recorded, and the Z-direction position can be obtained by referring to it.

Further, the intersection points P1 and P2 at the pixel level obtained in step S5 are converted into coordinate values in the XZ direction (step S6 in FIG. 2).
Further, with respect to the laser slit light L2, the processes in steps S3 to S6 are similarly performed, and the coordinate values of the intersections P3 and P4 are obtained (step S7 in FIG. 2).
Then, the calculation unit 12 calculates the gap dimension d1 and the step dimension d2 in the measurement target G based on the obtained intersection points P1 (P3) and P2 (P4).

As described above, according to the embodiment of the present invention, the center line LC of the slit light is extracted from the image of the measurement target G irradiated with the laser slit light L1 (L2), and the workpiece end W1a in the measurement target G is extracted. , The edge lines of the workpieces W1 and W2 are extracted from the image of W2a. Then, the gap dimension d1 and the step dimension d2 are calculated based on the intersections P1 (P3) and P2 (P4) between the center line LC and each edge line.
That is, even if the workpiece end portion (for example, the tip E of the workpiece W2 in FIG. 6B) cannot be detected by the laser slit light L1 (L2) (in other words, with respect to the measurement target G (works W1, W2)). The positions of the workpiece end portions W1a and W2a can be accurately detected without the laser irradiation device 4 (5) being correctly aligned. Accordingly, the gap dimension d1 and the step dimension d2 of the measurement target G can be easily and accurately obtained.

In the above embodiment, the measurement target G is irradiated with the two laser slit lights L1 and L2. However, only one of the laser slit lights alone can sufficiently obtain the effects of the present invention. it can.
Alternatively, the measurement may be performed by irradiating laser slit light to each of three or more sites in the measurement target. In that case, it is possible to perform measurement with higher accuracy by obtaining intersections between the center line of each laser slit light and the edge lines at both ends of the workpiece, and obtaining the dimensions of the measurement object based on the respective intersection positions.

  In the above embodiment, the slit light irradiating means is the laser irradiating devices 4 and 5, and the laser slit light is irradiated to the measurement object G. However, in the present invention, the light source is the laser light. It is not limited, The slit light may be formed by a light source (for example, LED) other than the laser, and the measurement target G may be irradiated.

In the embodiment, after binarizing each image (first plane image and second plane image) acquired by the CCD camera 6, the slit light center line LC and the workpieces W1, W2 are processed. An example in which the edge line is extracted at the pixel level is shown.
However, the present invention is not limited thereto, and each image acquired by the CCD camera 6 is not binarized, and the center line LC of the slit light and the edge lines of the workpieces W1 and W2 are obtained from each image. May be extracted. In this case, for example, it is preferable to extract the center line LC by obtaining luminance center-of-gravity pixels in the width direction of the slit light L1 (L2) in the first planar image and connecting them in the length direction of the slit light. .
In this way, more accurate center line LC and edge line positions can be extracted, and the positions of the intersections P1 (P3) and P2 (P4) can be obtained with higher accuracy.

DESCRIPTION OF SYMBOLS 1 Gap level | step difference measuring apparatus 2 Inspection stand 3 Frame member 4 Laser irradiation apparatus (slit light irradiation means)
5 Laser irradiation device (slit light irradiation means)
6 CCD camera (imaging means)
DESCRIPTION OF SYMBOLS 7 Irradiation drive part 8 Irradiation drive part 9 A / D conversion part 10 Control part 11 Memory | storage part 12 Calculation part G Measurement object L1 Laser slit light (slit light)
L2 Laser slit light (slit light)
P Gap step measurement program W1 work W2 work

Claims (9)

A gap step measuring device for measuring a gap and a step formed between two workpieces and obtaining a dimension of the measurement target,
Slit light irradiating means for irradiating the slit light obliquely from above with respect to the measurement target so that a deviation occurs in reflected light of the slit light irradiated on the surfaces of the two workpieces ;
A first planar image including the measurement object that is disposed at the top of the measurement object and at least irradiated with the slit light, and a pair of workpieces that form the measurement object without being irradiated with the slit light An imaging means for acquiring a second planar image including the end;
Control means for calculating the dimensions of the measurement object based on the image acquired by the imaging means,
The control means includes
A center line of slit light irradiated on the workpiece surface is extracted from the first planar image captured by the imaging means, and edge lines of the pair of workpiece end portions are extracted from the second planar image, respectively. A gap level difference measuring device that calculates a dimension of the measurement object based on each intersection of a center line of the slit light and an edge line of the pair of workpiece end portions.   The control means performs binarization processing on the first image and the second image acquired by the imaging means, respectively, and extracts the center line and the edge line. 1 is a gap level difference measuring device.   2. The gap level difference measuring device according to claim 1, wherein the control unit extracts the center line from the barycentric position of the luminance value in the width direction of the slit light in the first image. The slit light irradiating means irradiates a plurality of parts to be measured with independent slit light,
The control means extracts a center line for each irradiated laser slit light, obtains each intersection with the edge line of each of the pair of workpiece ends, and based on the obtained plurality of intersections, the dimension of the measurement object The gap level difference measuring device according to claim 1, wherein the gap level difference measuring device is calculated. A gap step measurement method for measuring a gap and a step formed between two workpieces and obtaining a dimension of the measurement target,
The measurement target is irradiated with the slit light obliquely from above so that the reflected light of the slit light irradiated on the surfaces of the two workpieces is shifted , and at least the slit light is irradiated. Obtaining a first planar image comprising:
Obtaining a second planar image including a pair of workpiece end portions forming the measurement object in a state where the slit light is not irradiated;
Extracting a center line of slit light applied to the workpiece surface from the first planar image;
Extracting each edge line of the pair of workpiece ends from the second planar image;
Calculating each intersection of the center line of the slit light and the edge line of the pair of workpiece ends;
And a step of calculating a dimension of the measurement object based on the intersections.   6. The gap step measuring method according to claim 5, wherein the first image and the second image are respectively binarized and the center line and the edge line are extracted.   6. The gap step measuring method according to claim 5, wherein in the first image, the center line is extracted from a barycentric position of luminance values in the width direction of the slit light. Irradiate independent slit light to a plurality of measurement target parts,
A center line is extracted for each irradiated slit light,
8. The intersection of the edge line of the pair of workpiece ends is obtained for each extracted center line, and the dimension of the measurement object is calculated based on the obtained plurality of intersections. The gap level | step difference measurement method described in any one of. A gap and a step formed between two workpieces are to be measured, and the slit light is applied obliquely from above to the measurement target so that a deviation occurs in reflected light of the slit light irradiated on the surfaces of the two workpieces. A slit light irradiating means for irradiating, a first planar image including at least the measurement target in a state in which the slit light is irradiated, and a pair of workpiece end portions that form the measurement target in a state in which the slit light is not irradiated In a gap level difference measuring apparatus comprising: an imaging unit that acquires a second planar image including: and a control unit that calculates a dimension of the measurement target based on the image acquired by the imaging unit.
The control means;
Means for extracting a center line of slit light irradiated on the workpiece surface from the first planar image imaged by the imaging means;
Means for extracting edge lines of the pair of workpiece ends from the second planar image,
Means for calculating each intersection of the center line of the slit light and the edge line of the pair of workpiece ends;
A gap step measurement program that functions as means for calculating a dimension of the measurement object based on each intersection.

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