JP5313862B2 - Dimension measuring method and apparatus by two-dimensional light cutting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring a gap and a difference level by two-dimensional optical cutting method that accurately calculate a gap and a difference level in the two-dimensional optical cutting method regardless of the shape of edges. <P>SOLUTION: The laser emission line in the facing surfaces in which a user want to obtain a gap dimension and a difference level dimension, is designated on the screen 20 of a monitor 17. A CPU 14 extracts the position of the laser emission line within the designated range for the gap dimension and the difference level dimension in sub-pixel accuracy, and, when measuring the gap dimension, the straight line equations of the laser emission lines on the facing surfaces are respectively used to calculate a gap between both straight lines. When measuring the difference level, the CPU 14 uses the straight line equations of the laser emission lines on the two surfaces forming the difference level to calculate a gap between both straight lines. The obtained gap dimension and difference level dimension are indicated on a monitor 17. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method and an apparatus for measuring a gap and a step size by a two-dimensional light cutting method.

  A method for measuring gaps and steps using the two-dimensional light cutting method will be described. In the light cutting method, light from a light source (laser) is illuminated onto a measurement target, and reflected / scattered light generated from the measurement target is imaged on a sensor using an imaging lens. The distance from the image formation position of the scattered light to the measurement object is measured based on the principle of triangulation. When the position of the measurement object is changed or the shape is changed, the imaging position on the sensor is shifted, so that the position and shape of the measurement object can be obtained.

  However, if the longitudinal direction of the linear beam is not matched with the normal direction of the opposing surface, the measured distance is larger than the actual distance between the opposing surfaces. For this reason, when it is going to measure a surface space | interval with high precision, it is necessary to make a linear beam parallel to the normal line direction of an opposing surface.

  In general, when measuring the surface interval, a method of extracting each edge of the opposing surface and obtaining a distance between the extracted edges is used. For extracting the edge, a method of extracting the position of the laser bright spot corresponding to the edge on the captured image is used. The extraction accuracy at this time is determined by the pixel size w (= sampling interval) on the measurement target. For this reason, normally, sub-pixel processing is performed, and extraction is performed with an accuracy equal to or smaller than the pixel size.

  However, since the edges of machined products are chamfered or there are burrs even immediately after chamfering, edge positions are unstable and edge extraction is stable. I can't do it. As a result, the measurement accuracy of the surface interval is lowered.

  Therefore, in Patent Document 1, Patent Document 2, and Patent Document 3, when measuring a measurement object having a gap or a step, if the linear beam is not irradiated perpendicularly to the surface to be measured, Pay attention to the fact that the dimension that is larger than the step is output, and conversely when irradiated vertically, the measured dimension is minimized, so that the measured dimension is minimized. Is a dimension measuring device provided with a mechanism for rotationally adjusting the posture.

  Further, in Patent Document 4, a concave portion is formed, and the convex portion formed on the measurement object is measured when measuring the dimension of the measurement object on which the convex portions having different heights are formed so as to sandwich the concave portion. When the corner portion where the highest surface and the side surface are continuous is R-shaped, only a few pieces of data of the object to be measured are extracted, and each data is connected by a straight line and replaced with a straight line component. A method is described in which a circle corresponding to the R shape is extracted, and the width dimension of the convex portion or the step size of the convex portion is obtained by subtracting the radius of the circle from the distance between the centers of the extracted circles. .

  In addition, in the description of Patent Document 5, when measuring a gap and a step between two adjacent edge portions of a work such as an automobile body, first, an optical cutting image of a step edge portion with an R is used. An end point is obtained, and then an equation of a straight line representing a portion extending in a straight line is obtained using a light section image of a flat portion of the step. Next, a perpendicular line is drawn from the edge end point to a straight line, and an intersection of the perpendicular line and the straight line is obtained. Then, the same process is performed on the other step edge, and the distance between the two intersections obtained is calculated to obtain the gap interval and the step.

In Patent Document 6, in the light cutting method in which the object is irradiated with light and the reflected light from the object is received to detect the width and the step, first, the step portion from the point that the change in the amount of received light is large. The positions x ₁ and x ₂ at both ends of the side wall are obtained, and this distance is defined as the gap interval. Next, a straight line y = a ₁ x + b ₁ is obtained by using data with little variation in light amount change at a relatively flat upper surface portion of the step, and similarly, data with less variation in light amount change is obtained at the other step upper surface portion. straight _y = seeking a ₂ x + _b 2, obtains the value _{y 1} of y by substituting _{x 1} corresponding to the straight line _{y = a 1 x + b 1} , substituting _{x 2} corresponding to the straight line _y = a ₂ x + _b 2 using obtains the value y2 of y, there is described a method for the step distance of y ₁ and y _2.

JP-A-8-1222021 JP-A-8-136224 JP-A-8-136225 JP-A-10-38525 Japanese Patent No. 2737045 Japanese Examined Patent Publication No. 7-21404

  However, the techniques described in Patent Document 1 to Patent Document 3 do not describe a specific method for obtaining a gap or a step.

  Moreover, although the technique described in Patent Document 4 describes a specific method for obtaining a gap or a step, it is effective only when the corner has an R shape, and the corner is not an R shape. The correspondence in the case of an unspecified shape is not described.

  In the techniques described in Patent Document 5 and Patent Document 6, the edge position is first extracted using the edge image. However, the edge position is unstable due to the occurrence of burrs or the like, and the edge extraction is stable. There is no information about what to do if you can't.

  An object of the present invention is to realize a dimension measuring method and apparatus by a two-dimensional optical cutting method capable of calculating a dimension of a measurement object in a two-dimensional optical cutting method with high accuracy regardless of the shape of the edge. It is.

  In order to achieve the above object, the present invention is configured as follows.

  The dimension measuring method and apparatus according to the two-dimensional light cutting method of the present invention irradiates a measurement object with a linear light beam, images the measurement object irradiated with the linear light beam, and images the measurement object. The above-described linear light beams irradiated on two surfaces separated from each other on the obtained image are extracted, a linear expression indicating each of the extracted linear light beams on the two surfaces is calculated, and the two calculated straight lines The distance between two straight lines represented by the equation is calculated, and the shape dimension of the measurement object is measured.

  According to the present invention, it is possible to realize a dimension measuring method and apparatus by a two-dimensional optical cutting method capable of calculating the dimension of a measurement target in a two-dimensional optical cutting method with high accuracy regardless of the shape of the edge. Can do.

It is a schematic block diagram of the measuring apparatus of the space | interval of a clearance gap and a level | step difference dimension by the two-dimensional light cutting method to which the Example of this invention is applied. It is a figure explaining the mode of the illumination of the linear beam to the measurement object of U shape in Example 1 of this invention, and the laser bright line position in an opposing surface. It is a figure explaining a mode that a straight line is fitted to coordinate point group data obtained by the opposing surface of the measurement object in Example 1 of this invention, and coordinate point group data. It is a figure explaining a mode that a surface space | interval is calculated | required from the space | interval of the straight line fitted to the coordinate point group data obtained by the opposing surface of the measuring object in Example 1 of this invention. It is a figure explaining the mode of the illumination of the linear beam to the measuring object in Example 1 of this invention, and the laser emission line position in the front and back surface of a level | step difference. It is a figure explaining a mode that a straight line is fitted to coordinate point group data obtained on the level | step difference surface of the measurement object in Example 1 of this invention, and coordinate point group data. It is a figure explaining a mode that a level | step difference is calculated | required from the space | interval of the straight line fitted to the coordinate point group data obtained by the level | step difference surface of the measurement object in Example 1 of this invention. It is an operation | movement flowchart in Example 1 of this invention. It is a figure which shows an example of the internal functional block of CPU14 in Example 1 of this invention. It is a figure which shows the other example of the internal functional block of CPU14 in Example 1 of this invention. It is a figure explaining generation | occurrence | production of the speckle by illumination of a laser beam. It is a figure which shows the laser emission line when the speckle which generate | occur | produced by the laser beam illumination generate | occur | produced, and the speckle are suppressed. It is a figure which shows the mode of an image formation at the time of using the imaging lens which has a normal angle of view in the case of the image formation of the laser bright line in the opposing surface in Example 1 of this invention. It is a figure which shows the mode of image formation at the time of using the imaging lens which has a wide angle of view in the case of imaging of the laser bright line in the opposing surface in Example 1 of this invention. It is a figure which shows the 2 beam type optical cutting displacement meter in Example 2 of this invention. It is a figure explaining the mode of the illumination of two linear beams to the U-shaped measurement object in Example 2 of the present invention, and the laser emission line positions on the opposite surface and the front and back surfaces of the step. . It is a figure which shows the optical cutting displacement meter which has 2 imaging systems with the same azimuth | direction and different focus positions in Example 3 of this invention. It is a figure which shows the optical cutting displacement meter which has two imaging systems which image a different direction in Example 4 of this invention. It is a figure in Example 5 of this invention which demonstrates the state of a step and the illumination of the linear beam to the cylindrical shape which has an opposing surface, and a laser emission line position. It is a figure explaining a mode that rolling adjustment of an optical cutting sensor is performed so that the longitudinal direction of a laser beam may become in parallel with a cylinder axis in Example 5 of the present invention. It is a figure explaining a mode that pitch adjustment of an optical section sensor is performed so that a laser beam may become an angle which passes along the center coordinates of a cylinder (circle) in Example 5 of the present invention. It is a schematic diagram which shows the principle of the light cutting method. It is a figure which shows the comparative example for demonstrating the structure of the two-dimensional light cutting method of the principle different from this invention. It is a figure which shows the comparative example for demonstrating the two-dimensional light cutting method of a principle different from this invention. It is a figure which shows the comparative example for demonstrating the two-dimensional light cutting method of a principle different from this invention. It is a figure which shows the comparative example for demonstrating the two-dimensional light cutting method of a principle different from this invention. It is a figure explaining chamfering of a machined product. It is a figure explaining the burr | flash of a machined product.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  A first embodiment of the present invention will be described with reference to FIGS. In the first to fourth embodiments, a U-shape in which the step and the opposite surface are flat will be described as an example of a measurement target (measurement target).

  FIG. 1 is a schematic configuration diagram of an apparatus for measuring a shape dimension such as a gap interval and a step by a two-dimensional light cutting method to which Embodiment 1 of the present invention is applied.

  In FIG. 1, a laser beam oscillated from a laser source 1 is converted into a linear (slit) beam 6 by a beam shaping unit 5 and projected onto a measurement object 2. The linear beam 6 propagates through the measurement space and is projected onto the surface of the measurement object 2. The operation of the laser source 1 is controlled by a computer 26 via a laser controller 12.

  Here, as shown in FIG. 2 and FIG. 5, surfaces 301L and 301R whose spacing dimensions are to be measured are surfaces 301L and 301R, and surfaces whose step dimensions are to be measured are 302F and 302B. The linear beam 6 is projected onto all of the surfaces 301L and 301R whose distance dimensions are to be measured and the surfaces 302F and 302B whose height dimensions are to be measured.

  The reflected / scattered light generated in the measurement object 2 is imaged on the area sensor 4 using the polarizing filter 10, the wavelength filter 9, and the imaging lens 3. At this time, the area sensor 4 is imaged so that all of the surface for which the interval dimension is to be measured and the surface for which the step dimension is to be measured are reflected in the area sensor 4. The area sensor 4 is connected to a power source 13.

  An image captured by the area sensor 4 is taken into the storage device 15 in the computer 26 via the image input board 16 of the computer 26. The CPU (arithmetic processing means) 14 of the computer 26 detects the imaging position of the laser emission line projected onto the measurement object 2 from the image captured in the storage device 15 with subpixel accuracy, and uses the principle of triangulation. The coordinates of the laser position on the measurement object 2 are calculated.

  For the position of the laser emission line, the center of gravity of the laser emission line may be obtained, or the peak may be estimated.

  Next, a method for obtaining the distance between the opposing surfaces will be described with reference to FIGS.

  As shown in FIG. 3, the coordinate point group data corresponding to the linear beams projected onto the opposing surfaces 301L and 301R are 30L and 30R, respectively. Next, a straight line is applied to the point group data 30L and 30R. The obtained straight lines are 25L and 25R (corresponding to the laser emission lines 24L and 24R shown in FIG. 2), respectively, and are expressed by the following equations (1) and (2).

  Next, the value of the straight line 25L obtained by the above equation (1) is set as t, and is rewritten by the following equation (3).

  Similarly, the value of the straight line 25R obtained by the above equation (2) is set as u and rewritten by the following equation (4).

  The distance between the two straight lines 25L and 25R is obtained as in the following equation (5).

  The above formula (5) is modified to obtain the following formulas (6) and (7).

  Therefore, t and u are obtained by the following equation (8).

  Here, when the straight line 25L and the straight line 25R are parallel to each other, the inverse matrix in the above equation (8) cannot be obtained. In that case, a straight line expression is obtained as follows.

  Now, let the equations of any two straight lines (straight line 1 and straight line 2) be the following expressions (9) and (10), respectively.

From the above formulas (9) and (10), the distance L ₁₂ between the point (x ₀₁ , y ₀₁ , z ₀₁ ) passing through the straight line 1 and the straight line 2 is given by the following formula (11).

However, in the above formula (11), X = (x ₀₁ -x ₀₂ ), Y = (y ₀₁ -y ₀₂ ), Z = (z ₀₁ -z ₀₂ ).

  As shown in FIG. 4, the distance 27 between the straight line 25L and the straight line 25R can be obtained using the above equation (11). Here, it is also possible to determine the distance to the other straight line for each point group data that is the basis of one straight line and perform an averaging process to obtain a distance 27 between the straight lines.

  Next, a method for obtaining the step size will be described with reference to FIGS.

  The coordinate point group data corresponding to the linear beams projected onto the step surfaces 302F and 302B are 31F and 31B, respectively. Further, a straight line is applied to the point cloud data 31F and 31B, and the obtained straight lines are 29F and 29B (corresponding to the bright lines 28F and 28B in FIG. 5), respectively, and are expressed by the following equations (12) and (13). It shall be assumed.

  Using these equations (12) and (13), the step size can be obtained in the same manner as when the distance between the opposing surfaces is obtained.

  Here, as shown in FIG. 7, when the distance between the faces is calculated, even when the straight line 29 </ b> F and the straight line 29 </ b> B are parallel to each other, the above formula (11) The dimension of the step 33 can be obtained using

  Here, it is also possible to obtain the distance between the other straight lines by obtaining the distance to the other straight line and to obtain the distance 33 between the straight lines with respect to each of the point group data that is the origin of one straight line.

  Here, a method of selecting the point groups 25L, 25R, 31F, and 31B to which a straight line is applied will be described. In the first embodiment, a method in which the user designates while looking at the user monitor 17 will be described.

  As shown in FIG. 1, an imaging screen 20 is displayed on the monitor 17. The user selects with the mouse 18 or the keyboard 19 so as to enclose the surface 301L and the surface 301R for which the distance dimension is to be measured, and the laser emission lines 24L, 24R, 28F, and 28B on the surfaces 302F and 302B for which the step size is to be measured, To do.

  When the selection of the laser emission line is completed, the distance is calculated according to the flow shown in FIG.

  That is, in step S1g in FIG. 8, the user designates the laser emission lines 24L and 24R in the facing surface for which the distance dimension is to be obtained. On the other hand, when obtaining the step size, in step S1s, the user designates the laser emission lines 28F and 28B in the step surface for which the step size is to be obtained.

  Next, in step S2, the CPU 14 extracts the position of the laser emission line within the specified range with sub-pixel accuracy for both the interval dimension and the step dimension. And when measuring a space | interval dimension, CPU14 calculates the equation of the straight lines 25L and 25R (step S4g), and calculates the space | interval of the straight lines 25L and 25R (step S5g).

  Further, when measuring the step size, the CPU 14 calculates the equations of the straight lines 29F and 29B (step S4s), and calculates the interval between the straight lines 29F and 29B (step S5s). Then, the calculated interval size and step size are displayed on the monitor 17.

  FIG. 9 is an internal functional block diagram of the CPU 14 for performing the dimension calculation.

  In FIG. 9, the image from the sensor 4 is captured by the image capturing unit 14a, output to the monitor 17, and supplied to the laser emission line position extracting unit 14b. The laser emission line position extraction unit 14b extracts the position of the laser emission line for which an interval dimension or a step dimension is to be calculated based on an area selection command from the user.

  The position information of the laser emission line extracted by the laser emission line position extraction unit 14bb is supplied to the 3D image conversion unit 14d, and the 3D global coordinates are extracted by the 3D image conversion unit 14d.

  Then, the extracted three-dimensional global coordinates are supplied to the distance calculation unit 14 c between straight lines, the interval dimension or the step dimension is calculated, and the calculated result is displayed on the monitor 17.

  The example shown in FIG. 9 is an example in which the user designates an area in which an interval size and a step size are to be calculated while observing the monitor 17, but the user automatically designates an interval and a step in the image without designation. It is also possible to detect them automatically, calculate the interval dimension and the step dimension in the image, and display them on the monitor 17.

  The example shown in FIG. 10 is an internal functional block diagram of the CPU 14 when the interval and step in the image are automatically detected without the user's designation.

  In FIG. 10, the image from the sensor 4 is captured by the image capturing unit 14a, output to the monitor 17, and supplied to the line detection unit 14e. The line detection unit 14e detects a laser emission line in the image of the measurement target 2 by Hough conversion or the like. The detected laser emission line is supplied to the pixel value calculation unit 14f, and the pixel value calculation unit 14f calculates a pixel value corresponding to the detected straight line.

  Next, the three-dimensional image conversion unit 14d converts the pixel value corresponding to the straight line calculated by the pixel value calculation unit 14f into three-dimensional global coordinates. The converted three-dimensional global coordinates are supplied to the inter-line distance calculation unit 14c, and the detected straight line is applied to the three-dimensional image, and the inter-line distance is calculated for all combinations of the detected straight lines. Then, the result is displayed on the monitor 17 and the calculated distance and which part of the image the distance corresponds to are displayed.

  The user can select a desired one of the interval size and the step size displayed on the monitor 17.

  By the way, as shown in FIG. 11, when the measurement object 2 is illuminated with the laser beam 6 having high coherency, the laser beams reflected and scattered by the minute unevenness on the measurement object 2 interfere with each other, and noise called speckle is generated. To do.

  For this reason, as shown in FIG. 12A, noise such as whiskers occurs in the laser emission line, and the laser emission line spreads. As a result, the position of the laser emission line cannot be accurately obtained, resulting in a measurement error.

  In order to reduce the speckle noise, if a polarizing filter 10 is arranged in front of the imaging lens 3 and only a specific polarization component is detected, the laser emission line as shown in FIG. Can be suppressed. The same effect can be obtained by reducing the aperture (not shown) of the imaging lens 3. When a measure for reducing the speckle is implemented, a part of the laser emission line may disappear as shown in FIG.

  However, in the method of applying a straight line from the point cloud data as in the first embodiment of the present invention, even if a part of the laser emission line disappears, it is only necessary to apply the straight line, so this is not a problem.

  In addition, as shown in FIG. 1, if a wavelength filter 9 that transmits only the laser wavelength is attached in front of the imaging lens 3 to suppress disturbance light, it is possible to prevent a decrease in extraction accuracy of the laser emission line position due to the disturbance light. It is also possible to do.

  Also, when imaging two opposing surfaces, as shown in FIG. 13, when a lens 80 with a narrow angle of view 40 is used, the distance on the sensor 4 for different points on the plane is shortened, making separation difficult. There is a case. Therefore, as a lens used for imaging, it is better to use a lens 81 having a wide angle of view 41 as shown in FIG.

  Here, a specific example regarding “wide angle of view” will be described.

  In a lens for a photographic camera, a 35 mm silver salt film has been used for many years, and for the sake of convenience, a focal length display by a 35 mm film camera, so-called 35 mm equivalent display is generally used.

  The screen size on the film of the 35 mm camera is 24 × 36 mm, and the length of the diagonal line is 43.27 mm. A focal length of 50 mm, which is a little longer than this, is called a standard lens because it is close to the perspective of the human eye and can capture almost the same range as that seen by the human eye.

  Further, in general, about 28 to 35 mm is often referred to as a wide angle lens, and about 21 to 24 mm is often referred to as a super wide angle lens.

  When the focal length is 28 mm, the horizontal field angle is 65.57 degrees and the vertical field angle is 46.39 degrees.

  Therefore, “a wide angle of view” in the first embodiment is based on a focal length of 28 mm or less in terms of 35 mm.

  As described above, according to the first embodiment of the present invention, the interval dimension and the step dimension of the measurement object 2 are obtained by calculating the distance between the laser emission lines in the image. Regardless of this, it is possible to realize a dimension measuring method and apparatus by a two-dimensional light cutting method that can be calculated with high accuracy.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  The second embodiment of the present invention is different from the first embodiment in that the number of laser beams to be illuminated is plural (two in the second embodiment).

  As shown in FIG. 15, the laser beam generated from the beam shaping unit 5 of the laser source 1 is branched in two directions by the beam splitter 35, and one of the laser beams is to be measured via the linear polarizing plate 102. 2 is irradiated. The other laser beam branched by the beam splitter 35 is reflected by the total reflection mirror 36 and applied to the measurement object 2 via the linear polarizing plate 101.

  The other basic configuration of the second embodiment is the same as that of the first embodiment shown in FIG.

  In Example 2, when the distance between the opposing surfaces of the measurement target 2 is obtained, as shown in FIG. 16, a straight line obtained from coordinate point group data corresponding to the linear beam projected on the opposing surface is represented by 62L, 63L and 62R, 63R, and the distance between the plane obtained from the straight lines 62L and 63L and the plane obtained from the straight lines 62R and 63R is defined as the facing surface interval.

  Further, as shown in FIG. 16, the straight lines obtained from the coordinate point group data corresponding to the linear beam projected on the step surface are 60F, 61F and 60B, 61B, and are obtained from the straight lines 60F and 61F. The distance between the plane and the plane obtained from the straight lines 60B and 61B is defined as a step surface.

  The calculation of the interval dimension and the step dimension is executed by the CPU 14 as in the first embodiment.

  In the second embodiment of the present invention, the same effects as in the first embodiment can be obtained, and by using a plurality of laser beams, not only more point cloud data can be used, but also a surface other than a straight line can be used. It is possible to define the measurement, and it is possible to perform measurement in consideration of the parallelism (tilt state) of the surface.

  Next, Embodiment 3 of the present invention will be described with reference to FIG.

  The third embodiment is different from the first embodiment in that there are a plurality of imaging systems (two systems in the third embodiment).

  As shown in FIG. 17, a plurality of imaging lenses 3 and an area sensor 4 are arranged. The wavelength filter 9 and the polarization filter 10 can be mounted as necessary.

  Since the other basic configuration is the same as that of the example of FIG. 1, detailed description thereof is omitted.

  In the case of a measurement target having a deep step, the front and back surfaces of the step are outside the range of the depth of field, and the image is blurred or the resolution at the back surface is reduced.

  As a result, measurement may be impossible or measurement accuracy may be reduced.

  Therefore, as shown in FIG. 17, the first imaging system 3, 4 images the front surface of the step of the measurement object 2, and the second imaging system 3, 4 images the back surface of the measurement object 2 step. By doing so, a clear laser emission line image can be obtained on both the front and back surfaces of the step and it is possible to prevent a decrease in measurement accuracy.

  The calculation of the interval dimension and the step dimension is executed by the CPU 14 as in the first embodiment.

  In the second embodiment of the present invention, the same effect as that of the first embodiment can be obtained, and a clear laser emission line image can be obtained even for a measurement object having a deep step.

  Next, a fourth embodiment of the present invention will be described with reference to FIG.

  The fourth embodiment of the present invention has a plurality of imaging systems (two systems in the fourth embodiment) as in the third embodiment, but is different from the third embodiment in that the imaging directions are different from each other. Since the other basic configuration is the same as that of the example of FIG. 1, detailed description thereof is omitted.

  In FIG. 18, in the case of the measurement object 2 having the opposed surfaces with a wide interval, both sides of the opposed surfaces are out of the range of the angle of view, and the opposed surfaces cannot be imaged at the same time.

  Therefore, if one surface is imaged by the first imaging systems 3 and 4 and the other surface is imaged by the second imaging systems 3 and 4, the surface interval can be measured even in a measurement object having a wide step. It becomes possible to do.

  The calculation of the interval dimension and the step dimension is executed by the CPU 14 as in the first embodiment.

  In the fourth embodiment of the present invention, the same effect as in the first embodiment can be obtained. In addition, a laser emission line image with a wide interval can be obtained at the same time even for a measurement target having a wide step. Have.

  Next, a fifth embodiment of the present invention will be described with reference to FIGS.

  The fifth embodiment of the present invention is an example in which a measurement object 2 having a cylindrical shape having a step and an opposing surface can be measured.

  In FIG. 19, when the measurement target 2 has a cylindrical shape, the laser emission line generated on the measurement target 2 does not become a straight line unless the longitudinal direction of the laser beam 6 is parallel to the cylindrical axis of the measurement target 2. Further, unless the laser beam 6 is illuminated at an angle that passes through the center coordinates of the cylinder (circle) that is the measurement target 2, the desired level difference cannot be obtained accurately.

  Therefore, in order to measure the interval dimension and the step dimension of the cylinder as shown in FIG. 19, it is necessary to perform alignment between the measurement object 2 and the entire optical cutting measuring apparatus.

  The fifth embodiment of the present invention describes a method for performing this alignment efficiently and uniquely, and the basic configuration is the same as the example of FIG. Omitted.

  In describing the alignment method, it is necessary to define a coordinate system. In the coordinate system described in the fifth embodiment, as shown in FIG. 19, the center of the imaging lens 3 is the origin, the horizontal direction is the x method, the downward direction is the y direction, and the imaging axis direction is the z direction. For rotation, the rotation angle around the x-axis and the rotation angle around the z-axis are α and S (the Greek character theta in FIG. 19), respectively.

  First, the angle S is adjusted so that the longitudinal direction of the laser beam 6 is parallel to the cylindrical axis of the measurement target 2. As shown in FIG. 20, when the longitudinal direction of the laser beam 6 is parallel to the cylindrical axis of the measurement object 2, the laser emission line on the measurement object 2 is a straight line and the vector in the x direction is 1 ( The laser emission line is in the same direction as the x-axis direction (the angle between them is 0).

  Therefore, if the linear equation is obtained and the rotation angle S is adjusted so that the vector in the x direction becomes 1, the longitudinal direction of the laser beam 6 and the cylindrical axis can be made parallel.

  Next, as shown in FIG. 21, it is necessary to illuminate the measurement target 2 at an angle such that the laser beam 6 passes through the center coordinates of the cylinder (circle) that is the measurement target 2.

  Here, when the laser beam 6 is illuminated at an angle passing through the center coordinates of the cylinder (circle), the gap between the steps is minimized. Therefore, it is possible to illuminate the laser beam 6 at an angle that passes through the center coordinates of the cylinder (circle) by adjusting α so that the step interval is minimized.

  If the alignment described above is performed, it is possible to measure the step distance and the surface interval of the cylinder having the step and the opposed surface with high accuracy using a two-dimensional light cutting sensor.

  As described above, according to the present invention, in measurement of a workpiece having a step and an opposed surface by the two-dimensional light cutting method, a straight line is applied to the obtained point group coordinate data, and a distance between the applied straight lines is obtained. Thus, it becomes possible to measure the step and the distance between the opposing surfaces with high accuracy.

  Next, an example different from the present invention, in which an edge to be measured is detected and an interval dimension and a step dimension are measured will be described. This is for explaining a comparative example for comparison with the present invention.

  As shown in FIG. 22, the light cutting method illuminates the measurement object 2 with light from the light source 1, and reflects and scattered light generated from the measurement object 2 onto the sensor 4 using the imaging lens 3. The distance from the imaging position of the reflected / scattered light on the sensor 4 to the measurement object is measured based on the principle of triangulation. When the position of the measurement object changes or the shape changes (Δz in FIG. 22), the imaging position on the sensor 4 shifts (Δm in FIG. 22), so the position and shape of the measurement object 2 are obtained. be able to.

  As shown in FIG. 23, if the shape of the beam from the laser light source 1 is a linear beam (slit beam) 6 using a beam shaping element (lens) 5 and a two-dimensional sensor (area sensor) is used as the sensor 4. Two-dimensional information can be obtained collectively.

  However, as shown in FIG. 25, when the distance between the opposing surfaces is to be determined accurately, the longitudinal direction of the linear beam 6 needs to coincide with the normal direction (n in FIG. 25) of the opposing surface. is there. When the longitudinal direction of the linear beam 6 is not coincident with the normal direction n of the opposing surface, the measured distance becomes a value d ′ larger than d even though the distance between the opposing surfaces is d. Because it ends up.

  For this reason, when it is going to measure a surface space | interval with high precision, it is necessary to make the linear beam 6 parallel to the normal line direction of an opposing surface.

  Normally, when measuring the surface interval, as shown in FIG. 24, a method of extracting the edges 21L and 21R of the opposing surface and obtaining the distance between the extracted edges 21L and 21R is used. .

  For extracting the edge, as shown in FIG. 26, a method of extracting the position of the laser bright spot corresponding to the edge on the captured image is used. The extraction accuracy at this time is determined by the pixel size w (= sampling interval) on the measurement object 2. For this reason, normally, sub-pixel processing is performed, and extraction is performed with an accuracy equal to or smaller than the pixel size.

  However, the edge of the machined product is chamfered as shown in FIG. 27, or even immediately after machining before chamfering is performed, the burr 23 is present as shown in FIG. Edge position is unstable or edge extraction cannot be performed stably. As a result, the measurement accuracy of the surface interval dimension is lowered.

  On the other hand, in the present invention, since the distance between the laser emission lines on both planes for measuring the distance dimension or the step dimension to be measured is measured, the edge of the machined product is chamfered or burrs are not formed. By being present, the measurement accuracy of the inter-surface distance dimension is not reduced.

  DESCRIPTION OF SYMBOLS 1 ... Laser generation source, 2 ... Measurement object, 3 ... Imaging lens, 4 ... Sensor (area sensor), 5 ... Beam shaping part (lens), 6 ... Linear (Slit) beam, 9 ... wavelength filter, 10 ... polarizing filter, 12 ... laser controller, 13 ... camera power supply, 14 ... CPU, 14a ... image capturing unit, 14b,. Laser bright line position extraction unit, 14c ... straight line distance calculation unit, 14d ... three-dimensional image conversion unit, 14e ... line detection unit, 14f ... pixel value calculation unit, 15 ... storage device , 16 ... Image input board, 20 ... Captured image display screen, 17 ... Monitor, 18 ... Mouse, 19 keyboard, 21L ... Left edge, 21R ... Right edge, d, d '... Surface spacing, 22 ... Chamfer, 23 ..Burr, 24L, 62L, 63L ... laser emission lines on the left inner surface, 24R, 62R, 63R ... laser emission lines on the right inner surface, 30L ... coordinate points corresponding to laser emission lines on the left inner surface Data, 30R: Coordinate point group data corresponding to the laser emission line on the right inner surface, 25L: Straight line applied to the coordinate point group data corresponding to the laser emission line on the left inner surface, 25R: On the right inner surface A straight line applied to the coordinate point group data corresponding to the laser emission line, 26... Computer, 27... Distance between the straight lines 25 L and 25 R (surface interval), 28 F, 60 F, 61 F. Laser emission lines, 28B, 60B, 61B ... laser emission lines on the back surface, 31F ... coordinate point group data corresponding to laser emission lines on the front surface, 31B ... coordinate points corresponding to laser emission lines on the back surface Group data 29F: A straight line applied to the coordinate point group data corresponding to the laser emission line at the front surface, 29B: A straight line applied to the coordinate point group data corresponding to the laser emission line at the back surface, 33: A straight line 29F and straight line 29B distance (step), 35 ... beam splitter, 36 ... total reflection mirror, 101, 102 ... linear polarizing plate, 80 ... imaging lens with narrow angle of view, 81.・ An imaging lens with a wide angle of view, 40, 41.

Claims (10)

In the dimension measurement method by the two-dimensional light cutting method,
Irradiate the measurement target with a linear light beam,
One surface of the two surfaces forming steps with different distances from the generation source of the linear light beam of the measurement object irradiated with the linear light beam is imaged by a first imaging system, and the 2 Image the other of the two surfaces with the second imaging system ,
The linear light beams applied to two surfaces that are spaced apart from each other on the imaged image of the measurement object are extracted, and a linear expression representing each of the extracted linear light beams on the two surfaces is calculated. ,
Calculate the distance between the two straight lines represented by the two calculated linear equations,
A dimension measuring method by a two-dimensional light cutting method, characterized by measuring a step size of the measurement object.   2. The dimension measuring method by a two-dimensional light cutting method according to claim 1, wherein the linear light beam irradiates the measurement object through an interference filter that transmits only the wavelength of the linear light beam. Dimension measurement method by two-dimensional light cutting method. 3. The dimension measuring method by a two-dimensional light cutting method according to claim 2 , wherein the linear light beam is applied to the measurement object through the interference filter and a polarizing filter that transmits only a specific polarization component. A dimension measurement method by a two-dimensional light cutting method.   2. The dimension measuring method using a two-dimensional light cutting method according to claim 1, wherein the measurement object irradiated with the linear light beam is imaged using a wide-angle lens. Dimension measurement method.   The dimension measuring method by the two-dimensional light cutting method according to claim 1, wherein only a necessary region is selected from the linear light beams irradiated on the measurement object, and is calculated in the selected region. A dimension measuring method by a two-dimensional light cutting method, wherein the shape dimension of the measurement object is calculated using only coordinate point group data. In a dimension measuring device using a two-dimensional light cutting method,
Means for generating a linear light beam for irradiating the measurement object;
A first imaging system that images one surface of two surfaces that form steps with different distances from the source of the linear light beam of the measurement object irradiated with the linear light beam; An imaging means having a second imaging system for imaging the other of the two surfaces ;
Display means for displaying the imaged measurement object;
The linear light beams applied to two surfaces that are spaced apart from each other on the imaged image of the measurement object are extracted, and a linear expression representing each of the extracted linear light beams on the two surfaces is calculated. An arithmetic processing means for calculating a distance between two straight lines represented by the two calculated straight line formulas, measuring a step size of the measurement object, and displaying it on the display means;
A dimension measuring apparatus using a two-dimensional light cutting method. 7. The dimension measuring apparatus according to the two-dimensional light cutting method according to claim 6 , wherein the imaging means includes an interference filter that transmits only a wavelength of a linear light beam, and the linear light beam passes through the interference filter, and the linear light beam passes through the interference filter. A dimension measuring apparatus using a two-dimensional light cutting method, wherein the object to be measured is irradiated. 8. The size measuring apparatus using a two-dimensional light cutting method according to claim 7 , wherein the imaging hand has a polarization filter that transmits only a specific polarization component, and the linear light beam passes through the interference filter and the polarization filter. A dimension measuring apparatus using a two-dimensional light cutting method, wherein the measuring object is irradiated. 7. The dimension measuring apparatus using a two-dimensional light cutting method according to claim 6 , wherein the imaging means has a wide-angle lens, and the measurement object irradiated with the linear light beam is imaged using a wide-angle lens. A dimension measuring apparatus using a two-dimensional light cutting method. 7. The dimension measuring apparatus according to the two-dimensional light cutting method according to claim 6 , wherein the arithmetic processing unit is a coordinate point calculated in a region selected from the linear light beam irradiated onto the measurement object. A dimension measuring apparatus using a two-dimensional light cutting method, wherein the shape dimension of the measurement object is calculated using only group data.

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