JP4156457B2 - Measuring method of outer diameter of object to be measured, outer diameter measuring device and outer peripheral surface grinding device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an outer diameter measuring method, an outer diameter measuring device, and an outer diameter measuring device that can automatically measure the outer diameter of a measuring object having a substantially cylindrical or substantially cylindrical shape such as nuclear fuel pellets. The present invention relates to an outer peripheral surface grinding apparatus for an object to be measured, which can control grinding of an outer peripheral surface based on diameter data.
[0002]
[Prior art]
Conventionally, in a nuclear fuel pellet production line having a substantially cylindrical shape, for example, a sintered centerless grinder is ground to finish the sintered pellet to a specified outer diameter. Since the pellet is inserted into the fuel rod after grinding and reacted in the nuclear reactor as nuclear fuel, it is necessary to perform grinding and subsequent inspection of the outer diameter with high accuracy.
In such a conventional pellet outer diameter measuring means, the pellet manufactured from the production line is extracted, the pellet is fixed to the reference surface, and the outer diameter is measured by sandwiching the pellet on the parallel surface with an outer diameter measuring instrument. is doing. Alternatively, there is a method in which the dried pellets are placed on a measuring table to secure a cylindrical axis, and then the outer diameter is measured using a transmission laser outer diameter measuring device or a reflective displacement sensor.
However, in such a measurement method, it is difficult to perform high-speed automatic measurement because it is difficult to perform measurement in an environment where the pellet cannot pass through or on a conveying means in which the central axis of the pellet is shifted vertically and horizontally.
Examples of high-speed automatic measurement means for pellet outer diameter include those described in Patent Documents 1 and 2 below. In patent document 1, the outer diameter of a pellet is measured from the distance and height to a pellet by position detection data in a state where the pellet is pressed by a contact assist plate. In Patent Document 2, a pellet conveyed by a feeder is held in a stopped state by a positioning stopper, and the outer diameter of the pellet is measured using transmitted light by a laser-type outer diameter measuring device.
[0003]
[Patent Document 1]
JP-A-5-1996 [Patent Document 2]
Japanese Patent No. 3051049 gazette
[Problems to be solved by the invention]
However, it is difficult to transport many nuclear fuel pellets over a long period of time while maintaining a coaxial state. When a transmission type laser outer diameter measuring instrument is used as a measuring means, the transmitted light is perpendicular to the pellet. There is a drawback that the measured value becomes excessive when it is incident obliquely without incident. Further, when using a reflective displacement sensor, there is no guarantee that the measurement is performed on the central axis of the pellet, and the measurement value may be too small. Furthermore, when a contact-type outer diameter measuring device is used, there is a drawback that high-speed measurement cannot be performed because the measurement speed is low, and a portion that contacts the measuring device is worn by contact.
In addition, when using a flat jig that forms the measurement reference surface as the conveying means used to measure the outer diameter of the pellet, if the wet pellet is placed and slid during grinding, the measurement reference surface will be worn, resulting in measurement errors. There was a problem that caused. Therefore, it was actually difficult to use the measurement reference surface as the pellet placing means in the measuring apparatus that measures the outer diameter while conveying at high speed.
Further, in Patent Document 1, measurement is possible even when the pellets are wet due to wet grinding, but dedicated products such as a measurement auxiliary plate, a position sensor, a stopper pin, and a discharge roller for preventing the inclination of the pellets are required. The configuration was complicated and expensive. In addition, there is a drawback that requires special handling. In Patent Document 2, it is indispensable to position the pellet at right angles to the laser beam. However, it is difficult to measure the pellet by conveying it in the same posture, and it is not suitable for measurement by high-speed conveyance. It was. Further, neither of Patent Documents 1 and 2 was able to perform automatic measurement at high speed in order to measure the outer diameter dimension with the pellets in a stationary state.
[0005]
In view of such circumstances, the present invention provides a method for measuring an outer diameter of an object to be measured and an outer diameter measuring apparatus capable of measuring the outer diameter at high speed and in a non-contact manner even when the object to be measured is tilted or displaced. The purpose is to provide.
Another object of the present invention is to provide an outer peripheral surface grinding apparatus which can perform grinding of an object to be measured with high accuracy.
[0006]
[Means for Solving the Problems]
According to the method for measuring the outer diameter of an object to be measured according to the present invention, a plurality of line laser beams are irradiated in the vertical direction on both side surfaces opposite to each other in the radial direction on the columnar or cylindrical outer peripheral surface of the object to be measured. Photographing both side surfaces, extracting a plurality of projection lines forming convex curves protruding in the horizontal direction of the object to be measured with respect to a plurality of line laser beams formed on both sides of the object to be measured from the captured image, A fitting curve is obtained from a plurality of projection lines, the maximum horizontal projection point of the fitting curve is determined as a vertex projecting on both sides, and a three-dimensional position is determined based on the vertex, and a plurality of vertices on each side. The straight line passing through is determined as side outer diameter lines on both sides, and the outer diameter of the outer peripheral surface of the object to be measured is calculated from the distance between the side outer diameter lines on both sides.
In the present invention, when the line laser beam is irradiated to both side surfaces of the object to be measured, the projection lines on both side surfaces are curved along the side surface shape of the object to be measured. extracted and can be calculated outside diameter of the object vertices projecting sides from the projection line be determined respectively. Therefore, the outer diameter can be accurately measured even when the object to be measured is not placed on the reference plane and is inclined vertically and horizontally.
[0007]
Further, since the maximum protruding point in the horizontal direction of the fitting curve obtained from the projection line indicates the apex , the apex can be obtained with certainty. Further, the line laser beam is disposed so as to be positioned vertically on the (water) plane including the reference center axis of the object to be measured, and is inclined so as to form an acute angle or an obtuse angle with respect to the conveyance direction of the object to be measured. If arranged at an angle, the outer diameter lines obtained on both side surfaces of the object to be measured will protrude most , and the distance between the outer diameter lines can be obtained as the outer diameter.
[0008]
In the outer peripheral surface grinding method of an object to be measured according to the present invention, the outer diameter of the object to be measured is measured after the outer peripheral surface is ground by a grinding device, and the outer diameter of the object to be measured according to claim 1. The outer diameter data obtained by the measurement method is fed back to the grinding device to adjust the grinding of the outer peripheral surface.
Grinding characteristics of the grinding device can be adjusted immediately by detecting the outer diameter data obtained by the method of measuring the outer diameter of the object to be measured, and detecting the distortion and straightness of the ground outer diameter and feeding back to the grinding device. it can.
[0009]
An apparatus for measuring an outer diameter of an object to be measured according to the present invention includes a plurality of line laser projectors disposed on both side surfaces opposed to each other in a radial direction on a columnar or cylindrical outer peripheral surface of the object to be measured, and a plurality of line lasers. a photographing means for photographing the both side surfaces of the object to be measured irradiated with the light in the vertical direction, the plurality of line laser light formed along both sides of the object from the obtained captured image in the photographing means Extraction means for extracting a plurality of projection lines that form a convex curve projecting in the horizontal direction of the object to be measured, and both sides by obtaining a fitting curve from the plurality of projection lines and obtaining a horizontal maximum projection point from the fitting curve side of the indexing means for calculating a vertex projecting respectively, a straight line both sides through a plurality of vertices from the vertex to confirm the three-dimensional position of both sides of the fitting curve in Each determined as the external diameter of the line, characterized by comprising an outer diameter calculating means for calculating the outer diameter of the outer peripheral surface of the object to be measured from the distance between the side surfaces outside diameter line on each side.
The line laser beam is irradiated to both sides of the object to be measured, and both sides of the object to be measured whose projection lines on both sides are curved along the shape of the side of the object to be measured are respectively photographed by the photographing means, and extracted by the extracting means. After extracting only the projection line from the photographed image, an optimum fitting curve is obtained from the projection line by the indexing means, and its vertex is determined. And the outer diameter of a to-be-measured part can be calculated | required from the distance between the vertices of several fitting curves of both sides. Therefore, even if the object to be measured is inclined in the vertical direction or the horizontal direction, the outer diameter can be reliably obtained by detecting a plurality of vertices protruding on opposite side surfaces.
For this purpose, it is preferable to dispose the line laser projector so that the optical axis of the line laser beam is located on a (water) plane including the reference center axis of the object to be measured. More preferably, the line laser beam may be disposed so as to project at an angle that is perpendicular to the (horizontal) plane and is acute or obtuse with respect to the conveyance direction of the object to be measured.
[0010]
An outer peripheral surface grinding apparatus for an object to be measured according to the present invention includes a grinding apparatus for grinding an outer peripheral surface of an object to be measured, and the above-described outer diameter measuring apparatus for measuring an outer diameter of the object to be measured ground by the grinding apparatus. The outer diameter data of the object to be measured obtained by the outer diameter calculation unit of the outer diameter measuring device is fed back to the grinding device to adjust the grinding of the object to be measured.
Grinding characteristics can be adjusted by detecting and feeding back the distortion of the ground outer diameter, the degree of straightness, and the like from the outer diameter data obtained by the outer diameter measuring device of the object to be measured.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
1 and 2, the outer diameter measuring device 1 is provided after the pellet grinding device 2 (grinding device). The pellet grinding apparatus 2 includes, for example, a wet centerless grinder. The pellet P that is ground while cooling water is applied by the grinding apparatus 2 is conveyed at high speed to the outer diameter measuring apparatus 1 by the ladder chain 3 and is removed from the pellet P. The diameter dimension will be measured automatically.
As shown in FIG. 2, the ladder chain 3 is slidably mounted in the concave portion 4 a of the ladder chain guide 4 having a concave shape in the longitudinal section, and conveys the pellet P from the pellet grinding device 2 to the outer diameter measuring device 1. The ladder chain 3 is endless and revolves in a state of being wound around a pair of wheels (not shown) provided on both sides of the ladder chain guide 4. The ladder chain guide 4 is formed with a drain hole 5 communicating downward from the recess 4 a, and the cooling water adhering to the pellet P used for grinding the pellet P is collected through the drain hole 5.
[0012]
The outer diameter measuring device 1 includes an outer diameter measuring unit 6 and a measurement control unit 7. The outer diameter measuring unit 6 is provided on both sides of the ladder chain 3. On one side of the ladder chain 3, an area camera 8A (photographing means) that photographs one side surface (outer peripheral surface) of the pellet P on the ladder chain 3 is provided. The area camera 8A is equipped with a telecentric lens 9A at the tip, and its photographing optical axis Lo is arranged so as to be substantially orthogonal to the ladder chain 3.
Line laser projectors 10A and 10B are disposed on both sides of the area camera 8A, and the optical axes of the line laser beams La and Lb are positioned at an appropriate angle with respect to the photographing optical axis Lo, for example, an equal angle of 45 °, for example. is doing. In addition, the line laser projectors 10A and 10B emit the line laser beams La and Lb so as to irradiate the peripheral side surface P1 (outer peripheral surface) of the pellet P when the pellet P is conveyed onto the imaging optical axis Lo of the area camera 8A. positioned.
[0013]
The line laser beams La and Lb emitted from the line laser projectors 10A and 10B have a linear shape extending in the vertical direction. When the peripheral surface P1 of the pellet P is irradiated, the line laser beams La and Lb are substantially along the cylindrical surface shape. Arc-shaped projection lines La1 and Lb1 are formed. The projection lines La1 and Lb1 intersect each other in a substantially x shape so as to draw a convex curve inwardly (see FIGS. 3, 4, and 5). The projection lines La1 and Lb1 are captured by the area camera 8A and captured as image data.
The same members as those of the area camera 8A and the line laser projectors 10A and 10B are arranged, for example, line symmetrically on the opposite side across the ladder chain 3, and these members on the opposite side are area cameras 8B having a telecentric lens 9B. The line laser projectors 10C and 10D are configured. The vertical line laser beams Lc and Ld emitted from the line laser projectors 10C and 10D are irradiated onto the peripheral side surface P1 of the pellet P to form substantially arc-shaped projection lines Lc1 and Ld1 (see FIGS. 4 and 5).
Then, assuming that the pellets P placed on the ladder chain 3 are virtually arranged in parallel with the conveying direction of the ladder chain 3, the central axis thereof is set as a reference central axis O. When a horizontal plane including the reference central axis O is assumed, the line laser projectors 10A, 10B, 10C, and 10D are arranged so that the optical axes of the line laser beams are positioned on the horizontal plane.
[0014]
Each of the line laser projectors 10A to 10D is electrically connected to the laser power control unit 13 of the measurement control unit 7, and the laser light projected from each of the projectors 10A to 10D by the laser power control unit 13 is a vertical line. Control to the light projection. Further, the measurement control unit 7 is provided with an image input unit 14 for inputting images taken by the area cameras 8A and 8B, and an operation control unit 15 for analyzing the input image and calculating the outer diameter of the pellet P. . The outer diameter data calculated by the arithmetic control unit 15 is fed back from the data output unit 16 to the pellet grinding apparatus 2 to control the outer diameter grinding of the pellet P to be ground by the pellet grinding apparatus 2.
Further, the arithmetic control unit 15 extracts, for example, two projection lines La1, Lb1 or Lc1, Ld1 from the captured image, and a curve portion near the convex peak of the extracted convex curved projection line. The first indexing means 21 for calculating the optimum fitting curve by calculating the horizontal line projection center, the second indexing means 22 for calculating the maximum point from the optimum fitting curve as a vertex, and two projection lines on each side of the pellet P And an outer diameter calculating means 23 for calculating the outer diameter of the pellet P by determining the three-dimensional position based on the calculated vertexes and obtaining an outer diameter measuring line. The first indexing means 21 and the second indexing means 22 constitute indexing means.
[0015]
Next, captured images obtained by the area cameras 8A and 8B will be described.
The pellets P that are placed and conveyed on the ladder chain 3 from the pellet grinding apparatus 2 at a predetermined interval are not necessarily arranged coaxially with the reference central axis O and stably conveyed in the same straight line. 3, the central axis of the pellet P is conveyed with a slight inclination in the left-right direction and the vertical direction with respect to the reference center axis O.
In FIG. 4, (1) to (8) are images showing postures at the time of photographing the pellets P placed and transported on the ladder chain 3, each showing different postures. 4A is a side image of each pellet P photographed by the area camera 8B, FIG. 4B is a top view, and FIG. 4C is a side image of each pellet P photographed by the area camera 8A. 4A and 4C, there is no boundary line on the side surface of the pellet P because it is hidden behind the ladder chain 3 or the ladder chain guide 4 during photographing.
The pellet P shown in (1) is at the reference position at the time of measurement, the center axis coincides with the reference center axis O, and the optical axis of each area camera 8A or 8B is irradiated to the center of the center axis of the pellet P. . Then, the line laser beams La, Lb, Lc, and Ld of the line laser projectors 10A, 10B, 10C, and 10D are projected on the side surface of the pellet P as the substantially arc-shaped projection lines La1, Lb1, or Lc1, and Ld1, respectively. La1 and Lb1 and the projection lines Lc1 and Ld1 are axisymmetric with respect to the central axis, and are also symmetrical with respect to a perpendicular perpendicular to the central axis.
(2) of FIG. 4 is an image when the outer diameter is larger by 0.2 mm, for example, than the pellet P of (1) without shifting the central axis, and (3) is an image when the outer diameter is also smaller by 0.2 mm. FIGS. 4 (4) and 4 (5) are images when the position is shifted by, for example, +0.1 mm or −0.1 mm in the reference central axis O direction. 4 (6) shows an image when the central axis of the pellet P is inclined by 5 ° in the horizontal direction with respect to the reference central axis O, and FIG. 4 (7) shows the central axis 5 in the vertical direction relative to the reference central axis O. FIG. 4 (8) shows an image when the center axis is tilted by 5 ° in the vertical and horizontal directions with respect to the reference center axis O. FIG.
[0016]
Next, a method for measuring the outer diameter of the pellet P based on the photographed image of the pellet P will be described.
In the present embodiment, a method for measuring the outer diameter of the pellet P based on the photographed image of the pellet P shown in FIGS. 4 (8) and 5 will be described with reference to the process chart of FIG.
When the pellet P after grinding is placed on the ladder chain 3 while being tilted vertically and horizontally and conveyed at high speed to the outer diameter measuring unit 6 of the outer diameter measuring device 1, the line laser beams are emitted from the line laser projectors 10A to 10D. Is irradiated onto the pellet P, and both side surfaces of the pellet P are photographed by the area cameras 8A and 8B.
Here, the image captured by the area camera 8A will be described. The image captured by the area camera 8A is input to the image input unit 14 of the measurement control unit 7 (step 100) and analyzed by the arithmetic control unit 15. The outer diameter measurement process is started (step 102) by recognizing the captured image of the pellet P by the arithmetic control unit 15 (step 101).
[0017]
First, as shown in FIG. 7, the extraction unit 20 extracts the projection lines La1 and Lb1 by image processing (step 103), and then the first indexing unit 21 forms the projection line La1 and the vicinity of the peak of the curved portion that protrudes to the left side. When the brightness distribution on each horizontal direction line is enlarged and the brightness distribution on each horizontal direction line is taken, the brightness of the mountain shape that forms a horizontal line orthogonal to the projection line La1 along the longitudinal direction of the projection line La1 (projection ray). A plurality of distributions are obtained (see FIG. 8). If plotting is performed at the center of projection light from the calculated brightness distribution of each horizontal line, a substantially line-shaped plot image at the center of projection light shown in FIG. 9 is obtained. Abnormal values are excluded from this data, and the mountain-shaped optimum fitting curves La1 ′ and Lb1 ′ having one convex vertex as shown in FIG. 10 are obtained.
The second indexing unit 22 calculates the maximum point as the vertex of the optimum fitting curve La1 ′ shown in FIG. 10, and determines the maximum point pa of the projection line La1 by determining the three-dimensional position with the calibration coefficient calculated in advance. it can. The maximum point pb of the projection line Lb1 is determined by the same procedure.
Since these local maximum points pa and pb are the maximum values of the projection lines La1 and Lb1 projected onto one side surface of the cylindrical circumferential surface shape of the pellet P, they are determined as the maximum horizontal protruding point on the side surface of the pellet P. In the outer diameter calculating means 23, a straight line passing through the two points pa and pb is determined as one side outer diameter line p1. Similarly, on the facing area camera 8B side, two local maximum points pc and pd are obtained from the captured images of the projection lines Lc1 and Ld1 obtained by projecting the line laser beams Lc and Ld onto the cylindrical circumferential surface of the pellet P. Specifically, it can be determined as the maximum horizontal protruding point on the other side surface of the pellet P, and a straight line passing through these two points pc and pd can be determined as the other side surface outer diameter line p2. In the figure, the maximum points pc and pd are omitted.
The distance D between the two side surface outer diameter lines p1 and p2 can be calculated as the outer diameter of the pellet P.
[0018]
In this way, the outer diameter is measured at high speed in a non-contact manner without causing the pellet P to stand still while being conveyed by the ladder chain 3 at high speed. The pellets P are ground on the ladder chain 3 after being ground by the pellet grinding device 2 and conveyed to the outer diameter measuring device 1, but the orientation of the pellets P on the ladder chain 3 is not constant. When a plurality of, for example, 20 points are measured for the outer diameter of these pellets P, the average outer diameter of the pellets P can be calculated, and the degree of distortion and linearity of the outer diameter shape in the horizontal direction can be calculated. If the measured outer diameter of the pellet P obtained by the outer diameter measuring unit 6 is within the set allowable range, it is transported to the next process and filled in the fuel rod. If the measured outer diameter of the pellet P is outside the allowable range, the pellet P1 is removed from the transport line by the abnormal product sorting unit and discharged.
For example, the grinding actual condition of the pellet grinding apparatus 2 can be monitored by statistically convolving the outer diameter of the plurality of pellets P such as 20 in the horizontal direction, the degree of distortion of the outer diameter, and the degree of straightness. Then, the data on the actual grinding condition of the pellet P is fed back from the data output unit 16 to the grinding adjusting unit 25 of the pellet grinding apparatus 2 to control the wet centerless grinder of the grinding apparatus 2 to adjust the outer diameter grinding of the pellet P. Grinding accuracy can be maintained stably.
[0019]
As described above, according to the outer diameter measuring apparatus 1 according to the present embodiment, the outer diameter of the outer peripheral surface P1 can be measured at high speed without contact without placing the pellet P on the ladder chain 3 and carrying it at high speed without stopping. Therefore, it is possible to measure all of them. In addition, without using a specific transporter having a reference surface, it is not necessary to secure an accurate reference surface, measurement axis, or transmission area, and even if each central axis of the pellets P to be sequentially transferred is displaced in the vertical and horizontal directions. The pellet diameter P can be recognized and measured by the outer diameter measuring device 1 itself. It is possible to recognize and correct the normal conveyance blur and inclination of the pellet P and measure it.
[0020]
In addition, since the optimum fitting curve is obtained from a large number of pixels and the vertex position of the curve is determined, it is possible to measure the outer diameter with high accuracy and high accuracy with a high average surface resolution.
In addition, the outer diameter data obtained by the measurement is fed back to the grinding adjusting unit 25 of the grinding device 2 as the outer diameter feature value by statistics, so that the grinding amount, the grinding position, etc. with respect to the outer peripheral surface P1 of the pellet P can be adjusted as needed. High precision grinding is possible.
In addition, abnormal parts such as chipping of the pellet P can be detected from the photographed image, so that defective abnormal pellets are discharged and abnormal grinding control is not included by including an incorrect outer diameter evaluation in the feedback data. it can. Further, since troubles in the pellet grinding apparatus 2 appear in the pellet P and can be detected by the outer diameter measuring apparatus 1, it is possible to set the apparatus to optimally stop operation during abnormal grinding, report abnormal conditions, and the like.
[0021]
In the present embodiment, the line laser projectors 10A, 10B, 10C, and 10D are arranged at an equal angle with respect to the optical axis Lo of the area cameras 8A and 8B, but may be at different angles.
In addition, although two line laser projectors are arranged on one line camera 8A or 8B side, three or more line laser projectors may be arranged. In this case, side outer diameter lines p1 and p2 are set. Since the maximum point of the optimum fitting curve to be set can be set to three or more points, the side outer diameter lines p1 and p2 can be determined with higher accuracy.
Further, in the above-described embodiment, the outer diameter is measured while the pellet is being conveyed. However, the outer diameter may be measured in a stopped state, and in this case, the measurement efficiency is slightly reduced, but more accurate measurement is possible. Can be done. In addition, the transport member on which the pellet P is placed when measuring the outer diameter of the pellet P is not limited to the ladder chain, and other appropriate members can be adopted.
The present invention is not limited to the measurement of the outer diameter of the nuclear fuel pellet P, but includes the outer diameter of the outer peripheral surface of the object to be measured having other columnar shape, cylindrical shape, elliptical shape, or other appropriate outer peripheral shape. It can be used to measure the distance between the outer peripheral surfaces.
[0022]
【The invention's effect】
As described above, the outer diameter measuring method and apparatus according to the present invention recognizes and corrects the movement blur and the inclination in the vertical and horizontal directions and increases the outer diameter even when the object to be measured is not placed on the reference surface. And it can measure accurately without contact.
[0023]
Moreover, in the outer peripheral surface grinding apparatus of the measured object according to the present invention, the outer diameter data obtained by measuring the outer diameter of the measured object can be fed back to the grinding apparatus to adjust the grinding of the outer peripheral surface of the measured object. .
[Brief description of the drawings]
FIG. 1 is an explanatory view of a pellet outer diameter measuring apparatus according to an embodiment of the present invention.
FIG. 2 is a front view of the outer diameter measuring apparatus shown in FIG.
3A and 3B show a ladder chain for conveying pellets, where FIG. 3A is a plan view and FIG. 3B is a side view.
4A and 4B are diagrams showing projection lines projected on pellets of different postures according to (1) to (8), where (a) is a view of one side image, (b) is a top view, and (c) is the other side. FIG.
5 (a) is an enlarged view of the pellet shown in FIG. 4 (8), (a) is a side image, (b) is a top view, and (c) is a side image. FIG.
FIG. 6 is a process diagram showing an outer diameter measurement processing procedure of the outer diameter measuring apparatus.
FIG. 7 is an image of a projection line irradiated on one side surface of an inclined pellet.
FIG. 8 is a brightness distribution diagram on one horizontal line in a convex curve portion of a projection line image.
FIG. 9 is a diagram plotting the projection center of a horizontal line at a convex curve portion of a projection line.
FIG. 10 is a diagram showing an optimum fitting curve obtained from projection center data of a horizontal line.
[Explanation of symbols]
1 Outer diameter measuring device (peripheral surface distance measuring device)
2 Pellet grinding equipment (grinding equipment)
3 Ladder chain (conveying member)
6 outer diameter measuring unit 7 measurement control unit 8A, 8B area camera (photographing means)
10A, 10B, 10C, 10D Line laser projector 15 Operation control unit 20 Extraction means 21 First indexing means (indexing means)
22 Second indexing means (indexing means)
La, Lb, Lc, Ld Line laser beams La1, Lb1, Lc1, Ld1 Projection lines La1 ′, Lb1 ′, Lc1 ′, Ld1 ′ Optimal fitting curve P Pellet (object to be measured)
P1 outer peripheral surface pa, pb, pc, pd local maximum point (vertex)
p1, p2 outer diameter measurement line

Claims (3)

A plurality of line laser beams are irradiated in a vertical direction on both side surfaces facing the radial direction on the columnar or cylindrical outer peripheral surface of the object to be measured, and both side surfaces of the object to be measured are photographed, and the object is measured from the photographed image. A plurality of projection lines having a convex curve shape that are formed on both side surfaces of the measurement object and project in the horizontal direction of the measurement object are extracted from the plurality of line laser beams , and fitting curves are obtained from the plurality of projection lines and the fitting is performed. The maximum horizontal projecting point of the curve is determined as a vertex projecting on each side surface, a three-dimensional position is determined based on the vertex, and a straight line passing through each of the vertexes on each side surface is defined as a side surface of each side surface. An outer diameter measuring method for an object to be measured, which is determined as an outer diameter line and calculates an outer diameter of an outer peripheral surface of the object to be measured from a distance between side surface outer diameter lines on both side surfaces. A plurality of line laser projectors respectively disposed on both side surfaces facing the radial direction of the columnar or cylindrical outer peripheral surface of the object to be measured;
Imaging means for imaging both side surfaces of the object to be measured irradiated with a plurality of line laser beams in the vertical direction ,
Extraction that extracts a plurality of projected lines that form a convex curve projecting in the horizontal direction of the object to be measured for a plurality of line laser beams formed along both side surfaces of the object to be measured from the photographed image obtained by the photographing means Means,
Indexing means for obtaining a fitting curve from the plurality of projection lines and obtaining a maximum projecting point in the horizontal direction from the fitting curve and calculating as a vertex projecting on both side surfaces ;
The three-dimensional positions of the both side surfaces are determined from the vertices of the fitting curve, and straight lines passing through the plurality of vertices are respectively determined as side surface outer diameter lines on both side surfaces, and from the distance between the side surface outer diameter lines on the both side surfaces. An outer diameter measuring device for an object to be measured, comprising: an outer diameter calculating means for calculating an outer diameter of an outer peripheral surface of the object to be measured.   A grinding device for grinding an outer peripheral surface of the object to be measured, and an outer diameter measuring device according to claim 2 for measuring the outer diameter of the object to be measured ground by the grinding device. An outer peripheral surface grinding apparatus for an object to be measured, wherein the outer diameter data of the object to be measured obtained by the diameter calculating means is fed back to the grinding apparatus to adjust the grinding of the object to be measured.

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