JP2005292081A - Chip shape inspection apparatus and chip inspection method for disk-shaped parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chip inspection device and a chip inspection method for a disk-shaped part which can perform a chip inspection of a disk-shaped inspection object stably at high speed and which has a relatively simple configuration.
A side surface of an object to be inspected 1 is illuminated by a disk side surface illumination means 2 from a direction perpendicular to the side surface, and the inspection object 1 is imaged by a disk-shaped component imaging means 3 from a central axis direction of the inspection object 1. The disc side grayscale image data input from the disc-shaped component imaging means 3 is stored in the image data storage means 5, and the position coordinates of the outer peripheral position (edge) on the surface of the inspection object 1 are measured by the side face position detection means 6. After calculating the reference circle by the side reference circle calculating means 7 from all the position coordinates of this edge and calculating the reference circle by the predetermined angle pitch in the direction, the defect defect determining means 8 determines the missing portion from the difference between the radius in each chart and the reference circle radius. Determine presence or absence.
[Selection] Figure 1

Description

  The present invention relates to a chip inspection device and a chip inspection method for a disk-shaped component that automatically inspects the presence or absence of a chip on a test object such as a rotary blade component having a disk shape, for example. is there.

  With respect to inspection of chipping defects and the like by conventional image processing, for example, as described in Patent Document 1, reflected illumination for obtaining a reflected image of an inspection object with respect to the inspection object such as a camera and an injection molded product And transmission illumination for obtaining a transmission image of the inspection object at a position opposite to the imaging position of the camera via the inspection object, while selectively driving and controlling the reflection illumination and the transmission illumination There is a method of performing pass / fail determination of an inspection object by performing image processing on the obtained reflection image and transmission image.

JP-A-6-160065 (page 2-4, FIG. 1-2)

  The conventional technique such as Patent Document 1 described above has a problem that it is difficult to reduce the size of the inspection apparatus because the object to be inspected needs to be reflected and transmitted.

  Further, since image processing is performed while controlling a plurality of lighting devices, there is a problem that the image processing becomes complicated.

  Further, when the shape of the object to be inspected is a plate shape, the reflected light of the chipped portion may not be successfully imaged depending on the irradiation angle of the reflected illumination.

  The present invention has been made in order to overcome the above-described problems in the prior art, and is capable of stably performing a chip inspection of a disk-shaped inspection object at a high speed and having a relatively simple configuration. An object of the present invention is to obtain a chip inspection device and a chip inspection method for a disk-shaped part.

A disk-shaped component chip inspection apparatus according to the present invention includes a disk side illumination means for irradiating a disk-shaped inspection object in a direction perpendicular to the side surface of the inspection object,
A disk-shaped component imaging means for imaging the inspection object from the direction of the central axis of the disk shape of the inspection object and outputting gray image data of the inspection object;
Side surface position detecting means for obtaining the position coordinates of the outer periphery on the grayscale image data output from the disk-shaped component imaging means at a predetermined angular pitch in the circumferential direction;
Side reference circle calculation means for obtaining a reference circle for determining whether or not the inspection object is missing from all of the position coordinates obtained by the side face position detection means;
Chipping defect determination means for determining the presence or absence of chipping of the inspection object based on the coordinates of the reference circle obtained by the side face reference circle calculation means and the position coordinates obtained by the side face position detection means;
It is equipped with.

A method for inspecting a chip of a disk-shaped component according to the present invention includes:
A disk-shaped component imaging step of imaging the inspection object from the central axis direction of the disk shape of the inspection object, and outputting gray image data of the inspection object;
A side surface position detecting step for obtaining position coordinates of the outer periphery on the grayscale image data output in the disk-shaped component imaging step at a predetermined angular pitch in the circumferential direction;
A side reference circle calculation step for obtaining a reference circle for determining the presence or absence of the lack of the inspection object from all of the position coordinates obtained in the side surface position detection step;
A chipping defect determination step for determining the presence or absence of the chipping of the inspection object based on the coordinates of the reference circle obtained in the side surface reference circle calculation step and the position coordinates obtained in the side surface position detection step;
It is equipped with.

  According to the configuration of the present invention described above, it is possible to realize a chip-shaped part chip inspection apparatus that automatically inspects the presence or absence of a disk-shaped inspection object at high speed with a relatively simple apparatus configuration. There is.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing Embodiment 1 of a disk-shaped component chip inspection apparatus according to the present invention. As shown in the figure, the disk side illumination means 2 that irradiates perpendicularly with respect to the side surface of the disk-shaped inspection object 1 to be inspected, that is, at an irradiation angle of 0 °, and directly above the inspection object 1. A disk-shaped part imaging means 3 that is arranged in a direction (center axis direction), receives illumination light reflected from the side surface of the inspection object 1, and outputs grayscale image data of the inspection object 1, and a disk-shaped part And an electronic computer 4 that processes the grayscale image data of the inspection object 1 output from the imaging means 3 and realizes various functions for determining a defect defect.

  For example, LED illumination is used for the disc side illumination means 2, and the illumination intensity is controlled by a control means (not shown).

  The disk-shaped component imaging unit 3 includes a driving unit that adjusts the distance from the inspection object 1 and the disk side illumination unit 2 using, for example, a television camera using a CCD (Charge Coupled Device) imaging device. It is supposed to be configured.

  The electronic computer 4 has an image data storage means 5 for storing the grayscale image data of the object to be inspected 1 output from the disk-shaped component imaging means 3, and the outer peripheral position coordinates on the grayscale image data at a predetermined angular pitch in the outer circumferential direction. Side position detection means 6 obtained by the above, side reference circle calculation means 7 for obtaining a reference circle for determining the presence or absence of the chip 1 from the position coordinates obtained by the side position detection means 6, and side reference circle calculation means 7 is provided with chipping defect determination means 8 for determining whether or not the inspection object 1 is chipped based on the coordinates of the reference circle obtained in step 7 and the position coordinates obtained by the side surface position detection means 6.

  The image data storage means 5 is realized by a storage medium such as a hard disk device, a CD-ROM, or a DVD of the electronic computer 4, for example.

  The side surface position detecting means 6 corresponds to the edge of the inspection object 1 whose density value in the radial direction of the inspection object 1 changes from light (white) to dark (black) or from dark (black) to light (white). The outer circumference is obtained.

  The side reference circle calculation means 7 obtains a reference circle from all the outer peripheral position coordinates detected by the side face position detection means 6.

  FIG. 2 is a flowchart showing the operation of the disk-shaped component chipping inspection apparatus according to the first embodiment, and FIG. 3 is a diagram showing the state of non-defective products and defective products during operation of the disk-shaped part chipping inspection device. FIG. 4 is a diagram for explaining the operation of processing for detecting the position coordinates of the outer periphery of grayscale image data, FIG. 5 is a diagram for explaining the operation of processing for calculating a reference circle of grayscale image data, and FIG. It is a figure explaining operation | movement of a determination process. In the following, description will be given of the processing for determining a chip defect of a disk-shaped inspection object according to FIG. 2, FIG. 3, FIG. 4, FIG.

  First, so as to be illuminated from a direction perpendicular to the side surface of the inspection object 1 by the illumination of the disk side surface illumination means 2 at a position directly below the CCD camera or the like constituting the disk-shaped part imaging means 3, and The inspection object 1 is arranged so that the entire inspection object 1 enters the field of view of the CCD camera from above (see FIG. 1).

  As shown in the side view of FIG. 3A, the illumination light from the ring-shaped illumination 32 that surrounds the inspection object 1 includes reflected light that is reflected upward by the side surface 33 of the inspection object. On the other hand, as shown in the side view of FIG. 3 (b), since the illumination light is irregularly reflected at the defective portion 34, the reflected light on the side surface 33 of the normal inspection object 1 is reflected. In addition, irregularly reflected light at the chipped position is also reflected upward. Therefore, as shown in the plan view of FIG. 3C, the shape of the captured image 31 in the grayscale image data 35 obtained by the disk-shaped component imaging means 3 does not become a perfect circle. At this time, in order to increase the intensity of the reflected light received by the disk-shaped part imaging means 3, the object to be inspected 1, the disk side illumination means 2 and the disk-shaped part are used by using a position adjusting means (not shown). You may make it adjust each distance of the imaging means 3. FIG. Thereafter, in step ST1 shown in FIG. 2, the disk-shaped component imaging unit 3 outputs the captured grayscale image data 35, and the grayscale image data 35 is immediately stored in the image data storage unit 5 in the electronic computer 4. (Image data input step).

  Next, in step ST2, the side surface position detection means 6 detects the position coordinates of the outer periphery in the grayscale image data 35 stored in the image data storage means 5 (side surface position detection step).

  In step ST2, as shown in FIG. 4, in order to find the position coordinates of the outer periphery from the image data 41 read from the image data storage means 5 (same as the grayscale image data 35), a radial pattern is generated from the center position of the image data 41. An edge point 43 whose density value changes from dark (black) to light (white) or from light (white) to dark (black) is obtained using a one-dimensional differential filter on the edge detection line 42 extending to The edge point 43 is set as the outer peripheral position coordinate. In a similar process, a total of 360 edge detection straight lines 42 are provided at a predetermined angular pitch, for example, 1 ° pitch, and the position coordinates of the outer periphery of a total of 360 points are obtained.

  Next, in step ST3, the side reference circle calculation unit 7 obtains a reference circle serving as a reference for determining the presence or absence of a chip from all the outer peripheral position coordinates detected by the side surface position detection unit 6 (side reference circle calculation step). ).

  In step ST3, as shown in FIG. 5, based on the coordinate group 51 (360 points in total) of outer peripheral positions detected by the side surface position detecting means 6 (FIG. 5A), LmedS (Least Median). of Squares: least square median) Constants a, b, and r in the following equation (1) in the reference circle 52 shown in FIG. 5B are obtained using a robust circular regression algorithm.

  Here, the LMedS robust circular regression algorithm will be described. The LMedS standard is one of the robust fitting standards, and as a reference proposed by Rousseeuw, Rousseeuw R. J. et al. Leroy A. M.M. : Robust Regression and Operator Detection, John Wiley & Sons 1986.

  This fitting criterion is expressed by the following equation (2), and is a criterion for minimizing the median of the square of the deviation ri.

  On the other hand, the least common method (LMS: Least Minimum of Squares), which is the most general fitting criterion, is expressed by the following equation (3).

  A major feature of the LMedS standard is that an exceptional value called “outlier” that is far from the normal measurement value is automatically excluded from the calculation, and a stable result is always obtained.

In the least squares fitting criterion, if there is even one outlier in the data, when applying to the estimated regression parameter ((x−a) ² + (y−b) ² −r ² = 0) circle, The center coordinates (a, b) and the radius r are the regression parameters. The center coordinates (a, b) and the radius r are completely different from the original values. On the other hand, when the LMedS criterion is used, Theoretically, if the outlier value is less than 50% of the measured value, the correct center coordinates (a, b) and radius r can be estimated even if such an outlier value is included.

  Next, in step ST 4, from the distance error between the coordinate group 51 of the outer peripheral position detected by the side surface position detection unit 6 and the coordinates of the reference circle 52 calculated by the side surface reference circle calculation unit 7 by the chip defect determination unit 8. It is determined whether or not the disk-shaped part is chipped (chip defect determination step).

  In step ST4, as shown in FIG. 6, for each of the coordinate group 51 (coordinate positions: x (i), y (i)) (total number of 360 points) of the outer peripheral position detected by the side surface position detecting means 6, The distance dis (i) from the center coordinates (a, b) of the reference circle 52 is obtained using the following formula (4). However, i = 0, 1,.

  Subsequently, for each coordinate group 51 at the outer peripheral position, a radius error rdiff (i) between the coordinate group 51 at the outer peripheral position and the radius r of the reference circle 52 is obtained using the following equation (5).

  Next, the standard deviation value stdev is obtained from the radius error rdiff (i), and the ratio (%) of the standard deviation value to the radius r of the reference circle is set as a judgment value JudgeVal as shown in the following formula (6). Ask.

  It is examined whether or not the judgment value JudgeVal obtained as described above satisfies the following formula (7) with respect to a preset threshold ThJudgeVal.

  When the judgment value JudgeVal does not satisfy the above formula (7), it indicates that the reference circle 52 and the coordinate group 51 of the outer peripheral position are greatly deviated, and as shown in FIG. It is conceivable that the chip 71 has occurred, and the outer peripheral position (edge) is greatly deviated from the reference circle 52. Thereby, the chip defect determination means 8 determines the presence or absence of the chip of the inspection object.

  As described above, according to the first embodiment, the side surface of the disk-shaped inspection object 1 is irradiated in the vertical direction, and the inspection object 1 is inspected from the central axis direction of the disk shape. The object 1 is imaged, the grayscale image data of the inspection object 1 is output, the position coordinates of the outer circumference on the output grayscale image data are obtained at a predetermined angular pitch in the circumferential direction, and the inspection object 1 is detected from the obtained position coordinates. Since the reference circle for determining the presence / absence of chipping is obtained and the presence / absence of chipping of the inspection object 1 is determined based on the obtained coordinates of the reference circle and the respective position coordinates obtained at a predetermined circumferential pitch in the circumferential direction, the surface film Chip-shaped part inspection equipment for disc-shaped parts that can be automatically inspected stably and at high speed without being affected by reflections in materials such as metals whose light reflection is likely to change depending on the finish or processing finish. Is realized with a relatively simple device configuration It can be.

Embodiment 2. FIG.
In the first embodiment, the standard deviation value stdev is obtained from the radius error rdiff (i) between the reference circle 52 and the outer peripheral position coordinate group 51, and the ratio (%) of the standard deviation value to the radius r of the reference circle 52 is obtained. Although the determination value for the presence / absence of a chip is obtained, the presence / absence of a chip may be determined using a determination value using another method.

  For example, the coordinate group 51 (coordinate positions: x (i), y (i)) (total 360 points) of the outer peripheral position is calculated from the center coordinates (a, b) of the reference circle 52 using the above equation (4). After obtaining the distance dis (i), the distance difference ddiff (i) between adjacent ones in the coordinate group 51 of the outer peripheral position is calculated using the following formula (8). However, i = 0, 1,.

  The standard deviation value stdev2 is obtained from the distance difference ddiff (i) between adjacent ones in the coordinate group 51 of the outer peripheral position, and the radius r (dis (i (i (i) )) Is determined as a judgment value JudgeVal2.

  It is checked whether or not the determination value JudgeVal2 obtained as described above satisfies the following formula (10) with respect to a preset threshold ThJudgeVal2.

  When the judgment value JudgeVal2 does not satisfy the above formula (10), it indicates that the outer periphery is rough in a local range, and the chipping defect judgment means 8 closely observes the chipping state and disc-shaped parts. There is an effect that it is possible to determine the presence or absence of chipping.

  The chip inspection device and chip inspection method for a disk-shaped component according to the present invention automatically inspects the presence or absence of a chip on a disk-shaped component such as a rotary blade component having a disk shape at high speed. Can be used.

It is a block diagram which shows Embodiment 1 in the chip | tip inspection apparatus of the disk-shaped components which concerns on this invention. It is a flowchart which shows operation | movement of the chip | tip inspection apparatus of a disk-shaped component. It is a figure which shows the state of the quality goods and inferior goods at the time of operation | movement of a disc-shaped component chip | tip inspection apparatus. It is a figure explaining operation | movement of the process which detects the position coordinate of the outer periphery of grayscale image data. It is a figure explaining operation | movement of the process which calculates the reference | standard circle of grayscale image data. It is explanatory drawing for operation | movement of a defect defect determination process. It is a figure which shows the example of the inferior goods detected in the chip | tip inspection apparatus of the disk-shaped components which concern on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 To-be-inspected object, 2 disc side surface illumination means, 3 disc shape part imaging means, 4 electronic computer, 5 image data storage means, 6 side surface position detection means, 7 side reference circle calculation means,
8 chipping defect judging means, 31 photographed image, 32 ring-shaped illumination, 33 side surface of inspection object,
34 chipped defective portion, 35 grayscale image data, 41 disc-shaped part image,
42 edge detection straight line, 43 edge point, 51 position coordinate group of outer peripheral position, 52 reference circle, 71 missing portion.

Claims (10)

Disc side illumination means for irradiating in a direction perpendicular to the side of the inspection object having a disc shape,
A disk-shaped component imaging means for imaging the inspection object from the direction of the central axis of the disk shape of the inspection object and outputting gray image data of the inspection object;
Side surface position detecting means for obtaining the position coordinates of the outer periphery on the grayscale image data output from the disk-shaped component imaging means at a predetermined angular pitch in the circumferential direction;
Side reference circle calculation means for obtaining a reference circle for determining whether or not the inspection object is missing from all of the position coordinates obtained by the side face position detection means;
Chipping defect determination means for determining the presence or absence of chipping of the inspection object based on the coordinates of the reference circle obtained by the side face reference circle calculation means and the position coordinates obtained by the side face position detection means;
A chip inspection device for a disk-shaped part, comprising: The side surface position detection means has a density value from dark (black) to bright (white) or bright (white) on a straight line extending radially from the center of the grayscale image data output by the disk-shaped component imaging means. 2. The disc-shaped component chipping inspection apparatus according to claim 1, wherein an edge point that changes from dark to black is obtained, and the position of the edge point is determined as the position coordinate. 2. The side reference circle calculating means obtains the reference circle from the position coordinates detected by the side face position detecting means using an LMedS (least square median) robust circle regression algorithm. Disc inspection device for disk-shaped parts. The missing determination means obtains the difference between the radius of the reference circle obtained by the side face reference circle calculation means and the distance from the center coordinate of the reference circle to the position coordinate for each of the position coordinates, and calculates the standard of the difference 2. The disk-shaped component chip inspection apparatus according to claim 1, wherein presence or absence of the chip of the inspection object is determined from a deviation value. The missing determination means obtains a distance between adjacent position coordinates among the position coordinates, obtains a standard deviation value of the distance between the adjacent position coordinates, and determines the distance between the adjacent position coordinates with respect to the radius of the reference circle. 2. The disk-shaped component chip inspection apparatus according to claim 1, wherein the presence or absence of the chip of the inspection object is determined from a ratio of a standard deviation value of the distance. A disc side illumination step for irradiating the disc-shaped object side surface in a direction perpendicular to the side surface;
A disk-shaped component imaging step of imaging the inspection object from the central axis direction of the disk shape of the inspection object, and outputting gray image data of the inspection object;
A side surface position detecting step for obtaining position coordinates of the outer periphery on the grayscale image data output in the disk-shaped component imaging step at a predetermined angular pitch in the circumferential direction;
A side reference circle calculation step for obtaining a reference circle for determining the presence or absence of the lack of the inspection object from all of the position coordinates obtained in the side surface position detection step;
A chipping defect determination step for determining the presence or absence of the chipping of the inspection object based on the coordinates of the reference circle obtained in the side surface reference circle calculation step and the position coordinates obtained in the side surface position detection step;
A chip inspection method for a disk-shaped part, comprising: In the side surface position detection step, the density value is dark (black) to bright (white) or bright (white) on a straight line extending radially from the center of the image information captured in the disk-shaped component imaging step. 7. The method for inspecting a chip of a disk-shaped part according to claim 6, wherein an edge point changing from dark to dark (black) is obtained and the position of the edge point is determined as the position coordinate. The said side reference | standard circle calculation step calculates | requires the said reference | standard circle using the LMedS (least square median) robust circle regression algorithm from the said position coordinate detected by the said side surface position detection step. A chip inspection method for disk-shaped parts. The missing determination step obtains the difference between the radius of the reference circle obtained in the side reference circle calculation step and the distance from the center coordinate of the reference circle to the position coordinate for each of the position coordinates. 7. The method for inspecting a chip of a disk-shaped part according to claim 6, wherein the presence or absence of a chip of the inspection object is determined from the deviation value. The missing determination step obtains a distance between adjacent position coordinates among the position coordinates, obtains a standard deviation value of the distance between the adjacent position coordinates, and determines the distance between the adjacent position coordinates with respect to the radius of the reference circle. 7. The method for inspecting a chip of a disk-shaped part according to claim 6, wherein presence or absence of the inspected object is determined from a ratio of a standard deviation value of the distance.

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