JP2024033867A - Surface inspection device and surface inspection method - Google Patents

Abstract

An object of the present invention is to detect flaws such as dents on a machined surface while reducing the influence of machining marks generated on the machined surface when flattening is performed by milling. A surface inspection device 10 detects a rotation radius r±permissible from an arbitrary point Pn of an object surface image 101 based on an object surface image 101 obtained by capturing a surface S of an object 100 by an imaging unit 20 and rotation center image data 14a. It is searched whether or not the rotation center VCi exists within the range of the error δ, and if it exists, the vector direction from the arbitrary point Pn to the rotation center VCi is specified, and the direction vector of the arbitrary point Pn is calculated. Then, the brightness gradient angle caused by the machining mark SM at the arbitrary point Pn is calculated, and if the brightness gradient angle and the vector angle of the direction vector are within a predetermined range, the pixel value of the arbitrary point Pn is corrected to the surrounding average value. It was configured so that [Selection diagram] Figure 1

Description

The present invention relates to a surface inspection device and a surface inspection method that can detect scratches such as dents on a machined surface while reducing the influence of machining marks generated on the machined surface when flattening by milling. .

Conventionally, a surface inspection method is known in which flaws existing on the surface of an object are detected separately from grinding marks. For example, in Patent Document 1, for each pixel of an image taken of an object surface, a vector whose components are a differential value in the X-axis direction and a differential value in the Y-axis direction is calculated, and the angle of the vector of each pixel with respect to the X-axis is calculated. Measures the frequency of the angle, identifies the direction perpendicular to the angle with the high frequency as the direction in which the grinding marks extend, and performs correction to weaken the brightness value of the pixel of the vector of the angle with the high frequency among each pixel of the image data. Alternatively, a technique has been disclosed that performs correction to increase the brightness value of a pixel of a vector at an angle that is not high in degree.

Japanese Patent Application Publication No. 2012-008018

However, in Patent Document 1, if the degree of the angle of the vector of each pixel becomes high, even if this pixel is caused by a scratch rather than a grinding mark, it is in the extending direction of the grinding mark. , and the brightness value is corrected. As a result, a problem arises in that scratches other than grinding marks are treated as grinding marks and removed.

The present invention has been made in order to solve the above-mentioned problems (issues), and when flattening by milling, reduces the influence of machining marks generated on the machined surface, and also reduces the impact of the machining marks on the machined surface. It is an object of the present invention to provide a surface inspection device and a surface inspection method that can detect flaws such as marks.

In order to solve the above-mentioned problems and achieve the purpose, the present invention uses an object surface image captured by an imaging unit that captures an image of the surface of a cut object while rotating a cutting tool attached to a predetermined rotation axis. A surface inspection method in a surface inspection apparatus that inspects the surface of a predetermined object using a method, wherein the method includes: a method for inspecting a surface of a predetermined object; a first identifying step of identifying a second pixel of the first pixel; and a brightness gradient of a direction vector to a second pixel on the movement locus of the rotation center of the cutting tool among the plurality of brightness gradients in the first pixel. and a correction step of correcting the pixel value of each pixel forming the object surface image based on the gradient angle specified in the second specifying step. do.

Further, in the above invention, the present invention provides an inspection step of inspecting flaws caused by other than the machining marks formed on the surface of the object based on a corrected image in which the object surface image is corrected in the correction step. It is characterized by further including.

Further, in the above invention, the present invention provides a face milling cutter having a plurality of blades attached on the circumference of a predetermined rotating body and rotatable about the predetermined rotation axis, or a face milling cutter or an object cutting tool. It is characterized by being an abrasive brush that polishes the surface.

Further, in the above-mentioned invention, the present invention provides that the first identifying step uses a movement trajectory image in which a predetermined pixel value is assigned to a pixel forming a movement trajectory of the rotation center of the cutting tool. The present invention is characterized in that the second pixel on the movement locus of the rotation center of the cutting tool that affects the first pixel forming the surface image is specified.

Further, in the above invention, the present invention provides that the correction step corrects the pixel value of the first pixel on the object surface image that forms the gradient angle of the brightness gradient specified in the second specifying step. Features.

Further, in the above invention, the present invention is characterized in that the correction step lowers the pixel value of the first pixel on the object surface image that forms the gradient angle of the brightness gradient specified in the second specifying step. shall be.

The present invention also provides a surface inspection method for inspecting the surface of a predetermined object using an object surface image captured by an imaging unit that captures an image of the surface of the cut object while rotating a cutting tool attached to a predetermined rotating shaft. A surface inspection method in an inspection device, comprising: a first specifying step of specifying a first pixel affected by a second pixel on a movement locus of a rotation center of the cutting tool; and the first specifying step. a second specifying step of specifying a gradient angle of a brightness gradient in a direction from the first pixel to the second pixel among the plurality of brightness gradients in the specified first pixel; The present invention is characterized in that it includes a correction step of correcting the pixel value of each pixel forming the object surface image based on the gradient angle specified in the specifying step.

The present invention also provides a surface inspection method for inspecting the surface of a predetermined object using an object surface image captured by an imaging unit that captures an image of the surface of the cut object while rotating a cutting tool attached to a predetermined rotating shaft. an inspection device, a first specifying means for specifying a second pixel on a movement locus of the rotation center of the cutting tool that affects an arbitrary first pixel forming the object surface image; a second specification for specifying a gradient angle of a brightness gradient in a direction from the first pixel to the second pixel among the plurality of brightness gradients in the first pixel specified by the first specifying means; and a correction means for correcting the pixel value of each pixel forming the object surface image based on the gradient angle specified by the second specifying means.

The present invention also provides a surface inspection method for inspecting the surface of a predetermined object using an object surface image captured by an imaging unit that captures an image of the surface of the cut object while rotating a cutting tool attached to a predetermined rotating shaft. A surface inspection device in an inspection device, comprising a first specifying means for specifying a first pixel affected by a second pixel on a movement locus of a rotation center of the cutting tool, and the first specifying means. a second specifying means for specifying a gradient angle of a brightness gradient in a direction from the first pixel to the second pixel among the plurality of brightness gradients in the specified first pixel; The present invention is characterized by comprising a correction means for correcting the pixel value of each pixel forming the object surface image based on the gradient angle specified by the specifying means.

According to the present invention, when performing planarization by milling, it is possible to detect flaws such as dents on the machined surface while reducing the influence of processing marks generated on the machined surface.

FIG. 1 is a functional block diagram showing the configuration of a surface inspection apparatus according to the first embodiment. FIG. 2 is an explanatory diagram for explaining the process of specifying the rotation center from an arbitrary point Pn. FIG. 3 is an explanatory diagram for explaining calculation of a direction vector. FIG. 4 is a flowchart showing the processing procedure of the surface inspection apparatus shown in FIG. FIG. 5 is a flowchart showing the processing procedure of the correction process shown in FIG. FIG. 6 is a diagram showing an example of an object surface image and a processed image of the surface inspection apparatus shown in FIG. 1. FIG. 7 is a functional block diagram showing the configuration of a surface inspection device according to the second embodiment. FIG. 8 is an explanatory diagram illustrating the process of specifying the coordinates of an arbitrary point from the center of rotation. FIG. 9 is an explanatory diagram for explaining calculation of a direction vector. FIG. 10 is a flowchart showing the processing procedure of the surface inspection apparatus shown in FIG.

DESCRIPTION OF EMBODIMENTS Below, embodiments of a surface inspection apparatus and a surface inspection method according to the present invention will be described in detail based on the drawings. In this embodiment, a case will be described in which face milling of an object is performed using a cutting tool that rotates a rotating body having blades attached at a plurality of positions on the circumferential edge around a rotation axis.

[Embodiment 1]
<Configuration of surface inspection device 10>
First, the configuration of the surface inspection apparatus 10 according to the first embodiment will be described. FIG. 1 is a functional block diagram showing the configuration of a surface inspection apparatus 10 according to the first embodiment. As shown in FIG. 1, the surface inspection apparatus 10 includes a display section 11, an input section 12, a storage section 14, a control section 15, and an imaging section 20.

The display unit 11 is a display device such as a liquid crystal display that displays various information. The input unit 12 is an input device such as a mouse or a keyboard.

The storage unit 14 is a storage device such as a hard disk drive or a nonvolatile memory, and stores rotation center image data 14a and image data 14b. The rotation center image data 14a is image data indicating the coordinates of the rotation center VC _i of the cutting tool and a rotation center locus L that is the locus of the rotation center VC _i of the cutting tool. The image data 14b is image data obtained by capturing an image of the surface of the object 100 by the imaging unit 20. It is assumed that the pixels in the rotation center image data 14a and the pixels in the image data 14b are associated so as to point to the same position on the object surface.

The control unit 15 is a control unit that controls the entire surface inspection apparatus 10, and includes an image acquisition processing unit 15a, a rotation center coordinate identification unit 15b, a direction vector calculation unit 15c, a brightness gradient angle identification unit 15d, a correction processing unit 15e, and It has a flaw detection section 15f. In reality, by loading these programs into the CPU and executing them, the image acquisition processing section 15a, rotation center coordinate identification section 15b, direction vector calculation section 15c, lightness gradient angle identification section 15d, correction processing section 15e, and scratches are processed. This causes each detection unit 15f to execute a corresponding process.

The image acquisition processing unit 15a is a processing unit that controls the imaging unit 20 to capture an object surface image of the surface S of the object 100, and acquires the object surface image of the imaged surface S of the object 100. The position of the object surface corresponding to the pixel forming the image data 14b is associated with the position of the object surface forming the rotation center image data 14a. In this way, the image data 14b is subjected to alignment, scaling, rotation, distortion correction, etc. so that it becomes the same area on the object surface indicated by the rotation center image data 14a stored in the storage unit 14 in advance.

When a machining mark is generated at the coordinate position of an arbitrary pixel of the image data 14b (hereinafter referred to as "arbitrary point Pn"), the rotation center coordinate specifying unit 15b determines the rotation center VC of the cutting tool that caused the machining mark. This is a processing unit that specifies the coordinates of _i . That is, when the position of the object surface corresponding to the arbitrary point Pn of the image data 14b is cut by the cutting tool, the rotation center VC _i of the cutting tool always exists at a position a predetermined distance away from the arbitrary point Pn. It should be. Therefore, the coordinates of the rotation center VC _i of the cutting tool located a predetermined distance away from the arbitrary point Pn are specified. Note that if the rotation center VC _i of the cutting tool that was located a predetermined distance away from the arbitrary point Pn does not exist, and the pixel value of this arbitrary point Pn is decreasing, for example, this arbitrary point It can be seen that the scratches generated at point Pn are not machining marks.

Specifically, the rotation center coordinate specifying unit 15b checks whether the rotation center VC _i of the cutting tool exists within the range of rotation radius r±tolerance δ from an arbitrary point Pn of the rotation center image data 14a, and If the center VC _i exists, the coordinates of the rotation center VC _i are specified, and a process is performed to calculate the vector angle θ _C from the arbitrary point Pn to the rotation center VC _i .

The direction vector calculation unit 15c performs a process of calculating a direction vector from the coordinates of the rotation center VC _i specified by the rotation center coordinate identification unit 15b to an arbitrary point Pn. For example, when the brightness of a portion of the surface of an object damaged by a blade provided on a cutting tool decreases, a gradient in which the brightness decreases in a direction from the rotation center VC _i toward an arbitrary point Pn occurs. Here, the direction vector is a vector indicating a direction perpendicular to the direction of the machining mark at the arbitrary point Pn.

The brightness gradient angle specifying unit 15d calculates a plurality of brightness gradients around the arbitrary point Pn by applying a differential operator to the pixels at the arbitrary point Pn of the object surface image captured by the imaging unit 20, and the direction vector calculating unit 15c calculates a plurality of brightness gradients around the arbitrary point Pn. This is a processing unit that specifies whether the brightness gradient angle falls within a predetermined angle range that includes the calculated direction vector. As this differential operator, a first-order differential operator such as Sobel or Roberts, a second-order differential operator, etc. can be used. For example, a Sobel differential operator in the X-axis direction is applied to generate a brightness gradient V _X in the X-axis direction, and a Sobel differential operator in the Y-axis direction is applied to generate a brightness gradient V _Y in the Y-axis direction.

Then, the brightness gradient angle specifying unit 15d calculates the ratio of the brightness gradient V _X in the X-axis direction to the brightness gradient V _Y in the Y-axis direction, and the arctangent function (tan ^-1 (V _X /V _Y )), the brightness gradient angle is calculated. Thereafter, the brightness gradient angle specifying unit 15d determines whether the calculated brightness gradient angle falls within a predetermined angle range that includes the direction vector calculated by the direction vector calculating unit 15c. The brightness gradient angle specifying unit 15d also determines whether the calculated brightness gradient angle falls within a predetermined angle range that includes the inverse vector direction of the direction vector calculated by the direction vector calculation unit 15c.

The correction processing unit 15e corrects the image data 14b when the brightness gradient angle identifying unit 15d determines that the calculated brightness gradient angle is within a predetermined angle range that includes the direction vector calculated by the direction vector calculation unit 15c. A correction process is performed to lower the pixel value of the arbitrary point Pn to the surrounding average value. Further, if the brightness gradient angle specifying unit 15d determines that the calculated brightness gradient angle is not within a predetermined angle range that includes the direction vector calculated by the direction vector calculating unit 15c, no correction processing is performed.

Further, the correction processing unit 15e determines that when the brightness gradient angle specifying unit 15d determines that the calculated brightness gradient angle is within a predetermined angle range that includes the inverse vector direction of the direction vector calculated by the direction vector calculation unit 15c. Then, a correction process is performed to lower the pixel value of the arbitrary point Pn of the image data 14b to the surrounding average value. Further, if the brightness gradient angle specifying unit 15d determines that the calculated brightness gradient angle is not within a predetermined angle range that includes the direction of the inverse vector of the direction vector calculated by the direction vector calculating unit 15c, a correction process is performed. Not performed. As a result, processing marks are reduced from the image data 14b.

The flaw detection unit 15f is a processing unit that detects information regarding flaws from the image data 14b corrected by the correction processing unit 15e. For example, it is possible to output the probability of scratch occurrence using a trained model that has undergone supervised learning using deep learning, machine learning, etc., and to output a scratch score by multiplying the probability of scratch occurrence by a coefficient. Furthermore, scratches longer than a predetermined length can also be detected using template matching or line segment tracing techniques.

<Processing to identify rotation center VC _i >
Next, a process for specifying the rotation center VC _i from an arbitrary point Pn will be described. FIG. 2 is an explanatory diagram for explaining the process of specifying the rotation center VC _i from an arbitrary point Pn. Here, a state in which the image data 14b and the rotation center image data 14a are superimposed is illustrated. The object surface image 101 is an image captured by the imaging unit 20, and is obtained by overlapping the coordinates of the rotation center VC _i of the cutting tool with the locus (rotation center locus L) of the rotation center VC _i of the cutting tool. There is.

First, it is determined whether or not a rotation center VC _i exists within a range of rotation radius r±permissible error δ with an arbitrary point Pn as the center. When making such a determination, it is sufficient to set the center of the circular template to an arbitrary point Pn and specify the coordinates of the rotation center VC _i existing within the circle.

Once the coordinates of the rotation center VC _i are determined in this way, the rotation center vector CV directed from the arbitrary point Pn toward the rotation center VC _i is determined, and the vector angle θ _C between this rotation center vector CV and the X-axis is calculated. Calculate. In addition, if there are multiple rotation centers VC _i within the range of rotation radius r±tolerance δ from arbitrary point Pn, specify the coordinates of each rotation center VC _i and calculate the vector of each rotation center vector CV. Calculate the angle θ _Cn .

<Direction vector at arbitrary point Pn>
Next, calculation of the direction vector BV at the arbitrary point Pn will be explained. FIG. 3 is an explanatory diagram for explaining calculation of the direction vector BV. Here, the vector of a machining mark created at an arbitrary point Pn by the blade of a cutting tool will be expressed as a machining mark vector SV.

As shown in FIG. 3A, the machining mark vector SV at the arbitrary point Pn is orthogonal to the rotation center vector CV from the arbitrary point Pn toward the rotation center coordinates. Since the direction vector BV with respect to the machining mark vector SV is orthogonal to the machining mark vector SV, the direction vector BV is, as a result, the inverse vector of the rotation center vector CV (180 degrees phase of the vector angle θ _C of the rotation center vector CV). are different).

As shown in FIG. 3(b), when the shape of the surface around an arbitrary point Pn is schematically expressed, the arbitrary point Pn on the machining mark vector SV is at the bottom of the gouged part as a machining mark, and the area around it is It rises along the trace vector SV. In other words, if the image is a 256-level black and white gray image, and the whiter the pixel, the higher the pixel value, if the pixel value of the pixel that is a processing mark is lower, the pixel value of the arbitrary point Pn will be lower, and the rotation The pixel value becomes higher toward the center VC _i . Therefore, the direction vector BV of the arbitrary point Pn is a vector directed from the rotation center VC _i toward the arbitrary point Pn, and its direction is the opposite direction of the rotation center vector CV.

<Processing procedure of surface inspection device 10>
Next, the processing procedure of the surface inspection apparatus 10 shown in FIG. 1 will be explained. FIG. 4 is a flowchart showing the processing procedure of the surface inspection apparatus 10 shown in FIG. As shown in FIG. 4, the surface inspection apparatus 10 first obtains an object surface image 101 of the surface S of the object 100 captured by the imaging unit 20 (step S101).

Then, the surface inspection device 10 aligns this object surface image 101 with a rotation center image that is a movement trajectory image showing the coordinates of the rotation center VC _i of the cutting tool and the locus of the rotation center VC _i of the cutting tool. At the same time, preprocessing is performed to remove noise from the object surface image 101 (step S102). As this noise removal process, for example, a known smoothing filter, median filter, etc. may be applied.

After that, an arbitrary pixel on the object surface image 101 from which noise has been removed is selected (step S103). Then, the surface inspection device 10 determines, based on the object surface image 101 and the rotation center image, whether the rotation center VC _i exists within the range of rotation radius r ± tolerance δ from a predetermined pixel of the image. , if a rotation center VC _i exists, the coordinates of the rotation center VC _i are specified (step S104).

The surface inspection device 10 determines whether the coordinates of the rotation center VC _i have been specified, and if the coordinates of the rotation center VC _i have not been specified (step S105; No), selects the next pixel (step S110). ), the process moves to step S104.

On the other hand, if the coordinates of the rotation center VC _i are specified (step S105; Yes), a rotation center vector CV directed from the arbitrary point Pn to the coordinates of the rotation center VC _i is calculated (step S106). Then, the surface inspection apparatus 10 calculates the direction vector BV of the arbitrary point Pn based on the calculated rotation center vector CV (step S107).

After that, the surface inspection apparatus 10 performs a correction process on the pixel value of the selected pixel (step S108), and determines whether the processed pixel is the last pixel (step S109). If it is not the last pixel (step S109; No), the next pixel is selected (step S110), and the process moves to step S104. On the other hand, if it is the last pixel (step S109; Yes), a flaw is detected based on the image in which all pixels have been processed (step S111), and the series of processes ends. .

<Correction processing procedure>
Next, the correction process will be explained. FIG. 5 is a flowchart showing the processing procedure of the correction process shown in FIG. As shown in FIG. 5, the surface inspection apparatus 10 calculates the brightness gradient V _X of the selected pixel (arbitrary point Pn) in the X-axis direction (step S201), and also calculates the brightness gradient V X of this pixel in the Y-axis direction. _Y is calculated (step S202).

After that, the surface inspection device ₁₀ determines the ^ratio ( _{V X /} V _{Y )} of the brightness gradient V V _Y ) is calculated as the brightness gradient angle (step S203).

Then, the surface inspection apparatus 10 compares the calculated brightness gradient angle and the vector direction (vector angle) of the direction vector BV (step S204). If the calculated brightness gradient angle and the vector direction of the direction vector BV are not within the predetermined range (step S205; No), the process moves to step S109 in FIG. 4.

On the other hand, if the calculated brightness gradient angle and the vector direction of the direction vector BV are within the predetermined range (step S205; Yes), the pixel value is corrected to the surrounding average value (step S206), and as shown in FIG. The process moves to step S109. Here, the predetermined range in which the correction process is performed is, for example, ±10 degrees with respect to the angle of the direction vector BV, and the direction of the direction vector BV and the direction of its inverse vector are targeted for correction.

<Example of object surface image 101 and processed image>
Next, an example of the object surface image 101 and processed image of the surface inspection apparatus 10 shown in FIG. 1 will be described. FIG. 6 is a diagram showing an example of an object surface image 101 and a processed image of the surface inspection apparatus 10 shown in FIG. 1. As shown in FIG. 6A, an object surface image 101 captured by the imaging unit 20 is visually recognizable because it is difficult to distinguish between scratches such as unintentional dents existing on the object 100 and machining marks caused by machining. This results in an image that is difficult to capture.

On the other hand, if the object surface image 101 in FIG. 6(a) is processed by the surface inspection device 10, the brightness gradient of the machining mark will be corrected at each pixel, as shown in FIG. 6(b). As a result, a processed image with processing marks removed can be obtained. As a result, an image is obtained in which the defective parts P1, P2, P3, and P4, which are not machining marks, are clearly and easily visible.

As described above, in the first embodiment, the surface inspection apparatus 10 calculates the arbitrary point Pn of the object surface image 101 based on the object surface image 101 captured by the imaging unit 20 of the surface S of the object 100 and the rotation center image data 14a. Search to see if the rotation center VC _i exists within the range of rotation radius r±tolerance δ from , and if it exists, specify the vector direction from the arbitrary point Pn to the rotation center VC _i , Calculate the direction vector BV of Pn. Then, the brightness gradient angle caused by the machining mark SM at an arbitrary point Pn is calculated, and when the brightness gradient angle and the direction vector BV are within a predetermined range, the pixel value of the arbitrary point Pn is set to the surrounding average value. With this configuration, flaws such as dents on the machined surface can be detected while reducing the influence of the process marks.

[Embodiment 2]
By the way, in the first embodiment described above, in order to delete the machining marks SM from the object surface image 101, a case was explained in which the coordinates of the rotation center VC _i are searched from an arbitrary point Pn, but in the present embodiment 2, the coordinates of the rotation center VC i A case will be described in which an arbitrary point Pn where a machining mark SM is generated is determined from _i and the machining mark SM at the arbitrary point Pn is deleted. Note that the same parts as in Embodiment 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

<Configuration of surface inspection device 30>
Next, the configuration of the surface inspection device 30 according to the second embodiment will be explained. FIG. 7 is a functional block diagram showing the configuration of a surface inspection device 30 according to the second embodiment. As shown in FIG. 7, the surface inspection device 30 includes a display section 11, an input section 12, a storage section 14, a control section 35, and an imaging section 20.

The control unit 35 is a control unit that controls the entire surface inspection apparatus 30, and includes an image acquisition processing unit 15a, a direction vector calculation unit 15c, a brightness gradient angle identification unit 15d, a correction processing unit 15e, a flaw detection unit 15f, and an arbitrary point. It has a coordinate specifying section 35a. Actually, by loading and executing these programs on the CPU, the image acquisition processing section 15a, the direction vector calculation section 15c, the brightness gradient angle specification section 15d, the correction processing section 15e, the flaw detection section 15f, and the arbitrary point coordinates are calculated. The specifying unit 35a is caused to execute the corresponding process.

The arbitrary point coordinate specifying unit 35a is a processing unit that specifies the coordinates of an arbitrary point where a cutting tool produces a machining mark around an arbitrary rotation center VC _i of the rotation center image data 14a. That is, when the cutting tool rotates around an arbitrary rotation center VC _i of the rotation center image data 14a, machining marks should be produced at a position a predetermined distance away from the arbitrary rotation center VC _i . Therefore, the coordinates of an arbitrary point Pn located a predetermined distance away from the center of rotation VC _i are specified.

Specifically, from the rotation center VCi of the rotation center image data 14a, the coordinates of an arbitrary point Pn on the circumference of the rotation radius r±tolerance δ are specified, and an arbitrary point vector directed from the rotation center VC _i to the arbitrary point Pn is determined. Processing is performed to specify the vector angle θ _P of PV.

<Processing to identify arbitrary point Pn>
Next, a process for specifying the coordinates of an arbitrary point Pn from the center of rotation VC _i will be described. FIG. 8 is an explanatory diagram illustrating the process of specifying the coordinates of an arbitrary point Pn from the center of rotation VC _i . Here, a state in which the image data 14b and the rotation center image data 14a are superimposed is illustrated. The object surface image 101 is an image captured by the imaging unit 20, in which the coordinates of the rotation center VC _i of the cutting tool and the locus of the rotation center VC _i of the cutting tool overlap.

As shown in FIG. 8, the coordinates of an arbitrary point Pn on the circumference within a range of rotation radius r±permissible error δ from a predetermined rotation center VC _i on the image are specified.

Once the coordinates of the arbitrary point Pn are specified in this way, the arbitrary point vector PV directed from the rotation center VC _i to the arbitrary point Pn is determined, and the vector angle θ _P between this arbitrary point vector PV and the X-axis is calculated. do.

<Calculation of direction vector BV>
Next, calculation of the direction vector BV at the arbitrary point Pn will be explained. FIG. 9 is an explanatory diagram for explaining calculation of the direction vector BV. As shown in FIG. 9, the machining mark vector SV at the arbitrary point Pn is orthogonal to the arbitrary point vector PV directed from the rotation center VC _i to the coordinates of the arbitrary point Pn. Since the direction vector BV with respect to the machining mark vector SV is orthogonal to the machining mark vector SV, the direction vector BV becomes the same direction vector as the arbitrary point vector PV.

<Processing procedure of surface inspection device 30>
Next, the processing procedure of the surface inspection device 30 will be explained. FIG. 10 is a flowchart showing the processing procedure of the surface inspection apparatus 30 shown in FIG. As shown in FIG. 10, the surface inspection device 30 first obtains an object surface image 101 of the surface S of the object 100 captured by the imaging unit 20 (step S301).

Then, the surface inspection device 30 aligns this object surface image 101 with a rotation center image showing the coordinates of the rotation center VC _i of the cutting tool and the locus of the rotation center VC _i of the cutting tool, and Preprocessing is performed to remove noise from the surface image 101 (step S302). As this noise removal process, for example, a known smoothing filter, median filter, etc. may be applied.

Thereafter, the surface inspection device 30 selects the coordinates of an arbitrary rotation center VC _i on the screen from which noise has been removed (step S303). Then, the coordinates of an arbitrary point Pn to be processed on the circumference of the rotation radius r±permissible error δ are specified from the rotation center coordinates (step S304).

Then, the surface inspection device 30 calculates an arbitrary point vector PV from the rotation center VC _i to the coordinates of the arbitrary point Pn (step S305), and then calculates a direction vector BV based on the arbitrary point vector PV (step S305). S306), and correction processing is performed (step S307). The surface inspection device 30 determines whether the processed arbitrary point Pn is the last arbitrary point, and if it is not the last arbitrary point (step S308; No), then selects the arbitrary point (step S309), the process moves to step S304.

On the other hand, if the processed arbitrary point Pn is the last arbitrary point (step S308; Yes), it is determined whether the processed rotation center VC _i is the last rotation center VC _i . (Step S310). If the processed rotation center VC _i is not the last rotation center VC _i (step S310; No), the next rotation center VC _i is selected (step S311), and the process moves to step S303.

On the other hand, if the processed rotation center VC _i is the last rotation center VC _i (step S310; Yes), a flaw is detected (step S312) and the series of processes ends. Note that the correction process (step S307) in FIG. 10 is the same as the correction process (step S108) in FIG. 4 of the first embodiment, so a description thereof will be omitted.

As described above, in the second embodiment, the surface inspection device 30 detects an arbitrary value within the range of the rotation radius r±permissible error δ from the rotation center VC _i based on the object surface image 101 captured by the imaging unit 20 of the object 100. The coordinates of point Pn are specified, the vector direction from rotation center VC _i to arbitrary point Pn is calculated, and the direction vector BV of arbitrary point Pn is specified. Then, the brightness gradient angle caused by the machining mark SM at an arbitrary point Pn is calculated, and if the brightness gradient angle is within a predetermined range of the vector angle of the direction vector BV, the pixel value of the arbitrary point Pn is set to the surrounding average value. With this structure, it is possible to detect flaws such as dents on the machined surface while reducing the influence of the process marks.

In the first and second embodiments described above, the movement trajectory of the rotation center of the cutting tool is a movement trajectory image in which a predetermined pixel value is assigned to the pixels forming the movement trajectory of the rotation center of the cutting tool. Although a case has been described in which rotation center image data is used, the present invention is not limited to this, and processed data including a locus of the rotation center may be used. Alternatively, it may be coordinate data indicating a locus of the center of rotation. Further, the movement trajectory image in which predetermined pixel values are assigned to pixels forming the movement trajectory of the rotation center of the cutting tool may be an image in a bitmap format or a vector format.

Note that in the first and second embodiments described above, a case has been described in which the brightness gradient angle of an arbitrary point Pn is determined and correction is performed, but a line concentration filter may also be used. Furthermore, in the first and second embodiments described above, a case has been described in which a face milling cutter is used as the cutting tool, but the present invention is not limited to this, and an abrasive brush may be used as the cutting tool.

The configurations illustrated in each of the above embodiments are functionally schematic and do not necessarily have to be physically configured as illustrated. In other words, the form of dispersion/integration of each device is not limited to the one shown in the diagram, but all or part of it can be functionally or physically distributed/integrated in arbitrary units depending on various loads and usage conditions. Can be configured.

The surface inspection device and surface inspection method according to the present invention are suitable for detecting flaws such as dents on the machined surface while reducing the influence of machining marks generated on the machined surface when flattening by milling. ing.

10 Surface inspection device 11 Display section 12 Input section 14 Storage section 14a Rotation center image data 14b Image data 15 Control section 15a Image acquisition processing section 15b Rotation center coordinate specifying section 15c Direction vector calculation section 15d Correction processing section 15e Flaw detection section 20 Imaging Section 30 Surface inspection device 35 Control section 35a Arbitrary point coordinate specifying section 100 Object 101 Object surface image BV Direction vector CV Rotation center vector L Rotation center locus Pn Arbitrary point PV Arbitrary point vector P1, P2, P3, P4 Defect surface r Rotation radius S Surface SM Machining mark SV Machining mark vector VC _i Rotation center δ Tolerance θ _C Rotation center vector angle θ _P Arbitrary point vector angle

Claims (9)

A surface inspection method in a surface inspection device that inspects the surface of a predetermined object using an object surface image captured by an imaging unit that images the surface of a cut object while rotating a cutting tool attached to a predetermined rotating shaft. And,
a first specifying step of specifying a second pixel on a movement trajectory of the rotation center of the cutting tool that affects an arbitrary first pixel forming the object surface image;
A second step of identifying a brightness gradient of a direction vector toward a second pixel on the movement locus of the rotation center of the cutting tool among the plurality of brightness gradients at the first pixel identified in the first identifying step; a specific process,
A surface inspection method comprising: a correction step of correcting a pixel value of each pixel forming the object surface image based on the gradient angle specified in the second specifying step. Claim further comprising: an inspection step of inspecting flaws caused by other than the machining marks formed on the surface of the object based on a corrected image in which the object surface image is corrected in the correction step. 1. The surface inspection method described in 1. The cutting tool is
A claim characterized in that the blade is a face milling cutter or an abrasive brush for polishing the surface of an object, in which a plurality of blades are attached to the circumference of a predetermined rotating body, and is formed to be rotatable about the predetermined rotation axis. 1. The surface inspection method described in 1. The first specifying step is
The cutting tool influences the first pixels forming the object surface image using a movement trajectory image in which a predetermined pixel value is assigned to the pixels forming the movement trajectory of the rotation center of the cutting tool. 2. The surface inspection method according to claim 1, further comprising specifying the second pixel on a movement locus of a rotation center. The correction step includes:
5. The surface inspection method according to claim 4, further comprising correcting a pixel value of a first pixel on the object surface image that forms a gradient angle of the brightness gradient specified in the second specifying step. The correction step includes:
6. The surface inspection method according to claim 5, further comprising lowering a pixel value of a first pixel on the object surface image that forms a gradient angle of the brightness gradient specified in the second specifying step. A surface inspection method in a surface inspection device that inspects the surface of a predetermined object using an object surface image captured by an imaging unit that images the surface of a cut object while rotating a cutting tool attached to a predetermined rotating shaft. And,
a first specifying step of specifying a first pixel affected by a second pixel on the movement trajectory of the rotation center of the cutting tool;
Among the plurality of brightness gradients in the first pixel identified in the first identifying step, the brightness of the direction vector from the second pixel on the movement trajectory of the rotation center of the cutting tool to the first pixel. a second identifying step of identifying the slope;
A surface inspection method comprising: a correction step of correcting a pixel value of each pixel forming the object surface image based on the gradient angle specified in the second specifying step. A surface inspection device that inspects the surface of a predetermined object using an object surface image captured by an imaging unit that images the surface of a cut object while rotating a cutting tool attached to a predetermined rotation axis,
first specifying means for specifying a second pixel on the movement trajectory of the rotation center of the cutting tool that affects any first pixel forming the object surface image;
A second method for specifying a brightness gradient of a direction vector toward a second pixel on the movement locus of the rotation center of the cutting tool among the plurality of brightness gradients at the first pixel identified by the first identifying means; specific means,
A surface inspection apparatus comprising: a correction means for correcting a pixel value of each pixel forming the object surface image based on the gradient angle specified by the second specifying means. A surface inspection device that inspects the surface of a predetermined object using an object surface image captured by an imaging unit that images the surface of a cut object while rotating a cutting tool attached to a predetermined rotation axis,
a first specifying means for specifying a first pixel affected by a second pixel on the movement trajectory of the rotation center of the cutting tool;
Among the plurality of brightness gradients in the first pixel specified by the first specifying means, the brightness of a direction vector from a second pixel on the movement trajectory of the rotation center of the cutting tool to the first pixel. a second identifying means for identifying the slope;
A surface inspection apparatus comprising: a correction means for correcting a pixel value of each pixel forming the object surface image based on the gradient angle specified by the second specifying means.

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