JP5202437B2 - Surface inspection device - Google Patents

Description

  The present invention relates to a surface inspection apparatus that inspects a surface of a workpiece that has been machined.

In an automobile manufacturing process, a bore is cut in a cylinder block of an engine, and then a cylinder head, a crankcase, and the like are assembled to the cylinder block. In boring, the bore is formed by moving the boring tool back and forth with respect to the cylinder block, forming a bore on the inner surface of the bore, which is used as an engine oil passage (oil pit). ing.
In addition, since the inner surface of the bore becomes the sliding surface of the piston, it is necessary to maintain the sliding surface with an appropriate surface roughness and surface properties in order to suppress the sliding resistance and to exert the desired performance on the engine. is there. Therefore, after the boring process, a honing process is performed to polish and finish the inner surface of the bore so that oil pits remain. Then, after the honing process, in order to inspect the polishing residue that causes the sliding resistance, an inspection of the smooth state of the inner surface of the bore is performed.

As this inspection technique, for example, a two-dimensional Fourier transform is performed on a digital image obtained by photographing the inner surface of the bore to generate a two-dimensional power spectrum image, and based on each pixel value of the two-dimensional power spectrum image. A technique for evaluating the smooth state of the inner surface of the bore is known (for example, see Patent Document 1).
Japanese Patent Publication No. 2004-132900

However, in the inspection using the power spectrum image, although it is possible to determine the overall roughness of the inner surface of the bore, there is no spatial information in the power spectrum image. It is not possible to know the range or size of the polishing residue. Therefore, in order to specify the remaining polishing location, the operator visually looks at the digital image obtained by photographing the bore to find a location that is estimated to be polished or the operator directly observes the bore. Is required. Then, after the operator visually confirms the portion estimated to be the polishing residue, the final judgment is made as to whether it is an oil pit or the polishing residue in consideration of its size and shape. The Rukoto.
In other words, since the two-dimensional power spectrum image analysis comprehensively analyzes frequency components for 360 degrees in all directions as a plane, information on a target direction, position information on a line segment in the target direction, etc. Is missing. That is, although it is suitable for integrated evaluation of the smooth state of the entire surface, it is impossible to obtain position information and size information such as specific polishing residue and cutting traces. Since 360 degrees in all directions are analyzed, the amount of information to be processed is large and the processing takes time.

Thus, in the prior art, only the degree of the overall roughness of the inner surface of the bore can be known, and the range and size of the remaining polishing is not known. There is a problem that it is necessary to find and judge by visual inspection, and it takes time for inspection.
The present invention has been made in view of the above-described circumstances, and can detect the presence or absence of deep machining traces on the surface of a workpiece that has been machined, and can estimate the position and size thereof. An object of the present invention is to provide a surface inspection apparatus capable of shortening the inspection time.

  In order to achieve the above object, the present invention provides a surface inspection apparatus for inspecting a surface based on a digital image of a machined surface of a workpiece, and orthogonal to the direction of machining based on the digital image. Based on the pixel value of each pixel of the evaluation image generating means for generating the evaluation image by generating a one-dimensional power spectrum image in the direction along the machining direction and arranging them in parallel And an evaluation means for evaluating the surface.

According to the present invention, by generating a one-dimensional power spectrum image in which the direction orthogonal to the machining direction is a one-dimensional direction, an image in which pixel values corresponding to the difference in brightness of the reflected light of the machining trace appears. Is obtained as a one-dimensional power spectrum image at a location corresponding to the pitch of the machining trace. When this difference in brightness is large, cutting traces are often deep. Then, by arranging the one-dimensional power spectrum images in parallel, an image in which the parallel direction coincides with the machining direction is obtained as an evaluation image.
The pixel value represents the intensity of the signal of the luminance image, that is, the intensity of the amplitude of the luminance change of the reflected light. In other words, the pixel value represents the magnitude of the difference between the luminance brightness and the darkness. It is a representation.
Therefore, based on the pixel value of the evaluation image, it is possible to easily detect the presence or absence of not only deep machining traces but also shallow machining traces generated periodically. Moreover, it becomes easy to specify the position of the machining trace. Furthermore, the size (extending length) of the machining trace can be estimated based on the spread of the pixel value indicating the machining trace in the parallel direction. Thereby, the operator can detect the presence or absence of deep machining traces or shallow machining traces without visual observation, and can estimate the location and size. Further, even when the worker actually confirms visually, the inspection time can be shortened because the portion of the machining trace can be narrowed down.

  In order to achieve the above object, the present invention provides a surface inspection apparatus for inspecting an inner surface of a bore formed on a cylinder block by cutting, and based on the digital image. An evaluation image generating means for generating a one-dimensional power spectrum image in a direction orthogonal to the cutting direction along the cutting direction and generating an evaluation image by arranging them in parallel; and the evaluation image Evaluation means for evaluating the polishing residue on the inner surface of the bore based on the pixel value of each pixel.

According to the present invention, by generating a one-dimensional power spectrum image in which the direction orthogonal to the cutting direction is a one-dimensional direction, the position corresponding to the pitch of the cutting process corresponds to the depth of the cutting mark. An image in which pixel values appear is obtained as a one-dimensional power spectrum image. For this reason, it is possible to efficiently extract only the frequency component of the cutting trace necessary for evaluation of the polishing residue. Further, by arranging the one-dimensional power spectrum images in parallel, an image in which the parallel direction matches the cutting direction can be obtained as an evaluation image.
Therefore, it is possible to efficiently evaluate only the polishing residue of the cutting trace based on the pixel value of the evaluation image, and it becomes easy to specify the position of the polishing residue. Furthermore, the size (length extending) of the polishing residue can be estimated based on the spread of the pixel values indicating the polishing residue in the parallel direction. As a result, the operator can detect the polishing residue and visually estimate the location and size without visual inspection. Even when the operator actually confirms visually, the remaining portion of the polishing can be narrowed down, so that the inspection time can be shortened.

  In order to achieve the above object, the present invention provides a surface inspection apparatus for inspecting a surface based on a digital image of a surface on which a workpiece is machined, and a one-dimensional power spectrum image based on the digital image. In addition to generating images sequentially generated along a predetermined direction and arranged in parallel, the predetermined direction is rotated by a predetermined angle with respect to the digital image, and the image is generated at each rotation angle. Evaluation image generation means for selecting an image containing the largest amount of spectrum signals as an evaluation image; and evaluation means for evaluating the surface based on the pixel value of each pixel of the evaluation image selected by the evaluation image generation means; It is characterized by providing.

According to the present invention, images in which one-dimensional power spectrum images are sequentially generated along a predetermined direction and arranged in parallel are respectively generated by rotating the predetermined direction by a predetermined angle with respect to the digital image. In order to select the image containing the most spectrum signal from the image for evaluation as the evaluation image, it is possible to select an image composed of a one-dimensional power spectrum image orthogonal to the machining direction as the evaluation image without acquiring the machining direction. It is also possible to specify the machining direction.
Furthermore, the presence or absence of deep machining traces or shallow machining traces can be detected based on the pixel values of the evaluation image, and the positions of these machining traces can be easily identified. Furthermore, based on the spread in the parallel direction of the pixel values indicating these processing marks, the size (extending length) of the processing marks can be estimated. Thereby, the operator can detect the presence or absence of deep machining traces or shallow machining traces without visual observation, and can estimate the location and size. Even when the operator actually confirms visually, the inspection time can be shortened because the portion of the machining trace can be narrowed down.

  Here, in the above-described invention, the pixel for which the pixel value exceeds a predetermined pixel value may be color-coded together with each pixel of the one-dimensional power spectrum image that includes the pixel. By doing so, the range in which deep machining traces or shallow machining traces are present becomes clear.

According to the present invention, an image in which a pixel value corresponding to the depth of the machining trace appears at a position corresponding to the pitch of the machining trace is obtained as a one-dimensional power spectrum image, and the one-dimensional power spectrum image is parallelized. By arranging them in order, an image for evaluation in which the parallel direction coincides with the machining direction can be obtained. Therefore, it is possible to detect the presence or absence of deep machining marks or shallow machining marks based on the evaluation image, and further to estimate the position and size, thereby shortening the inspection time.
Further, when inspecting the inner surface of the bore of the cylinder block, the polishing residue of the cutting trace can be determined efficiently, and the position and size thereof can be estimated.
Further, an image in which a one-dimensional power spectrum image is sequentially generated along a predetermined direction and arranged in parallel is generated by rotating the predetermined direction by a predetermined angle with respect to the digital image, and a spectrum signal is generated from each image. By selecting the image containing the most as the evaluation image, it is possible to select an image composed of a one-dimensional power spectrum image orthogonal to the machining direction as the evaluation image without acquiring the machining direction. it can.
In addition, deep machining traces or shallow machining traces are present by color-coding pixels whose pixel values exceed a predetermined pixel value together with the pixels of the one-dimensional power spectrum image including the pixels. The range to do can be clarified.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a bore inner surface inspection system 1 according to an embodiment of the present invention and a cylinder block 5 in which a bore 3 to be inspected is formed.
The bore 3 is formed by a so-called boring process in which a cutting tool is provided in a radial direction on a boring head provided on a rotating shaft, and the boring head is advanced and retracted with respect to the cylinder block 5 as a workpiece while rotating. By this boring, a spiral cutting trace having directionality is formed on the inner surface 3A of the bore 3. After that, honing is performed using a machining head provided with a honing grindstone so as to obtain surface roughness and surface properties capable of exhibiting desired engine performance while leaving an oil pit on the inner surface 3A of the bore 3. Processing has been applied.

The bore inner surface inspection system 1 evaluates the presence or absence of a polishing residue based on a digital image obtained by photographing the inner surface 3A of the bore 3. That is, the bore inner surface inspection system 1 generates a digital image based on the sensor head 7 that scans the inner surface 3A of the bore 3, and an output signal of the sensor head 7, and evaluates a polishing residue based on the digital image. An inspection device 9 and a drive mechanism 11 for moving and driving the sensor head 7 are provided.
The sensor head 7 is formed in a cylindrical shape that can enter the bore 3, and is attached to the drive mechanism 11 so as to be rotatable around the central axis 12 and movable in the direction of the central axis 12. The sensor head 7 irradiates laser light toward the inner surface 3 </ b> A of the bore 3 from the opening 15 provided on the peripheral surface, detects the amount of reflected light according to the shape of the cutting trace, and outputs it to the surface inspection device 9.
Specifically, the sensor head 7 includes an LD (laser diode) 17 as a light source, an optical fiber 19, and a condensing optical unit 21, and guides the light from the LED 17 to the condensing optical unit 21 through the optical fiber 19. The light is condensed by the optical unit 21 and emitted from the opening 15. The sensor head 7 includes a light receiving sensor 23 that receives the reflected light, and a plurality of optical fibers 25 that guide the reflected light returning through the condensing optical unit 21 to the light receiving sensor 23 are adjacent to the optical fiber 19. Arranged.

The drive mechanism 11 includes a rotation drive mechanism 31 that rotates the sensor head 7 and an advance / retreat mechanism 33 that advances and retracts the rotation drive mechanism 31.
The rotation drive mechanism 31 includes a housing 34, a shaft 35 provided with the sensor head 7 at the tip and penetrating the housing 34 vertically, and a shaft that rotates the shaft 35 under the control of the surface inspection apparatus 9. A motor 37 and a rotary encoder 39 that detects the rotation speed and rotation angle of the shaft 35 and outputs the detected rotation speed to the surface inspection device 9 are provided.
The advancing / retreating mechanism 33 is a feed screw mechanism, and detects a shaft portion 41 in which a screw is engraved, an advancing / retreating motor 43 that rotationally drives the shaft portion 41, and a rotation speed and a rotation angle of the shaft portion 41 to detect a surface. 9 and a rotary encoder 45 that outputs to N. The shaft portion 41 is screwed into the nut portion 36 of the housing 34, and the shaft portion 41 is rotated by driving the advance / retreat motor 43, so that the rotation drive mechanism 31 is advanced and retracted.

  The surface inspection apparatus 9 controls the drive mechanism 11 to control the position of the sensor head 7 and an imaging that generates a digital image of the inner surface 3A of the bore 3 based on the light reception signal of the sensor head 7. A unit 53; an evaluation image generation unit 55 that generates an evaluation image for evaluating the polishing residue based on the digital image; and an evaluation unit 57 that evaluates the polishing residue based on the evaluation image. . The surface inspection apparatus 9 can be configured by causing a personal computer to execute a program for realizing each unit, for example.

  The parts of the surface inspection apparatus 9 will be described in more detail. The position control unit 51 includes a servo mechanism that drives the shaft motor 37 and the advance / retreat motor 43, and controls the position and rotation angle of the sensor head 7 on the central axis 12. To do. That is, the position control unit 51 inserts the sensor head 7 into the bore 3 at the start of inspection and positions the opening 15 at the lower end position Ka of the inspection range K. Then, the opening 15 of the sensor head 7 reaches the upper end position Kb of the inspection range K in such a manner that the sensor head 7 is raised while rotating around the central axis 12 so as to follow the trajectory of the boring tool during boring. The sensor head 7 scans the entire surface of the inspection range K in a spiral shape. This inspection range K is determined by a range that functions as a sliding surface with the cylinder.

The imaging unit 53 A / D-converts the light reception signal from the sensor head 7 and outputs it as a digital signal indicating luminance, and the inner surface 3A of the bore 3 based on this digital signal. And an imaging unit 61 that constitutes a digital luminance image 70 for the inspection range K.
As shown in FIG. 2A, the digital luminance image 70 is obtained by imaging the reflected light intensity obtained by the sensor head 7 at each inspection position in the bore 3 in correspondence with the inspection position. In the embodiment, the height position of the sensor head 7 and the rotation angle of the sensor head 7 are imaged with the vertical axis and the horizontal axis, respectively. In addition, the broken line in the digital luminance image 70 in the figure schematically shows the cutting trace P at the time of boring.

As shown in FIG. 2, the evaluation image generation unit 55 generates a one-dimensional power spectrum image 71 in a direction orthogonal to the direction of the cutting trace P along the direction of the cutting trace P based on the digital luminance image 70. And a one-dimensional parallel power spectrum processing unit (evaluation image generation means) 63 that generates the evaluation image 73 by arranging them in parallel. The one-dimensional power spectrum image 71 and the evaluation image 73 will be described in detail later.
The evaluation unit 57 evaluates the polishing residue of the inner surface 3 </ b> A of the bore 3 based on the luminance value of each pixel of the evaluation image 73.

FIG. 3 is a diagram illustrating a generation process of the one-dimensional power spectrum image 71 by the evaluation image generation unit 55.
The evaluation image generation unit 55 is an extraction window having a width W of 1 pixel and a height L of several pixels (for example, 200 pixels) as a window for defining a region to be subjected to one-dimensional power spectrum processing in the digital luminance image 70. (Column) 75 is preset. The height direction of the extraction window 75 is a unified direction of the one-dimensional power spectrum.
2A, the evaluation image generation unit 55 arranges the extraction window 75 in the digital luminance image 70 so that the height direction is orthogonal to the direction of the cutting mark P. ), A digital luminance image in a range corresponding to the extraction window 75, that is, a one-dimensional digital luminance image 70A having a width W of one pixel is extracted. In FIG. 3A, a cutting mark P that is not sufficiently polished by the honing process is schematically shown as a polishing residue Q.

Next, the evaluation image generation unit 55 performs a one-dimensional Fourier transform on the one-dimensional digital luminance image 70A to generate a one-dimensional power spectrum as shown in FIG. In this one-dimensional power spectrum, a signal indicating the cutting trace P appears as a frequency component corresponding to the pitch of the cutting trace P.
More specifically, as shown in FIG. 4A, in the one-dimensional digital luminance image 70A, when black and white changes for each pixel, the luminance value of each pixel is as shown in FIG. When this is represented by a change in luminance in a one-dimensional direction, a waveform as shown in FIG. 4C is obtained. On the other hand, when represented by a power spectrum, black and white are interchanged every two pixels, so that a signal of a frequency component corresponding to 2 pixels / cycle appears as shown in FIG. That is, in the boring process, the cutting trace P has a spiral shape with a substantially constant pitch, and therefore, in the one-dimensional power spectrum, the cutting trace P appears as a signal of a frequency component corresponding to the helical pitch. At this time, the intensity of the signal increases as the difference in brightness of the reflected light that is irradiated to the cutting mark P and reflected is larger. Usually, when the cutting mark P is deep, the difference in brightness between reflected light often increases, that is, the signal intensity increases. In addition, when the inner surface 3A of the bore 3 has irregularities due to dents or the like in addition to the cutting trace P, a signal having an intensity corresponding to the brightness of the irregularities appears as another frequency component.

  Returning to FIG. 3, the evaluation image generation unit 55 excludes the cutting trace P having a depth corresponding to the oil pit and extracts only the cutting trace P having a depth that can be regarded as the polishing residue Q. Since the cutting trace P is spiral with a substantially constant pitch, the cutting trace P appears as a signal of a frequency component corresponding to the helical pitch. Therefore, as shown in FIG. Frequency components other than the frequency component corresponding to the pitch of P are attenuated to the intensity Th or less. At this time, in order to reliably detect only the polishing residue Q, a process of amplifying only the frequency component corresponding to the pitch of the cutting trace P is performed, and after adding a difference from other frequency components, the strength is predetermined. Only frequency components exceeding the threshold may be extracted. Then, as shown in FIG. 3D, a one-dimensional power spectrum image 71 is generated in a multi-valued manner according to a legend in which the luminance value is lowered as the signal intensity increases. In contrast to the legend, the power spectrum image 71 may be generated by increasing the luminance value as the signal intensity increases.

  As shown in FIG. 2A, the evaluation image generation unit 55 moves the extraction window 75 in the height direction L along the direction A of the cutting trace P by moving the rotation angle from 0 degrees to 360 degrees. A one-dimensional power spectrum image 71 is sequentially generated, and as shown in FIG. 2B, these are arranged in parallel along the cutting direction to generate an evaluation image 73. As a result, an image in which one-dimensional power spectra are arranged in parallel corresponding to the rotation angle of the sensor head 7 is obtained.

Based on the evaluation image 73 obtained in this way, the evaluation unit 57 evaluates the polishing residue Q. More specifically, as shown in FIG. 2 (C), the evaluation unit 57 excludes the oil pit and leaves only the strength corresponding to the polishing residue Q more reliably. A binarized image 78 is generated by performing binarization processing with the luminance threshold.
Then, as shown in FIG. 2D, the evaluation unit 57 extracts each pixel remaining in the binarization process from the extraction window 75 (that is, the one-dimensional power including the pixel). By applying a spectral image 71), an unpolished extracted image 79 is generated in which the area corresponding to the extraction window 75 is color-coded by coloring. As a result, in the unpolished extraction image 79, the range R in which the unpolished residue Q exists is clearly indicated by color.

FIG. 5 is a flowchart of the bore inner surface inspection process by the bore inner surface inspection system 1.
After the cylinder block 5 in which the bore 3 to be inspected is formed is set at a predetermined position directly below the drive mechanism 11, the position control unit 51 causes the sensor head 7 to enter the bore 3 and advance and retract while rotating the bore 3. The inner surface 3A is scanned over the inspection range K, and the digital luminance image 70 of the inspection range K is generated by the imaging unit 53 based on the signal obtained by this scanning (step S1). Next, the one-dimensional power spectrum processing unit 63 of the evaluation image generating unit 55 sets an extraction window 75 extending in a direction orthogonal to the cutting mark P in the digital luminance image 70, and sets 1 from the range of the extraction window 75. A dimensional digital luminance image 70A is extracted (step S2). Then, the one-dimensional power spectrum processing unit 63 generates a one-dimensional power spectrum image 71 from the one-dimensional digital luminance image 70A (step S3). Until the one-dimensional power spectrum image 71 is generated for all of the inspection range K (Step S4 is No), the extraction window 75 is moved along the cutting mark P in the digital luminance image 70 (Step S5). The generation of the one-dimensional power spectrum image 71 is repeated. Next, the one-dimensional power spectrum processing unit 63 arranges these one-dimensional power spectrum images 71 in parallel to generate an evaluation image 73 (step S6).

  Next, the evaluation unit 57 generates a binarized image 78 by binarizing the evaluation image 73 with a predetermined luminance threshold in order to leave only the intensity corresponding to the polishing remaining Q (step S7). A range corresponding to the extraction window 75 from which the remaining pixels are extracted (that is, all pixels of the one-dimensional power spectrum image 71 including the remaining pixels) is color-coded by coloring to generate a polishing residual extraction image 79 (step S8). ). Next, the evaluation unit 57 evaluates that there is no polishing residue on the inner surface 3A of the bore 3 when there is no coloring range in the polishing residual extraction image 79 generated in this way (step S9: NO). (Step S10) When there is a coloring range (Step S9: YES), it is evaluated that there is a polishing residue (Step S11).

  When there is a polishing residue, the polishing residue extraction image 79 is displayed on a monitor device (not shown) and presented to the operator. According to this polishing residue extraction image 79, the size of the polishing residue Q can be estimated from the width of the colored range. Further, it is possible to easily estimate the position where the polishing residue Q exists from the position of the coloring range, and it becomes easy to find the polishing residue Q when actually checking visually.

Thus, according to the present embodiment, the one-dimensional power spectrum image 71 is generated in which the direction orthogonal to the direction of the cutting trace P is a one-dimensional direction. Thereby, in the one-dimensional power spectrum, a signal corresponding to the depth of the cutting mark P is obtained as a frequency component corresponding to the pitch of the cutting mark P. A one-dimensional power spectrum image 71 can be generated by efficiently extracting only the cutting trace P in distinction from the unevenness.
Further, by arranging the one-dimensional power spectrum images 71 in parallel, an image in which the parallel direction corresponds to the direction of the cutting mark P is obtained as the evaluation image 73.
Thereby, based on the pixel value of the evaluation image 73, only the presence or absence of the polishing residue Q of the cutting trace P can be efficiently evaluated, and the range R where the polishing residue Q exists can be specified. . Further, the size (extended length) of the polishing residue Q can be estimated based on the spread of the range R in the parallel direction.
Therefore, the operator can estimate the presence / absence, the location and size of the polishing residue Q without visual observation, and the quality of the bore 3 can be easily determined. Even when the operator actually confirms visually, the inspection remaining time Q can be narrowed down, so that the inspection time can be shortened.

  Further, according to the present embodiment, with respect to the polishing residual extraction image 79 obtained by binarizing the evaluation image 73, the pixels remaining by binarization are each pixel of the one-dimensional power spectrum image 71 including the pixels. In addition, it was configured to be color-coded. By doing so, the range R in which the polishing residue Q exists is clarified, and it becomes easier for the operator to find the portion of the polishing residue Q when actually observing.

In addition, embodiment mentioned above shows the one aspect | mode of this invention to the last, and can change arbitrarily within the scope of the present invention.
For example, in the embodiment, the apparatus for inspecting the inner surface 3 </ b> A of the bore 3 is illustrated, but the present invention is not limited to the apparatus for inspecting the machined surface of the hole like the bore 3. That is, as shown in FIG. 6, the present invention can also be applied to an apparatus for inspecting a machined surface obtained by cutting a plane surface of a workpiece 90 in the same direction at a substantially equal pitch. In this case, since the machined surface is a flat surface, a digital luminance image 70 of the machined surface can be obtained by photographing the entire image with the camera 91 at a time.

Even if the machining direction (direction of the cutting mark P) is not known in advance, as shown in FIGS. 7A to 7C, each time the digital luminance image 70 on the machined surface is rotated, A one-dimensional power spectrum image 71 is sequentially generated along a direction B orthogonal to the one-dimensional direction (height direction) of the one-dimensional power spectrum, and arranged in parallel to generate an evaluation image 73. Thereby, when the digital luminance image 70 is rotated so that the one-dimensional direction (height direction) of the one-dimensional power spectrum is orthogonal to the direction of the cutting mark P, the evaluation image 73 in which the strongest spectrum signal appears most. Thus, the machining direction can be specified by specifying the evaluation image 73.
Then, as shown in FIG. 6, the surface inspection device 109 of the surface inspection system 100 is configured by including the processing direction determination unit 92 that determines the machining direction in this way, so that the direction of the cutting mark P is determined in advance. The surface inspection device 109 that can evaluate the machined surface of the workpiece 90 that is not known can be configured.

It is a figure which shows schematic structure of the cylinder block in which the bore | bore inner surface inspection system which concerns on one Embodiment of this invention, and the bore | bore used as test object were formed. It is the figure which showed the image produced | generated by the hole inner surface inspection along the flow of inspection. It is a figure which shows the production | generation process of the one-dimensional power spectrum image by the image production | generation part for evaluation. It is a figure which shows the relationship between a one-dimensional digital luminance image and a one-dimensional power spectrum. It is a flowchart of a bore | bore inner surface inspection process. It is a figure which shows schematic structure of the surface inspection system 100 which concerns on the modification of this invention with the workpiece | work of inspection object. It is a figure for demonstrating the determination of a process direction.

DESCRIPTION OF SYMBOLS 1 Bore inner surface inspection system 3 Bore 3A Inner surface 5 Cylinder block 7 Sensor head 9, 109 Surface inspection apparatus 51 Position control part 55 Evaluation image generation part 57 Evaluation part 63 One-dimensional power spectrum processing part 70 Digital luminance image 70A One-dimensional digital Luminance image 71 One-dimensional power spectrum image 73 Evaluation image 75 Extraction window 78 Binary image 79 Unpolished extraction image 90 Work 91 Camera 92 Machining direction determination unit 100 Surface inspection system P Cutting mark Q Unpolished

Claims (4)

In a surface inspection apparatus for inspecting a surface based on a digital image of a surface subjected to machining of a workpiece,
Evaluation image generating means for generating a one-dimensional power spectrum image in a direction orthogonal to the machining direction based on the digital image along the machining direction and generating an evaluation image by arranging them in parallel ,
Evaluation means for evaluating the surface based on a pixel value of each pixel of the evaluation image;
A surface inspection apparatus comprising: In a surface inspection apparatus for inspecting the inner surface based on a digital image of the inner surface of a bore formed and polished in a cylinder block,
An image generation unit for evaluation that generates a one-dimensional power spectrum image in a direction orthogonal to the direction of cutting based on the digital image along the direction of cutting, and generates an evaluation image by arranging them in parallel.
Evaluation means for evaluating the polishing residue of the inner surface of the bore based on the pixel value of each pixel of the evaluation image;
A surface inspection apparatus comprising: In a surface inspection apparatus for inspecting a surface based on a digital image of a surface subjected to machining of a workpiece,
Based on the digital image, a one-dimensional power spectrum image is sequentially generated along a predetermined direction to generate an image arranged in parallel, and the predetermined direction is rotated by a predetermined angle with respect to the digital image. And generating the image, and an evaluation image generating means for selecting an image containing the most spectrum signal from each image as an evaluation image;
Evaluation means for evaluating the surface based on the pixel value of each pixel of the evaluation image selected by the evaluation image generation means;
A surface inspection apparatus comprising:   The pixel for which the pixel value exceeds a predetermined pixel value with respect to the image for evaluation is color-coded together with each pixel of the one-dimensional power spectrum image that includes the pixel. The surface inspection apparatus described in 1.

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