JP2005010038A - Visual examination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technological means for setting the vicinity of the end part in the axial center direction of the image of the developed outer peripheral surface of an object to be inspected as a non-inspection target, even if the inclinations and linearities of the end parts in the axial center direction of the image are not necessarily constant. <P>SOLUTION: This visual examination device 1 is constituted so as to inspect the appearance of a columnar object W to be inspected and to be fed, while the object is rotated about the axis of a feed direction A and equipped with an imaging part 2 for imaging the outer peripheral surface of the object W, while being rotated to obtain the image of the developed outer peripheral surface becoming the inclined end part, wherein both end parts 25 and 25 in the axial center direction of the outer peripheral surface of the object W have an inclination and a processing part 4 for scanning the range of the developed outer peripheral surface 20 in the image obtained by the imaging part 2 to perform visual examination processing. In the processing part 4, a predetermined width D, as viewed in the axial center direction X from the position of the inclined end part 25, is set as a non-inspection target, on the basis of the inclined end part 25 of the developed outer peripheral surface 20 to inspect the inside of the developed outer peripheral surface 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an appearance inspection apparatus for a cylindrical inspection object.
[0002]
[Prior art]
The columnar inspection object appearance inspection device is to inspect the outer periphery with a camera while rotating the inspection object at a predetermined position, process the imaged image, and inspect the inspection object for flaws, For example, there is one described in Patent Document 1.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-335150
[Problems to be solved by the invention]
When inspecting an inspection object at a predetermined position, when inspecting many inspection objects, the inspection takes time. Therefore, the applicants of the present application (Japanese Patent Application No. 2002-51778) have proposed that the inspection object is conveyed while being rotated to shorten the inspection time.
Here, most cylindrical inspection objects have tolerances in their axial dimensions, and therefore there are individual differences in the accuracy of the axial end of the inspection object. In order to prevent this individual difference from being determined as a defect, it is desired to exclude the axial direction end of the inspection object from the inspection object.
[0005]
However, when the outer peripheral surface of the inspection object being conveyed while rotating is imaged, the outer peripheral surface of the inspection object in the image is inclined at both axial ends. The degree of inclination and linearity at both ends in the axial direction change due to changes or disturbances in the conveyance speed and are not necessarily constant.
Therefore, the present invention excludes the vicinity of the axial end portion from the inspection target even when the inclination and linearity of the axial end portion of the developed outer peripheral surface image of the inspection target are not always constant. It aims at providing the new technical means for doing.
[0006]
[Means for Solving the Problems]
The present invention is an appearance inspection apparatus for a cylindrical inspection object that is conveyed while rotating around an axis in the conveying direction, and images the outer peripheral surface of the inspection object that is conveyed while rotating, An imaging unit that obtains an image of a developed outer peripheral surface in which both ends in the axial direction of the outer peripheral surface of the inspection target object are inclined ends, and a range of the developed outer peripheral surface in the image obtained by the imaging unit. A processing unit that scans and performs an appearance inspection process, and the processing unit excludes a predetermined width from the position of the inclined end portion in the axial direction with respect to the inclined end portion of the development outer peripheral surface. The inspection in the development outer peripheral surface is performed.
In the present invention, since the range of the predetermined width from the inclined end position is excluded from the inspection object with reference to the inclined end portion of the development outer peripheral surface, even if the inclination of the inclined end portion changes or becomes non-linear. Thus, a predetermined range near the end in the axial direction can be easily excluded from the inspection object.
[0007]
It is preferable that the appearance inspection apparatus includes an adjustment unit that adjusts the predetermined width that is not to be inspected. Since the predetermined width can be adjusted, an appropriate inspection range can be set according to the type of inspection object.
[0008]
Further, the appearance inspection apparatus is shorter than the width detected by the width detection means and means for detecting the axial width of the inspection object from the image obtained by imaging the inspection object rotating without being conveyed. It is preferable to include means for setting an inspection width and means for calculating the predetermined width to be excluded from the inspection object from the axial width of the inspection object and the inspection width. In this case, when the width of the inspection object and the inspection width are determined, a predetermined width that is not to be inspected is automatically determined.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the appearance inspection apparatus 1 irradiates light to the imaging unit 2 that images the inspection object (hereinafter referred to as “work”) W being conveyed, and the workpiece W in the imaging range by the imaging unit 2. And an illuminating unit 3 that performs image capturing from the image capturing unit 2 and a processing unit 4 that performs image processing and the like.
[0010]
In addition, the appearance inspection apparatus 1 includes a transport unit 5 that sends the workpiece W to the imaging range by the imaging unit 2 and a rotating unit 6 that rotates the workpiece W in the imaging range. The workpiece W is rotated about the axis while being conveyed in the conveying direction A parallel to the axial direction X in a state where a plurality of workpieces W are aligned in the axial direction X by the conveying unit 5 and the rotating unit 6.
[0011]
The conveyance unit 5 is located on the upstream side of the rotation unit 6 and sends the workpiece W to the rotation unit 6 side on the downstream side. The transport unit 5 includes a work transport belt 8 and a work extrusion roller 9, and includes a transport belt 8 disposed below the aligned works W and an extrusion disposed above the work W. The roller 9 is disposed so as to sandwich the workpiece W. Due to the rotation of both 8 and 9, the workpiece W aligned in the axial direction X is sent toward the conveyance direction A toward the imaging range by the imaging unit 2 and passes through the imaging range. That is, the appearance inspection apparatus 1 is a through-feed method. In addition, the conveyance part 5 may send out the workpiece | work W by pinching and rotating the workpiece | work W from right and left, and the specific structure is not limited.
[0012]
The transport unit 5 continuously feeds the work W at a substantially constant speed without stopping. Therefore, even if the workpiece W comes into the imaging range of the imaging unit 2, the workpiece W does not stop but always moves and passes through the imaging range. For this reason, the workpiece | work W can pass the imaging range one after another, and can test | inspect efficiently.
[0013]
The rotation unit 6 rotates the workpiece W sent from the conveyance unit 5 around the axis X, and a pair of workpiece rotation rollers 10 whose axis is directed in the same direction as the axis X of the workpiece W. , 10 are provided. The pair of rotating rollers 10 and 10 are juxtaposed in the horizontal direction and are driven to rotate in the same direction. The workpiece W is pushed onto the pair of rotating rollers 10 and 10 by the transport unit 5 and rotates in a predetermined direction by the rotation of the rotating rollers 10 and 10. Further, the workpiece W pushed out onto the rotating rollers 10 and 10 is moved in the conveying direction A by the rear workpiece W, and thus moves on the rotating rollers 10 and 10 in the conveying direction A. That is, the workpiece W moves in the transport direction A while rotating around the axis in the rotating unit 6.
In the present embodiment, the transport unit 5 and the rotating unit are configured by separate mechanisms, but may be configured by a single mechanism in which the transport function and the rotating function of the workpiece W are integrated.
[0014]
The imaging unit 2 is disposed above the rotating unit 6 so that the workpiece W being conveyed while rotating can be imaged. The imaging unit 2 is configured by a line sensor camera, is provided so that the camera scanning direction at the time of imaging coincides with the X direction, and performs scanning to acquire a line image in the X direction near the top of the workpiece W. Since scanning in the X direction is repeated, the imaging unit 2 scans different positions in the circumferential direction of the workpiece W as the workpiece W rotates. Therefore, when the work W rotates once, a two-dimensional image in which the outer peripheral surface of the work W is developed is obtained. When the workpiece W is rotated without moving in the X direction, the deployed outer peripheral surface is rectangular. However, when the workpiece W is moved in the X direction with rotation, the deployed outer peripheral surface is in the X direction. It will be inclined.
[0015]
The appearance inspection apparatus 1 includes an inter-work detection unit 12 as a timing acquisition unit for acquiring an imaging timing by the imaging unit 2. The inter-work detection unit 12 is disposed on the rear side in the transport direction A with respect to the imaging unit 2 and includes a contact sensor, an optical sensor, and the like for detecting a work gap portion passing through the detection position 13. When the workpiece gap portion passes through the detection position 13, the workpiece detection unit 12 outputs a detection signal indicating that the workpiece interval has been detected to the processing unit 4. By detecting the interval between the workpieces, the timing for each movement time for one workpiece can be obtained, and even when the movement speed of the workpiece W changes, the timing corresponding to the movement time for one workpiece is always obtained. Note that the timing may be acquired by detecting the inter-work position based on the image obtained by the imaging unit 2.
[0016]
2 and 3 show an inspection width setting process as a pre-process of the appearance inspection process based on the image obtained by the imaging unit 2. In this inspection width setting process, a reference workpiece W is placed on the rotating unit 6 and imaged in a transport stop state (step S1). Based on the image obtained by this imaging, the inspection width and a predetermined non-inspection object are selected. The width is determined (steps S2 to S4).
[0017]
Specifically, first, the same reference workpiece W that is actually inspected is placed on the rotating unit 6, and is rotated around the axis by the rotating unit 6. At this time, no movement in the transport direction A occurs. When the workpiece W rotating without being conveyed is imaged by the imaging unit 2 (step S1), a reference image as shown in FIG. In FIG. 3, a white range 20 is a developed outer peripheral surface of the workpiece W, and ranges 21 on the left and right sides of the range 20 are workpiece gap portions between the workpieces W. The developed outer peripheral surface 20 appears bright, but the workpiece gap portion appears darker, and the width (work width) W1 in the axial direction of the developed outer peripheral surface 20 in the reference image can be detected based on this brightness difference. (Step S2).
[0018]
Since there is a tolerance in the width dimension in the axial direction of the workpiece W, the width dimension has individual differences for each workpiece W. In order not to determine this individual difference as a workpiece defect, the inspection range is brought to the center in the axial direction, and both ends in the axial direction are excluded from inspection. The inspection width W2 to be inspected is set by an operator input (step S3). The inspection width W2 is set to a value shorter than the workpiece axial direction width W1. The inspection width W2 is input by input means (keyboard or the like) not shown. Since the inspection width W2 can be set by input, the inspection width W2 can be freely set, and the inspection range can be finely adjusted.
[0019]
The non-inspection range is calculated by the processing unit 4 based on W1 and W2. Specifically, the predetermined width D in the axial direction in the case of being excluded from the inspection target is obtained as D = (W1−W2) / 2 (step S4). The predetermined width D can be easily finely adjusted by finely adjusting the inspection width W2. That is, the function of the processing unit 2 that sets and adjusts the inspection width W2 and calculates the predetermined width D functions as an adjustment unit for the predetermined width D.
[0020]
After the above pre-inspection process, an appearance inspection process is performed. In the appearance inspection process, a plurality of workpieces W are continuously conveyed side by side in the conveyance direction and imaged while rotating. The image obtained by the imaging is an image for almost one rotation of the workpiece W, is taken into the processing unit 2, and an appearance inspection process of the workpiece W is performed by image processing. 4 and 5 show the scanning process of the inspection image for the appearance inspection process.
[0021]
In the image shown in FIG. 5, not only the workpiece W to be inspected, but also a part of the developed outer peripheral surfaces 20 and 20 of other workpieces W adjacent to the front and rear in the transport direction are shown. Further, unlike the reference image of FIG. 3, the developed outer peripheral surface is inclined because the image is taken during conveyance. That is, in FIG. 5, the direction from right to left is the transport direction, the upper side is earlier in time, and the position of the outer peripheral surface is shifted in the transport direction (leftward) as it goes downward. The axial direction (x direction) both ends 25a and 25b of the development outer peripheral surface are inclined end portions that are inclined by the amount of this shift. When the conveyance speed is not completely constant, the inclined end portions 25a and 25b are not straight but curved as shown in FIG. Further, depending on the timing at which the workpiece is imaged, the positions of the inclined ends 25a and 25b vary in the x direction. When the inclined end portion 25a changes, the position / shape of the development outer peripheral surface 20 to be inspected also changes. Note that the x and y coordinates in FIG. 5 coincide with the X and Y directions in FIG. The image coordinates in FIG. 5 take values in the range of x coordinate xm: 0 to xmax and y coordinate yn: 0 to ymax, with the upper left being the origin: 0.
[0022]
In order to inspect the development outer peripheral surface 20 whose position and shape are not necessarily constant, the inspection range is determined based on the position of the inclined end portion 25a. For this reason, in the appearance inspection process, first, the position of the inclined end portion 25a on the traveling direction side of the development outer peripheral surface 20 of the workpiece to be inspected is detected (step S5). The position of the inclined end portion 25a is obtained by discriminating the boundary between the development outer peripheral surface 20 and the work gap portion 21 by image processing. The position (coordinates) of the inclined end portion 25a is stored in the scanning reference array arr_x [yn]. The scanning reference array is a one-dimensional array. Yn in the scanning reference array arr_x [yn] is the y coordinate in FIG. 5 and takes a value in the range of 0 to ymax. As each array value arr_x [yn], the x coordinate when the y coordinate is yn is stored, and takes a value in the range of 0 to xmax.
[0023]
As already described, the inspection target range is the inspection width W2 in the middle in the axial direction excluding the predetermined width D in the vicinity of both ends in the axial direction of the development outer peripheral surface 20. In the inspection width setting process, the inspection width W2 is set on the basis of the rectangular developed outer peripheral surface 20, but in order to apply this to the inclined developed outer peripheral surface 20, the image is scanned in the following range.
[0024]
x-coordinate xm: arr_x [yn] + D to arr_x [yn] + D + W2
y coordinate yn: 0 to ymax
[0025]
The scanning position is shifted by a predetermined width D (arr_x [yn] + D) from the position (arr_x [yn]) of the inclined end portion 25a indicated by the scanning reference array arr_x [yn] with respect to the x coordinate. That is, the predetermined width D is a scanning shift amount. With respect to the x coordinate, scanning for the inspection width W2 is performed from the shifted position. As a result, the portion between the inclined end portion 25a and the predetermined width D is excluded from the inspection target, and the portion between the inclined end portion 25b and the predetermined width D is also excluded from the inspection target. As described above, since the scanning is performed based on the inclined end portion 25a, the shift amount D is automatically determined even if the position and shape of the inclined end portions 25a and 25b are changed simply by setting the inspection width W2. Therefore, the appearance inspection can be performed by accurately distinguishing the inspection target range and the non-target range. In addition, the inspection width W2 can be uniformly adjusted by the reference image regardless of the change in the inclined end portions 25a and 25b, so that the inspection object range can be easily adjusted.
[0026]
The present invention is not limited to the above embodiment. For example, the inclined end portion 25b may be used as a scanning reference position.
[0027]
【The invention's effect】
According to the invention, since the range of the predetermined width from the inclined end position is excluded from the inspection object with reference to the inclined end portion of the development outer peripheral surface, the inclination of the inclined end portion changes or becomes non-linear. In addition, it is possible to easily exclude a predetermined range in the vicinity of the end portion in the axial direction from the inspection target.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an appearance inspection apparatus.
FIG. 2 is a flowchart of an inspection width setting process.
FIG. 3 is a work image when an inspection width is set.
FIG. 4 is a flowchart of scanning processing for appearance inspection processing.
FIG. 5 is a work image at the time of appearance inspection.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Appearance inspection apparatus 2 Imaging part 4 Processing part A Conveying direction D Predetermined width W Work W1 Axial direction width W2 Inspection width

Claims (3)

An appearance inspection device for a cylindrical inspection object conveyed while rotating around an axis in a conveyance direction,
The outer peripheral surface of the inspection object being conveyed while rotating is imaged to obtain an image of the developed outer peripheral surface in which both end portions in the axial direction of the outer peripheral surface of the inspection object are inclined end portions. An imaging unit;
A processing unit that scans a range of the developed outer peripheral surface in the image obtained by the imaging unit and performs an appearance inspection process,
The processing unit performs an inspection in the development outer peripheral surface with a predetermined width being excluded from an inspection object from the inclined end position in the axial direction with reference to the inclined end portion of the development outer peripheral surface. Appearance inspection process. The appearance inspection apparatus according to claim 1, further comprising an adjusting unit that adjusts the predetermined width that is not to be inspected. Means for detecting the axial width of the inspection object from an image obtained by imaging the inspection object rotating without being conveyed;
Means for setting an inspection width shorter than the width detected by the width detection means;
Means for calculating the predetermined width to be excluded from the inspection object from the axial direction width of the inspection object and the inspection width;
The visual inspection apparatus according to claim 1, further comprising:

Images