JP2000266685A - Method and apparatus for visual inspection of object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus in which even an object having a face to be inspected, not as a uniformly flat face as a whole, can be visually inspected precisely. SOLUTION: This inspection apparatus is an apparatus which inspects the face to be inspected of an object W comprising the face to be inspected, not as a uniformly flat face as a whole. The apparatus is provided with a CCD TV camera 45 which picks images of a prescribed image picking-up range including the face to be inspected. In addition, the apparatus is provided with a processing means 46 and a processing means 47 which judge the quality of the object to be inspected, on the basis of pieces of luminance information in a plurality of dots which equally divide the imaging range. By the processing means 46, 47, a plurality of lines to be inspected, which connect points having a small luminance change are set in advance on the image of the face to be inspected, the pieces of luminance information in the plurality of dosts along the lines to be inspected are found sequentially, this series of luminance information are divided into a plurality of dot groups containing the prescribed number of dots, and the quality of the face to be inspected is judged on the basis of the pieces of luminance information in the dots in the respective dot groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for inspecting the appearance of an object. More specifically, for example,
Rubber stoppers, caps, tablets, capsules, etc. for injection solution containers
The present invention relates to a method and apparatus for inspecting the quality of the surface of an object having a surface to be inspected that is not entirely uniform and flat. The inspection targets include flaws, dirt, and foreign matter (dust, hair, etc.) on the surface.

[0002]

2. Description of the Related Art A rubber stopper of an injection solution container is attached to the mouth of a container containing the injection solution, and its peripheral portion is fixed by a stopper. Then, when injecting the injection solution in the container into the syringe, the injection needle is pierced through the center of the rubber stopper.

[0003] As described above, since the rubber stopper of the injection container directly touches the injection needle, it is necessary to perform an appearance inspection before mounting the rubber stopper on the container.

As a method of inspecting a uniform flat surface, a surface to be inspected is imaged by two-dimensional imaging means such as a CCD television camera, and the surface to be inspected is subjected to a plurality of horizontal scanning lines of a video signal and a predetermined clock signal. The image is divided into dots, and the luminance information of each dot is divided into a bright portion and a dark portion by a predetermined threshold value.
There is known an image forming apparatus which determines the quality based on the number of dots which are converted into a value and which is a bright portion or a dark portion.

However, in the case of a rubber stopper, the surface has irregularities, and the surface to be inspected is not a uniform flat surface as a whole. Therefore, the method described above cannot inspect the surface of the rubber stopper.

The rubber stopper may be a rotating body. In such a case, when an image of the surface to be inspected is taken in the direction of the axis, a change in luminance is small on a concentric circle centered on the axis.
Therefore, it is conceivable that a plurality of concentric circles are set on the surface to be inspected, and the quality is determined from the luminance information of the dots on each concentric circle.

For example, it is conceivable to check whether or not the luminance information exceeds a predetermined threshold value for all the dots on each concentric circle, and if any of the dots exceeds the predetermined threshold value, it is conceivable that the dot is determined to be defective. In this way, when there is a bright foreign substance on a concentric circle that is entirely dark, or when there is a dark part on a concentric circle that is entirely bright, this can be accurately determined as abnormal. However, in this method, it is necessary to change a threshold value between a bright portion and a dark portion of the surface to be inspected, and the process is troublesome. In addition, there is a variation in shape of the rubber stopper, and depending on the rubber stopper, a concentric circle may straddle two different adjacent surfaces. In such a case, in the above method, even if there is no abnormality on the inspection surface, a change in luminance is large over the entire concentric circle, and a dot whose luminance exceeds the threshold may appear. Despite the fact, it is erroneously determined to be abnormal. Further, even in the case of a tapered surface, even if there is no abnormality, the luminance change on one concentric circle may be large, and therefore, there is a similar problem.

By differentiating each part on the concentric circle, a luminance change in each part is obtained, and when there is a part whose luminance change exceeds a predetermined threshold value, it is determined to be abnormal. Then, even when the luminance change over the entire concentric circle is large as described above, it is not erroneously determined that the image is normal but abnormal. Also,
Even when there is a bright foreign substance on a concentric circle that is entirely dark, or when there is a dark part on a concentric circle that is entirely bright, this can be accurately determined as abnormal. However, when testing based on the magnitude of the luminance change, it is necessary to determine the presence or absence of an abnormality such as surface dirt that causes a gradual change in luminance, or to determine the size of the abnormal part. Can not.

[0009] In the case of an object other than the rubber stopper of the injection container, which has a surface to be inspected that is not entirely flat, the same problem as described above occurs.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and to accurately and simply perform an appearance inspection even on an object having a surface to be inspected that is not entirely flat. It is an object of the present invention to provide a method and a device which can be used.

[0011]

A method for inspecting the appearance of an object according to the present invention is a method for inspecting the surface to be inspected of an object having a surface to be inspected which is not entirely flat. The predetermined imaging range including the surface to be inspected is set to 2
In the method of imaging by the two-dimensional imaging means and determining the quality of the surface to be inspected based on luminance information of a plurality of dots equally dividing the imaging range, a point having a small luminance change on the image of the surface to be inspected. A plurality of lines to be inspected are set in advance, and for each of the lines to be inspected, luminance information at a plurality of dots along the line to be inspected is sequentially obtained. , And based on the luminance information of the dots of each dot group, the quality of the inspection line is determined.

The number of dots in the dot group is preferably determined such that the length of the entire dot group is several times longer than the smallest abnormal size to be detected. This can be determined by calculation or experiment.

Preferably, a maximum value, a minimum value, and an average value of the luminance information in the dot group are obtained based on the luminance information in the dots of each dot group.
Based on these, pass / fail on the inspection line is determined.

For example, based on the difference between the maximum value and the average value and the difference between the average value and the minimum value, the maximum value or the minimum value is set as a reference value, and the difference from the reference value is determined by a predetermined threshold value. It is characterized in that the number of large dots is counted, and the pass / fail on the line to be inspected is determined based on the counted value.

For example, if the difference between the maximum value and the average value, which is the difference between the average value and the average value, is larger than the difference between the average value and the minimum value, which is the difference between the minimum value and the average value, the minimum value is set as a reference value. If the difference on the minimum value side is larger than the difference on the maximum value side, the maximum value is used as the reference value.If the difference on the maximum value side is equal to the difference on the minimum value side, one of the maximum value and the minimum value is used. Is set as a reference value.

Since the number of dots in the dot group obtained by dividing the line to be inspected is relatively small, the change in luminance in each dot group is relatively small even if the change in luminance is large over the entire line to be inspected. For this reason, it is not erroneously determined that the state is normal but abnormal.

In addition, the quality is determined not on the basis of the luminance change (differential value) in each part of the line to be inspected but on the basis of the luminance information of each dot in each dot group. Can be reliably detected.

In addition, by determining the acceptability based on the difference between the luminance of each dot in each dot group and the reference value, it is not necessary to change the threshold value for each dot group, thereby simplifying the processing. In each dot group, the maximum value, the minimum value, and the average value of the luminance information are obtained,
Since it is only necessary to find the difference between the luminance of each dot and the reference value and compare this difference with a threshold value, processing can be performed quickly and easily using a relatively inexpensive computer or the like.

Further, the size of an abnormal portion in each line to be inspected is obtained by summing the number of dots having a difference in luminance from a reference value larger than a threshold value in each dot group for the entire line to be inspected. By summing the size of the abnormal part in each line to be inspected for the entire surface to be inspected, the size of the abnormal part in the entire surface to be inspected can be obtained. For this reason, a more accurate appearance inspection can be performed.

Therefore, according to the method of the present invention, the appearance can be accurately and easily inspected even for an object having a surface to be inspected which is not entirely flat.

According to the present invention, there is provided an apparatus for inspecting the appearance of an object, which inspects the inspected surface of an object having a surface to be inspected which is not uniform and flat. An apparatus comprising: a two-dimensional imaging unit that captures an image of a range; and a processing unit that determines the quality of the surface to be inspected based on luminance information of a plurality of dots that equally divide the imaging range. On the image of the surface to be inspected, a plurality of lines to be inspected, each of which is connected to a point having a small change in luminance, are set in advance, and for each of the lines to be inspected, luminance information at a plurality of dots along the line to be inspected is determined in order. This series of luminance information is divided into a plurality of dot groups including a predetermined number of continuous dots, and the pass / fail on the line to be inspected is determined based on the luminance information on the dots in each dot group. And it is characterized in and.

Preferably, the processing means obtains a maximum value, a minimum value, and an average value of the luminance information of the dot group based on the luminance information of the dots of each dot group, and, based on these, obtains a value on the line to be inspected. Is determined.

For example, the processing means sets a maximum value or a minimum value as a reference value based on the difference between the maximum value and the average value and the difference between the average value and the minimum value, and determines whether the difference from the reference value is a predetermined value. The number of dots larger than the threshold value is counted, and the quality of the line to be inspected is determined based on the counted value.

For example, when the difference on the maximum value side which is the difference between the maximum value and the average value is larger than the difference on the minimum value side which is the difference between the average value and the minimum value, the processing means sets the minimum value. When the difference on the minimum value side is larger than the difference on the maximum value side, the maximum value is used as the reference value, and when the difference on the maximum value side is equal to the difference on the minimum value side, the maximum value is used as the reference value. One of the minimum values is used as a reference value.

According to the apparatus of the present invention, for the same reason as in the above-described method, even if the object has a surface to be inspected which is not entirely uniform and flat, the appearance inspection can be performed accurately and easily. Can be.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to the appearance inspection of a rubber stopper of an injection liquid container will be described below with reference to the drawings.

FIGS. 1 to 3 show a rubber stopper 1 as an object to be inspected.
FIG. 1 is a vertical sectional view of a rubber plug in an upright posture, and FIG.
Is a plan view, and FIG. 3 is a bottom view. This rubber stopper is a rotating body about a vertical axis (A) in the upright posture.

The rubber stopper is formed by integrally forming a short columnar projection (2) at the center of the lower surface of the disk portion (1), and a circular recess (3) is formed at the center of the lower surface of the projection (2). ) Is formed. Disk part
The outer peripheral surface (4) of (1) is a cylindrical surface.

On the upper surface side of the rubber plug, a circular flat surface (inside flat surface) (5), an annular projection (6), an annular flat surface (intermediate flat surface) (7), and a tapered surface (8) ) And an annular flat surface (outside flat surface) (9) are formed in order from the inside. The inner flat surface (5) and the intermediate flat surface (7) are in the same plane with each other, and the outer flat surface (9) is at a position slightly higher than these. The tapered surface (8) gradually increases toward the outside.
The projection (6) is low and narrow, the top of which is lower than the outer flat surface (9).

On the lower surface side of the rubber plug, a circular flat surface (inner flat surface) (10), a tapered surface (inner tapered surface) (11), an annular flat surface (intermediate flat surface) (12), and a taper A surface (outer tapered surface) (13), a cylindrical surface (14), and an annular flat surface (outer flat surface) (15) are formed in this order from the inside. Outer flat surface (1
5) is formed by the outer peripheral portion of the lower surface of the disk portion (1).
The outer tapered surface (13) and the cylindrical surface (14) are formed by the outer peripheral surface of the projection (2). The intermediate flat surface (12) is formed by the lower end surface of the projection (2). Inner tapered surface (11) is concave
The inner diameter of (3) is formed, and the inner diameter gradually increases toward the lower side. The inner flat surface (10) is formed by the bottom of the recess (3) and is substantially in the same plane as the outer flat surface (15).

Although not shown, when the rubber stopper is attached to the container, the projection (2) fits inside the mouth of the container, and the cylindrical surface (14) comes into close contact with the inner peripheral surface of the mouth. The outer flat surface (15) is in close contact with the end surface of the mouth. The portion above the outer peripheral surface of the disk portion (1) is located outside the mouth, but the portion outside the projection (6) is covered with a stopper. Then, when injecting the injection solution in the container into the syringe, the inner flat surface on the top side (5)
The injection needle is pierced from to the inner flat surface (10) on the lower surface side.

FIGS. 4 and 5 show one example of the configuration of the visual inspection apparatus.
An example is shown.

The inspection device includes an alignment supply device (20), a guide rail (21), a first transport device (22), a second transport device (23) and a third transport device as transport means for the inspected object (W). Transport device (2
4), and the object (W) is transported from the left side to the right side in FIGS. 4 and 5 along the transport devices (22), (23), and (24). The first transport unit (22) has a first inspection unit (25) and a defective product discharging unit (26), and the second transport unit (23) has a second inspection unit (27). And a defective product discharge section (28). In the following description, front, rear, left and right refer to the moving direction of the object (W). That is, the right side of FIGS. 4 and 5 is the front, the left side is the rear, the upper side of FIG. 5 is the left, and the lower side is the right.

The alignment supply device (20) supplies the object (W) in an upright posture and aligns and supplies the object (W) in a line in the front-rear direction, and may use a known parts feeder or the like. The guide rail (21) guides the object (W) supplied from the alignment supply device (20), regulates its position in the left-right direction, and supplies it to the first transfer device (22). . The first transporting device (22) is a known belt conveyor, which supports the object (W) in the upright posture from below at a constant position in the left-right direction so as to have a constant interval in the front-rear direction, and moves forward at a constant speed. Transport to As will be described in detail later, the second transfer device (23) supports the object (W) in the upright posture from above at a constant position in the left-right direction so as to have a constant interval in the front-rear direction and at a constant speed. Carry forward. The third conveyor (24) is a belt conveyor similar to the first conveyor (22). First
The transfer surface of the transfer device (22) (the upper surface of the upper part of the belt) and the transfer surface of the third transfer device (24) are substantially horizontal and at substantially the same height.

FIG. 6 shows an example of the structure of the second transfer device, and FIG. 7 shows a part of the structure.

Pulleys (30) and (31) rotating around a horizontal horizontal axis are provided above the rear part of the third transfer device (24) and above the front part of the first transfer device (22). Are these pulleys
A pair of left and right endless flat belts (32) and (33) are wound around (30) and (31). One of the front and rear pulleys (30) and (31) is a driving pulley, and the belts (32) and (33) are driven at a constant speed so that the lower portion moves forward. Inside a belt (32) (33) between the front and rear pulleys (30) (31), a rectangular parallelepiped suction box (34) having an open bottom surface is provided. A suction port (35) is provided on one side wall of the suction box (34). At a plurality of locations in the front-rear direction of the suction box (34), roller support members (36) are fixed at predetermined intervals in the left-right direction below the opposing surfaces of the left and right side walls, and a lower end of each member (36) is provided. The guide rollers (37) and (38) that freely rotate around the horizontal axis in the left-right direction are provided in the section. And each belt (3
2) The upper surface of the lower portion of (33) is guided in contact with the corresponding rollers (37) and (38). The distance between the left and right belts (32), (33) is smaller than the outer diameter of the disk portion (1) of the object (W). Transfer device (2
The transport surface of (3) (the lower surface of the lower part of the belts (32) and (33)) is substantially horizontal, and this transport surface and the first and third transport devices (2
2) The vertical distance from the transfer surface in (24) is slightly larger than the height of the object (W) in the upright posture. The suction port (35) is connected to a vacuum pump (not shown), and the inside of the suction box (34) is maintained in a negative pressure state by driving the vacuum pump.

The first inspection section (25) includes a circular lamp (40),
The camera is provided with a CCD television camera (41), an image processing device (42), and an arithmetic processing device (43) which constitute two-dimensional imaging means.
Similarly, the second inspection unit (27) also has a circular lamp (44), CC
A D television camera (45), an image processing device (46) and an arithmetic processing device (47) are provided.

The first defective product discharging section (26) includes a first inspection section.
(25) and the second transfer device (23) and the first transfer device
(22) is disposed leftward at a position slightly above the right transfer surface to blow the object (W) on the first transfer device (22) to the left side of the transfer device (22) by compressed air. And a defective product accommodating device (51) disposed on the left side of the first transporting device (22) and receiving the object (W) blown off by the eliminating device (50) and accommodating it. ).
Similarly, the second defective product discharging device (28) is a defective product removing device.
(52) and a defective product storage device (53).

The objects (W) are aligned in an upright posture in a line by an alignment supply device (20), and are supplied one by one to a first transfer device (22) through a guide rail (21). Transfer device (2
The object (W) supplied to (2) is sent forward at a constant speed at a constant interval in the front-rear direction, and while passing under the first inspection unit (25), the object (W) is An appearance inspection is performed on the inspection surface on the upper side of (). As a result of the inspection, if the defective product passes through the first defective product discharging section (26), compressed air is blown out from the rejection device (50). Blown to the left side of the transport device (22),
It is received by the storage device (51) and stored therein. Since the transfer speed of the object (W) in the transfer device (22) is constant,
As a result of the inspection, when it is determined that the product is defective, a defective product signal is output from the first inspection unit (25), and after a predetermined time from the output of this signal, compressed air is discharged from the rejection device (50). By blowing it out, the transfer device (2
2) can be discharged from. As a result of the inspection, if the inspection result indicates that the object (W) is good, the object (W) is sent further forward, and when the object (W) reaches below the rear end of the suction box (34) of the second transporting device (23), the suction box ( It is sucked by the negative pressure in 34), and the outer flat surface (9) of the upper surface of the disk portion (1) is held in pressure contact with the belts (32), (33). The object (W) held on the belts (32) and (33) is sent forward at a constant speed at a constant interval in the front-rear direction,
While passing over the inspection section (27), an appearance inspection is performed on the inspection surface under the object (W). As a result of the inspection, if the product is defective, it is discharged from the transfer device (23) by the second defective product discharge unit (28) as described above. Object (W)
Is relatively light, and the object (W)
Since the suction holding force of the object (W) is relatively small, the object (W) is separated from the transfer device (23) by blowing compressed air from the removing device (52) to the object (W) held by the transfer device (23). Is blown off to the storage device (53). Test results,
If it is good, the object (W) is sent further forward,
When the suction box (34) reaches the front end, the suction holding force is lost, so that the suction box (34) falls from the second transfer device (23) onto the third transfer device (24). Then, it is sent to the next step by the third transfer device (24).

In the second inspection section (27), the lamp (44)
Is the object (W) being transferred by the second transfer device (23)
Illuminate the lower side of the. TV camera (45) is a lamp
The lower side of the object (W) illuminated by (44) is imaged, and its image signal (video signal) is output to the image processing device (46). The image processing device (46) equally divides an image captured by the television camera (45) into a plurality of dots by using a horizontal scanning line of an image signal and a predetermined clock signal, and converts an image signal corresponding to each dot into luminance information. After conversion, the arithmetic processing unit (4
Output to 7). The luminance information is represented, for example, by a digital value where black (darkest part) is 0 and white (lightest part) is 255. Processing means is constituted by the image processing device (46) and the arithmetic processing device (47).

FIG. 8 shows an example of an image picked up by the television camera (45). The same portions of this image and the surface to be inspected shown in FIG. 3 are denoted by the same reference numerals in the drawings. In this image, the background is white, but is actually black. For the part corresponding to the object (W), the brightest part is expressed in white, the darker part is cross-hatched, and the dark part is changed in cross-hatching density according to luminance so that the density of cross-hatching is increased. ing. The image processing device (46) represents the dots of the image using the X axis and the Y axis as follows. That is, as shown in FIG.
The vertical line connecting the axis and the left end point of the image is defined as the Y axis, and the intersection thereof is defined as the origin (O). In this case, the direction of the horizontal scanning line (horizontal direction) is the X-axis direction, and the vertical scanning direction orthogonal thereto is the Y-axis direction. The X coordinate value of each dot of the image is represented by the number of reference clock signals that equally divide the horizontal scanning line with the origin (O) being 0, and the Y coordinate value is the origin (O).
With 0 as the number of horizontal scanning lines. The distance between the dots is, for example, 50 μm when converted to the size of the object (W).
It is.

The arithmetic processing unit (47) includes a computer or the like, and determines whether there is any abnormality in the appearance of the lower side of the object (W) based on luminance information of each dot output from the image processing unit (46). judge.

The arithmetic processing unit (47) is provided with a line-to-be-inspected table, in which the coordinates of a plurality of dots constituting each line-to-be-inspected are set for a large number of lines to be inspected set on the object (W). The value is stored. The line to be inspected is a series of points having little change in luminance. In the case of an object that is a rotating body, when the object is imaged in the direction of the axis, a number of concentric circles around the axis become inspection lines. In the case of this embodiment, a large number of concentric circles whose radii change at intervals of dots are set as inspection lines, and for each inspection line, coordinate values of dots on or close to the inspection line are stored. . These are stored, for example, counterclockwise from an appropriate starting point, with the center set to an appropriate value.

The arithmetic processing unit (47) determines the presence / absence of an abnormality for all the lines to be inspected, obtains the size of the abnormal part, and, based on the result, determines the presence / absence of the entire abnormality and the size of the abnormal part. Ask for it. That is, the arithmetic processing unit (47)
When the luminance information is read from the image processing device (46), first, the outline of the object (W) on the image is obtained by a known method, and the coordinate value of the center of the inspection surface is obtained from this. Then, for each line to be inspected, the luminance information of all dots on the line to be inspected is read in order. At this time, the coordinate value of the center of the inspection line (concentric circle) stored in the inspection line table matches the coordinate value of the center of the object (W) on the image obtained as described above. Perform coordinate transformation. Next, a series of dots on the line to be inspected are divided into dot groups including a predetermined number of continuous dots, and the presence or absence of an abnormality is determined based on the luminance information of the dots in each dot group as follows. At the same time, determine the size of the abnormal part. The number of dots in the dot group is determined so that the length of the entire dot group is several times or more longer than the minimum abnormal dimension to be detected. In this case, it is ten. The arithmetic processing unit (47) sequentially reads the luminance information of each dot in the dot group, and obtains the maximum value, the minimum value, and the average value of the luminance information. Next, the difference between the maximum value, which is the difference between the maximum value and the average value, and the difference between the minimum value, which is the difference between the average value and the minimum value, are determined, and the difference on the maximum value side is larger than the difference on the minimum value side. In this case, the minimum value is used as the reference value, and otherwise, the maximum value is used as the reference value. Then, for all the dots, the difference from the reference value is obtained, and it is checked whether or not this difference exceeds a predetermined threshold value. The number of dots is counted and stored.
When processing is completed for all dot groups,
The number of dots exceeding the threshold value in each dot group is summed and stored for the entire inspection line. From this number, the size of the abnormal portion on the inspection line can be determined. When the processing has been completed for all the lines to be inspected, the number of dots exceeding the threshold value in each line to be inspected is totaled and stored for the entire inspected surface. From this number, the size of the abnormal portion on the entire inspection surface can be determined.

Next, with reference to FIGS. 9 to 21, some specific examples of the determination of the presence or absence of an abnormality will be described.

FIG. 9 shows the luminance of all dots on the line to be inspected when the line to be inspected is on the same plane, the luminance on the line to be inspected is almost uniform, and there is no abnormality. is there. In this case, since the change in luminance is small even on the whole line to be inspected, and the change in luminance within the dot groups obtained by dividing the luminance is also small, the dots whose luminance difference from the reference value exceeds the threshold value in each dot group are It is accurately determined that there is no abnormality.

FIG. 10 shows, in order, the brightness of all the dots on the line to be inspected when there is a relatively bright foreign substance such as white hair on the line to be inspected which has a substantially uniform luminance and is relatively dark. In this case, the brightness is increased in the portion of the dot corresponding to the foreign matter. Therefore, in the dot group having no foreign matter, there is no dot whose luminance difference from the reference value exceeds the threshold value. In the dot group with foreign matter, the minimum value is the reference value, and as shown in FIG. 11, in some dots, the difference between the luminance of the dot and the reference value exceeds the threshold value (40 in this case). . Therefore, it is accurately determined that there is an abnormality.

FIG. 12 shows the luminance of all dots on the line to be inspected in the case where there is a relatively dark foreign substance such as black hair on the line to be inspected whose luminance is almost uniform and relatively bright. In this case, the brightness is reduced at the corresponding dot portion of the foreign matter. Therefore, in the dot group having no foreign matter, there is no dot whose luminance difference from the reference value exceeds the threshold value. In a dot group having a foreign substance, the maximum value is the reference value, and as shown in FIG. 13, in some dots, the difference between the luminance of the dot and the reference value exceeds the threshold value. Therefore, it is accurately determined that there is an abnormality.

FIG. 14 shows, in order, the luminance of all the dots on the line to be inspected when there is an abnormality such as dirt on the line to be inspected whose luminance is substantially uniform and relatively bright. In this case, the luminance gradually changes at the dot corresponding to the abnormality.
Therefore, in a dot group having no abnormality, there is no dot whose luminance difference from the reference value exceeds the threshold value. In the abnormal dot group, the maximum value becomes the reference value, and as shown in FIG. 15, in some dots, the difference between the luminance of the dot and the reference value exceeds the threshold value. Therefore, it is accurately determined that there is an abnormality. In such a case, since the luminance change in the abnormal part is small, the method of determining the luminance change on the line to be inspected and checking whether or not the magnitude of the luminance change exceeds a threshold value determines that there is an abnormality. Can not.

FIG. 16 shows, in order, the luminance of all dots on the line to be inspected when the line to be inspected straddles two surfaces. In this case, the luminance change is large in the whole line to be inspected, but in the divided dot groups, as shown in FIG. 17, the luminance change is small, and there is no dot whose luminance difference from the reference value exceeds the threshold value. . Therefore, it is accurately determined that there is no abnormality. In such a case, since the luminance change of the entire inspection line is large, the method of checking whether there is a dot whose luminance exceeds the threshold value for the entire inspection line may be erroneously determined to be abnormal. I will.

FIG. 18 shows the case where the line to be inspected straddles two surfaces, and the brightness of all dots on the line to be inspected when there is a bright foreign substance in a relatively dark portion of the line to be inspected is sequentially shown. It is shown. In this case, the brightness is increased in the portion of the dot corresponding to the foreign matter. Therefore, in the dot group having no foreign matter, there is no dot whose luminance difference from the reference value exceeds the threshold value. In a dot group with foreign matter,
The minimum value is the reference value, and as shown in FIG. 19, in some dots, the difference between the brightness of the dot and the reference value exceeds the threshold value. Therefore, it is accurately determined that there is an abnormality.

FIG. 20 shows the case where the line to be inspected straddles two surfaces, and the brightness of all the dots on the line to be inspected when there is a dark foreign substance in a relatively bright portion of the line to be inspected. It is shown. In this case, the brightness is reduced at the dot portion corresponding to the foreign matter. Therefore, in the dot group having no foreign matter, there is no dot whose luminance difference from the reference value exceeds the threshold value. In a dot group with foreign matter,
The maximum value is the reference value, and as shown in FIG. 21, in some dots, the difference between the brightness of the dot and the reference value exceeds the threshold value. Therefore, it is accurately determined that there is an abnormality.

FIGS. 16 to 21 show the case where the line to be inspected is on one tapered surface or the like and the overall luminance change is large.

In the first inspection section (25), an image processing device
(42) is similar to the image processing device (46) of the second inspection section (27).

In the above embodiment, while the object (W) is being conveyed by the two conveyance devices (22) and (23), the appearance inspection of the upper and lower sides thereof can be easily performed.

The present invention can be applied to the appearance inspection of any object having a surface to be inspected which is not a uniform flat surface as well as the rubber stopper of the injection solution container.

The line to be inspected can be determined and set in advance by calculation as in the above embodiment. Alternatively, depending on the object, an object having no abnormality is imaged and the line to be inspected is determined and set from the image data. You can also.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rubber stopper of an injection solution container showing an example of an object to be inspected.

FIG. 2 is a plan view of the rubber stopper of FIG. 1;

FIG. 3 is a bottom view of the rubber stopper of FIG. 1;

FIG. 4 is a schematic side view showing an example of a visual inspection device.

FIG. 5 is a plan view of the appearance inspection device of FIG. 4;

FIG. 6 is an enlarged cross-sectional view showing a portion of a second transfer device of the appearance inspection device of FIG. 4;

FIG. 7 is an enlarged sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is a diagram illustrating an example of an image obtained by capturing an object to be inspected;

FIG. 9 is an explanatory diagram illustrating an example of luminance information on one inspection line.

FIG. 10 is an explanatory diagram illustrating another example of the luminance information on one inspected line.

FIG. 11 is an explanatory diagram showing a difference between luminance and a reference value in a plurality of dots in one dot group on the line to be inspected in FIG. 10;

FIG. 12 is an explanatory diagram showing still another example of the luminance information on one inspected line.

FIG. 13 is an explanatory diagram illustrating a difference between a luminance and a reference value in a plurality of dots in one dot group on the line to be inspected in FIG. 12;

FIG. 14 is an explanatory diagram illustrating still another example of the luminance information on one inspection line.

FIG. 15 is an explanatory diagram illustrating a difference between a luminance and a reference value in a plurality of dots in one dot group on the line to be inspected in FIG. 14;

FIG. 16 is an explanatory diagram showing still another example of the luminance information on one inspection line.

FIG. 17 is an explanatory diagram showing a difference between a luminance and a reference value in a plurality of dots in one dot group on the line to be inspected in FIG. 16;

FIG. 18 is an explanatory diagram showing still another example of the luminance information on one inspection line.

FIG. 19 is an explanatory diagram illustrating a difference between a luminance and a reference value in a plurality of dots in one dot group on the line to be inspected in FIG. 18;

FIG. 20 is an explanatory diagram showing still another example of the luminance information on one inspection line.

FIG. 21 is an explanatory diagram showing a difference between luminance and a reference value in a plurality of dots in one dot group on the line to be inspected in FIG. 20;

[Explanation of symbols]

(W) Rubber stopper (object to be inspected) (10) Inner flat surface (11) Inner tapered surface (12) Intermediate flat surface (13) Outer tapered surface (15) Outer flat surface (27) Second inspection unit (45) ) CCD TV camera (two-dimensional imaging means) (46) Image processing device (47) Arithmetic processing device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G051 AA01 AA90 AB02 AB20 BA01 CA03 CA04 CA07 DA01 DA06 DA13 EA08 EA11 EA20 EB01 EC03 EC10 ED01 ED09 5B057 AA01 BA02 CA08 CA12 CA16 CB08 CB11 DA03 DB01 DB09 DC22 5L03A

Claims (8)

[Claims] 1. A method for inspecting an inspected surface of an object having an inspected surface that is not entirely uniform and flat, wherein a predetermined imaging range including the inspected surface is imaged by two-dimensional imaging means. In the method of judging the quality of the surface to be inspected on the basis of luminance information on a plurality of dots equally dividing the imaging range, a plurality of points on the image of the surface to be inspected, each of which has a point having a small change in luminance. Inspection lines are set in advance, and for each of the lines to be inspected, luminance information at a plurality of dots along the lines to be inspected is sequentially obtained, and this series of luminance information is divided into a plurality of dot groups including a predetermined number of continuous dots. Then, based on the luminance information of the dots in each of the dot groups, the quality of the object is determined on the inspection line. 2. A method for determining a maximum value, a minimum value, and an average value of luminance information in a dot group based on luminance information of dots in each dot group, and judging pass / fail on the line to be inspected based on these values. 2. The method for inspecting the appearance of an object according to claim 1, wherein: 3. A method according to claim 1, wherein a maximum value or a minimum value is set as a reference value based on a difference between the maximum value and the average value and a difference between the average value and the minimum value. 3. The method according to claim 2, wherein the number of large dots is counted, and the quality of the object line is determined based on the counted value. 4. When the difference on the maximum value side, which is the difference between the maximum value and the average value, is larger than the difference on the minimum value side, which is the difference between the average value and the minimum value, the minimum value is used as a reference value. If the difference on the minimum value side is larger than the difference on the maximum value side, the maximum value is used as the reference value.If the difference on the maximum value side is equal to the difference on the minimum value side, one of the maximum value and the minimum value is used. 4. The method according to claim 3, wherein the reference value is a reference value. 5. An apparatus for inspecting an inspected surface of an object having an inspected surface that is not entirely uniform and flat, wherein two-dimensional imaging means for imaging a predetermined imaging range including the inspected surface. And a processing unit that determines the quality of the surface to be inspected based on luminance information of a plurality of dots that equally divide the imaging range, wherein the processing unit includes an image on the surface to be inspected. A plurality of lines to be inspected, which are connected with points having little change in luminance, are set in advance, and for each of the lines to be inspected, luminance information at a plurality of dots along the line to be inspected is sequentially obtained, and this series of luminance information is continuously obtained. An object appearance inspection apparatus for dividing an object into a plurality of dot groups including a predetermined number of dots, and determining pass / fail on the line to be inspected based on luminance information of dots in each of the dot groups. 6. The processing means obtains a maximum value, a minimum value, and an average value of the luminance information in the dot group based on the luminance information in the dots of each dot group, and, based on these, obtains a value on the line to be inspected. 6. The apparatus for inspecting the appearance of an object according to claim 5, wherein the apparatus is configured to determine pass / fail. 7. The processing means sets a maximum value or a minimum value as a reference value based on the difference between the maximum value and the average value and the difference between the average value and the minimum value, and determines whether the difference from the reference value is a predetermined value. 7. The object appearance inspection apparatus according to claim 6, wherein the number of dots larger than the threshold value is counted, and the quality of the inspection line is determined based on the counted value. 8. When the difference between the maximum value and the average value, which is the difference between the maximum value and the average value, is larger than the difference between the average value and the minimum value, which is the minimum value, the processing means determines the minimum value. As the reference value,
If the difference on the minimum value side is larger than the difference on the maximum value side, the maximum value is used as the reference value.If the difference on the maximum value side is equal to the difference on the minimum value side, either of the maximum value or the minimum value is used. The visual inspection apparatus for an object according to claim 7, wherein the reference value is set as a reference value.