JPH09161057A - Device for inspecting inside of hollow route - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of inspection by receiving light irregularly reflected in a hollow route and outgoing from the route, picking up an image of the received light and judging the existence of abnormality in the route by features such as the area value of a bright picture. SOLUTION: In the case of inspecting a head cylinder 1 of an engine as a subject, a supporting member 7 is elevated/revoluted by an elevating/revoluting mechanism and a projection part 8 and an image pickup part 9 are inserted into a pair of sand removing holes 4 e.g. Light is projected from the projection part 8 inside the hollow route 4a and diffused light irregularly reflected in the route 4a and going out from the route 4a is received on the two-dimensional plane by a microcamera built in an image pickup part 9 to obtain a plane image. Further, inspection is repeated by changing the image pickup direction or the inserting direction by revoluting the member 7 or rotating the image pickup part 9. Then, the area value or the like of a bright picture picked up by each camera is discriminated to judge the block or jamming of the route 4a. Since the inside of the route 4a is image-picked up in plural directions, the abnormality of the labyrinth-like hollow route can be inspected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow path internal inspection device for inspecting the inside of an inspected object having a bent hollow path whose inside cannot be observed from the outside.

[0002]

2. Description of the Related Art A water-cooled engine has a cooling water passage (water jacket) in a combustion chamber in a cylinder block and a head cylinder, and cooling water is circulated to this portion to prevent engine seizure. 4 (a) (b)
FIG. 3C shows a bottom view, a partial vertical cross-sectional view, and a partial horizontal cross-sectional view of the head upper surface side of an example of the head cylinder (1). The head cylinder (1) is shown in FIG.
As shown in (b), a plurality of water holes (3) are formed on the lower surface side of the head (cylinder block side) along the circumference of the cylinder tube (2), and the spark plug and the suction plug on the upper surface side of the head are formed. Sand removal holes (4) are formed around the exhaust valve.
The water holes (3) form a circulating cooling water passage by the head cylinder (1) being connected to the cylinder block,
In addition, a bent cooling water channel hollow path (3a) that cannot be observed from the outside is formed between adjacent water holes. Further, a hollow passage (4a) for a cooling water passage is formed between the sand removing holes on the upper surface side of the head. The head cylinder (1) is an example of an object to be inspected having curved hollow paths (3a) (4a),
In particular, as shown in FIG. 4C, the hollow path (4a) on the upper surface side of the head forms a mesh-like complicated bending labyrinth.

When forming the water hole (3) for the cooling water passage and the hollow passages (3a) (4a), after setting the core in the mold and pouring molten metal (for example, molten aluminum alloy) and solidifying it Although the mold and the core are removed to obtain a product, the cooling water channel of the head cylinder (1) has a more complicated shape than the cooling water channel of the cylinder block, and the core sand is likely to remain without being removed. In particular, since the inside of the hollow paths (3a) and (4a) cannot be observed from the outside, the core sand often moves to the final process with the core sand remaining. As a result, in the worst case, the engine is disposed of as a defective product. There is something we cannot help but do.

When the core is partially missing or has cracks at the time of molding the core or setting it in the mold, if the core is set as it is, the molten metal poured into the core will be damaged. As a result of casting burrs flowing into spots and cracks and remaining as casting burrs, the cooling water passages are blocked and the cooling effect of the engine deteriorates.

Therefore, the hollow path (3a) (4)
It is necessary to inspect the inside of a) to inspect for any abnormalities such as abnormal shapes and remaining cores. An example of the inspection means will be described below with reference to FIG. The inspection means includes a pair of first and second photoelectric sensors (5) for projecting and receiving light which are respectively inserted into the water holes (3) on the lower surface side of the head cylinder (1) and the sand removing holes (4) on the upper surface side. ) (6) is provided. Then, for example, when the photoelectric sensors (5) and (6) are inserted into the water holes (3), respectively, and the light (La) projected from the first photoelectric sensor (5) is received by the second photoelectric sensor (6). , The inside of the hollow path (3a) is determined to be normal.

[0006]

The problem to be solved is that the inner surface of the hollow path (3a) has a fine textured surface with a satin finish, so that the light is diffusely reflected and the second sensor (6) on the light receiving side is accurate. The quality of the light from the first photoelectric sensor (5) for light projection is about 1 mm.
Due to the spot light of the diameter, only complete occlusion can be detected.
When the core (m) is half clogged as shown in (b), the spot light sometimes passes through the half clogged portion and becomes undetectable, and further, as shown in FIG. 4 (c). In addition, since the hollow path (4a) around the spark plug on the upper surface side of the head is a complicated mesh-shaped bending maze, the core (m) is inside the mesh (4c).
Even if it is clogged, the inspection cannot be performed not only by visual inspection but also by a photoelectric sensor method.

[0007]

According to the present invention, there is provided a supporting member which can be raised and lowered and swung with respect to an object to be inspected having a hollow path by an ascending and descending swivel mechanism coupled to a central portion, and a projecting member at one end of the supporting member. And a light projecting portion capable of projecting the diffused light emitted from the light emitting source toward the central portion of the entrance of the hollow path, and the other end of the support member, which is provided so as to directly face the light projecting portion and project. And a diffused light that is diffusely reflected from the inside of the hollow path and emitted from the inside of the hollow path is received by a two-dimensional plane and imaged in a planar manner. It is characterized by determining whether or not there is an abnormality.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an internal inspection device for a hollow path according to the present invention will be described below with reference to FIGS. In the figure, (7) is a supporting member, (8) is a light projecting portion,
(9) is an imaging unit. The support member (7) is provided so as to be able to move up and down and rotate with respect to the object to be inspected having the hollow path (4a) by an elevating and rotating mechanism connected to the central portion.
The light projecting unit (8) has an optical fiber (light guide) connected to a light emitting source (not shown) of diffused light, and a plane mirror (10) arranged to face the exit of the optical fiber. 7) Projected at one end. Then, the diffused light (Lb) derived from the light emitting source through the optical fiber is reflected by the plane mirror (10) and projected toward the center of the entrance of the hollow path (4a). Here, when the head cylinder (1) of the engine is inspected as an object to be inspected, for example, the light projecting portion (8) is inserted into the sand removing hole (4) and light is projected to the inlet of the bent hollow path (4a). .

The imaging section (9) receives a curved mirror (not shown) arranged opposite to the plane mirror (10) of the light projecting section (8) and the light reflected from the curved mirror on a two-dimensional plane for imaging. It has an imaging means, for example, a micro camera (not shown). Then, while keeping it standing upright on the rotating support table (11), the other end of the support member (7) is provided so as to directly face the light projecting part (8) so as to be rotatable, and the support table (11) is rotated. The imaging direction can be changed appropriately. Therefore, the diffused light emitted from the light projecting unit (8) and reflected and reflected by the curved mirror is received by a two-dimensional plane by a microminiature camera and is planarly imaged. Here, when the head cylinder (1) of the engine is inspected as an object to be inspected, the image pickup section (9) is inserted into the sand removal hole (4) through the light projecting section (8), and the hollow path (4a) is inserted. The diffused light that has been incident, diffused and internally reflected is then received and imaged.

The operation of the present invention based on the above configuration will be described below. First, the support member (7) is rotated up and down by the up-and-down rotating mechanism to insert the light projecting and imaging portions (8) and (9) into, for example, the pair of sand removing holes (4). Then, the diffused light emitted from the light projecting unit (8) into the hollow path (4a), diffusely reflected in the path and emitted is received by the microminiature camera of the imaging unit (9) in a two-dimensional plane and is planar. Image. Further, the inspection is performed by rotating the support member (7) or rotating the imaging unit (9) to change the imaging direction and the insertion position. Therefore, the area value or the like of the brightness image captured by each camera is identified to determine blockage or half clogging in the hollow path (4a).

Further, as another embodiment of the present invention, an optical fiber (12) connected to a light source of diffused light is used as a light projecting portion directly from the water hole (3) of the head cylinder (1) to the hollow path (3a). ) Flood inside. Then, the light emitted from the hollow path (3a) is diffusedly reflected and emitted in the hollow path (3a) by using the camera (13) as an imaging unit, and similarly to the above, whether or not there is an abnormality in the hollow path (3a) is determined from the captured image. At this time, if the insides of the hollow paths (3a) and (4a) are simultaneously imaged by the imaging section (9) and the camera (13), the insides of a plurality of different hollow paths can be inspected at once.

Further, as another embodiment, an optical fiber (14) is additionally disposed as a diffused light projecting portion so as to face the image pickup portion (9). Then, by rotating the image pickup section (9) to change the image pickup direction, the diffused light that is incident from the optical fiber (14) to the other adjacent hollow path (4a), diffusely reflects inside and is emitted in a two-dimensional plane. It is also possible to receive light, image it in a plane, and identify the characteristics of the captured image to determine the presence or absence of an internal abnormality in the hollow path.

Here, when the discriminant check is performed by, for example, fuzzy inference, 2 for imaging is performed prior to fuzzy inference.
The threshold value (H) is automatically set according to the hollow path which is the inspection object. Then, a binarized image having a luminous intensity equal to or higher than a predetermined level is taken out from the image picked up by the image pickup section (9) or the camera (13), and is inspected based on the feature amount such as the area or the perimeter of the image. Therefore, in the above threshold setting, first, the distributions of the feature quantities such as the area and perimeter of the images that serve as a plurality of reference images of the object to be inspected are measured in advance, and the membership function of fuzzy reasoning is created for each hollow path. deep. Further, as shown in FIGS. 2A and 2B, a plurality of binarizations are performed in order from the highest luminance distribution diagram (Ba) (Bb) of the image captured by the image capturing unit (9) and the camera (13). Threshold (Ha) (Hb)
Set (Hc). Then, in the case of a non-defective product, the binarized image area of each level gradually increases as the level of the threshold (H) decreases, and conversely, in the case of a defective product, the binarized image area remains constant. Alternatively, as shown in FIG. 2D, the threshold values (Ha) to (Hc) remain 0.

Therefore, the plane image picked up by the image pickup section (9) and the camera (13) is first binarized by the maximum threshold value (Ha), and the binarized image (Da) shown in FIG. 2C is taken out. . The degree of suitability of the binarized image area (Sa) at that time to the corresponding reference area is determined by fuzzy reasoning, etc., and if it is approximately equal to the reference area, the threshold value (Ha) is set to the optimum threshold value (Ho).
Then, the process shifts to the next inspection for the presence / absence of an internal abnormality.
When the binarized image area (Sa) becomes too large than the reference area, the level of the maximum threshold value (Ha) is set to a larger value and readjustment is performed.

Next, when the binarized image area (Sa) is smaller than the reference area, the object to be inspected is defective, or the luminance distribution shown by the dotted line in FIG. Even if the product is a non-defective product, the inner surface of the hollow path is rough or has a satin finish, so that the amount of emitted light is reduced. In this case, 1
The step level is lowered and the binarized image area is remeasured at the next highest threshold value (Hb). When the binarized image area (Sb) at that time is larger than the binarized image area (Sa) by the previous threshold value (Ha), or when the binarized image area substantially matches the corresponding reference area, it is determined as a good product, The threshold value (Hb) at that time is set as the optimum threshold value (Ho). If it gets too big,
The optimum value is a threshold value slightly raised from the threshold value (Hb). And, even if the threshold is lowered, the binarized image area (Sb)
Is constant or 0 from the beginning, it is determined as a defective product. The above operation is repeated a plurality of times, for example, about 5 times in sequence, and if the binarized image area is constant or 0, it is determined as a defective product. In this way, the binarized image area is determined, and the threshold level is appropriately automatically adjusted accordingly to set the optimum binarized threshold value (Ho).

There is also a means for directly setting the optimum threshold value (Ho) by using the centroid calculation of fuzzy inference. For example, as shown in FIG. 3A, each membership function (Ma) (Mb) of the binarized image area and the threshold is set as the input / output unit. Next, the binarized image area (So) is extracted from the luminance distribution shown in FIG. 2 (a) by a predetermined threshold value, and the goodness of fit (Ta) (Tb) is calculated from the membership function (Ma) of the input section.
Is determined. Then, the conformity (Ta) (Tb) is substituted into the membership function (Mb) of the output part, and as shown in FIG. 3 (b), it is optimized by calculating the center of gravity of the corresponding combined trapezoidal area (hatched part). Calculate the threshold value (Ho).

When the optimum binarization threshold value (Ho) is set, next, as shown in FIG. 3 (c), the threshold value (Ho) is set.
A binarized image (Do) is taken out from the image picked up by the image pickup unit (9) or the camera (13) based on the above, and the characteristic amount of the image (Do), for example, the area or the perimeter is measured. And FIG.
As shown in (d), a fuzzy reasoning membership function (Mc) is set in advance for each different hollow path, and the measured area data is substituted into the membership function (Mc), for example. Therefore, the goodness of fit (α) of the measured data to the normal data is derived from the membership function (Mc) of fuzzy reasoning. Therefore, the goodness of fit (α) is set to the reference value (A).
When α> A, it is judged as a non-defective product and the presence or absence of abnormality in the hollow path is inspected.

The membership function (Mc) measures the area and perimeter of a plurality of non-defective or defective works,
Probability distribution is drawn with a) as the normal region and (Nb) and (Nc) as the abnormal regions, and it is created for each hollow path and for each feature quantity such as area and perimeter. For example, in the area distribution, if the measured area is (Pa), the goodness of fit for normal data is (Qa), and from that, (Qa) and (A)
And the presence / absence of abnormality in the hollow path is determined based on the magnitude. The inside of the area (Nb) indicates an abnormal area caused by a decrease in the light amount due to the exit side of the path or the core, and the inside of the area (Nc) indicates an abnormality caused by an increase in the light quantity due to a closed casting burr at the middle of the path or the entrance. Indicates the area.

Alternatively, in the case of a plurality of route exits, the plurality of exits are imaged at once, and a binarized image including a plurality of each exit image in one image is taken out. Then, based on the image data, the presence / absence of an abnormality in the hollow path may be inspected by fuzzy reasoning using, for example, the total area of a plurality of images or the ratio of each image to the total area. Further, when a plurality of exits are imaged at once, the suitability of each of the plurality of images for each exit may be combined and, for example, the presence or absence of abnormality may be determined from the multiplication value. Further, in addition to the area and the perimeter, the position of the center of gravity of the image is added as a discriminant, and each fitness is multiplied.
It is possible to improve the inspection accuracy for a defective boundary.

Further, as shown in FIG. 4 (c), when inspecting the inside of a bent labyrinthine hollow path (4a), an abnormality in the mesh (4c) can be picked up only by projecting light from one direction. It may not be reflected at all, so it is not possible to determine whether there is an abnormality in the route (4a) sufficiently. Therefore, for example, the support member (7)
The light is projected from a plurality of different angles by turning or rotating the light projecting portion (8). Therefore, first, light is projected from one direction toward one side surface (4b) of the hollow path (4a), and the light passing through the path (4a) and the mesh (4c) thereof is imaged. Similarly, the light is projected from the other direction toward the other side surface (4d) in the hollow path (4a), and the light passing through the path (4a) and the mesh (4c) is imaged. Then, two different picked-up images are obtained by projecting light on two different side surfaces (4b) and (4d) of the hollow path (4a), and a difference in brightness area value or the like occurs depending on each image. . Therefore, the respective captured images are combined and the characteristics such as the brightness area value are compared and determined to determine whether or not there is an abnormality in the path (4a). Or,
The support member (7) is turned by 180 ° to invert the respective positions of the light projecting section (8) and the image capturing section (9) to project and image in the same manner as above. The presence / absence of abnormality may be determined.

In addition to the head cylinder as the object to be inspected,
The cylinder block can also be inspected for internal abnormality by the device of the present invention, and the invention can be similarly applied to other inspected objects having other hollow paths.

[0022]

According to the present invention, when the presence or absence of an internal abnormality in an object to be inspected having a bent hollow path in which the inside cannot be observed from the outside, a light projecting portion is provided at one end of a support member that can be raised and lowered. In addition, an image pickup unit is rotatably provided at the other end, and the light projected into the hollow path, diffusely reflected in the path, and emitted is received by the two-dimensional plane and imaged. Since the presence / absence of abnormality in the hollow path is determined from the characteristics such as the value, it is possible to accurately receive diffusely reflected light even in the bent hollow path.
Further, since the characteristics of diffusely reflected light such as brightness are discriminated and discriminated, not only complete occlusion but also half-clogging can be detected, and the inspection accuracy is greatly improved. Further, even if the inside of the hollow path is complicated with a labyrinth, the support member is appropriately swung to displace the light projecting section and the imaging section, and the presence or absence of an abnormality in the labyrinth-like hollow path can be inspected by taking images from a plurality of directions. .
Further, by adding a light projecting section which is directly inserted into the hollow path and an imaging section which captures the light emitted by diffusely reflecting the inside of the path, it is possible to inspect at once the presence or absence of abnormality in the plurality of hollow paths. Furthermore, by additionally arranging another light projecting unit so as to face the image pickup unit projecting from the support member, it is possible to inspect other hollow passages adjacent to the image pickup unit by rotating the image pickup unit, improving workability. To do.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of essential parts showing an embodiment of an internal inspection device for a hollow path according to the present invention.

FIG. 2A is a graph showing an example of the luminance distribution of a captured image in the internal inspection device for a hollow path according to the present invention and several kinds of binarized threshold values. (B) is a graph of another example of the luminance distribution of the captured image in the hollow path internal inspection apparatus according to the present invention and several kinds of binarized threshold values. (C)
FIG. 3 is a diagram showing an example of an image binarized with the threshold values shown in FIGS. FIG. 2D is a diagram showing a case where an image could not be extracted with the threshold values of FIGS. 2A and 2B.

FIG. 3A is a membership function of an input / output unit for threshold setting by fuzzy inference. (B) is a membership function showing an example of a centroid calculation of fuzzy inference.
(C) is a figure which shows an example of a binarized image. (D) is a waveform diagram showing an example of a fuzzy determination membership function.

FIG. 4A is a bottom view showing an example of a head cylinder. (B) is a partial vertical sectional view showing an example of a method for inspecting a head cylinder and a conventional hollow body. (C) is a partial horizontal sectional view of the upper surface side of the head cylinder.

[Explanation of symbols]

 1 Inspected object 3a, 4a Hollow path 7 Support member 8, 12, 14 Light projecting section 9, 13 Imaging section

Claims (3)

[Claims] 1. A support member which can be raised and lowered and swung with respect to an object to be inspected having a hollow path by an ascending and descending swivel mechanism coupled to a central portion, and one end of the support member projecting from the light emitting source. A light projecting portion capable of projecting diffused light in the direction of the central portion of the hollow path entrance, and a projection provided at the other end of the support member so as to face the light projecting portion, and enter the hollow path from the light projecting portion. An image pickup unit for receiving diffused light that is diffusely reflected inside and emitted in a two-dimensional plane and imaged in a plane, and distinguishes the presence or absence of an internal abnormality in the hollow path by identifying the characteristics of the above-mentioned imaged image. Internal inspection device for hollow path. 2. A light projecting unit for projecting diffused light to the entrance of the hollow path, and diffused light that is incident on the hollow path from each of the light projecting sections, diffusely reflects the inside, and exits on a two-dimensional plane. An image pickup section for planarly picking up images is added to the hollow path internal inspection apparatus according to claim 1, and diffused light emitted from each light projecting section entering different hollow path entrances and diffusely reflected inside is emitted. An internal inspection device for a hollow path, which is characterized by receiving light from a two-dimensional plane, imaging it at a time on a plane, and identifying the characteristics of each captured image to determine whether or not there is an internal abnormality in a plurality of different hollow paths. 3. A diffused light projecting unit is additionally arranged in the internal inspection device of the hollow path according to claim 1 so as to face the image pickup unit, and the image pickup unit is rotated to change the image pickup direction. The diffused light that has entered the hollow path inlet from the light projecting part, diffusedly reflected inside, and exited is received by a two-dimensional plane and imaged in a plane, and the features of the captured image are identified to determine whether there is an internal abnormality in the hollow path. An internal inspection device for a hollow path, which is characterized in that