JPH11175737A - Positioning method for honeycomb structure and machining method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning method and a machining method for a honeycomb structure which are not affected by the mechanical positioning precision of the honeycomb structure and the warpage and shrinkage rate of cells. SOLUTION: The positioning method for the honeycomb structure which determines the position of a specific cell of the honeycomb structure measures the end surfaces of the honeycomb structure by a camera and finds the center coordinates of the specific cell from the position relation of the cell 1 with the product center. Further, the center position coordinates of the specific cell from the cell in the produce center are found by implementing a horizontal axis search rule, a vertical axis search rule, and a target cell search rule. Further, the honeycomb structure is machined by applying the search rules.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for positioning and processing a honeycomb structure in which contraction and deformation are different for each product, and mechanical positioning accuracy is difficult to obtain with a jig or the like.

[0002]

2. Description of the Related Art Conventionally, in order to process a honeycomb structure with high accuracy, it has been necessary to accurately determine the position of a cell on an end face of the honeycomb structure. FIG. 7 is a diagram showing an end face of a metal honeycomb heater as an example. In this type of metal honeycomb heater, a plurality of slits 5 are formed in the honeycomb structure 51 in order to obtain a predetermined resistance value for heat generation.
2 are formed, and the cell row to be processed and the position of the end point cell in forming the slit 52 are determined by design.
Therefore, it is necessary to accurately determine the cell row and the end point cell on the end face of the honeycomb structure as a product.

Further, when the slit 52 is to be formed on the honeycomb structure just extruded before firing, a processing pin 54 is inserted into the center position of each cell 53 as shown in FIG. Then, the cell 5 is
The slit 52 is formed by tearing off the wall of No. 3. Therefore, in this case as well, it is essential to accurately grasp the position of the center of the cell 53 for high-precision slit processing.

[0004]

As one method for this purpose, an attempt has been made to obtain the position of a cell by image processing. However, even if a conventionally known image processing technique is simply applied, the following method is required. As described above, the cell position on the end face of the honeycomb structure could not be determined accurately.

That is, in the conventional image processing technology, an apparatus that can move the center of the camera to an arbitrary position of the honeycomb structure by an automatic stage or a robot is used. When the target cell is at the position indicated by a black circle on the drawing as shown in FIG. 9, the target cell is moved to the position indicated by the black circle on the drawing by the coordinate system of the automatic stage or the robot, and is enlarged to capture the image shown in FIG. . The most central cell in this image is regarded as a target cell, and the shift amount is calculated. In this method, it is not possible to distinguish the neighboring cell and the target cell shown in the screen by the shape, and due to the difference in the warp and the shrinkage ratio, FIG.
As shown in FIG. 1, when the cell size is shifted by セ ル or more, there is a problem that a neighboring cell is erroneously detected.

When a cylindrical ceramic honeycomb structure is set in an image processing apparatus by using a jig 61 as shown in FIG. 12, it is difficult to obtain positioning accuracy in the rotational direction. Since it is difficult to match the horizontal and vertical directions of the image processing apparatus, the target cell position is significantly shifted from the design position, and there is a problem that erroneous detection is performed.

Further, in processing the honeycomb structure, the position of the cell at the processing start point and the position of the cell at the processing end point are determined, and the honeycomb is simply processed linearly from the cell at the processing start point to the cell at the processing end point. If the cells of the structure are warped or deformed, there is a problem that a portion other than the cell wall to be processed is cut off.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a positioning method and a processing method of a honeycomb structure that are not affected by mechanical positioning accuracy of the honeycomb structure, cell warpage, and shrinkage.

[0009]

According to a method for positioning a honeycomb structure of the present invention, an end face of the honeycomb structure is measured by a camera, wherein the position of a specific cell of the honeycomb structure is determined. With respect to the measured image, the center position coordinates of a specific cell are obtained based on the positional relationship from the cell at the center of the product.

In the method of positioning a honeycomb structure according to the present invention, when the coordinates of the center position of a specific cell are determined, the coordinates are not determined by moving a stage or a camera on which the honeycomb structure is set based on a positional relationship in design. By determining based on the positional relationship from the center cell of the honeycomb structure as an actual product, it is possible to position the honeycomb structure without being affected by the mechanical positioning accuracy of the honeycomb structure and the cell warpage and shrinkage. Become.

Further, the method for processing a honeycomb structure according to the present invention is the method for processing a honeycomb structure, wherein an end face of the honeycomb structure is measured by a camera, and
Recognize the cell next to the right, left, upper or lower from the processing start cell, and recognize the right next, left next,
It is characterized in that it is processed to the center of the upper or lower adjacent cell.

In the method for processing a honeycomb structure according to the present invention,
Recognizes the cell on the right, left, upper, or lower side from the cell at the processing start point, and processes to the center of the cell on the right, left, upper, or lower side recognized from the center of the cell at the processing start point. With such a configuration, even when the cells of the honeycomb structure are warped or deformed, portions other than the cell wall to be processed are not cut.

[0013]

FIG. 1 is a flowchart showing an example of a method for positioning a honeycomb structure according to the present invention. FIG.
The method of positioning the honeycomb structure of the present invention will be described in accordance with the following. First, the end face of the honeycomb structure is measured by a camera, and an image of the end face is captured as, for example, one byte per pixel.
A threshold value for binarization is determined from a histogram of the pixel density of the captured image, and a binarized image is obtained based on the determined threshold value. This binarization processing includes inversion 2
It is preferable that the cell be whitened by performing a value processing. Next, by performing an expansion process, a black portion between the cell and the node is painted out, the whole honeycomb structure is made into one mass, and the center of gravity of the honeycomb structure as a product based on the honeycomb structure recognized as this mass. And stores the address of the center of gravity. At the same time, after labeling each cell based on the inverted binary image before the dilation processing and specifying each cell,
The center of gravity of each cell is calculated and stored. This center of gravity becomes the coordinates of the center position of each cell. Next, on the binarized image, the cell closest to the address of the center of gravity of the product obtained in advance is determined as the center cell. Thereafter, based on the determined center cell, a horizontal axis search, a vertical axis search, and a target cell search are performed, and finally the coordinates of the center position of the specific target cell are obtained.

Next, an example of a cell search according to the present invention will be described. First, the horizontal axis is determined from the determined center cell according to the horizontal axis search rule. In the search of the horizontal axis, when the cell shape of the honeycomb structure is a hexagonal cell, the cell closest to the right within ± 30 degrees from the center cell position is recognized as the cell to the right, and the search for the honeycomb structure is performed. If the cell shape is a square cell, ± 45 from the center cell position
This is performed by recognizing the closest cell within the degree as the cell on the right. The horizontal axis can be determined by repeating the above horizontal axis search rule and connecting a plurality of cells on the right.

FIG. 2 is a diagram for explaining a method of determining adjacent cells forming the horizontal axis according to the horizontal axis search rule in a honeycomb structure having a hexagonal cell. In the example shown in FIG. 2, the virtual axis A is drawn to the right with respect to the center cell C0 regardless of the orientation of the cells of the honeycomb structure, and the cells C1, which are within ± 30 degrees of the virtual axis A, C2, C
3 is determined to be the cell on the right. Here, since the cell C1 is the cell closest to the center cell C0, the cell C1 is determined to be the cell on the right. Next, a similar horizontal axis search rule is executed with reference to the cell C1, and the cell C1
By determining the cell to the right of 1 and repeating this search rule thereafter, the horizontal axis extending from the center cell C0 of the honeycomb structure can be obtained regardless of the orientation of the cells of the honeycomb structure. Note that, even in a honeycomb structure having a square cell shape, the horizontal axis can be determined in exactly the same manner except that the angle for taking in the cell is within ± 45 degrees with respect to the virtual axis A.

After the horizontal axis from the center cell is determined by the method described above, the vertical axis is determined from the center cell according to the vertical axis search rule. When the honeycomb structure has a hexagonal cell shape, the search for the vertical axis is performed for cells located at an arbitrary upper position from the center cell position, that is, preferably within ± 60 degrees with respect to the direction perpendicular to the determined horizontal axis. The nearest cell and the second nearest cell are selected, and one of them is alternately recognized as the upper neighboring cell. When the cell shape of the honeycomb structure is a square cell, an arbitrary upper side from the center cell position is selected. That is, it is preferably performed by recognizing the nearest cell within ± 45 degrees with respect to the direction perpendicular to the determined horizontal axis as the cell immediately above. The vertical axis can be determined by repeating the above vertical axis search rule and connecting a plurality of cells on the upper side.

FIG. 3 is a diagram for explaining a method of determining adjacent cells forming a vertical axis in accordance with a vertical axis search rule in a honeycomb structure having a hexagonal cell. In the example shown in FIG. 3, a virtual axis B is drawn to the center cell C0 at an arbitrary upper side, preferably perpendicular to the horizontal axis, and ± 6
The closest cell and the second closest cell among the cells C1 to C5 within the angle of 0 degrees are selected, and one of them is alternately determined as the upper adjacent cell. Here, the cells C1 and C2 are selected as the closest cell and the second closest cell, and one of them is assumed to be the left cell C
1 is determined as the cell on the upper side. Next, a similar vertical axis search rule is executed with reference to the cell C1, but the left cell of the two selected cells is determined to be the upper adjacent cell in the previous time. The cell on the right is selected as the cell on the upper side. In a honeycomb structure having a square cell shape, the vertical axis can be obtained by a method similar to the above-described horizontal search rule for a honeycomb structure having a square cell, unlike the case of the hexagonal cell described above. .

After the horizontal axis and the vertical axis from the center cell are determined by the above-described method, a specific target cell is determined from the center cell according to a target cell search rule. The target cell search rule first determines the vertical distance (the number of cells) from the center cell of the specific cell from the address of the specific cell on the design drawing, and sets a position separated by the distance obtained on the vertical axis as a starting point. decide. Thereafter, when the cell shape of the honeycomb structure is a hexagonal cell, the nearest cell within ± 30 degrees from the position of the starting point with respect to the horizontal axis is recognized as the next cell in the horizontal direction, and the honeycomb structure is formed. When the cell shape of the body is a square cell, this is performed by recognizing the closest cell within ± 45 degrees with respect to the horizontal axis from the position of the starting point as the next cell in the horizontal direction.

FIG. 4 is a view for explaining a method of determining a specific cell in accordance with a target cell search rule in a honeycomb structure having a hexagonal cell. In the example shown in FIG.
When determining the specific cells C1, C2, and C3, first, the respective starting points are CS1 (= C0), CS2, and C2 on the vertical axis.
S3 is obtained, and the specific cell C1 and the specific cell C1 are moved by moving in the horizontal axis direction (the number of cells) obtained from the design drawing around these starting points according to the target cell search rule.
C2 and C3 can be obtained. It should be noted that a target specific cell can be obtained in the same manner as in the above-described method also for a honeycomb structure having a square cell shape.

Since the number of cells of the honeycomb structure which is an object of the present invention is very large and the number of pixels which can be used for image processing is limited, sufficient resolution may not be obtained in some cases. In such a case, as shown in an example in FIG. 5, cells may not be continuous in a binarized image, for example, as shown in part A thereof. Such two
When the center of gravity of each cell is obtained based on the valued image, the center of gravity of two consecutive cells is obtained, and therefore the center of gravity of each cell cannot be obtained accurately, and the position of a specific cell cannot be obtained accurately. Therefore, in such a case, each cell is reliably separated by subjecting the binarized image to a contraction process to uniformly thicken the cell walls and to make the cell walls continuous as shown in FIG. Then, the center of gravity can be determined accurately.

When the length of the honeycomb structure in the axial direction is short, when the irradiation light is irradiated from directly above, reflection occurs on the bottom surface of the pedestal of the product, and the reflected light adversely affects image processing. In such a case, it is desirable to use irradiation light of oblique projection.

The actual time required to measure a specific cell is compared between the prior art and the present invention. The time required to obtain the cell coordinates at both ends of the eleven slit rows is calculated according to the conventional technique: Stage moving time *. Both ends * number of rows = 2 (seconds) * 2
(Pieces) * 11 (rows) = 88 seconds, whereas the present invention:
Image processing time + search processing time = 26 seconds, indicating that the measurement time of the present invention can be reduced as compared with the related art.

In the above-described embodiment, it has been described that each search rule is formed by obtaining the cell on the right side when the horizontal axis is obtained and by the cell on the upper side when the vertical axis is obtained. It goes without saying that the same algorithm can be used even if the horizontal and vertical axes are used to determine the horizontal and vertical axes.

Next, when processing the honeycomb structure,
The above-described method for positioning the honeycomb structure can be applied. That is, in the method for processing a honeycomb structured body of the present invention, the right next cell, the left cell, the upper cell or the lower cell are recognized from the cell at the processing start point, and the right cell, the left cell, and the left cell are recognized from the center of the cell at the processing start point. It is configured to process to the center of the next, upper, or lower cell. Then, by continuing this processing, final processing can be performed. At this time, right next, left next,
As the rule for recognizing the upper neighbor and the lower neighbor, the above-described horizontal axis search rule and vertical axis search rule of the present invention can be used. According to the method for processing a honeycomb structure, even when the honeycomb structure is warped or deformed,
No part other than the cell wall to be processed is cut. Also, when performing processing on a cell row that is arranged horizontally on the horizontal axis, by searching for the processing start point and end point from the vertical axis to the left and right, the center coordinates of all cells on that row You can know the relationship. This makes it possible to obtain information for processing so as to connect the center of the cell from the processing start point to the end point without increasing the processing time.

[0025]

As is apparent from the above description, according to the present invention, when obtaining the center position coordinates of a specific cell,
Instead of moving the stage or camera on which the honeycomb structure is set based on the positional relationship in the design,
Since it is determined based on the positional relationship from the center cell of the honeycomb structure as an actual product, it is possible to position the honeycomb structure without being affected by the mechanical positioning accuracy of the honeycomb structure and the cell warpage and shrinkage ratio Becomes Further, by applying the above search rule, the processing of the honeycomb structure can be performed without cutting a portion other than the cell wall to be processed.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a method for positioning a honeycomb structure of the present invention.

FIG. 2 is a diagram for explaining a method of determining an adjacent cell according to a horizontal axis search rule according to the present invention.

FIG. 3 is a diagram for explaining a method for determining an adjacent cell according to a vertical axis search rule according to the present invention.

FIG. 4 is a diagram illustrating a method for determining a specific cell according to a target cell search rule according to the present invention.

FIG. 5 is a diagram showing an example of a binarized image to be subjected to contraction processing in the present invention.

FIG. 6 is a diagram illustrating a result of a contraction process performed on the binary image illustrated in FIG. 5;

FIG. 7 is a diagram illustrating an example of an end face of a metal honeycomb.

FIG. 8 is a diagram for explaining an example of slit processing.

FIG. 9 is a diagram illustrating an example of an end face of a honeycomb structure in conventional image processing.

FIG. 10 is a diagram for explaining an example of a method of determining a target cell in conventional image processing.

FIG. 11 is a diagram illustrating an example of a measurement error in conventional image processing.

FIG. 12 is a diagram for explaining another example of a measurement error in conventional image processing.

Claims (8)

[Claims] 1. A method for positioning a honeycomb structure, which determines a position of a specific cell of the honeycomb structure, wherein an end face of the honeycomb structure is measured by a camera, and a measured image is determined based on a positional relationship from a cell at the center of a product. A method for positioning a honeycomb structure, comprising: obtaining coordinates of a center position of a specific cell. 2. The positioning of the specific cell based on the positional relationship from the product center cell is performed by determining the center of gravity of the entire product from an image, recognizing each cell, determining the position of the center of gravity of each cell, and determining the position of the center of gravity of the product. The closest cell is determined as the center cell, the horizontal axis is determined from the center cell according to the search rule, the vertical axis is searched from the center cell vertically to the horizontal axis according to the search rule, the vertical axis is determined, and the target cell is set at the vertical axis. 2. The method for positioning a honeycomb structure according to claim 1, wherein the specific cell is determined by performing a horizontal search. 3. When the cell shape of the honeycomb structure is a hexagonal cell, the horizontal axis search rule is such that the nearest cell within ± 30 degrees to the right of the current cell position is defined as the cell to the right. The search rule of the vertical axis is a rule for recognizing that the nearest cell and the second nearest cell are selected within ± 60 degrees from the current cell position, and any one of them is alternately placed on the upper side. 3. The method for positioning a honeycomb structure according to claim 2, wherein the rule is a rule for recognizing the cell as a cell. 4. When the cell shape of the honeycomb structure is a quadrangular cell, the horizontal axis search rule is such that the nearest cell within ± 45 degrees to the right of the current cell position is defined as the cell to the right. 3. The honeycomb structure according to claim 2, wherein the rule for recognizing is a rule for recognizing a closest cell among cells located within ± 45 degrees above the current cell position as an adjacent cell above. Positioning method. 5. A target cell search rule for determining a specific cell by searching for the target cell in a horizontal direction with a vertical axis as a starting point is a current cell when the cell shape of the honeycomb structure is a hexagonal cell. This is a rule for recognizing the nearest cell within ± 30 degrees from the position to the horizontal axis as the next cell in the horizontal direction. If the cell shape of the honeycomb structure is a square cell, the current cell position is determined. ± 45 from the horizontal axis
The method for positioning a honeycomb structure according to any one of claims 2 to 4, wherein the rule is such that a cell closest to the cell within a degree is recognized as a next cell in the horizontal direction. 6. A method for processing a honeycomb structure, wherein an end face of the honeycomb structure is measured by a camera, and a cell on the right side, left side, upper side or lower side from a cell at a processing start point is measured with respect to the measured image. A method for processing a honeycomb structure, comprising: recognizing and processing to the right, left, upper, or lower adjacent cell center recognized from the center of the cell at the processing start point. 7. When the cell shape of the honeycomb structure is a hexagonal cell, a right or left ± 3 from the cell position of the processing start point.
Recognizes the closest cell within 0 degrees as the cell to the right or left, and the cell closest to the cell within ± 60 degrees above or below the cell position of the processing start point and the second closest cell 7. The method for processing a honeycomb structure according to claim 6, wherein any one of the cells is selected as an upper adjacent cell or an adjacent lower cell. 8. When the cell shape of the honeycomb structure is a quadrangular cell, a right or left side ± 4 from the cell position of the processing start point.
Recognizes the closest cell within 5 degrees as the cell next to the right or left, and the cell closest within ± 45 degrees above or below the cell position of the processing start point is next to the cell above or below. The method for processing a honeycomb structure according to claim 6, wherein the honeycomb structure is recognized as a cell.