JP2003254719A - Method of inspecting coating area - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method precisely inspect a coating condition without depending on manual work by a worker. <P>SOLUTION: This method is provided with an image inputting process for inputting an image as to one, or two or more of applied area(s) 6 applied on a base material 5, a converting process for AD-converting an image data provided by the image inputting process, an image processing process for calculating a position of each boundary 7 of the one, or two or more of applied area(s) 6 based on the data provided by the converting process, and an inter-applied- area-boundary distance calculating process for calculating a distance between the boundaries 7 based on the positions of the boundaries 7 calculated hereinbefore. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a product in which a sheet-shaped body such as an adhesive tape is coated with a coating material such as a pressure sensitive adhesive, an adhesive, and a back surface treating agent.

[0002]

2. Description of the Related Art Products such as adhesive tapes are made by applying a coating material such as an adhesive material to a sheet-shaped body, and after the coating material is automatically applied by a coating machine, the product is inspected. Is done.

Conventionally, the inspection has been performed by the operator's visual inspection or manual work. However, in the case of a product in which the application is performed not on the entire surface of the sheet-shaped formed body but on the application region of a specific shape, It is necessary to perform inspections such as the distance between the application areas, the dimensions of the application areas, and the position of the application area on the sheet-shaped forming body by a sampling inspection, etc.These inspections are performed using a caliper or the like. In addition, the inspection results were manually entered on the form.

[0004]

In the conventional visual inspection, it is difficult to perform a uniform inspection with no variation in results among operators, and even the same operator may suffer from deterioration of measurement accuracy due to fatigue. is there. In addition, a loupe with a scale may be used instead of a caliper due to accuracy requirements, but there is a problem in that measurement takes time. In addition, since the worker manually fills in the inspection result, there is a possibility that a filling error may occur. Further, the written inspection result is a list of numbers, and it is difficult to grasp the state of the application part.

The present invention solves the problems of the prior art, and an object of the present invention is to provide a coating area inspection method capable of accurately inspecting the coating state without the manual work of an operator. There is.

[0006]

A coating area inspection method according to the present invention comprises an image inputting step of inputting an image of one or more coating areas coated on a substrate in order to achieve the above object, and A conversion step of AD-converting the image data obtained by the image input step; an image processing step of calculating each boundary position of the one or more coating areas based on the data obtained by the conversion step; And a coating area boundary distance calculating step of calculating a distance between the boundaries from each boundary position.

In the coating area inspection method having the above structure, in the image input step, 1 or 2 formed on the base material is used.
The image data of the above-mentioned application area is taken in and then converted into a digital signal in a conversion step. Next, in the image processing step, the positions of the boundaries of the one or more coating areas are calculated, and from this result, the distance between the coating area boundaries is calculated in the coating area boundary distance calculating step. That is, it is possible to quickly obtain the distance between the boundaries of the coating areas on the base material without the need of the operator's hand. As the base material to which the application area is applied, a thin plate-like base material is used as well as a sheet-like base material.

Further, in the coating area inspection method according to the present invention, the distance between the calculated coating area boundaries and
It is preferable to include a step of comparing the reference values set in advance to judge the quality of the coating state. This allows
The quality of the product can be objectively determined without the operator's subjectivity.

Further, in the coating area inspection method according to the present invention, when the one or more coating areas are successively coated, the transition of the calculated distance between the coating area boundaries is recorded. And a step of displaying the transition of the distance between the recorded application area boundaries, based on the transition of the distance between the application area boundaries in the operating state of the applicator for applying the application area. It is preferable to include a step of displaying the evaluation result and correcting the operating condition of the coating machine based on the evaluation result.

In the step of displaying the recorded change in the distance between the boundaries of the respective application areas, the change in the distance is displayed on a screen of a personal computer or the like in a form that a worker can visually recognize it.

Further, the operating state of the coating machine is evaluated based on the transition of the distance between the coating area boundaries, and the result is displayed, whereby the operator can easily judge the operating state of the coating machine. can do. Further, the coating machine can always perform coating under optimum coating conditions by providing a step of correcting the operating conditions of the coating machine based on the result of the evaluation.

Further, the coating area inspection method according to the present invention includes an image input step of inputting an image of the base material and the coating area coated on the base material, and AD conversion of the image data obtained by the image input step. A conversion step for performing the image processing step of calculating the position of the boundary between the base material and the application area based on the data obtained by the conversion step; And a coating area position calculating step of calculating a distance of the area from the base material boundary.

In the coating area inspection method having the above structure, in the image input step, image data of both the base material and the coating area formed on the base material are captured, and then converted into digital signals in the conversion step. It Next, in the image processing step, the positions of the boundaries of the base material and the coating area are calculated, respectively, and from this result, in the coating area position calculating step,
The distance of the coating area from the substrate boundary is calculated. That is, it is possible to quickly obtain information on the position of the application region without the need for the operator's hand.

In the coating area inspection method according to the present invention, the calculated distance from the substrate boundary of the coating area and
It is preferable to judge whether the coating state is good or bad by comparing preset reference values. As a result, the quality of the product can be objectively determined without the operator's subjectivity.

Further, in the coating area inspection method according to the present invention, when the coating area is continuously coated, the transition of the calculated distance from the substrate boundary of the coating area is recorded. A step of displaying a transition of the recorded distance from the base material boundary of the coating area, and a transition of the distance of the coating area from the base material boundary of the operating state of the coating machine for applying the coating area. It is preferable to include a step of displaying the result of the evaluation and correcting the operating condition of the coating machine based on the result of the evaluation.

In the step of displaying the distance of the recorded application area from the base material boundary, the transition of the distance such as a graph is displayed on the screen of a personal computer in a form that can be visually recognized by an operator.

Further, the operating condition of the coating machine is evaluated based on the distance from the substrate boundary of the coating area, and the result is displayed, whereby the operator can easily judge the operating condition of the coating machine. can do. Further, the coating machine can always perform coating under optimum coating conditions by providing a step of correcting the operating conditions of the coating machine based on the result of the evaluation.

Further, in the image processing step in the coating area inspection method described above, a step of applying a differential process to the data obtained in the converting step to emphasize the boundary line of the image, and a boundary of the emphasized image. It is preferable to include a step of calculating a position where the pixel value is maximum near the line and a step of calculating a boundary position from the pixel value near the calculated position.

By differentiating the data obtained by image input and emphasizing the boundary line, the boundary between the coating region and the base material can be reliably extracted. Further, if the calculation is performed using the position where the pixel value is maximum and the pixel values in the vicinity of the position, the position of the boundary can be accurately obtained with a precision of pixel unit or less. As a concrete method, for example, there is a method in which the position of the maximum pixel value and the position of the center of gravity of the peak of the pixel value in the vicinity thereof are obtained and used as the boundary position.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a coating area inspection method according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows the arrangement of an apparatus for carrying out the coating area inspection method according to the first embodiment of the present invention. This apparatus includes an image capturing unit 1 that performs an image input process and an A that performs a conversion process.
It includes a D conversion unit 2, an image processing unit 3 that performs an image processing process, an arithmetic processing unit 4 that performs a coating region boundary distance calculation process, or a coating region position calculation process.

The image pickup section 1 converts the image of the product to be inspected into an electric signal, and the AD conversion section 2 further converts it into a digital signal. A CCD camera can be used as the imaging unit 1. The CCD camera can use both an area camera and a line sensor, but in the case of the line sensor, a driving unit such as an XY stage for scanning a product is required.

If an image scanner having the image pickup section 1 and the AD conversion section 2 is used, the apparatus can be constructed easily and inexpensively. A personal computer may be used as the image processing unit 3 and the arithmetic processing unit 4. Connect the image scanner to the personal computer, input image data and perform post-processing. Save the processing result in the hard disk in the personal computer. After multiple measurements, it is possible to display the transition of measured values on the screen of a personal computer from the accumulated data.

When the coating material to be measured is colored, it is possible to secure the contrast by using a color image as the image captured by the image pickup section 1.

The processing performed by the image processing section 3 and the arithmetic processing section 4 will be described below. FIG. 2 shows a flowchart of processing in the image processing unit 3. The measurement target is a coated product P having two rows of strip-shaped coating regions 6 made of an adhesive material on the sheet-shaped formed body 5 as shown in FIG.

In the image processing section 3, first, in order to correct the inclination of the image, inclination detection 11 is performed. As a method of detecting the inclination, the image is binarized to obtain a plurality of coordinate values for the right end or the left end of any of the stripe-shaped coating areas 6, 6, and a least-squares approximation straight line is calculated from these coordinate values. The inclination of this straight line is set as the inclination of the image, and the image is rotated by this inclination amount to perform the angle correction 12. In the present embodiment, since the application areas 6 applied in stripes are targeted, the inclination is corrected. However, for example, when the application area is circular, the inclination correction is unnecessary.

When the affine transformation is used for the rotation processing, linear interpolation or quadratic interpolation is performed because the accuracy deteriorates if the neighboring pixels are used as they are after the transformation.

Next, a differentiation process 13 is performed in order to emphasize the boundary line 7 between the application areas 6 and 6, and a differential image is obtained. In the case of the present embodiment, the boundary line 7 between the application areas 6 and 6 is a vertical line, and therefore the vertical line is emphasized. Therefore, the absolute value of the difference between the pixel values of the pixels on the left and right of the target pixel is obtained. Next, a projection value 1 in which a projection value obtained by integrating pixel values in the vertical direction of the differential image is projected
Determined by 4. Then, in the obtained projection value data, 4
The peak detection 15 for obtaining the coordinates of the peak is performed for each of the two boundary lines 7, and the positions of the boundary lines 7 of the coating areas 6, 6 are set.

Although the resolution depends on the resolution of the input image data, as shown in FIG. 4, the center of gravity is calculated from the peak of the differential image by the differential processing and a total of five pixel values around the peak according to the following formula 1. The position Xg is calculated and the boundary 7,
By setting the position to 8, the boundary position can be calculated with an accuracy of pixel unit or less.

[Equation 1]

The number of pixel values used at this time is determined from the peak shape of the differential image. Although five pixel values are used in FIG. 4, two pixels or three pixels are used when the peak is steeper, and seven pixels are used when the peak is gentle. When the peak shape and the pixel to be used are determined manually, the peak can be displayed on the screen of the personal computer, the shape can be visually determined, and the pixel to be used can be input from the keyboard. When this process is automatically performed, the shape is determined based on the height and width of the peak, the number of pixels used is determined based on this, and the pixels used in the peak and its surroundings are determined.

As another method for calculating the coordinates of a peak with an accuracy of less than a pixel unit, a pixel value near the peak is used to interpolate using an interpolation function such as a spline function, and the pixel value after the interpolation is the maximum. There is a method of setting the coordinates of as the boundary position.

Further, as a method of calculating the positions of the boundaries 7 and 8, the differentiation process is not performed, and as shown in FIG. 5, the pixel values are projected in the vertical direction and the values of the accumulated image are used to generate the spline function. There is also a method in which interpolation is performed using an interpolation function such as the above, and coordinates having the same pixel value as a preset threshold value are used as boundary coordinates.

In the arithmetic processing section 4, from the data of the boundary positions of the coating areas 6 obtained by the image processing section 3, the widths of the coating areas 6 and 6 represented by the distance between the coating area boundaries and the mutual relations are represented. Find the distance between. Next, multiply these values by the conversion coefficient to the actual distance on the inspection object of the coordinate data set in advance,
The actual width La between the coating areas 6, 6 and the mutual distance Lb are determined. When image data is input by an image scanner, its resolution is known, and since the resolution is the actual distance corresponding to two adjacent pixels of the input image, the resolution can be used as a conversion coefficient.

In order to accurately obtain the value of the actual distance, the calibration count K is calculated by calibration as follows.
It is better to calculate and multiply the obtained distance. First, the interval is D
The image of the reference product having the two boundary lines is input, the positions of the boundary lines are calculated by the same method as the calculation of the boundaries of the coating areas 6 and 6, and the distance between them is calculated and set as d. Then, D / d is set as a calibration meter coefficient K.

The position of the boundary of the sheet-shaped formed body 5 can also be calculated by the arithmetic processing unit 3 in the same manner as the position of the boundary of the coating regions 6, 6. In the arithmetic processing unit 4, the distance L between the application areas 6 and 6 and the boundary of the sheet-like formed body 5 is determined in the same manner as when the width La of the application areas 6 and 6 and the mutual distance Lb are obtained.
c can be obtained.

When an image is input for the coated product P in order to calculate the position of the boundary of the sheet-shaped forming body 5, the brightness contrast between the boundary portion of the sheet-shaped forming body 5 and the background portion is required. A background having a lightness different from that of the shape-forming body 5 is used. When the image captured by the imaging unit is a color image, backgrounds having different hues are used.

Depending on the combination of the lightness or hue of the sheet-shaped forming body 5 and the coating material, the boundary between the coating regions 6, 6 becomes unclear, and it becomes difficult to detect the coating material especially when the coating material is transparent. In such a case, when the coating material has adhesiveness or adhesiveness such as an adhesive material or an adhesive, the sheet-shaped forming body 5 and the entire application regions 6 and 6 have a lightness or a hue different from that of the sheet-shaped forming body 5. The powder in the application area 6, 6 can be left by only wiping it with a powder having a powder and wiping it off to remove the powder in the part of the sheet-like forming body 5 which is not sticky or adhesive, thereby ensuring the contrast. be able to.

When the sheet-shaped forming body 5 is made of a material that is permeable to water, such as paper or cloth, and the coating material is water-repellent such as silicone, the aqueous ink is sheet-shaped. When the entire formed body 5 and the application areas 6 and 6 are applied and wiped off, the ink on the application areas 6 and 6 is wiped off, and the ink remains only on the sheet-like formed body 5.

FIG. 6 shows the structure of an apparatus for carrying out the coating area inspection method according to the second embodiment of the present invention. The configuration and operation from the image capturing unit to the arithmetic processing unit 4 are the same as those of the device according to the first embodiment, so description thereof will be omitted.

Reference numeral 21 denotes a determination unit for performing the determination process, which is the width La of the coating regions 6, 6 obtained by the arithmetic processing unit 4 for performing the arithmetic processing step, the mutual distance Lb, and the coating regions 6, 6 and the sheet-like formation. If the value of the distance Lc to the boundary of the body 5 is within the preset allowable range, the application state is judged to be good, and if it is not within the allowable range, it is judged to be defective. The results of these judgments are displayed on the display unit 22 such as the screen of the personal computer in order to inform the operator.

FIG. 7 shows the structure of an apparatus for carrying out the coating area inspection method according to the third embodiment of the present invention. Also in this device, the configuration and operation from the image capturing unit to the arithmetic processing unit 4 are the same as those of the device according to the first embodiment, and therefore description thereof is omitted. In the following description, the distance Lc between the application areas 6 and 6 from the boundary of the sheet-shaped formed body 5 is the object of inspection, but the width La of each application area 6 and 6 and the mutual distance Lb are also inspected in the same manner. Can be the target of.

Reference numeral 31 is a recording unit for recording in the memory the distance Lc of the coating areas 6, 6 from the boundary of the sheet-like formed body 5 obtained by the arithmetic processing unit 4, and 32 is the data recorded in the recording unit 31. Is displayed on the display unit 33, an evaluation unit that evaluates the operating state of the applicator based on the data recorded in the recording unit 31, a display unit that displays the evaluation result, and a display unit 35 that displays the evaluation result on the basis of the evaluation result. It is an applicator adjustment unit that corrects the operating conditions of the applicator.

FIG. 8 shows one of the boundaries 7 between the application areas 6 and 6 on the continuously applied application product P recorded in the recording section 31 and one of the boundaries 8 of the sheet-like formed body 5. It is an example of a temporal transition of the distance Lc between. H is the upper limit value of the distance Lc, L is the lower limit value of the distance Lc, and S is the specification value of the distance Lc. In a, the position of the boundary fluctuates, but it is always within the allowable range. In b, the coating position is gradually moving, and there is a high possibility that the upper limit value H will be exceeded.

If the operator can know that the distance Lc may exceed the upper limit value by displaying the change of the value of the distance Lc on the display unit 32, the operator adjusts the applying process to set the applying position to the specified value S. It is possible to bring them closer and prevent the occurrence of defects.
The evaluation unit 33 detects that the distance value Lc has reached any of the threshold values by setting the threshold values close to the lower limit value H and the lower limit value L, and issues a warning to the display unit 34. With such a display, the operator can know that the application position has approached the upper limit value H or the lower limit value L of the distance Lc without referring to the display unit 32 even in such a case. Further, if the coating device is provided with a coating position automatic adjusting mechanism, the coating position can be automatically adjusted by the coating machine adjusting section 35 based on the evaluation.

Further, in the case of c, when the coating is carried out by the reverse coater shown in FIG. 9, abnormalities such as wear occur in the metering roll 16 and the applicator roll 17, and the coating position is in the cycle of the perimeter of these rolls. This is an example of fluctuation. Even in such a case, the operator can know from the display unit 32 that the distance Lc is changing periodically and can take a countermeasure. In addition, by analyzing the data of the transition of the distance Lc, the evaluation unit 33 is made to recognize that the distance Lc is changing periodically, and the display unit 34 displays that there is an abnormality in the coating device, so that the operator can see the abnormality. I can inform you.

[0046]

According to the coating area inspection method of the present invention, the dimensions of the coating area on the substrate necessary for the inspection, the distances between the boundaries of the coating areas, and the distances between the boundaries of the substrate and the coating areas are determined. It can be requested accurately and quickly without the need for the operator's hand.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an apparatus for carrying out a coating area inspection method according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing processing in an image processing unit.

FIG. 3 is a coated product to be measured.

FIG. 4 is a diagram illustrating a method of calculating a position of a center of gravity.

FIG. 5 is a diagram illustrating another method for obtaining the position of the boundary line.

FIG. 6 is a diagram showing a configuration of an apparatus for carrying out a coating area inspection method according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of an apparatus for carrying out a coating area inspection method according to a third embodiment of the present invention.

FIG. 8 is a diagram showing a transition of the position of a coating area.

FIG. 9 is a diagram showing a configuration of a main part of a reverse coater.

[Explanation of symbols]

5 base materials 6 Application area 7 Border of application area

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Osamu Degawa             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Akira Taguchi             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. F term (reference) 2F065 AA07 AA12 AA22 AA32 BB13                       CC02 DD06 FF04 JJ02 JJ03                       JJ25 JJ26 QQ04 QQ07 QQ18                       QQ31

Claims (7)

[Claims] 1. An image input step of inputting an image of one or more application areas applied on a base material, a conversion step of AD converting image data obtained by the image input step, and a conversion step of An image processing step of calculating each boundary position of the one or more coating areas based on the obtained data, and a coating area boundary distance calculating step of calculating a distance between the boundaries from each calculated boundary position. A method for inspecting a coating area, characterized by being provided. 2. The coating area inspection method according to claim 1, further comprising the step of comparing the calculated distance between the coating area boundaries with a preset reference value to judge whether the coating state is good or bad. 3. A step of recording the transition of the calculated distance between the application area boundaries when the one or more application areas are continuously applied, and each of the recorded application areas. A step of displaying a transition of the distance between the boundaries, and an operating state of a coating machine that performs coating of the coating area, displaying a result of evaluation based on a transition of the distance between the coating area boundaries, and the evaluation. The coating area inspection method according to claim 1, further comprising a step of correcting an operating condition of the coating machine based on the result of (1). 4. An image input step of inputting an image of a base material and a coating area applied on the base material, a conversion step of AD converting image data obtained by the image input step, and an conversion step of the conversion step. From an image processing step of calculating the position of the boundary between the base material and the coating area by the obtained data, from the position of the boundary between the calculated base material and the coating area,
And a coating area position calculating step of calculating a distance of the coating area from a boundary of the base material. 5. The coating area inspection according to claim 4, further comprising a step of comparing the calculated distance of the coating area from a substrate boundary with a preset reference value to judge whether the coating state is good or bad. Method. 6. The step of recording the transition of the calculated distance from the base material boundary of the application area when the application area is continuously applied, and the base material boundary of the recorded application area. And a step of displaying the transition of the distance from the, the operating state of the coating machine that performs the coating of the coating region, the result of evaluation based on the transition of the distance from the substrate boundary of the coating region is displayed, and The coating area inspection method according to claim 4, further comprising a step of correcting an operating condition of the coating machine based on an evaluation result. 7. The image processing step includes a step of applying a differentiation process to the data obtained in the converting step to emphasize a boundary line of the image, and a maximum pixel value in the vicinity of the boundary line of the emphasized image. And a step of calculating a boundary position with an accuracy of a pixel unit or less from a position where the calculated pixel value is maximum and a pixel value in the vicinity thereof. 4. The coating area inspection method according to 4, 5 or 6.