KR20210043326A - Method for inspecting film - Google Patents

Abstract

According to an embodiment of the present invention, a method for inspecting a film comprises the following steps of: obtaining an image photographing at least a portion of the film; calculating central coordinates on the center line of the film in the image; calculating a base line based on the central coordinates; and determining the bending degree of the film through the comparison between the central coordinates and the base line.

Description

Film inspection method {Method for inspecting film}

The present invention relates to a method for inspecting a film, and more particularly, to a method for inspecting a warp state of a film.

In the case of a thin film or a flexible film used in various industrial fields, whether the length of the film in the width direction is uniform and whether both ends of the film are manufactured side by side are closely related to the marketability of the thin film.

In particular, in the case of a film manufactured or distributed in a roll-to-roll method because the length in the length direction is significantly longer than the length in the width direction, the film must be manufactured to maintain a constant width and form a straight line at both ends.

Therefore, there are various techniques for preventing the thin film from snaking during the manufacturing process of the thin film.

Korean Patent Registration No. 10-1634669

The problem to be solved by the present invention is to provide a film inspection method capable of determining the warpage state of the film.

The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In the film inspection method according to an embodiment of the present invention for solving the above problem, the step of obtaining an image of at least a part of the film, calculating center coordinates on the center line of the film in the image, the center coordinate And calculating a reference line based on and determining a degree of warpage of the film through comparison of the center coordinates and the reference line.

The method further includes detecting coordinates of both sides of the film in the image, and in the calculating of the center coordinates, the center coordinates may be calculated based on the detected coordinates of both sides.

In the step of calculating the reference line, the reference line may be calculated to connect at least two or more of the center coordinates.

The reference line may be calculated to connect coordinates located at both ends of the center coordinates.

In determining the degree of warpage of the film, the degree of warpage of the film may be determined based on the distance between the center coordinate and the reference line.

In the step of determining the degree of warpage of the film, the degree of warpage of the film may be determined based on whether the center coordinate is located at one side or to the left of the reference line.

It may further include calculating a rotation correction amount of the image and rotationally correcting the center coordinates based on the calculated rotation correction amount.

In determining the degree of warpage of the film, the degree of warpage of the film may be determined based on a difference between the reference line and one of the components of the rotationally corrected center coordinates.

The rotation correction amount may be calculated based on angle information of a line segment connecting coordinates located at both ends of the rotationally corrected center coordinates.

In the step of calculating the reference line, the reference line may be calculated to connect coordinates located at both ends of the rotationally corrected center coordinates.

Other specific details of the present invention are included in the detailed description and drawings.

According to the embodiments of the present invention, there are at least the following effects.

The user can more easily determine the warp state of the film, and the warp state of the film, which the user cannot easily check with the naked eye, can also be accurately determined.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a view schematically showing a film inspection apparatus according to an embodiment of the present invention.
2 is a flow chart for explaining a film inspection method according to the first embodiment of the present invention.
3 is a diagram schematically showing an image of a good film.
FIG. 4 is a schematic representation of an image photographed of a film in which a warping phenomenon has occurred, and at the same time, is a view for explaining a process of determining a degree of warpage of a film using the film inspection method according to the first embodiment of the present invention.
5 is a flowchart illustrating a method of inspecting a film according to a second exemplary embodiment of the present invention.
6 is a diagram for explaining step S25.
7 is a diagram for explaining steps S26 to S28.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and are common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

Further, the embodiments described in the present specification will be described with reference to sectional views and/or schematic diagrams, which are ideal exemplary diagrams of the present invention. Accordingly, the shape of the exemplary diagram may be modified due to manufacturing techniques and/or tolerances. In addition, in each of the drawings shown in the present invention, each component may be somewhat enlarged or reduced in consideration of convenience of description. The same reference numerals refer to the same elements throughout the specification.

Hereinafter, the present invention will be described with reference to the drawings for explaining a film inspection apparatus and a film inspection method using the same according to an embodiment of the present invention.

1 is a view schematically showing a film inspection apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the film inspection apparatus 1 according to an embodiment of the present invention may include an image acquisition unit 10, a terminal 20, and an inspection stage 30. The terminal 20 may include an operation unit 21, an interface control unit 22, and a display 23.

The film B to be inspected passes over the inspection stage 30. As shown in FIG. 1, the film B may be configured to continuously pass over the inspection stage 30 in a roll-to-roll method, but the film B is placed on the inspection stage 30. The way of passing can be varied in various ways.

An image acquisition unit 10 is provided on the inspection stage 30 to photograph the film B on the inspection stage 30. The image acquisition unit 10 may include at least one line scan camera, but is not limited thereto, and various image acquisition means capable of acquiring an image of the film B may be used.

The image acquisition unit 10 transmits the acquired image of the film B to the terminal 20 side.

The operation unit 21 performs image processing on the image of the film B transmitted from the image acquisition unit 10 to perform steps of the film inspection method described later.

The interface control unit 22 displays an image of the film B transmitted from the image acquisition unit 10 and a film inspection result processed by the operation unit 21 through the display 23.

In addition, the interface controller 22 generates a graphic user interface displayed on the display 23, and a graphic displayed on the screen 32 in response to a user's input using a separate input device connected to the interface controller 22 Change the user interface.

The operation unit 21 and the interface control unit 22 have been described as separate configurations in order to functionally differentiate and describe, but in reality, they can be performed by one processing unit, and are individually configured by software that is operated on a computer. It can be configured or integrated.

1 illustrates an example in which the operation unit 21, the interface control unit 22, and the display 23 are integrated into one terminal 20, but according to the embodiment, the operation unit 21, the interface control unit 22, and the display ( At least one of 23) may be physically separated from other components and provided separately.

Hereinafter, a film inspection method using the above-described film inspection apparatus 1 will be described.

2 is a flow chart for explaining the film inspection method according to the first embodiment of the present invention, FIG. 3 is a schematic representation of an image taken of a good film, and FIG. 4 is an image taken of a film with a warpage phenomenon It is a schematic representation of, and at the same time, a view for explaining a process of determining the degree of warpage of a film using the film inspection method according to the first embodiment of the present invention.

As shown in Figure 2, the film inspection method according to the first embodiment of the present invention, the step of obtaining a film image (S11), the step of processing the image (S12), the step of detecting the coordinates of both sides of the film (S13), calculating the center coordinates of both sides (S14), calculating the reference line (S15), calculating the difference between the reference line and the center coordinate (S16), and displaying the warpage measurement result of the film (S17) ).

In the step of acquiring a film image (S11), the image acquisition unit 10 transmits an image of the film B on the inspection stage 30 to the terminal 20, and the operation unit 21 transfers the film B. Receive the captured image.

As shown in FIG. 3, when both sides of the film B in the image A are parallel to each other and are in a straight state, the film B in the image A is in a good state without warping.

However, as shown in FIG. 4, when at least a part of both sides of the film B in the image A is in a curved state, the film B in the image A has a curved section, and the degree of curvature is Therefore, it may result in defective treatment.

In the image processing step S12, the operation unit 21 may detect the boundary of the film B by processing the image transmitted from the image acquisition unit 10. In order to detect the boundary of the film B, the operation unit 21 may perform image processing such as binarizing the image.

In addition, the operation unit 21 may perform additional image processing to facilitate boundary detection of the film B. For example, image processing may be performed to remove a white portion or a black portion having a free shape from the binarized image.

In the step of detecting the coordinates of both sides of the film (S13), the operation unit 21 detects a plurality of coordinates located on both sides B1 and B2 of the film B in the image A processed in step S12. .

In the step of calculating the center coordinates of both sides (S14), the calculating unit 21 determines the center coordinates (P1) of both sides based on a plurality of coordinates located on both sides (B1, B2) of the film (B) detected in step S13. , P2, P3, P4, P5).

As shown in FIG. 4, in the case of the film B in which the X direction is the longitudinal direction and the Y direction is the width direction, the operation unit 21 is an X-axis among a plurality of coordinates detected at both sides B1 and B2. As the center coordinates of two coordinates having the same coordinates, the X-axis coordinates of the two coordinates may be used as the X-axis coordinates, and the average value of the Y-axis coordinates of the two coordinates may be used as the Y-axis coordinates.

In FIG. 4, only five representative center coordinates are displayed among a plurality of center coordinates for convenience of explanation. However, several center coordinates may be obtained in units of pixels of the image A. When the center coordinates are connected, the center line (C) Can be formed.

In the step S15 of calculating the reference line, the calculation unit 21 calculates the reference line based on the center coordinates calculated in the step S14.

For example, the calculation unit 21 may calculate a line connecting the coordinates P1 and P2 located at both ends of the center coordinates as the reference line S. In this case, the reference line S may be defined as follows.

Since the coordinates of P1 are (P1x, P1y) and the coordinates of P2 are (P2x, P2y),

The equation of the baseline can be defined as follows.

Alternatively, the calculation unit 21 may select two coordinates from among the center coordinates according to a predetermined rule, and calculate a line connecting the coordinates as a reference line.

In the step of calculating the difference between the reference line and the center coordinates (S16), the calculating unit 21 compares the plurality of center coordinates and the reference line S using the equation of the reference line S calculated in step S15 to compare the relative position between the two. Get information about the relationship.

For example, the calculation unit 21 may calculate a distance between the reference line S and the center coordinates, and a relative positional relationship between the reference line S and the center coordinates.

For example, the distance D3 between the reference line S and the coordinates P3x and P3y of one of the plurality of center coordinates P3 may be calculated by the following equation.

In addition, the distance D4 between the reference line S and the coordinates P4x and P4y of the other one P4 among the plurality of center coordinates may be calculated by the following equation.

Referring to FIG. 4, since P3 is located above the reference line S, the value of D3 is negative, and since P4 is located below the reference line S, the value of D4 is positive.

Accordingly, it is possible to determine whether the distance between the points P3 and P4 and the reference line S and whether the points P3 and P4 are located above or below the reference line S.

To generalize this, when the arbitrary coordinates among the center coordinates of the film B are (Pnx, Pny), the distance between (Pnx, Pny) and the reference line (S) ( Dn) and information about a relative position between (Pnx, Pny) and the reference line S may be obtained.

When the coordinates (P5x, P5y) of P5 coinciding with the reference line S are substituted into the above equation, the distance value is 0.

The calculation unit 21 may determine the degree of warpage of the film B based on the Dn value.

That is, depending on whether the distance (Dn) of the respective center coordinates with respect to the reference line (S) is positive or negative, it is determined whether the film (B) is located inside (or lower) or outside (or upper) on average with respect to the reference line. It may be determined, and it may be determined that the respective center coordinates are located far apart from the reference line S in proportion to the absolute value of the distance Dn.

For example, in the case of the film (B) shown in FIG. 4, based on the distance (Dn) of the center coordinates to the reference line (S), in the S1 section (from the point P1 to the point P5), the film (B) is On average, it is bent to have a shape located outside (or above) of the reference line (S), and in the S2 section (from point P5 to point P2), the film (B) is on average inside (or below) the reference line (S). It can be determined what is bent to have the shape to be positioned.

In addition, based on the absolute value of the distance (Dn) with respect to the reference line (S) of each center coordinate, in the S1 section (from the point P1 to the point P5), the film (B) is located at the outermost (or upper part) at approximately P3 Position, and in the S2 section (from the point P5 to the point P2), it may be determined that the film B is located at the innermost (or lower) position approximately at the point P4.

In the step (S17) of displaying the warpage measurement result of the film, the interface controller 22 may display the warpage measurement result of the film (B) on the display 23 based on the calculated result in step S16.

The interface control unit 22 receives distance (Dn) information about the reference line (S) of the center coordinates of the film (B) from the operation unit (21), and the image (A) of the film (B) photographed on the display (23) In addition, information about a direction in which the film B is bent and a distance between the coordinates and the reference line S may be displayed.

3 and 4 show an image (A) in which the longitudinal direction of the film (B) corresponds to the X-axis and the width direction to the Y-axis, and has been described based on this, but according to the embodiment, the length of the film (B) The film inspection method according to the first embodiment of the present invention may be similarly applied to an image whose direction corresponds to the Y axis and the width direction corresponds to the X axis.

When the above-described film inspection method is applied to an image in which the longitudinal direction of the film B corresponds to the Y axis and the width direction corresponds to the X axis, some of the above equations may be changed, but the length direction and the width direction are different. Since it is only, the modification of the equation can be easily predicted for those skilled in the art, and thus a detailed description thereof will be omitted.

5 is a flow chart for explaining a film inspection method according to a second embodiment of the present invention, FIG. 6 is a view for explaining step S25, and FIG. 7 is a view for explaining steps S26 to S28.

As shown in Figure 5, the film inspection method according to the second embodiment of the present invention, the step of obtaining a film image (S21), the step of processing the image (S22), the step of detecting the coordinates of both sides of the film (S23), calculating the center coordinates of both sides (S24), calculating the rotation correction amount of the image (S25), rotating the center coordinates (S26), calculating the reference line (S27), the reference line and Computing the difference between the center coordinates (S28) and displaying the warpage measurement result of the film (S29).

Steps S21 to S24 are similar to steps S11 to S14 described above, and detailed descriptions thereof will be omitted.

In the step of calculating the rotation correction amount of the image (S25), the calculation unit 21 calculates the rotation correction amount based on the center coordinates of the film B detected in step S24.

For example, as shown in FIG. 6, the calculation unit 21 may calculate information on the angle θ of a line segment connecting coordinates P1 and P2 located at both ends of the center coordinates as a rotation correction amount.

The angle θ of the line segment connecting P1 and P2 may be defined as follows.

Alternatively, the calculation unit 21 may select two coordinates among the center coordinates according to a predetermined rule, and calculate angle information of a line segment connecting the coordinates as a rotation correction amount.

In the rotation correction of the center coordinates (S26), the calculation unit 21 may rotationally correct the center coordinates of the film B based on the rotation correction amount calculated in the S24.

More specifically, the calculation unit 21 may rotate-correct the center coordinates of the film B so that the line segment connecting P1 and P2 is horizontal or vertical.

When rotating correction of the center coordinates (Pnx, Pny) of the film B so that the line segment connecting P1 and P2 is horizontal (parallel to the X-axis direction) based on FIG. 6, the corrected coordinates P' nx, P'ny) may be defined as the following rotation transformation matrix.

The above matrix is summarized as follows.

The operation unit 21 may rotationally correct the center coordinates of the film B based on the above equations.

7 shows an image of the film (B) rotationally corrected by step S25.

In the step of calculating the reference line (S27), the calculation unit 21 calculates a line connecting the coordinates (P'1, P'2) located at both ends of the center coordinates that have been rotationally corrected in step S26 as the reference line (S). I can. In this case, since the reference line S is parallel to the x-axis direction, the equation of the reference line S may be defined as follows.

또는

or

Hereinafter, for convenience of explanation, the equation of the reference line S will be described based on the former.

In the step (S28) of calculating the difference between the reference line and the center coordinate, the calculating unit 21 compares the corrected center coordinates of the film (B) with the reference line (S) using the equation of the reference line (S) calculated in step S27. Obtain information on the relative positional relationship between the two.

For example, the calculation unit 21 may calculate a distance between the reference line S and the rotationally corrected center coordinates, and a relative positional relationship between the reference line S and the rotationally corrected center coordinates.

The distance Dn between the plurality of rotationally corrected coordinates P'nx and P'ny and the reference line S may be defined as follows.

In the film inspection method according to the present embodiment, in step S25, the line segments connecting P1 and P2 are rotated so that they are parallel to the X-axis, and the center coordinates (Pnx, Pny) of the film B are also rotated. The reference line (S) connecting the rotationally corrected P'1 and P'2 by P2 is also parallel to the X axis, so the distance between the reference line (S) and the rotationally corrected center coordinates (P'nx, P'ny) (Dn) can be calculated only with the y component of the rotationally corrected center coordinates (P'nx, P'ny).

According to an embodiment, when rotation correction is performed so that the line segment connecting P1 and P2 is parallel to the Y axis in step S25, the reference line (S) is rotated with only the x component of the rotationally corrected center coordinate (P'nx, P'ny) The distance Dn between the corrected center coordinates P'nx and P'ny may be calculated.

Accordingly, the method of inspecting a film according to the present exemplary embodiment enables a fast operation speed in calculating the distance between the reference line S and the center coordinates of the film B.

In addition, according to the equation for calculating Dn, it can be checked whether the rotation-corrected center coordinates P'nx and P'ny are positioned above or below the reference line S.

In the case of P'3 (P'3x, P'3y), since P'3y, which is the y component, is greater than P'1y, D3 becomes a positive number, and in the case of P'4 (P'4x, P'4y), Since the y component P'4y is smaller than P'1y, D4 becomes negative.

Similar to the case of the first embodiment, it is possible to know whether the center coordinate is outside or inside the reference line S according to whether the Dn value is positive or negative.

Accordingly, the calculation unit 21 may determine the degree of warpage of the film B based on the absolute value and sign of the Dn value.

For example, in the case of the film B shown in Fig. 6, as shown in Fig. 7, based on the distance Dn of the center coordinates to the reference line S, the S1 section (from the point P'1) In the P'5 point), the film (B) is bent to have a shape located outside (or above) the reference line (S) on average, and in the S2 section (from the point P'5 to the point P'2), the film ( It may be determined that B) is bent so as to have a shape positioned inside (or below) the reference line S on average.

In addition, based on the absolute value of the distance (Dn) with respect to the reference line (S) of the respective center coordinates, the film (B) is the most in the S1 section (from the point P'1 to the point P'5) approximately at the point P'3. It may be determined that the film B is positioned at the outermost (or upper) side, and the film B is positioned at the innermost (or lower) position approximately at the point P'4 in the S2 section (from the point P'5 to the point P'2).

Since the step (S29) of displaying the warpage measurement result of the film is similar to the step S17 described above, a detailed description thereof will be omitted.

6 and 7 show an image (A) in which the longitudinal direction of the film (B) corresponds to the X-axis and the width direction to the Y-axis, and has been described based on this, but according to the embodiment, the length of the film (B) The film inspection method according to the first embodiment of the present invention may be similarly applied to an image whose direction corresponds to the Y axis and the width direction corresponds to the X axis.

When the above-described film inspection method is applied to an image in which the longitudinal direction of the film B corresponds to the Y axis and the width direction corresponds to the X axis, some of the above equations may be changed, but the length direction and the width direction are different. Since it is only, the modification of the equation can be easily predicted for those skilled in the art, and thus a detailed description thereof will be omitted.

As described above, according to the film inspection apparatus and the film inspection method using the same according to an embodiment of the present invention, the warpage status of the film is more easily displayed by the user because it calculates and determines whether or not the film is warped and the degree of warpage, and displays it to the user. Can be determined, and the bending state of the film that the user cannot easily check with the naked eye can also be accurately determined.

Those of ordinary skill in the art to which the present invention pertains will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and are not limiting. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

1: film inspection device 10: image acquisition unit
20: terminal 30: inspection stage
A: Image B: Film
C: center line S: baseline

Claims (10)

Obtaining an image of at least a portion of the film;
Calculating center coordinates on the center line of the film within the image;
Calculating a reference line based on the center coordinates; And
Determining the degree of warpage of the film through the comparison of the center coordinates and the reference line; including, film inspection method. The method of claim 1,
Further comprising; detecting coordinates of both sides of the film in the image,
In the calculating of the center coordinates, the center coordinates are calculated based on the detected coordinates of both sides. The method of claim 1,
In the step of calculating the reference line,
The reference line is calculated to connect at least two or more of the center coordinates. The method of claim 3,
The reference line is calculated to connect coordinates located at both ends of the center coordinates. The method of claim 1,
In the step of determining the degree of warpage of the film,
Determining the degree of warpage of the film based on the distance between the center coordinate and the reference line, film inspection method. The method of claim 1,
In the step of determining the degree of warpage of the film,
Determining the degree of warpage of the film based on whether the center coordinate is located on one side or the left side of the reference line, film inspection method. The method of claim 1,
Calculating a rotation correction amount of the image; And
Comprising the rotation correction of the center coordinates based on the calculated rotation correction amount; further comprising, a film inspection method. The method of claim 7,
In the step of determining the degree of warpage of the film,
Determining the degree of warpage of the film based on a difference between the reference line and one of the components of the rotationally corrected center coordinates. The method of claim 7,
The rotation correction amount is calculated based on angle information of a line segment connecting coordinates located at both ends of the rotationally corrected center coordinates. The method of claim 7,
In the step of calculating the reference line,
The reference line is calculated to connect coordinates located at both ends of the rotationally corrected center coordinates.

Images