Orange peel evaluation method and orange peel evaluation device

Abstract

To provide an orange peel evaluation method for quantitatively evaluating the degree of orange peel of a sheet-like member.SOLUTION: An orange peel evaluation method includes the steps of: preparing a sample in which a sheet-like member is fixed to a glass plate; irradiating a surface of the sheet-like member with light from a light source; photographing an image of the light source reflected on the sample by using an imaging apparatus to acquire image data; setting a measurement area including the contour of the light source in the image data; analyzing a variation of a feature amount from the image data included in the measurement area; and evaluating the degree of orange peel of the sheet-like member on the basis of the variation of the feature amount.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for evaluating yuzu skin and an apparatus for evaluating yuzu skin. More specifically, the present invention relates to a method for evaluating the degree of yuzu skin of a sheet-like member and an apparatus for evaluating yuzu skin.

Background Art

[0002] Patent Document 1 discloses a yuzu skin measuring device that measures the degree of unevenness on the surface of a painted surface or the like, that is, the yuzu skin value, using a pattern having light and dark portions with different light transmittances.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, the evaluation of the yuzu skin of a sheet-like member such as a resin film or a metal film has been determined visually, and there has been variation in the evaluation. Therefore, a method for quantitatively evaluating the yuzu skin of a sheet-like member has been demanded. Yuzu skin is a pattern in which the surface of a sheet-like member appears uneven like the skin of a yuzu fruit.

[0005] In addition, a method for simply and quantitatively evaluating the yuzu skin of a sheet-like member without using a complicated configuration and an expensive apparatus such as that of Patent Document 1 has been demanded.

[0006] One object of the present invention is to provide a method for evaluating yuzu skin for quantitatively evaluating the degree of yuzu skin of a sheet-like member.

Means for Solving the Problems

[0007] (1) The method for evaluating yuzu skin according to one aspect of the present invention includes the steps of preparing a sample in which a sheet-like member is fixed to a glass plate, irradiating light from a light source onto the surface of the sheet-like member, capturing an image of the image of the light source reflected on the sample with an imaging device to obtain image data, setting a measurement region including the contour of the light source in the image data, analyzing the variation of feature amounts from the image data included in the measurement region, and evaluating the degree of yuzu skin of the sheet-like member based on the variation of the feature amounts.

[0008] The method for evaluating yuzu skin in the above (1) can quantitatively evaluate the degree of yuzu skin of a sheet-like member by a simple method of analyzing the variation of feature amounts from image data using highly versatile devices such as a light source and an imaging device.

[0009] (2) In the method for evaluating yuzu skin described in the above (1), the image data is composed of an aggregate of a plurality of pixels arranged two-dimensionally. The feature amounts may be a plurality of numerical data for each pixel corresponding to the brightness or luminance of the image.

[0010] The method for evaluating yuzu skin in the above (2) can easily and accurately evaluate the degree of yuzu skin of a sheet-like member by calculating the variation of feature amounts using numerical data corresponding to brightness or luminance.

[0011] (3) In the method for evaluating yuzu skin described in the above (2), the value of the variation of the feature amounts may be the standard deviation or variance of the plurality of numerical data.

[0012] The method for evaluating yuzu skin in the above (3) can easily and accurately evaluate the degree of yuzu skin of a sheet-like member based on the variation of feature amounts by a simple analysis of calculating the standard deviation or variance.

[0013] (4) In the method for evaluating the yuzu-skin described in the above (2) or (3), the measurement region is a region having a length in the extending direction of the contour of the light source and a width perpendicular to the extending direction. The width is 1 pixel, and the length may be 200 pixels or more.

[0014] The method for evaluating the yuzu-skin according to the above (4) can aggregate the variation of the feature amount into the length of the measurement region by narrowing the width of the measurement region to 1 pixel. If the length of the measurement region is 200 pixels or more, the number of the feature amounts can be made sufficient, and it is easy to appropriately calculate the variation of the feature amount. Therefore, it is easy to accurately evaluate the degree of the yuzu-skin of the sheet-like member based on the variation of the feature amount.

[0015] (5) In the method for evaluating the yuzu-skin described in any one of the above (1) to (4), the shape of the contour of the light source may include a straight line portion, and the measurement region may be set to include the straight line portion.

[0016] The method for evaluating the yuzu-skin according to the above (5) makes it easy to set the measurement region including the contour of the light source in the image data.

[0017] (6) In the method for evaluating the yuzu-skin described in the above (2) or (3), each of the plurality of numerical data may be data of 12 bits or more.

[0018] If the numerical data of the feature amount is 12 bits or more, the yuzu-skin of the sheet-like member can be expressed in 4096 or more gradations. Therefore, the method for evaluating the yuzu-skin according to the above (6) makes it easy to accurately evaluate the degree of the yuzu-skin of the sheet-like member based on the variation of the feature amount.

[0019] (7) In the method for evaluating the yuzu-skin described in any one of the above (1) to (6), the light emitting surface of the light source is parallel to the surface of the sheet-like member, and the optical axis of the imaging device may be inclined with respect to a line perpendicular to the surface of the sheet-like member.

[0020] Regarding the method for evaluating the yuzu-skin described in (7) above, the imaging device can be arranged so as not to overlap with the light source, or the imaging device can be arranged so that the light source does not overlap with the optical axis of the imaging device. Oblique imaging is performed based on the arrangement relationship between the light source and the imaging device described above. Oblique imaging makes it easier to clearly capture the shadow of the yuzu-skin.

[0021] (8) In the method for evaluating the yuzu-skin described in (7) above, the angle formed by the optical axis of the imaging device with respect to a line perpendicular to the surface of the sheet-like member may be 5° or more and 20° or less.

[0022] When the angle formed by the optical axis of the imaging device with respect to a line perpendicular to the surface of the sheet-like member is 5° or more, it is easy to arrange the imaging device so as not to overlap with the light source, or to arrange the imaging device so that the light source does not overlap with the optical axis of the imaging device. When the above angle is 20° or less, it is easy to photograph the light source reflected on the sample. If the above angle is 20° or less, the difference in the size of the subject between the proximal and distal positions from the imaging device is less likely to occur.

[0023] (9) In the method for evaluating the yuzu-skin according to any one of (1) to (8) above, the sample has a glass portion where the glass plate is exposed from the sheet-like member. The image data includes a first region where the light source is reflected on the surface of the sheet-like member and a second region where the light source is reflected on the surface of the glass portion. The measurement region may be set in the first region based on the extension line of the contour of the light source in the second region.

[0024] Regarding the method for evaluating the yuzu-skin described in (9) above, it is easy to set a measurement region including the contour of the light source in the image data. Generally, the contour of the light source is clearer in the second region where the light source is reflected on the surface of the glass portion than in the first region where the light source is reflected on the surface of the sheet-like member.

[0025] (10) In the method for evaluating yuzu skin according to any one of (1) to (9) above, the sheet-like member may be an adhesive sheet. The adhesive sheet has a base material and an adhesive layer provided on one surface of the base material. The material of the base material may be polyethylene terephthalate, polypropylene, polyethylene, polystyrene, or polycarbonate.

[0026] The method for evaluating yuzu skin according to (10) above is applicable to an adhesive sheet having a general configuration.

[0027] (11) In the method for evaluating yuzu skin according to (10) above, the base material may include a metal film.

[0028] The method for evaluating yuzu skin according to (11) above can evaluate the degree of yuzu skin even if the adhesive sheet has a base material including a metal film.

[0029] (12) In the method for evaluating yuzu skin according to any one of (1) to (11) above, the glass plate may be colorless and transparent.

[0030] If the glass plate is colorless and transparent, the sheet-like member is less likely to be affected by the color of the glass plate. Therefore, the method for evaluating yuzu skin according to (12) above can easily evaluate the state of the yuzu skin of the sheet-like member with an appropriate contrast.

[0031] (13) An apparatus for evaluating yuzu skin according to one aspect of the present invention includes a sample stage on which a sample with a sheet-like member fixed to a glass plate is placed, a light source that irradiates light onto the surface of the sheet-like member, an imaging device that acquires an image of the light source reflected in the sample as image data, and an analysis device for the image data. The analysis device is configured to set a measurement region including the contour of the light source in the image data, analyze the variation in feature amounts from the image data included in the measurement region, and evaluate the degree of yuzu skin of the sheet-like member based on the variation in the feature amounts.

[0032] The evaluation device for yuzu skin of the above (13) can be used in the evaluation method for yuzu skin of the present invention. The evaluation device for yuzu skin of the above (13) has a simple configuration and can quantitatively evaluate the degree of yuzu skin of the sheet-like member.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0034] A specific example of the evaluation method for yuzu skin according to the embodiment of the present invention will be described with reference to the drawings. The same reference numerals in the figures indicate the same or corresponding parts. The sizes of the members shown in each drawing are expressed for the purpose of clarifying the description and do not necessarily represent the actual dimensions. It should be noted that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0035] Prior to the description of the evaluation method for yuzu skin according to the embodiment, the sheet-like member to be evaluated will be described. The sheet-like member is, for example, a resin film, a metal film, or an adhesive sheet. In the following description, the case where the sheet-like member is an adhesive sheet will be described as a representative.

[0036] <Adhesive Sheet> Referring to FIG. 1, an example of the adhesive sheet 1 will be described. The adhesive sheet 1, also called a tack paper, is used for materials such as seals or labels. The adhesive sheet 1 can be attached to an object such as a product package. FIG. 1 shows a cross-section perpendicular to the surface of the adhesive sheet 1. The adhesive sheet 1 has a base material 11 and an adhesive layer 12 in order from above. The adhesive layer 12 is provided on one surface of the base material 11. In FIG. 1, the adhesive sheet 1 before attachment with the release paper 13 is shown. In the adhesive sheet 1 shown in FIG. 1, the upper surface is the front surface and the lower surface is the back surface. The adhesive sheet 1 is not particularly limited and may be a known one.

[0037] (Base material) The base material 11 is not particularly limited. The base material 11 is, for example, a plastic film. The material of the base material 11 is, for example, polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polystyrene (PS), or polycarbonate (PC).

[0038] The base material 11 is, for example, transparent. Transparent means that light passes through and can be seen through. The visible light transmittance of the base material 11 is, for example, 80% or more. The "visible light" mentioned here means light in the wavelength range from 400 nm to 700 nm. The visible light transmittance of the base material 11 may be 85% or more.

[0039] The base material 11 may be provided with a metal film (not shown). The metal film is, for example, laminated on at least one surface of the base material 11. The metal film may be on either the front surface or the back surface of the base material 11. The material of the metal film is, for example, aluminum. The metal film is, for example, formed by a vacuum evaporation method. The base material 11 may have other layers as necessary. The other layer is, for example, a protective layer that protects the surface of the base material 11.

[0040] (Adhesive layer) The adhesive layer 12 is not particularly limited as long as it has the required adhesive force. The adhesive layer 12 is formed, for example, by applying an adhesive to the back surface of the base material 11. The adhesive is, for example, an acrylic adhesive, a silicone adhesive, a urethane adhesive, a polyester adhesive, or a rubber adhesive.

[0041] (Release paper) The release paper 13 is disposed on the back surface of the adhesive sheet 1 and is in contact with the adhesive layer 12. The release paper 13 is not particularly limited. The release paper 13 is also called a separator or a release liner. The release paper 13 is peeled off when the adhesive sheet 1 is attached to an object. The surface of the release paper 13 in contact with the adhesive layer 12 may be coated with a release agent. The release agent is, for example, a silicone-based release agent, a fluorine-based release agent, or a long-chain alkyl-based release agent.

[0042] The release paper 13 is, for example, laminated paper or a plastic film. The laminated paper is obtained by laminating a plastic film on the surface of a paper base material. The paper base material of the laminated paper is, for example, high-quality paper, kraft paper, or glassine paper. The material of the plastic film is, for example, PP, PE, polyamide (PA), or polyester (PEs). PEs includes PET.

[0043] Instead of the release paper 13, the adhesive sheet 1 may be provided with a release layer on the surface of the base material 11 (not shown). The release layer is formed by applying a release agent to the surface of the base material 11. The adhesive sheet 1 provided with the release layer is wound and stored in a roll shape so that the front and back surfaces of the adhesive sheet 1 are in contact. The adhesive sheet 1 provided with the release layer can prevent the base material 11 and the adhesive layer 12 from adhering to each other when they overlap in the rolled state. The adhesive sheet 1 wound in a roll shape is, for example, an adhesive tape.

[0044] 〈Yuzu skin〉 The texture of the adhesive sheet 1 is caused by the fine irregularities on the surface of the release paper 13 being transferred to the surface of the adhesive layer 12. Even when the adhesive sheet 1 is attached to an object, if the adhesive layer 12 remains deformed, the surface of the adhesive sheet 1 will appear textured. In particular, if the base material 11 is transparent or the base material 11 is provided with a shiny metal film, the textured appearance is more noticeable.

[0045] <Method for Evaluating the Textured Appearance> The method for evaluating the textured appearance of the embodiment is for quantitatively evaluating the degree of the textured appearance of the adhesive sheet 1. The method for evaluating the textured appearance includes the following steps A to F. Hereinafter, with reference to FIG. 2, the method for evaluating the textured appearance will be described. FIG. 2 shows an example of an apparatus for evaluating the textured appearance, and the configuration of the evaluation apparatus is not limited to the configuration shown in FIG. 2. For the constituent members of the adhesive sheet 1, refer to FIG. 1 as necessary. · Step A: Prepare a sample 20 in which the adhesive sheet 1 is fixed to a glass plate 2. · Step B: Irradiate light from a light source 3 onto the surface of the adhesive sheet 1. · Step C: Take an image of the image of the light source 3 reflected in the sample 20 with an imaging device 4 to obtain image data. · Step D: Set a measurement region including the contour of the light source 3 in the image data. · Step E: Analyze the variation in the feature amount from the image data included in the measurement region. · Step F: Evaluate the degree of the textured appearance of the adhesive sheet 1 based on the variation in the feature amount.

[0046] The apparatus 100 for evaluating the textured appearance shown in FIG. 2 includes the light source 3, the imaging device 4, a sample stage 6, and an analysis device 7. The sample stage 6 is where the sample 20 is placed. The analysis device 7 is configured to execute steps D to F.

[0047] (Step A) Sample 20 is produced by fixing the adhesive sheet 1 to the surface of the glass plate 2. The adhesive sheet 1 can be fixed by pasting it on the glass plate 2. The size of the adhesive sheet 1 is not particularly limited. FIG. 3 shows a plan view of Sample 20 as seen from above. The width W1 of the adhesive sheet 1 is, for example, 20 mm or more and 50 mm or less. The length L1 of the adhesive sheet 1 is, for example, 50 mm or more and 150 mm or less. In this example, the adhesive sheet 1 has a width W1 of 40 mm and a length L1 of 80 mm.

[0048] The adhesive sheet 1 is pasted as follows. After peeling off the release paper 13 to expose the adhesive layer 12, the adhesive sheet 1 is pasted on the surface of the glass plate 2 by bringing the adhesive layer 12 into close contact with the surface of the glass plate 2. When pasting the adhesive sheet 1 on the surface of the glass plate 2, care is taken so that no bubbles enter between the adhesive layer 12 and the glass plate 2. If bubbles enter between the adhesive layer 12 and the glass plate 2, it may affect the evaluation.

[0049] The adhesive sheet 1 used for Sample 20 may be stored at normal temperature and normal humidity until immediately before pasting it on the glass plate 2. Normal temperature and normal humidity mean a temperature of 5°C or more and 35°C or less and a relative humidity of 45%RH or more and 85%RH or less. The storage time is, for example, 2 hours or more.

[0050] The glass plate 2 is not particularly limited as long as it has no scratches and dirt and has a flat surface. Float glass can be used for the glass plate 2. In this example, the glass plate 2 is a colorless and transparent float glass. If the glass plate 2 is colorless and transparent, the adhesive sheet 1 is less likely to be affected by the color of the glass plate 2. For example, the influence of reflected light from the interface between the adhesive sheet 1 and the glass plate 2 can be reduced. Therefore, it is easy to evaluate the state of the adhesive sheet 1 with a texture like that of a loquat skin. The flatness of the glass plate 2 is, for example, 0.1 mm or less. The visible light transmittance of the glass plate 2 is, for example, 80% or more, and further 85% or more.

[0051] The size of the glass plate 2 is not particularly limited as long as it is equal to or larger than the size of the adhesive sheet 1. The width W2 of the glass plate 2 is, for example, 20 mm or more and 80 mm or less. The length L2 of the glass plate 2 is, for example, 50 mm or more and 180 mm or less. The length L2 may further be 80 mm or more and 180 mm or less. The thickness of the glass plate 2 is, for example, 1 mm or more and 5 mm or less. The thicker the glass plate 2, the lower the visible light transmittance of the glass plate 2. If the thickness of the glass plate 2 is 5 mm or less, the visible light transmittance of the glass plate 2 is likely to be high. In this example, the glass plate 2 has a width W2 of 40 mm, a length L2 of 120 mm, and a thickness of 2 mm.

[0052] In the sample 20 of this example, the size of the glass plate 2 is larger than the size of the adhesive sheet 1. The adhesive sheet 1 is attached to the surface of the glass plate 2 along the length of the glass plate 2. The sample 20 has a glass portion 2a in which the glass plate 2 is exposed from the adhesive sheet 1, as shown in FIG. 3. The glass portion 2a only needs to be exposed from at least one end of the adhesive sheet 1. In the sample 20 shown in FIG. 3, the glass portion 2a is exposed from both ends of the adhesive sheet 1.

[0053] The glass plate 2 used for the sample 20 may be cleaned before attaching the adhesive sheet 1. By cleaning the glass plate 2, dirt adhering to the surface of the glass plate 2 can be removed. The dirt on the surface of the glass plate 2 is, for example, dust, garbage, and oil and fat. The cleaned glass plate 2 may be dried at normal temperature and normal humidity for 30 minutes or more after cleaning.

[0054] (Step B) The light source 3 irradiates light toward the surface of the adhesive sheet 1. The light source 3 is not particularly limited as long as the light emitting surface emits light uniformly, that is, the luminance distribution of the light emitting surface is substantially uniform. The light source 3 is, for example, an LED light or a fluorescent lamp. The shape of the contour of the light source 3 is, for example, linear or circular. The shape of the contour of the light source 3 preferably includes a straight portion. The light source 3 in this example is a linear LED light.

[0055] The light emitting surface of the light source 3 is, for example, parallel to the surface of the adhesive sheet 1. In this case, as shown in FIG. 2, the light source 3 is disposed directly above the adhesive sheet 1. The "parallel" mentioned here is not limited to the geometric parallel, but also includes a substantially parallel state within a certain error range. Specifically, when the light emitting surface of the light source 3 is inclined within a range of less than ±5° with respect to the surface of the adhesive sheet 1, it is regarded as parallel to the surface of the adhesive sheet 1. The light emitting surface refers to the surface in the case of a light source having a planar light emitting window, and refers to the surface in the case of a light source having a surface extending in one direction such as a fluorescent lamp. The surface extending in one direction is the surface that contacts the plane when the light source is placed on the plane. For example, in the case of a straight tube fluorescent lamp, the light emitting surface is a plane that contacts the cylindrical outer peripheral surface.

[0056] The brightness of the light source 3 is set so that the illuminance on the surface of the adhesive sheet 1 is within a certain range. The luminous flux of the light source 3 is, for example, 600 lumens or more and 1200 lumens or less. By the luminous flux of the light source 3 being 600 lumens or more and 1200 lumens or less, it is easy to control the illuminance on the surface of the adhesive sheet 1 irradiated with light within a certain range. The illuminance on the surface of the adhesive sheet 1 is, for example, 500 lux or more and 1000 lux or less. By the illuminance on the surface of the adhesive sheet 1 being 500 lux or more and 1000 lux or less, it is easy to photograph the light source 3 reflected in the sample 20 by the imaging device 4 described later. The luminous flux of the light source 3 may be 700 lumens or more and 1000 lumens or less. The illuminance on the surface of the adhesive sheet 1 may be 600 lux or more and 900 lux or less.

[0057] The distance D3 from the surface of the adhesive sheet 1 to the light source 3 is not particularly limited as long as the light source 3 is clearly reflected in the sample 20 and the outline of the light source 3 is reflected. The distance D3 is, for example, 20 cm or more and 60 cm or less. By the distance D3 being 20 cm or more and 60 cm or less, it is easy to control the illuminance on the surface of the adhesive sheet 1 within a certain range. The distance D3 may be 25 cm or more and 50 cm or less. In this example, the distance D3 is 40 cm.

[0058] In this example, the sample 20 is placed on the sample stage 6 such that the direction along the length of the adhesive sheet 1 and the direction along the length of the linear light source 3 are substantially parallel to each other. The light source 3 irradiates light so as to protrude from both ends of the adhesive sheet 1. The light irradiated from the light source 3 is irradiated onto the surface of the adhesive sheet 1 and the surface of the glass portion 2a.

[0059] (Step C) The imaging device 4 captures an image of the image of the light source 3 reflected on the sample 20. The imaging device 4 is not particularly limited as long as it can acquire the captured image as digital data. The imaging device 4 is, for example, a digital camera.

[0060] In this example, the sample 20 is photographed so as to include the surface of the adhesive sheet 1 and the surface of the glass portion 2a. The image data acquired by the imaging device 4 includes a first region where the light source 3 is reflected on the surface of the adhesive sheet 1 and a second region where the light source 3 is reflected on the surface of the glass portion 2a.

[0061] The image data is composed of an aggregate of a plurality of pixels arranged two-dimensionally. Each pixel contains numerical data obtained by quantifying the feature amount of the image. The feature amount is, for example, a plurality of numerical data for each pixel corresponding to brightness or luminance. Each numerical data is, for example, data of 12 bits or more. If the numerical data is 12 bits, it is represented by 4096 gradations. By the numerical data of the feature amount being 12 bits or more, it is easy to evaluate the degree of the anti-slip texture of the adhesive sheet 1 based on the variation of the feature amount described later.

[0062] In this example, the imaging device 4 captures the reflected image of the light source 3 reflected on the surface of the adhesive sheet 1. The optical axis of the imaging device 4 is inclined, for example, with respect to a line perpendicular to the surface of the adhesive sheet 1. In this case, as shown in FIG. 2, the imaging device 4 is disposed obliquely above the adhesive sheet 1. Oblique imaging is performed based on the arrangement relationship between the light source 3 and the imaging device 4 described above. Oblique imaging makes it easier to clearly capture the shadow of the uneven skin. The angle θ formed by the optical axis of the imaging device 4 with respect to the line perpendicular to the surface of the adhesive sheet 1 is, for example, 5° or more and 20° or less. When the angle θ is 5° or more, it is easy to arrange the imaging device 4 so as not to overlap the light source 3, or to arrange the imaging device 4 so that the light source 3 does not overlap the optical axis of the imaging device 4. When the angle θ is 20° or less, it is easy to capture the light source 3 reflected on the sample 20. If the angle is 20° or less, the difference in the size of the subject between the proximal and distal positions from the imaging device 4 is less likely to occur.

[0063] When capturing the reflected image of the light source 3, as shown in FIG. 2, the background material 5 is disposed under the sample 20. The background material 5 is not particularly limited as long as it can suppress the reflection of the light transmitted through the sample 20. The color of the background material 5 is, for example, black. The black background material 5 is likely to absorb light and is less likely to reflect light. With the black background material 5, the reflection of the light transmitted through the sample 20 can be suppressed, and the influence of the reflected light can be reduced.

[0064] The distance D4 along the optical axis from the surface of the adhesive sheet 1 to the imaging device 4 is not particularly limited as long as the light source 3 reflected on the sample 20 is as large as possible within the imaging range and can be clearly captured. The distance D4 is, for example, 20 cm or more and 60 cm or less. When the distance D4 is 20 cm or more and 60 cm or less, it is easy to capture the light source 3 reflected on the sample 20. The distance D4 may also be 25 cm or more and 50 cm or less. In this example, the distance D4 is 35 cm.

[0065] The imaging of the sample 20 is performed in a dark room. By imaging the sample 20 in a dark room, the influence of the light entering from the outside can be suppressed, and it is easy to capture the light source 3 reflected on the sample 20. The illuminance of the dark room is, for example, 0.1 lux or less.

[0066] When photographing the sample 20, the exposure time may be changed depending on the presence or absence of the metal film on the base material 11 of the adhesive sheet 1. When the base material 11 is provided with a metal film, the reflectance of the surface of the adhesive sheet 1 tends to be increased by the metal film. The higher the reflectance of the surface of the adhesive sheet 1, the brighter the light source 3 reflected on the surface of the adhesive sheet 1 appears. When the base material 11 is provided with a metal film, since the reflected light becomes stronger, the adhesive sheet 1 appears white and the outline of the light source 3 tends to become unclear. Therefore, when the base material 11 is provided with a metal film, by shortening the exposure time compared to the case where the base material 11 is not provided with a metal film, the image of the light source 3 reflected on the sample 20 becomes clear. When the base material 11 is transparent, the exposure time is, for example, from 1 / 250 s to 1 / 750 s. When the base material 11 is provided with a metal film, the exposure time is, for example, from 1 / 1000 s to 1 / 2000 s.

[0067] The image data acquired by the imaging device 4 is sent to the analysis device 7. The analysis device 7 is realized by, for example, a computer. The analysis device 7 is configured to execute the following steps D to F.

[0068] (Step D) With reference to FIG. 4, an example of a method for setting a measurement region in the image data acquired by the imaging device 4 will be described. FIG. 4 is an example of an image of the sample 20 photographed by the imaging device 4. The image in FIG. 4 is a monochrome image represented by brightness. In FIG. 4, the white portion indicates the reflected image of the light source 3. In FIG. 4, the portion where the adhesive sheet 1 is attached is surrounded by a white dotted line. As shown in FIG. 4, in the image of the light source 3 reflected on the surface of the adhesive sheet 1, since the light of the light source 3 is diffusely reflected by the yuzu skin, the outline of the light source 3 tends to be blurred and unclear. The stronger the degree of the yuzu skin of the adhesive sheet 1, the more unclear the outline of the light source 3 becomes. On the other hand, in the image of the light source 3 reflected on the surface of the glass portion 2a exposed from the adhesive sheet 1, since the light of the light source 3 is less likely to be diffusely reflected, the outline of the light source 3 is clearer than the image of the light source 3 reflected on the surface of the adhesive sheet 1.

[0069] First, a method for selecting the contour of the light source 3 in the image data will be described. The image data includes a first region where the light source 3 is reflected on the surface of the adhesive sheet 1 and a second region where the light source 3 is reflected on the surface of the glass portion 2a. The contour of the light source 3 is selected, for example, as follows. Select the contour of the light source 3 in the second region. The contour of the light source 3 in the second region is the contour of the light source 3 reflected on the surface of the glass portion 2a exposed from at least one end of the adhesive sheet 1. Draw an extension line along the contour of the light source 3 reflected on the surface of the glass portion 2a exposed from at least one end of the adhesive sheet 1. In FIG. 4, the extension line is shown as a dashed-dotted line. This extension line is regarded as the contour of the light source 3 reflected on the surface of the adhesive sheet 1. The contours of the light source 3 reflected on the surfaces of the respective glass portions 2a exposed from both ends of the adhesive sheet 1 may be selected, and extension lines may be drawn so as to connect the contours of the respective light sources 3. In this way, selection based on the extension lines of the contours of the light source 3 reflected on the surfaces of the glass portions 2a on both sides exposed from both ends of the adhesive sheet 1 enables more accurate selection of the contour of the light source 3 than selection based on the extension line of the contour of the light source 3 reflected on the surface of the glass portion 2a on one side exposed from one end of the adhesive sheet 1. The method for selecting the contour of the light source 3 in the image data may be a method other than selection based on the extension lines of the contours of the light source 3 reflected on the surfaces of the glass portions 2a on both sides. For example, the contour of the light source 3 reflected on the surface of the adhesive sheet 1 may be visually judged, a line may be drawn at its average position, and this line may be regarded as the contour of the light source 3.

[0070] Next, set the measurement area. The measurement area is set to include the contour of the selected light source 3. The measurement area is an area having a length in the extending direction of the contour of the light source 3 and a width perpendicular to the extending direction of the contour of the light source 3. The width of the measurement area is, for example, 1 pixel. The length of the measurement area is, for example, 200 pixels or more. By setting the length of the measurement area to 200 pixels or more, it becomes easy to evaluate the degree of the slippery texture of the adhesive sheet 1 based on the variation of the feature amount described later. The length of the measurement area may be 300 pixels or more, 400 pixels or more, and further 450 pixels or more. The upper limit of the length of the measurement area is not particularly limited, but is, for example, 800 pixels. The length of the measurement area may be 200 pixels or more and 800 pixels or less, and further 300 pixels or more and 700 pixels or less. However, since air bubbles tend to remain at the ends of the adhesive sheet 1, the range of 1 cm from both ends of the adhesive sheet 1 is excluded from the measurement area. When the shape of the contour of the light source 3 includes a straight portion, the measurement area is set to include the straight portion.

[0071] (Step E) Extract feature amounts from the image data included in the measurement area and analyze the variation of the feature amounts. The feature amounts to be analyzed are, for example, a plurality of numerical data for each pixel corresponding to brightness or luminance. The value of the variation of the feature amounts is, for example, the standard deviation or variance of the plurality of numerical data. The analysis of the feature amounts can be performed using known image analysis software. The image analysis software is, for example, "ImageJ" developed by the National Institutes of Health (NIH) in the United States.

[0072] (Step F) The degree of the slippery texture of the adhesive sheet 1 is evaluated based on the variation of the feature amounts. The greater the degree of the slippery texture, the greater the variation of the feature amounts. Therefore, the degree of the slippery texture of the adhesive sheet 1 can be evaluated using the variation of the feature amounts as an index. For example, if the variation of the feature amounts is less than the reference value, it can be determined that the degree of the slippery texture of the adhesive sheet 1 is weak and the slippery texture is not noticeable. If the variation of the feature amounts is equal to or greater than the reference value, it can be determined that the degree of the slippery texture of the adhesive sheet 1 is strong and the slippery texture is noticeable.

[0073] For each of the above steps D to F, the operator may give an instruction to the analysis device 7 to execute each step, or the analysis device 7 may be configured to automatically and continuously perform a series of steps. For example, by processing step D as follows, the setting of the measurement area can be easily performed, and each subsequent step can be easily processed continuously. First, the image data of the second area where the light source 3 is reflected on the surface of the glass part 2a is binarized with a preset threshold value, and an approximate straight line along the boundary between the white image and the black image is taken as the contour of the light source 3. The extension line of this approximate straight line is superimposed on the image data of the first area before the binarization process, and the pixels overlapping the extension line are set as the measurement area. Thereafter, the calculation of the variation of the feature amount in the measurement area and the comparison with the reference value of the above variation may be sequentially and automatically performed.

[0074] [Test Example 1] Using the evaluation device 100 shown in FIG. 2, the degree of the dimpled skin of the adhesive sheet 1 was evaluated.

[0075] A sample 20 in which the adhesive sheet 1 was attached to the surface of the glass plate 2 was prepared. In Test Example 1, two types of adhesive sheets 1 were prepared and designated as Sample No. 1A and No. 1B. The size of the adhesive sheet 1 is 40 mm in width and 80 mm in length. The base material 11 is a transparent PET film. The adhesive constituting the adhesive layer 12 is an acrylic adhesive mainly composed of an acrylate ester. The adhesive characteristics of the adhesives used for the adhesive layer 12 of Sample No. 1A and Sample No. 1B are different. The adhesive strength of the adhesive B used for the adhesive layer 12 of Sample No. 1B is higher than the adhesive strength of the adhesive A used for the adhesive layer 12 of Sample No. 1A. The adhesive strength of the adhesive sheet of Sample No. 1B is about 1.28 times the adhesive strength of the adhesive sheet 1 of Sample No. 1A. The release paper 13 is a laminated paper in which a PE film is laminated on the surface of glassine paper. The adhesive sheet 1 was stored in an environment of 23°C and 50% RH for 2 hours or more until immediately before being attached to the glass plate 2.

[0076] For the glass plate 2, colorless and transparent float glass manufactured by Nippon Test Panel Co., Ltd. was used. The flatness of the glass plate 2 is 70 μm. The visible light transmittance of the glass plate 2 is approximately 90%. The size of the glass plate 2 is 40 mm in width, 120 mm in length, and 2 mm in thickness. The dielectric constant of the glass plate 2 is from 7.0 F / m to 7.5 F / m. After being cleaned with a solvent, the glass plate 2 was dried for 30 minutes or more in an environment of 23°C and 50% RH.

[0077] After the adhesive sheet 1 was attached to the glass plate 2, a 2 kg roller was reciprocated twice from above the adhesive sheet 1 to make it adhere closely to the surface of the glass plate 2.

[0078] The sample 20 was placed on the sample stage 6 of the evaluation device 100 installed in the darkroom, and the light of the light source 3 was irradiated onto the surface of the adhesive sheet 1. The background material 5 arranged under the sample 20 is a black felt cloth. The light source 3 reflected in the sample 20 was photographed with the imaging device 4. The photographing of the sample 20 was performed within 5 minutes after the adhesive sheet 1 was attached to the glass plate 2. The inside of the darkroom was maintained at normal temperature and humidity. The illuminance of the darkroom is 0.00 lux.

[0079] The light source 3 is a linear LED light. The illuminance on the surface of the sample 20 is approximately 730 lux. The specifications of the light source 3 are shown below. Luminous flux: Approximately 810 lumens Color temperature: Approximately 6000 K Beam angle: Approximately 140°

[0080] The distance D3 from the surface of the adhesive sheet 1 to the light source 3 is approximately 40 cm.

[0081] The imaging device 4 is an industrial digital camera. The camera used for the imaging device 4 is DFK33UX273 manufactured by The Imaging Source. The specifications of the used camera are shown below. Resolution: 159 dpi Number of pixels: 1440×1080 Storage format of image data: PNG (Portable Network Graphics)

[0082] The exposure conditions of the camera were set as follows. Brightness: 254 Gain: 0.00 dB Exposure time: 1 / 500 s

[0083] The image data acquired by the imaging device 4 is a 16-bit monochrome image. This image data has numerical data in which each pixel corresponds to the brightness of 65,536 gradations. Hereinafter, the "numerical data corresponding to the brightness" is simply referred to as "light and dark value".

[0084] The angle θ formed by the optical axis of the imaging device 4 with respect to the line perpendicular to the surface of the adhesive sheet 1 is about 10°. The distance D4 from the surface of the adhesive sheet 1 to the imaging device 4 is about 35 cm.

[0085] For the prepared sample 20, the variation in the feature amount was analyzed from the image data included in the measurement region of the image data acquired by the imaging device 4. The contour of the light source 3 in the image data was selected by the method described above with reference to FIG. 4. Specifically, extension lines were drawn so as to connect the contours of the light source 3 reflected on the surfaces of the glass parts 2a on both sides exposed from both ends of the adhesive sheet 1, and this extension line was regarded as the contour of the light source 3 reflected on the surface of the adhesive sheet 1. The measurement region was set parallel to the straight part of the selected contour of the light source 3. The length of the measurement region was set to 350 pixels.

[0086] The standard deviation of the light and dark values in the measurement region was calculated using ImageJ, which is image analysis software. Here, for the same image data, the contour of the light source 3 was selected 6 times, and the measurement region was set 6 times. The standard deviation of the light and dark values in each measurement region was calculated, and the average value of the standard deviations was calculated. The average value of this standard deviation was used as the representative value.

[0087] Furthermore, a glass plate without the adhesive sheet attached was prepared and designated as sample No. 10. For this sample No. 10, imaging was also performed under the same conditions as samples No. 1A and No. 1B, and the standard deviation of the light and dark values in the measurement region of the image data was analyzed.

[0088] Table 1 shows the standard deviation of the light and dark values and the visual evaluation for Samples No. 1A, No. 1B, and No. 10. For the visual evaluation, the surface of the sample was actually observed visually. When the degree of yuzu skin was weak and the yuzu skin was not prominent, it was rated as "A", and when the degree of yuzu skin was strong and the yuzu skin was prominent, it was rated as "B".

[0089] Images of Samples No. 1A, No. 1B, and No. 10 are shown in Fig. 5. The images in Fig. 5 are monochrome images represented by 65536 gradations of brightness. In Sample No. 1B with a visual evaluation of "B", the outline of the light source reflected on the surface of the adhesive sheet appears blurred. In contrast, in Sample No. 1A with a visual evaluation of "A", the outline of the light source reflected on the surface of the adhesive sheet appears relatively clear. In Sample No. 10 without the adhesive sheet attached, the outline of the light source reflected on the surface of the glass plate appears clearer.

[0090] [Table 1]

[0091] [Test Example 2] In Test Example 2, two types of adhesive sheets 1 in which the base material 11 is provided with a metal film were prepared. The base material 11 is a PET film on which an aluminum vapor deposition film is formed. The vapor deposition film is provided on the back surface of the base material 11. The adhesive constituting the adhesive layer 12 is Adhesive A or Adhesive B described in Test Example 1. The release paper 13 is the same laminated paper as in Test Example 1.

[0092] In the same manner as in Test Example 1, the adhesive sheet 1 was attached to the surface of the glass plate 2 to prepare Sample 20. Sample No. 2A uses Adhesive A for the adhesive layer 12. Sample No. 2B uses Adhesive B for the adhesive layer 12. Adhesive A and Adhesive B are common to Test Example 1 and Test Example 2.

[0093] For Samples No. 2A and No. 2B, the degree of the texture of the adhesive sheet 1 was evaluated using the evaluation apparatus 100 in the same manner as in Test Example 1. In Test Example 2, the same conditions were used except that the exposure time of the camera was changed to 1 / 1500 s. For Sample No. 10, imaging was also performed under the same conditions, and the standard deviation of the light and dark values in the measurement region of the image data was analyzed.

[0094] Table 2 shows the standard deviation of the light and dark values and the visual evaluation for Samples No. 2A, No. 2B, and No. 10.

[0095] Images of Samples No. 2A, No. 2B, and No. 10 are shown in Fig. 6. The images in Fig. 6 are monochrome images represented by the brightness of 65536 gradations. In Sample No. 2B with a visual evaluation of "B", the outline of the light source reflected on the surface of the adhesive sheet looks blurred. In contrast, in Sample No. 2A with a visual evaluation of "A", the outline of the light source reflected on the surface of the adhesive sheet looks relatively clear. In Sample No. 10 without the adhesive sheet attached, the outline of the light source reflected on the surface of the glass plate looks clearer.

[0096]

Table 2

[0097] As shown in Table 1 and Table 2, there is a correlation between the standard deviation of the light and dark values and the visual evaluation. Therefore, the degree of the texture of the adhesive sheet can be evaluated using the standard deviation of the light and dark values as an index. For example, if the standard deviation of the light and dark values is less than 4000, it can be determined that the texture is not prominent, and if the standard deviation of the light and dark values is 4000 or more, it can be determined that the texture is prominent.

[0098] In the above-described embodiments and Test Examples 1 and 2, an example of evaluating the texture of an adhesive sheet has been described. The sheet-like member to be evaluated is not limited to an adhesive sheet. The sheet-like member may be a resin film or a metal film that does not have an adhesive layer. The resin film or the metal film is, for example, one whose surface is finished to have a texture by rough processing or uneven processing. According to the method for evaluating the texture of the present embodiment, the degree of the texture of the sheet-like member subjected to rough processing or uneven processing can be quantitatively evaluated.

[0099] When the sheet-like member does not have an adhesive layer, for example, samples can be prepared by fixing both ends of the sheet-like member to a glass plate using an adhesive tape or the like. In this case, the measurement area should be set so as not to overlap with the adhesive tape or the like, and the range overlapping with the adhesive tape or the like should be excluded from the measurement area. As another fixing method for the sheet-like member, for example, both ends of the sheet-like member may be pressed by another glass plate. In this case, both ends of the sheet-like member should be excluded from the measurement area. Further, in Test Examples 1 and 2, the evaluation is performed using the light and dark values in the measurement area, but the evaluation may also be performed using numerical data corresponding to the luminance, that is, the luminance value.

Explanation of Reference Numerals

[0100] 1 Adhesive sheet 11 Base material, 12 Adhesive layer, 13 Release paper 2 Glass plate, 2a Glass part 20 Sample 3 Light source 4 Imaging device 5 Background material 6 Sample stage 7 Analysis device θ Angle L1, L2 Lengths W1, W2 Widths D3, D4 Distances 100 Evaluation device

Claims

1. A step of preparing a sample in which a sheet-like member is fixed to a glass plate; A step of irradiating light from a light source onto the surface of the sheet-like member; A step of capturing an image of the image of the light source reflected on the sample with an imaging device to obtain image data; A step of setting a measurement region including the contour of the light source in the image data; A step of analyzing the variation of the feature amount from the image data included in the measurement region; A step of evaluating the degree of orange peel of the sheet-like member based on the variation of the feature amount, comprising: A method for evaluating orange peel.

2. The image data is composed of an aggregate of a plurality of pixels arranged two-dimensionally, The feature amount is a plurality of numerical data for each pixel corresponding to the brightness or luminance of the image, and the method for evaluating orange peel according to claim 1.

3. The value of the variation of the feature amount is the standard deviation or variance of the plurality of numerical data, and the method for evaluating orange peel according to claim 2.

4. The measurement region is a region having a length in the extending direction of the contour of the light source and a width perpendicular to the extending direction, The width is 1 pixel, The length is 200 pixels or more, and the method for evaluating orange peel according to claim 2 or claim 3.

5. The shape of the contour of the light source includes a straight portion, The measurement region is set to include the straight portion, and the method for evaluating orange peel according to any one of claims 1 to 3.

6. Each of the plurality of numerical data is data of 12 bits or more, and the method for evaluating orange peel according to claim 2 or claim 3.

7. The light emitting surface of the light source is parallel to the surface of the sheet-like member, The optical axis of the imaging device is inclined with respect to a line perpendicular to the surface of the sheet-like member, and the method for evaluating orange peel according to any one of claims 1 to 3.

8. The angle formed by the optical axis of the imaging device with respect to a line perpendicular to the surface of the sheet-like member is 5° or more and 20° or less, and the method for evaluating orange peel according to claim 7.

9. The sample has a glass portion in which the glass plate is exposed from the sheet-like member, The image data includes a first region in which the light source is reflected on the surface of the sheet-like member and a second region in which the light source is reflected on the surface of the glass portion. The method for evaluating yuzu skin according to any one of claims 1 to 3, wherein the measurement region is set in the first region based on the extension line of the contour of the light source in the second region.

10. The sheet-like member is an adhesive sheet, The adhesive sheet has a base material and an adhesive layer provided on one surface of the base material, The material of the base material is polyethylene terephthalate, polypropylene, polyethylene, polystyrene, or polycarbonate. The method for evaluating yuzu skin according to any one of claims 1 to 3.

11. The method for evaluating yuzu skin according to claim 10, wherein the base material includes a metal film.

12. The method for evaluating yuzu skin according to any one of claims 1 to 3, wherein the glass plate is colorless and transparent.

13. A sample stage on which a sample with a sheet-like member fixed to a glass plate is placed, A light source that irradiates light onto the surface of the sheet-like member, An imaging device that acquires an image of the light source reflected in the sample as image data, An analysis device for the image data, and The analysis device sets a measurement region including the contour of the light source in the image data, analyzes the variation in feature amounts from the image data included in the measurement region, and is configured to evaluate the degree of yuzu skin of the sheet-like member based on the variation in the feature amounts. An apparatus for evaluating yuzu skin.

Images