JP5480669B2 - Image processing apparatus for contact angle meter and method for deriving outline shape of liquid droplet in plan view - Google Patents

Description

  The present invention relates to an image processing apparatus for a contact angle meter used in a contact angle meter for measuring a contact angle used as an index indicating the wettability of a liquid with respect to a solid surface, and a plan view contour shape of a droplet in the contact angle meter. The present invention relates to a method for deriving a contour shape in plan view of a droplet to be derived.

  Conventionally, the contact angle of a liquid on the surface of a solid is generally measured by dropping a predetermined amount of liquid onto a flat solid sample and imaging from the side. In other words, the droplet on the sample is imaged from the side by a CCD camera or the like, and the angle of the portion where the droplet contacts the sample surface is calculated based on the image of the side surface of the droplet thus obtained (for example, patent Reference 1).

  In this way, when the droplet is imaged from the side, a silhouette image of the droplet with clear contrast can be obtained by, for example, illuminating from behind the droplet. For this reason, it is possible to calculate the contact angle relatively easily from the captured image, and a contact angle meter that images a droplet from the side and obtains the contact angle is widely used as a simple device.

JP 2002-277373 A

  In such a contact angle meter that images a droplet from the side, the contact angle is measured on the assumption that the contour shape of the droplet in plan view is a perfect circle. However, the contour shape of the liquid droplet in plan view is not necessarily a perfect circle, and may be an ellipse or an irregular shape depending on the properties of the solid surface, which is one of the causes of variations in contact angle measurement. ing.

  For this reason, in recent development fields such as various new materials and surface coatings, there has been a demand for a more rigorous evaluation of the measured value of the contact angle by considering the contour shape of the droplet in plan view. In addition, there has been a demand for evaluating the properties of the solid surface in a more diversified manner by simultaneously evaluating the contact angle and the contour shape of the droplet in plan view.

  In view of such circumstances, the present invention provides a contact angle meter image processing apparatus and a droplet planar view contour derivation method capable of measuring the planar view contour shape of a droplet with higher accuracy in a contact angle meter. To do.

(1) The present invention is an image processing apparatus for processing an image obtained by imaging a droplet on the sample in a contact angle meter for measuring a contact angle of the droplet on the sample, wherein the droplet on the sample is Shape deriving means for deriving a planar view outline shape of the droplet based on a liquid drop planar image captured from above, and the droplet width deriving image based on the droplet imaged from the side of the sample. A droplet width deriving unit for deriving a width direction dimension of the droplet, and the shape deriving unit compares the respective pixels of the droplet plane image with other pixels, and the comparison result of the comparing unit And a determination unit for determining whether each pixel of the liquid droplet planar image shows a planar view outline shape of the liquid droplet, and a size in the width direction of the liquid droplet derived by the liquid droplet width deriving unit A comparison range setting means for setting a range of pixels to be compared by the comparison means based on When, characterized in that it comprises a an image processing apparatus for contact angle meter.

  (2) The present invention is further characterized by further comprising contact angle deriving means for deriving the contact angle of the droplet based on a droplet side image obtained by imaging the droplet on the sample from the side. The contact angle meter image processing device according to (1) above.

( 3 ) In the present invention, the comparison unit may also compare each pixel of the droplet plane image with a pixel at the same position in a reference plane image obtained by imaging a state where the droplet is not present on the sample from above. The contact angle meter image processing apparatus according to (1) or (2) , characterized in that:

( 4 ) In the above (1) or (2) , the comparison unit may compare each pixel of the droplet plane image with a surrounding pixel in the droplet plane image. It is an image processing apparatus for contact angle meters of description.

( 5 ) Further, in the present invention, the determination unit generates each pixel of the liquid droplet planar image in a similar shape to the planar view outline shape of the liquid droplet in the liquid droplet based on the comparison result of the comparison unit. The shape deriving means further comprises an enlarging means for deriving the contour shape of the droplet in plan view by enlarging the shape of the halo. The contact angle meter image processing device according to any one of ( 1 ) to ( 4 ).

( 6 ) In the present invention, the enlargement unit enlarges the shape of the optical ring based on the width-direction dimension of the droplet derived by the droplet width deriving unit, so that the contour shape of the droplet in plan view characterized in that you derive a contact angle meter image processing apparatus according to (5).

( 7 ) The contact according to any one of (1) to ( 6 ) above, further comprising calibration means for performing calibration based on a calibration image obtained by imaging a calibration standard sample. It is an image processing apparatus for a goniometer.

( 8 ) The present invention is also characterized in that the calibration means includes pixel size calibration means for calibrating the size of one pixel in an image obtained by imaging the droplet on the sample based on the calibration image. The contact angle meter image processing device according to ( 7 ) above.

( 9 ) In the present invention, the calibration unit may be configured based on a calibration plane image obtained by imaging the calibration standard sample from above and a calibration side image obtained by imaging the calibration standard sample from the side. ( 7 ) characterized in that it comprises positional relationship calibration means for calibrating the correspondence between positions in the image obtained by imaging the droplet on the top from above and the image obtained by imaging the droplet on the sample from the side. Or it is the image processing apparatus for contact angle meters as described in ( 8 ).

(10) The present invention also relates to the calibration standard samples are characterized and the flat plate, and the projection of the partially spherical protruding from the surface of the plate, to be composed of the above (7) to (9) The contact angle meter image processing device according to any one of the above.

( 11 ) The present invention also relates to a method for deriving the contour shape of the droplet in plan view by processing an image obtained by imaging the droplet on the sample in a contact angle meter that measures the contact angle of the droplet on the sample. A droplet width deriving step for deriving a width direction dimension of the droplet based on a droplet width deriving image obtained by imaging the droplet on the sample from a side, and deriving in the droplet width deriving step. A comparison range setting step for setting a comparison range based on the widthwise dimension of the droplet, and each pixel in the comparison range of the droplet plane image obtained by imaging the droplet on the sample from above. And a determination step of determining whether or not each pixel of the liquid droplet planar image shows a planar view contour shape of the liquid droplet based on the comparison result of the comparison step. Characteristic plane of droplet A contour shape derivation method.

( 12 ) In the comparison step, the present invention also compares each pixel of the droplet plane image with a pixel at the same position in the reference plane image obtained from above when the droplet is not present on the sample. A method for deriving a contour shape of a droplet in plan view as described in ( 11 ) above.

( 13 ) The droplet according to ( 11 ), wherein in the comparison step, each pixel of the droplet plane image is compared with a surrounding pixel in the droplet plane image. This is a method for deriving a contour shape in plan view.

( 14 ) According to the present invention, in the determination step, each pixel of the liquid droplet planar image is generated in a similar shape to the planar view outline shape of the liquid droplet in the liquid droplet based on the comparison result of the comparison step. ( 11 ), further comprising an enlarging step of determining whether or not the shape of the halo is indicated and deriving a contour shape of the droplet in plan view by enlarging the shape of the halo. A planar view contour shape deriving method for a droplet according to any one of ( 13 ) to ( 13 ).

( 15 ) Further, in the expansion step, the shape of the halo is enlarged based on the dimension in the width direction of the droplet derived in the droplet width deriving step, so that the contour shape of the droplet in plan view is obtained. characterized in that you derive a plan view contour shape derivation method of droplets according to the above (14).

( 16 ) The present invention further includes a pixel size calibration step of calibrating the size of one pixel in an image obtained by imaging the droplet on the sample based on a calibration image obtained by imaging the calibration standard sample. A method for deriving a contour shape of a liquid droplet in a plan view according to any one of ( 11 ) to ( 15 ) above.

(17) The present invention is also based on the calibration plane image obtained by imaging the school Tadashiyo standard sample from above, and the calibration standard samples for calibration side image taken from the side, the droplet on the sample ( 11 ) to ( 15 ), further comprising a positional relationship calibration step of calibrating the correspondence between the positions of the image captured from above and the image captured from the side of the droplet on the sample. A method for deriving a contour shape of a droplet in plan view according to any one of the above.

  According to the contact angle meter according to the present invention, the contact angle meter can have an excellent effect that the contour shape of the liquid droplet in plan view can be measured with higher accuracy.

It is the schematic of the contact angle meter which concerns on embodiment of this invention. (A)-(c) It is the schematic which showed the structure of the 2nd illuminating device. It is the block diagram which showed the main function structures of the image processing apparatus. (A)-(c) It is the schematic which showed the standard sample for calibration. It is the flowchart which showed the flow of the calibration procedure. It is the schematic which showed the image imaged in (a) and (b) calibration. It is the flowchart which showed the flow of the measurement procedure. It is the flowchart which showed the flow of the procedure of an image process. (A) And (b) It is the schematic which showed the outline | summary of derivation | leading-out of the contact angle by a contact angle derivation means. It is the flowchart which showed the flow of the derivation | leading-out procedure of a contact angle. It is the schematic which showed the outline | summary of derivation | leading-out of the planar view outline shape by a shape derivation | leading-out means. It is the flowchart which showed the flow of the derivation | leading-out procedure of planar view outline shape. It is the schematic which showed the case where a planar view outline shape was derived | led-out only from a droplet plane image. It is the flowchart which showed the flow of the procedure in the case of deriving planar view outline shape only from a droplet plane image. (A) And (b) It is the figure which showed the example in the case of imaging with a 2nd imaging device using a 1st illuminating device.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  First, a contact angle meter according to an embodiment of the present invention will be described. FIG. 1 is a schematic diagram of a contact angle meter 1 according to the present embodiment. The contact angle meter 1 measures the contact angle and plan view contour shape of the droplet 4 by imaging the droplet 4 of the liquid sample dropped on the flat solid sample 2.

  As shown in the figure, the contact angle meter 1 includes a base 10, a stage 20 disposed on the base 10, a first imaging device 30 disposed on the side of the stage 20, and the stage 20. The second imaging device 40 arranged, the first illumination device 50 arranged on the side of the stage 20 opposite to the first imaging device 30, and the first imaging device arranged between the stage 20 and the second imaging device 40. The second illumination device 60, the dispenser 70 disposed above the second illumination device 60, and the computer 100 are configured.

  The base 10 is a member that supports the stage 20, the first imaging device 30, the second imaging device 40, the first illumination device 50, the second illumination device 60, the dispenser 70, and the like. In the present embodiment, these devices are arranged at appropriate positions via the brackets 12, 14 and the like. Further, the base 10 is provided with a cover 16 made of a transparent material and covering the entire apparatus, so that the measurement atmosphere such as temperature and humidity can be kept constant. In addition, the base 10 includes a leg portion 18 having a height adjusting mechanism in order to maintain the level of the upper surface of the stage 20.

  The stage 20 is a so-called XY stage on which the solid sample 2 is placed on the upper surface, and can move in two directions (X and Y directions) in the horizontal plane to adjust the horizontal position of the solid sample 2. It is configured to be able to. Furthermore, in the present embodiment, the stage 20 is configured to be movable up and down (that is, movable in the Z direction), and is configured to be able to rotate the placed solid sample 2 around the vertical direction. Therefore, it is possible to observe the droplet 4 on the solid sample 2 from various directions. Furthermore, the upper surface of the stage 20 may be configured to be inclined at a predetermined angle.

  The first imaging device 30 images the droplet 4 on the solid sample 2 from the side. In the present embodiment, the first imaging device 30 includes a CCD camera including a magnifying lens system. The first imaging device 30 is controlled by the computer 100 to enlarge and image the droplet 4 on the solid sample 2 and transmit image data to the computer 100. The computer 100 stores the image data received from the first imaging device 30 in a predetermined storage unit (not shown) such as a hard disk and saves it.

  The second imaging device 40 images the droplet 4 on the solid sample 2 from above. In the present embodiment, the second imaging device 40 includes a CCD camera including a telecentric lens. Further, the second imaging device 40 of the present embodiment includes a coaxial epi-illumination device 42 that uses, for example, a halogen lamp as a light source. The second imaging device 40 is controlled by the computer 100 to enlarge and image the droplet 4 on the solid sample 2 and transmit image data to the computer 100. The computer 100 stores the received image data in a predetermined storage unit such as a hard disk.

  The first illumination device 50 illuminates the droplet 4 from behind when the first imaging device 30 images the droplet 4 on the solid sample 2. The first illumination device 50 includes a light source such as a halogen lamp or an LED, and is configured to emit light toward the solid sample 2 and the droplet 4 on the stage 20.

  The second illumination device 60 includes an annular light source, and illuminates the droplet 4 from the entire periphery slightly above when the second imaging device 40 images the droplet 4 on the solid sample 2. Therefore, in the present embodiment, when the second imaging device 40 performs imaging, either the coaxial incident illumination device 42 or the second illumination device 60 can be used. In the present embodiment, the state of the surface of the solid sample 2 (particularly the reflection of light) can be obtained when the droplet 4 on the solid sample 2 is imaged from above by appropriately using two different types of illumination devices as described above. Regardless of the characteristics, a clear image of the droplet 4 can be obtained.

  2A to 2C are schematic diagrams illustrating the configuration of the second illumination device 60. FIG. In addition, the figure (a) is a top view of the 2nd illuminating device 60, The figure (b) and (c) is a sectional side view of the 2nd illuminating device 60. FIG. As shown in FIG. 6A, the second illumination device 60 is configured to include a light source 65 configured by arranging a plurality of LEDs 64 on the circumference inside a cylindrical housing 62. A hole 66 is formed in the center of the housing 62, and the image pickup by the second imaging device 40 is performed through the hole 66.

  As shown in FIG. 2B, the LEDs 64 constituting the light source 65 are arranged in two upper and lower stages and are directed slightly inward. In front of the LED 64 (inside the light source 65), a shaded diffusion plate 68 whose diameter gradually increases from the top to the bottom is arranged, and the inner surface of the diffusion plate 68 is directed toward the inside. It is a light emitting surface that emits light. The diffusion plate 68 is subjected to a surface treatment that appropriately diffuses light from the light source 65.

  In the second illuminating device 60, the light source 65 and the diffusion plate 68 are arranged at positions where the optical axis S of the second imaging device 40 is the center (axial center). Further, the second illumination device 60 is arranged at a position where a gap H is opened from the solid sample 2 on the stage 20 so as not to affect the imaging by the first imaging device 30. Therefore, the light emitted from the light source 65 is emitted from the diffusion plate 68 toward the lower droplet 4 in the direction of convergence.

  Note that the inclination angle of the diffusion plate 68 with respect to the optical axis S is not particularly limited, and can be appropriately set according to the light reflection characteristics of the solid sample 2. Further, as shown in FIG. 5C, the diffusion plate 68 may be parallel to the optical axis S. That is, the diffusing plate 68 may be formed in a cylindrical shape so that light is emitted in a direction orthogonal to the optical axis S from the inner surface serving as the light emitting surface toward the inside.

  Further, the gap H between the second illumination device 60 and the solid sample 2 is not particularly limited, and is appropriately set according to the inclination angle of the diffusion plate 68 and the state of the solid sample 2 and the droplet 4. be able to. In the present embodiment, the second illumination device 60 is configured to be movable up and down, and the gap H can be adjusted according to the imaging state of the droplet 4. Further, as shown in FIG. 5C, it is possible to perform imaging by the second imaging measure in a state where the second illumination device 60 is in contact with the solid sample 2. In this case, when the first imaging device 30 performs imaging, the second illumination device 60 is retracted upward.

  Returning to FIG. 1, the dispenser 70 forms a droplet 4 by dropping a liquid sample onto the solid sample 2 from above. The dispenser 70 is configured to drop a predetermined amount of liquid droplets from the tip of the tubular needle 72 under the control of the computer 100. Further, the dispenser 70 is configured to move up and down under the control of the computer 100 so that the tip of the needle 72 can be moved close to and away from the solid sample on the stage 20.

  Before the imaging by the first imaging device 30 and the second imaging device 40, the dispenser 70 descends from the upper retracted position, brings the tip of the needle 72 closer to the upper surface of the solid sample 2, and puts an appropriate amount of liquid sample on the solid sample 2. Drops upward, then rises and returns to the retracted position. In the present embodiment, the dispenser 70 is disposed obliquely with respect to the vertical direction, and the needle 72 is bent halfway so that the tip end portion is substantially along the vertical direction. In this way, the tip of the needle 72 is perpendicularly opposed to the solid sample 2, and when the second imaging device 40 performs imaging while the droplet can be dropped from directly above, the needle 72 starts from the needle 72. The focus is removed so that the needle 72 does not appear in the image.

  As the liquid sample dropped by the dispenser 70, pure water is mainly used. However, depending on the purpose of the measurement, alcohols, fats and the like may be used, or a liquid metal such as solder may be used. It may be used.

  Although not shown, the computer 100 includes a CPU, storage means such as ROM, RAM, and hard disk, display means such as a liquid crystal display, and input means such as a keyboard and a mouse. The computer 100 also includes a control device 110 and an image processing device 120 as functional configurations realized by executing a program installed in the storage unit.

  The control device 110 controls the stage 20, the first imaging device 30, the second imaging device 40, the first lighting device 50, the second lighting device 60, the dispenser 70, and the like. Then, the image processing device 120 processes an image captured by the first imaging device 30 and the second imaging device 40. In the present embodiment, the control device 110 and the image processing device 120 are realized by executing a program. However, these devices may be configured by dedicated circuits.

  FIG. 3 is a block diagram illustrating the main functional configuration of the image processing apparatus 120. As shown in the figure, the image processing apparatus 120 includes a contact angle deriving unit 130, a shape deriving unit 140, a calibration unit 150, and a droplet width deriving unit 160.

  The contact angle deriving unit 130 derives the contact angle by performing image processing on an image obtained by imaging the droplet 4 on the solid sample 2 from the side by the first imaging device 30 (hereinafter referred to as a droplet side image). It is. The contact angle deriving unit 130 compares each pixel of the droplet side image with other pixels, and each pixel of the droplet side image is based on the comparison result of the comparison unit 132. Determination means 134 for determining whether or not the sample 2) shows the contour shape in side view.

  The shape deriving unit 140 performs image processing on an image obtained by imaging the droplet 4 on the solid sample 2 from above by the second imaging device 40 (hereinafter referred to as a “droplet plane image”), whereby the contour shape of the droplet 4 in plan view is obtained. And various parameters for evaluating the derived planar view contour shape are calculated.

  The shape deriving unit 140 compares each pixel of the liquid droplet planar image with other pixels, and each pixel of the liquid droplet planar image has a contour shape in plan view of the droplet based on the comparison result of the comparing unit 142. And a comparison range setting unit 146 for setting a pixel range to be compared by the comparison unit 142 in the liquid droplet plane image. Further, the shape deriving unit 140 enlarges the shape of the halo when deriving the contour shape in plan view based on the shape of the halo generated inside the droplet 4 in the droplet plane image (details will be described later). Enlarging means 148 for making the contour shape in plan view is provided.

  The comparison unit 132 of the contact angle deriving unit 130 and the comparison unit 142 of the shape deriving unit 140 may be realized by the same program, or may be realized by dedicated programs. The same applies to the determination unit 134 of the contact angle deriving unit 130 and the determination unit 144 of the shape deriving unit 140.

  The calibration unit 150 is for performing calibration of the image processing apparatus 120 in advance. The calibration unit 150 calibrates (sets) the correspondence between the pixel size calibration unit 152 that calibrates (sets) the size of one pixel in the droplet side image and the droplet plane image, and the position in the droplet side image and the droplet plane image. The positional relationship calibration means 154 is provided.

  The droplet width deriving unit 160 derives the width direction dimension of the droplet 4 based on the droplet side image. The comparison range setting unit 146 of the shape deriving unit 140 sets the comparison range based on the width direction dimension of the droplet 4 derived by the droplet width deriving unit 160. The droplet width deriving unit 160 may be provided independently as in the present embodiment, or may be provided as one function that the contact angle deriving unit 130 has.

  The contact angle meter 1 also includes a calibration standard sample 80 used in calibration of the image processing apparatus 120. 4A to 4C are schematic views showing a calibration standard sample 80. FIG. 2A is a plan view of the calibration standard sample 80, FIG. 2B is a front view of the calibration standard sample 80, and FIG. 2C is a cross-sectional view of the calibration standard sample 80. FIG. It is sectional drawing which expanded and showed a part.

  As shown in FIGS. 4A and 4B, the calibration standard sample 80 is composed of a flat plate 82 imitating the solid sample 2 and a partial spherical protrusion 84 imitating the liquid droplet 4. It is comprised in the shape which protruded at least one part of the spherical body from the surface (upper surface 82a) of 82. FIG. As shown in FIG. 5C, the protruding portion 84 is fixed by inserting a spherical body 88 into a tapered fixing hole 86 provided in the flat plate 82 and partially protruding from the upper surface 82a. It is formed.

  The fixing hole 86 has a circular cross section and is formed so that the inner diameter gradually decreases from the lower surface 82b toward the upper surface 82a. By inserting the sphere 88 from the lower surface 82b side, the fixing hole 86 is fixed to the upper surface 82a side with a predetermined protruding amount. It is formed so that it can be. The sphere 88 is fixed to the fixing hole 86 by an adhesive 89, for example. A cover for closing the fixing hole 86 may be provided on the lower surface 82 b side of the flat plate 82.

  The calibration standard sample 80 is set such that the diameter (droplet width) d, the radius r, the height h, and the contact angle θ of the protrusion 84 are set to predetermined values. The calibration unit 150 of the image processing device 120 includes an image obtained by imaging the calibration standard sample 80 by the first imaging device 30 (hereinafter, a calibration side image) and an image obtained by imaging the calibration standard sample 80 by the second imaging device 40. Calibration is performed based on (hereinafter referred to as a calibration plane image).

  The materials of the flat plate 82 and the sphere 88 for calibrating the calibration standard sample 80 are not particularly limited, but when the first imaging device 30 and the second imaging device 40 capture images, a clear image with clear contrast is obtained. In order to obtain it, it is preferable to use a metal such as stainless steel or glass which has a smooth surface and easily reflects light.

  Next, a calibration procedure performed prior to the measurement of the contact angle and the contour shape in plan view by the contact angle meter 1 will be described.

  FIG. 5 is a flowchart showing the flow of the calibration procedure. In the first step S101 of the calibration procedure, the calibration standard sample 80 is placed on the stage 20.

  In step S102, the calibration standard sample 80 on the stage 20 is imaged by the first imaging device 30, and the calibration side image 200 is acquired (see FIG. 6A). The calibration side image 200 is transmitted to the computer 100 and stored in storage means such as a hard disk. In step S103, the calibration standard sample 80 is imaged by the second imaging device 40, and the calibration planar image 210 is acquired (see FIG. 6B). The calibration plane image 210 is stored in a storage unit such as a hard disk included in the computer 100, similarly to the calibration side image 200.

  In step S104, image processing is performed on the calibration side image 200 and the calibration plane image 210 by the same procedure as image processing at the time of measurement described later.

  FIGS. 6A and 6B are schematic diagrams showing images to be captured in calibration. As shown in FIG. 5A, the calibration side image 200 is an image in which the flat lighting and the projection 84 are projected with a clear contrast as a dark silhouette when illuminated by the first lighting device 50 from behind. Become. Therefore, the calibration side image 200 is composed of a dark area 202 where the flat plate 82 is projected, a dark area 204 where the protrusion 84 is projected, and a bright background area 206.

  Further, as shown in FIG. 5B, the calibration flat image 210 is an image in which the protruding portion 84 is projected with a clear contrast with the flat plate 82 as a background. In imaging of the calibration standard sample 80 by the second imaging device 40, the flat plate 82 is dark and the protruding portion 84 is projected brightly when the second illumination device 60 is used, and the flat plate 82 when the coaxial incident illumination device 42 is used. Is bright and the protrusion 84 is darkly projected. In the calibration, any illumination device may be used, but here, a case where the coaxial incident illumination device 42 is used is shown. Therefore, the calibration planar image 210 is composed of a bright area 212 in which the flat plate 82 is projected and a dark area 214 in which the protruding portion 84 is projected.

  In step S <b> 104 of the calibration procedure, first, the contour shape (contour shape in side view) of the region 204 of the protruding portion 84 and the region 202 of the flat plate 82 is derived for the calibration side image 200. Based on this, two-dimensional coordinates (x, y) in the image based on the number of pixels are obtained for characteristic points in the region 204 of the protrusion 84. Here, for example, coordinates are obtained for points A and B that are end points in the x direction of the region 204, and points T that are vertices of the region 204 in the y direction.

  Next, similarly for the calibration flat image 210, the contour shape (planar contour shape) of the region 214 of the protrusion 84 is derived, and based on this, the characteristic point image in the region 212 of the protrusion 84 is extracted. The coordinates (x, y) of are obtained. Here, for example, coordinates are obtained for the points A ′ and B ′ that are the end points in the x direction and the points C ′ and D ′ that are the end points in the y direction.

  Returning to FIG. 5, in step S105, the pixel dimensions in the calibration side image 200 and the calibration plane image 210 are calibrated based on the coordinates of each point obtained in step S104. Here, for the calibration side image 200, the value of the diameter d of the protrusion 84 of the calibration standard sample 80 stored in advance is divided by the distance (number of pixels) in the x direction between the points A and B. Or by dividing the value of the height h of the protrusion 84 by the distance (number of pixels) in the y direction between the point T and the point A or B, the size per pixel in the calibration side image 200, That is, it is calculated how many μm, for example, one pixel in the image indicates. Then, the calculated size per pixel is set as the size per pixel in the image captured by the first imaging device 30, and is stored in a predetermined storage unit.

  Next, for the calibration planar image 210, the value of the diameter d of the protrusion 84 of the calibration standard sample 80 stored in advance is set to the distance (number of pixels) in the x direction between the points A ′ and B ′. The dimension per pixel in the calibration planar image 210 is calculated by a process such as division by the distance (number of pixels) in the y direction between the point C ′ and the point D ′. Then, the calculated size per pixel is set as the size per pixel in the image captured by the second imaging device 40, and is stored in a predetermined storage unit.

  In step S106, the correspondence of the positions in the calibration side image 200 and the calibration plane image 210 is obtained based on the coordinates of each point obtained in step S104. In this embodiment, the point A ′ of the calibration side image 210 corresponds to the point A of the calibration side image 200 (shows the same position), and the point B of the calibration side image 200 corresponds to the point B of the calibration side image 210. The orientations of the first imaging device 30 and the second imaging device 40 are set so that the point B ′ corresponds.

  Therefore, here, the relationship between the coordinates of the point A in the calibration side image 200 and the coordinates of the point A ′ in the calibration plane image 210, and the coordinates of the point B in the calibration side image 200 and B ′ in the calibration plane image 210. From the relationship between the coordinates of the points, the correspondence between the coordinates in the calibration side image 200 and the coordinates in the calibration plane image 210 is obtained. That is, a relational expression between the coordinates of the calibration side image 200 indicating the same position and the coordinates of the calibration plane image 210 is derived. And it sets as a relational expression of the coordinate in the image imaged with the 2nd imaging device 40, and the coordinate in the image imaged with the 1st imaging device 30, and memorize | stores in a predetermined memory | storage means.

  In step S107, other measurement values are calibrated as necessary. Here, similarly to the normal measurement, various parameters such as the contact angle of the protrusion 84 and the contour shape in plan view are derived based on the image processing in step S104, and the actual values set in the calibration standard sample 80 are calculated. Compare. Then, based on the comparison result, for example, a count for correcting lens distortion or the like is set and stored in a predetermined storage means.

  Next, a procedure for measuring a contact angle and a planar outline shape by the contact angle meter 1 will be described.

  FIG. 7 is a flowchart showing the flow of the measurement procedure. In the first step S201 of the measurement procedure, the solid sample 2 is placed on the stage 20. At this time, the stage 20 is operated as necessary, and the solid sample 2 is moved to an optimal position for imaging by the first imaging device 30 and the second imaging device 40. Moreover, the light quantity, position, etc. of the 1st lighting apparatus 50 and the 2nd lighting apparatus 60 are adjusted as needed. When the coaxial epi-illumination 42 is used, the light quantity of the coaxial epi-illumination 42 is adjusted as necessary.

  In step S202, the second imaging device 40 captures a state where there is no liquid droplet on the solid sample 2, and obtains a reference plane image. The reference plane image is compared with a droplet plane image obtained by imaging the droplet 4 on the solid sample 2 by the second imaging device 40 in image processing to be described later, thereby extracting a region where the droplet 4 is projected. Is for. The reference plane image is picked up by turning on only the second illumination device 60 or the coaxial incident illumination device 42 according to the surface state of the solid sample 2. The captured reference plane image is transmitted to the computer 100 and stored in a predetermined storage unit such as a hard disk.

  In step S203, the liquid sample is dropped onto the solid sample 2 by operating the dispenser 70, and the droplet 4 is generated. In step S204, the droplet 4 on the solid sample 2 is imaged from the side by the first imaging device 30, and a droplet side image is acquired. The imaging of the side surface image of the droplet is performed by turning on only the first lighting device 50. The captured droplet side surface image is transmitted to the computer 100 and stored in a predetermined storage unit such as a hard disk.

  In step S205, the second imaging device 40 images the droplet 4 on the solid sample 2 from above, and obtains a droplet plane image. The droplet plane image is captured using the same illumination device (second illumination device 60 or coaxial incident illumination device 42) as that of the reference plane image. The captured liquid droplet planar image is transmitted to the computer 100 and stored in a predetermined storage unit such as a hard disk. Note that the liquid droplet plane image may be captured before the liquid droplet side image.

  In step S206, it is determined whether or not the specified number of times of imaging has been performed. If the specified number of times of imaging has not been performed, the imaging of the droplet side image in step S204 and the imaging of the droplet plane image in step S205 are repeated until the specified number of times is reached. At this time, the stage 20 may be rotated for each imaging, and the contact angles in a plurality of different directions (for example, eight locations) may be measured. If the number of imaging has reached the specified number, the process proceeds to step S207.

  In step S207, the image processing device 120 provided in the computer 100 performs image processing on the droplet side surface image and the droplet plane image stored in the predetermined storage unit, and derives the contact angle and the planar view outline shape of the droplet 4. . In the present embodiment, the droplet side surface image, the droplet plane image, and the reference plane image stored in the predetermined storage unit are grayscale images, but may be color images.

  Next, the image processing procedure in step S207 in the measurement procedure will be described.

  FIG. 8 is a flowchart showing the flow of the image processing procedure. In the first step S301 of the image processing, the contact angle deriving unit 130 of the image processing device 120 derives the contact angle based on the droplet side surface image. Details of the derivation of the contact angle will be described later.

  In step S302, the droplet width deriving unit 160 of the image processing apparatus 120 uses the droplet side surface image to determine the droplet width d that is the width direction (x direction) size of the droplet 4 and the width direction of the droplet 4. The coordinates (see FIG. 9B) of the points A and B which are end points in the (x direction) are derived. In the present embodiment, the droplet width deriving unit 160 obtains the droplet width d and the coordinates of the points A and B derived and stored by the contact angle deriving unit 130 in the procedure described later in step S304. I have to.

  In step S303, the shape deriving unit 140 of the image processing apparatus 120 compares the droplet plane image with the reference plane image to derive the planar view contour shape of the droplet 4. Details of the derivation of the planar view contour shape will be described later.

  In step S304, it is determined whether or not the processing in steps S301 to S303 has been performed for all captured droplet side images and droplet plane images. If the above process has been performed for all images, the process proceeds to step S305. If there is a droplet side image and a droplet plane image that have not been subjected to the above process, the process returns to step S301 and the above process is repeated.

  In step S305, the various data derived in steps S301 and S303 are displayed on the display device of the computer 100 and stored in a predetermined storage unit such as a hard disk. When a plurality of measurements are performed, the contact angle calculated for each measurement, the average value of various parameters, Δ width, standard deviation, etc. are calculated and displayed and stored.

  Next, the procedure for deriving the contact angle in step S301 in image processing will be described.

  FIGS. 9A and 9B are schematic views showing an outline of the derivation of the contact angle θ by the contact angle deriving means 130. FIG. As shown in FIG. 6A, the liquid droplet side image 300 includes a dark region 202 in which the solid sample 2 is projected and a dark image in which the liquid droplet 4 is projected by illumination from behind by the first illumination device 50. The image is composed of an area 204 and a bright background area 206.

  In deriving the contact angle, first, the contour shape (side view contour shape) 308 of the region 304 of the droplet 4 and the region 302 of the solid sample 2 is derived. In the derivation of the side view contour shape 308, the pixels Po indicating the side view contour shape 308 are searched and extracted by sequentially comparing the pixels P adjacent to each other in the droplet side image 300. Then, a side view outline shape 308 is derived by connecting the extracted pixels Po.

  Specifically, for example, from the arbitrary start point in the background region 306, the difference between the gradation values of two pixels P adjacent in order toward a predetermined direction is calculated by the comparison unit 132. When the difference value calculated by the comparison unit 132 is less than a preset threshold value by the determination unit 134, it is determined that all of the compared pixels P are in the background region 306, and the difference value is the threshold value. In the case above, it is determined that the compared one pixel P is in the region 304 of the droplet 4 (or in the region 302 of the solid sample 2). That is, when the difference value is equal to or greater than the threshold value, the determination unit 134 determines that the compared one pixel P is the pixel Po indicating the side view contour shape 308.

  A plurality of pixels Po can be extracted by repeating the above procedure while shifting the position of the start point. At this time, only the pixel P near the boundary with the background region 306 may be extracted as the pixel Po, or all the pixels P in the region 304 of the droplet 4 and the region 302 of the solid sample 2 may be extracted. The pixel Po may be extracted. In this way, the side view contour shape 308 can be derived by connecting the extracted pixels Po.

  In addition, after the pixel Po showing the side view contour shape 308 is first extracted, the surrounding pixels P are sequentially compared with the pixel Po as a new start point, and the difference in gradation is less than the threshold value It may be determined that the pixel P compared to is a new pixel Po. That is, after extracting the pixel Po which shows the side view outline shape 308 first, you may make it extract the pixel P of the gradation equivalent to this as the pixel Po.

  Further, any point in the region 204 of the droplet 4 or the region 302 of the solid sample 2 from the beginning may be used as the comparison start point. Further, instead of comparing the single pixels P, the regions composed of a plurality of pixels P may be compared.

  After deriving the side view contour shape 308, the contact angle deriving means 130, as shown in FIG. 5B, based on the side view contour shape 308, points A and B, which are end points in the x direction, and The coordinates of the point T that is the apex in the y direction are obtained. Then, the diameter (droplet width) d and radius r of the droplet 4 are calculated from the difference between the x coordinates of the point A and the point B, and the height of the droplet 4 is calculated from the difference between the y coordinates of the point T and the point A or B. The length h is calculated. In the present embodiment, since the dimensions per pixel are set by prior calibration, actual values can be obtained for the diameter (droplet width) d, radius r, and height h of the droplet 4.

  The contact angle θ can be calculated by a known method, for example, the θ / 2 method. Specifically, the contact angle θ can be obtained from the value of the radius r and the height h of the droplet 4 using the formula θ = 2 · φ = 2 · arctan (h / r). Note that the contact angle θ may be obtained in more detail using other known methods such as a tangent method and a curve fitting method.

  FIG. 10 is a flowchart showing the flow of the procedure for deriving the contact angle θ. In the first step S401 for deriving the contact angle θ, two pixels P to be compared are selected. In step S <b> 402, the comparison unit 132 obtains and compares the gradation difference between the two selected pixels P. In step S403, the determination unit 134 determines whether one of the two compared pixels P is the pixel Po indicating the side view contour shape 308 based on the difference value obtained in step S402 and the threshold value. If it is determined that the visual contour shape 308 is indicated, the pixel Po is extracted.

  In step S406, it is determined whether or not the side view contour shape 308 can be derived from the extracted pixel Po. If the side view contour shape 308 can be derived, the process proceeds to step S405, and if it cannot be derived, the process returns to step S401 to further search for the pixel Po.

  In step S405, the extracted pixel Po is connected to derive the side view contour shape 308. In step S406, the contact angle θ is calculated based on the derived side view contour shape 308.

  Next, the procedure for deriving the contour shape in plan view in step S303 in the image processing will be described.

  FIG. 11 is a schematic diagram showing an outline of derivation of the planar view outline shape 408 by the shape deriving means 140. In addition, in the same figure, the example of the droplet plane image 400 and the reference plane image 500 at the time of imaging the droplet 4 on the solid sample 2 which is hard to reflect light using the 2nd illumination device 60 is shown. .

  In this case, the liquid droplet planar image 400 includes a slightly dark area 402 where the solid sample 2 is projected and a dark area 404 where the liquid droplet 4 is projected. Further, in the liquid droplet flat image 400, a slightly bright region 405 around the region 404 of the droplet 4 and a slightly bright region 406 in which a halo generated inside the region 404 of the droplet 4 is projected are generated depending on conditions. The reference plane image 500 includes only a slightly dark area 502 where the solid sample 2 is projected.

  In the case of the solid sample 2 that hardly reflects light, an image with a clear contrast may not be obtained even if any of the second illumination device 60 and the coaxial incident illumination device 42 is used. In such a case, a method for deriving the planar view contour shape 408 of the droplet 4 by comparing the droplet plane image 400 and the reference plane image 500 is effective.

  In derivation of the planar view contour shape 408, first, comparison ranges 407 and 507 for comparing the pixels P are set by the comparison range setting means 146, and extracted from the droplet plane image 400 and the reference plane image 500, respectively. The comparison ranges 407 and 507 are set to a size obtained by enlarging the droplet width d derived by the droplet width deriving unit 160 with a predetermined enlargement ratio. The comparison ranges 407 and 507 are based on the coordinates of the points A ′ and B ′ that are points corresponding to the points A and B of the droplet side surface image 300 derived by the droplet width deriving unit 160. The position including the area 404 is set.

  Next, the comparison unit 142 sequentially compares the pixels P in the comparison range 407 with the pixels P in the comparison range 507 at the same position. Specifically, for the pixel P in the comparison range 507 at the same position as the pixel P in the comparison range 407, the difference in gradation value is calculated by the comparison unit 142. Then, when the difference value calculated by the comparison unit 142 is less than a preset threshold value, the determination unit 144 determines that the pixel P in the compared comparison range 407 is outside the region 404 of the droplet 4, and the difference Is equal to or greater than the threshold value, it is determined that the pixel P in the comparison range 407 is within the region 404 of the droplet 4. That is, the determination unit 134 determines that the pixel P in the comparison range 407 is the pixel Po indicating the planar view contour shape 408 when the difference value is equal to or greater than the threshold value.

  Here, by appropriately setting the threshold value, or by determining that the pixel P in the comparison range 407 is the pixel Po only when the pixel P in the comparison range 407 is darker than the pixel P in the comparison range 507. The region 404 of the droplet 4 can be distinguished from the surrounding region 405 and the halo region 406.

  By performing the above procedure for all the pixels in the comparison ranges 407 and 507, it is possible to extract the pixel Po that is in the region 404 of the droplet 4 in the comparison range 407 and indicates the planar view contour shape 408. Based on this, the contour shape 408 in plan view of the droplet 4 can be derived.

  The shape of the halo produced in the droplet 4 is similar to the contour shape 408 in plan view of the droplet 4. Accordingly, the pixel Po that indicates the shape of the halo in the halo region 406 may be extracted from the comparison range 407 by the same procedure as described above. In this case, the shape of the halo region 406 is magnified by the magnifying means 148 based on the ratio between the droplet width d derived by the droplet width deriving means 160 and the width direction (x direction) dimension ds of the halo region 406. Is enlarged to derive the contour shape 408 in plan view of the droplet 4. This method is effective when the outline of the droplet 4 is blurred.

  FIG. 12 is a flowchart showing a flow of a procedure for deriving the planar view contour shape 408. In the first step S501 for deriving the planar view outline shape 408, the comparison range setting means 146 sets the comparison ranges 407 and 507 and extracts them from the droplet plane image 400 and the reference plane image 500, respectively. In step S502, the pixel P at the same position to be compared is selected from the comparison ranges 407 and 507.

  In step S503, the comparison unit 142 obtains and compares the gradation difference between the pixel P in the selected comparison range 407 and the pixel P in the comparison range 507. In step S504, the determination unit 144 determines whether or not the compared pixel P in the comparison range 407 is the pixel Po indicating the planar view contour shape 408 based on the difference value obtained in step S503 and the threshold value. If it is determined that the visual contour shape 408 is indicated, the pixel Po is extracted. When the planar view contour shape 408 is derived based on the halo generated in the droplet 4, it is determined whether or not the pixel P in the compared comparison range 407 is the pixel Po indicating the shape of the halo, and the shape of the halo. When it is determined that the pixel Po is indicated, the pixel Po is extracted.

  In step S505, it is determined whether or not all the pixels in the comparison ranges 407 and 507 have been compared. If all the pixels are compared, the process proceeds to step S506. If all the pixels are not compared, the process returns to step S502 to compare and determine the next pixel P.

  In step S506, a planar view contour shape 408 is derived based on the extracted pixel Po. When the planar view contour shape 408 is obtained based on the halo generated in the droplet 4, the planar view contour shape 408 is derived by enlarging the shape of the region 406 of the halo by the enlargement unit 148.

  In step S507, various parameters related to the planar view contour shape 408 are calculated. In this embodiment, for example, the roundness (= (maximum radius−minimum radius) / average radius), aspect ratio (= maximum diameter / minimum diameter), orientation (= tilt angle of the maximum diameter with respect to the y-axis), etc. are planar. The visual contour shape 408 is calculated as a parameter for evaluation.

  In addition, by using the same procedure as the derivation of the side view contour shape 308 described with reference to FIG. 9A, the plan view contour shape of the droplet 4 from only the droplet plane image 400 without using the reference plane image 500. 408 can also be derived.

  FIG. 13 is a schematic diagram showing a case where a planar view outline shape 408 is derived from only the liquid droplet planar image 400. In addition, in the same figure, the example of the droplet plane image 400 at the time of imaging the droplet 4 on the solid sample which reflects light easily using the 2nd illumination device 60 is shown.

  In this case, the droplet plane image 400 is an image with a clear contrast composed of a dark region 402 in which the solid sample 2 is projected and a bright region 404 in which the droplet 4 is projected. In addition, in the droplet plane image 400, a dark region 409 is generated inside the region 404 of the droplet 4 depending on conditions.

  In the case of the solid sample 2 that easily reflects light, an image with clear contrast can be obtained by using either the second illumination device 60 or the coaxial epi-illumination device 42. In such a case, the planar view contour shape 408 of the droplet 4 can be derived by the same procedure as the derivation of the side view contour shape 308.

  In the derivation of the planar view contour shape 408 of this example, the comparison range 407 is first set by the comparison range setting means 146 based on the droplet width d and the coordinates of the points A ′ and B ′ as in the above-described procedure. Extract from the droplet plane shape 400. When the droplet side image 300 is not captured, the comparison range 407 need not be set.

  Next, the comparison unit 142 sequentially compares adjacent pixels P in the comparison range 407, and determines whether one of the pixels P compared by the determination unit 144 is the pixel Po indicating the planar view contour shape 408. Thus, the pixel Po is searched.

  Specifically, similarly to the derivation of the side view contour shape 308, for example, the gradation value of two pixels P adjacent in order toward a predetermined direction from an arbitrary start point in the region 402 of the solid sample 2 The difference is calculated by the comparison unit 142. Then, when the difference value calculated by the comparison unit 142 is less than a preset threshold value, the determination unit 144 determines that all of the compared pixels P are within the region 402 of the solid sample 2, and the difference value Is equal to or greater than the threshold value, one of the compared pixels P is determined as a pixel Po in the region 404 of the droplet 4. And the planar view outline shape 408 is derived | led-out by connecting the some pixel Po extracted in this way.

  First, from the coordinates of the point A ′ or the point B ′, a pixel Po1 indicating the planar view contour shape 408 is obtained, and the comparison unit 142 and the determination unit 144 search for the pixel P having the same gradation as the pixel Po1, You may make it extract as pixel Po. Further, the planar view contour shape of the region 409 in the region 404 of the droplet 4 is derived, and the planar view contour shape of the region 409 is enlarged by the magnifying means 148 similarly to the case of the halo, thereby The visual contour shape 408 may be derived.

  FIG. 14 is a flowchart showing the flow of the procedure in the case of deriving the planar view contour shape 408 from only the liquid droplet planar image 400. In the first step S <b> 601, a comparison range 407 is set by the comparison range setting means 146 and extracted from the droplet plane image 400. Note that the comparison range 407 may be set as necessary. In step S602, two pixels P to be compared are selected from the comparison range 407.

  In step S603, the comparison unit 142 obtains and compares the gradation difference between the two selected pixels P. In step S604, the determination unit 134 determines whether one of the two compared pixels P is the pixel Po indicating the planar view contour shape 408 based on the difference value obtained in step S603 and the threshold value. If it is determined that the visual contour shape 408 is indicated, the pixel Po is extracted. When the planar view contour shape 408 is derived based on the region 409 in the region 404 of the droplet 4, it is determined whether one of the two compared pixels P is the pixel Po indicating the contour shape of the region 409. If it is determined that the contour shape of the region 409 is indicated, the pixel Po is extracted.

  In step S605, it is determined whether or not the planar view contour shape 408 can be derived from the extracted pixel Po. When the planar view contour shape 408 is derived based on the region 409, it is determined whether or not the contour shape of the region 409 can be derived. If the planar view contour shape 408 (contour shape of the region 409) can be derived, the process proceeds to step S606, and if it cannot be derived, the process returns to step S602 to further search for the pixel Po.

  In step S606, a planar view contour shape 408 is derived based on the extracted pixel Po. When the planar view contour shape 408 is obtained based on the region 409, the planar view contour shape 408 is derived by enlarging the shape of the region 409 by the enlargement unit 148.

  In the present embodiment, either the second illumination device 60 or the coaxial epi-illumination device 42 is used for imaging by the second imaging device 40. Instead, the first illumination device 30 is used for the first imaging. You may make it perform the imaging by the 2 imaging device 40. FIG.

  FIGS. 15A and 15B are diagrams illustrating an example in which imaging is performed by the second imaging device 40 using the first illumination device 50. In the example shown in FIG. 5A, the droplet 4 on the solid sample 2 is partially whitened by illumination by the first illumination device 50, and this is imaged from above by the second imaging device 40. Thereby, a part of the planar view contour shape 408 of the droplet 4 can be derived. Accordingly, by operating the stage 20 to perform imaging a plurality of times while rotating the solid sample 2 and the droplet 4, and combining the partial plan view contour shape 408 derived from the plurality of droplet planar images 400, the liquid is obtained. The overall plan view profile 408 of the drop 4 can be derived.

  Further, instead of rotating the stage 20, as shown in FIG. 5B, the plurality of first illumination devices 50 are arranged around the stage 20 to illuminate the liquid droplet 4 as a whole. You may make it shine white. In this case, the overall planar view contour shape of the droplet 4 can be derived by one imaging. In this case, when imaging is performed by the first imaging device 30, any one of the first illumination devices 50 may be retracted to a position that does not affect imaging.

  Depending on the state of the solid sample 2 and the droplet 4, it may be possible to obtain a clearer image by performing imaging with the second imaging device 40 using the first illumination device 50 as described above.

  Further, in the present embodiment, the planar view contour shape 408 of the droplet 4 on the solid sample 2 is derived from the droplet planar image 400 by the image processing apparatus 120. However, along with the derivation of the planar view contour shape 408, the droplet planar image Other information may be acquired from 400.

  For example, when the solid sample 2 is paper or the like, the area of the portion where the liquid sample oozes from the droplet 4 to the solid sample 2 may be derived. In this case, the area of the portion where the liquid sample oozes can be obtained in the same procedure as the derivation of the planar view contour shape 408. Then, the area of the droplet 4 is derived together with the area of the oozed portion, and for example, a parameter of bleed degree (= (area of the oozed portion + droplet area) / droplet area) is calculated, thereby further diversifying. It becomes possible to evaluate the properties of the solid surface from the viewpoint.

  Further, in the present embodiment, an example in which the light source 65 is configured from a plurality of LEDs 64 has been described, but the light source 65 may be configured from other illumination devices such as a fluorescent lamp and an organic EL. In this embodiment, an example in which the diffusion plate 68 is provided in front of the LED 64 is shown. However, the diffusion plate 68 may not be provided, and a normal transparent plate or the like may be used instead of the diffusion plate 68 to emit light. You may make it be a surface.

  As described above, the image processing apparatus 120 according to this embodiment captures an image of the droplet 4 on the sample 2 in the contact angle meter that measures the contact angle θ of the droplet 4 on the sample (solid sample) 2. Is provided with shape deriving means 140 for deriving a planar view outline shape 408 of the droplet 4 based on a droplet plane image 400 obtained by imaging the droplet 4 on the sample 2 from above. .

  For this reason, the planar view contour shape 408 of the droplet 4 can be measured with higher accuracy together with the contact angle θ. In addition, since various parameters such as roundness, aspect ratio, and orientation can be easily obtained for the contour 408 in plan view, the properties of the solid surface can be evaluated from various perspectives.

  In the present embodiment, an example of the contact angle meter 1 including the first imaging device 30 that images the droplet 4 on the solid sample 2 from the side is shown, but the present invention is not limited to this. For example, the present invention can be applied to a contact angle meter that includes only the second imaging 40 and calculates the contact angle θ from an image obtained by imaging the droplet 4 on the solid sample 2 from above and the volume of the droplet. it can.

  The image processing apparatus 120 further includes contact angle deriving means 130 for deriving the contact angle θ of the droplet 4 based on the droplet side image 300 obtained by imaging the droplet 4 on the sample 2 from the side. For this reason, the contact angle θ and the planar view contour shape 408 of the droplet 4 can be measured more easily and with high accuracy.

  In addition, the shape deriving unit 140 compares each pixel P of the droplet plane image 400 with another pixel P, and each pixel P of the droplet plane image 400 is a liquid based on the comparison result of the comparison unit 142. Determination means 144 for determining whether or not the contour shape 408 of the droplet 4 is viewed in plan view.

  For this reason, the planar view contour shape 408 of the droplet 4 can be derived from the droplet plane image 400 with high accuracy. In the present embodiment, since the gray scale image is used, the comparison unit 132, 142 obtains the difference in the gradation value of the pixel P. However, while using the color image, the comparison unit 132, For example, a difference such as chromaticity, lightness, or saturation may be obtained by 142 alone or in combination.

  Further, the comparison unit 142 compares each pixel P of the droplet plane image 400 with a pixel P at the same position in the reference plane image 500 obtained by imaging the state in which no droplet 4 is present on the sample 2 from above. For this reason, even when it is difficult to obtain the liquid droplet planar image 400 with clear contrast, the planar view contour shape 408 of the liquid droplet 4 can be derived with high accuracy.

  The comparison unit 142 can also compare each pixel P of the droplet plane image 400 with surrounding pixels P in the droplet plane image 400. For this reason, when the droplet plane image 400 is an image with clear contrast, it is possible to derive the planar view contour shape 408 of the droplet 4 from only the droplet plane image 400. As a result, the processing load on the image processing apparatus 120 can be reduced, and the measurement of the contact angle θ and the planar view contour shape 408 can be speeded up.

  In addition, the image processing apparatus 120 uses the droplet width derivation image obtained by imaging the droplet 4 on the sample 2 from the side (in this embodiment, also used as the droplet side image 300) in the width direction of the droplet 4. A droplet width deriving unit 160 for deriving a size (droplet width) d is further provided. The shape deriving unit 140 includes a comparing unit 142 based on the width dimension d of the droplet 4 derived by the droplet width deriving unit 160. A comparison range setting unit 146 is further provided for setting the range of the pixel P to be compared.

  With such a configuration, the range in which the pixels P are compared can be limited, so that the processing load on the image processing apparatus 120 is reduced and the measurement of the contact angle θ and the planar view contour shape 408 is speeded up. be able to. In the present embodiment, the example in which the droplet side surface image 300 is also used as the droplet width deriving image is shown, but the droplet width deriving image may be captured separately from the droplet side surface image 300. .

  In addition, the determination unit 144 is based on the comparison result of the comparison unit 142, and the shape of the halo in which each pixel P of the liquid droplet planar image 400 is generated in the liquid droplet 4 in a shape similar to the planar view contour shape 408 of the liquid droplet 4. The shape deriving unit 140 may further include an enlarging unit 148 for deriving the contour shape 408 in plan view of the droplet 4 by enlarging the shape of the halo.

  Further, the determination unit 144 is based on the comparison result of the comparison unit 142, and the shape of the halo in which each pixel P of the droplet plane image 400 is generated in the droplet 4 in a similar shape to the planar view contour shape 408 of the droplet 4. The shape deriving unit 140 enlarges the shape of the halo based on the width direction dimension d of the droplet 4 derived by the droplet width deriving unit 160, so that the plane of the droplet 4 An enlargement unit 148 for deriving the visual contour shape 408 may be further provided.

  By adopting such a configuration, even when the liquid droplet planar image 400 is unclear, the planar view contour shape of the liquid droplet 4 may be derived with high accuracy.

  The image processing apparatus 120 further includes a calibration unit 150 that performs calibration based on a calibration image (a calibration side image 200 and a calibration plane image 210) obtained by imaging the calibration standard sample 80.

  With such a configuration, the image processing apparatus 120 can be easily calibrated, so that it is possible to perform measurement with higher accuracy.

  Further, the calibration unit 150 calibrates the size of one pixel in the image obtained by capturing the droplet 4 on the sample 2 based on the calibration image (the calibration side image 200 and the calibration plane image 210). It has.

  With such a configuration, the actual dimensions can be easily obtained in the measurement of the contact angle θ and the contour shape 408 in plan view of the droplet 4, and more various evaluations are performed on the properties of the solid surface. be able to.

  Further, the calibration means 150 is configured to drop droplets on the sample 2 based on the calibration plane image 210 obtained by imaging the calibration standard sample 80 from above and the calibration side image 200 obtained by imaging the calibration standard sample 80 from the side. Position relation calibration means 154 is provided for calibrating the correspondence between positions in an image obtained by imaging 4 from above and an image obtained by imaging the droplet 4 on the sample 2 from the side.

  For this reason, it is possible to efficiently perform image processing by linking the image captured by the first imaging device 30 and the image captured by the second imaging device 40, and the speed of measurement can be increased.

  The calibration standard sample 80 includes a flat plate 82 and a partial spherical protruding portion 84 protruding from the surface of the flat plate 82. For this reason, it is possible to simultaneously calibrate both the imaging performed by the first imaging device 30 and the second imaging device 40 with one calibration standard sample 80.

  Further, the calibration standard sample 80 has a through-hole (fixed hole) 86 having a circular cross section and a tapered shape formed on the flat plate 82, and a part of the through-hole (fixed hole) 86 protrudes from the opening on the small diameter side. The protruding portion 84 is formed by fixing the sphere 88 in the state. With such a configuration, the calibration standard sample 80 can be created with high accuracy at low cost.

  In addition, in the method for deriving the contour shape of the droplet in plan view according to the present embodiment, the droplet 4 on the sample 2 is imaged by the contact angle meter 1 that measures the contact angle θ of the droplet 4 on the sample (solid sample) 2. Is a method of deriving a planar view contour shape 408 of the droplet 4 by processing the processed image, and each pixel P of the droplet planar image 400 obtained by imaging the droplet 4 on the sample 2 from above is defined as another pixel. A comparison step S503 for comparing P, a determination step S504 for determining whether or not each pixel P of the liquid droplet planar image 400 indicates a planar view outline shape 408 of the liquid droplet 4 based on the comparison result of the comparison step S503, have.

  For this reason, the planar view contour shape 408 of the droplet 4 can be derived from the droplet plane image 400 with high accuracy.

  In addition, in the planar view contour derivation method according to the present embodiment, in the comparison step S503, each pixel P of the droplet plane image 400 is captured in the reference plane image 500 obtained by imaging the state in which there is no droplet 4 on the sample 2 from above. Compare with the pixel P at the same position.

  For this reason, even when it is difficult to obtain the liquid droplet planar image 400 with clear contrast, the planar view contour shape 408 of the liquid droplet 4 can be derived with high accuracy.

  In addition, in the planar view contour derivation method of the present embodiment, each pixel P of the droplet plane image 400 can be compared with surrounding pixels P in the droplet plane image 400 in the comparison step S503.

  For this reason, when the droplet plane image 400 is an image with clear contrast, it is possible to derive the planar view contour shape 408 of the droplet 4 from only the droplet plane image 400. As a result, the processing load on the image processing apparatus 120 can be reduced, and the measurement of the contact angle θ and the planar view contour shape 408 can be speeded up.

  Further, the planar view contour derivation method of the present embodiment is based on a droplet width derivation image obtained by imaging the droplet 4 on the sample 2 from the side (also used in this embodiment also as the droplet side image 300). A droplet width deriving step S302 for deriving the width direction dimension (droplet width) d of the droplet 4 and a comparison in step S503 based on the width direction dimension d of the droplet 4 derived in the droplet width deriving step S302. And a comparison range setting step S501 for setting the range of the pixel P.

  With such a configuration, the range in which the pixels P are compared can be limited, so that the processing load on the image processing apparatus 120 is reduced and the measurement of the contact angle θ and the planar view contour shape 408 is speeded up. be able to.

  Further, in the planar view contour shape deriving method of the present embodiment, in the determination step S504, each pixel P of the liquid droplet planar image 400 is viewed in a plan view of the liquid droplet 4 based on the comparison result of the comparison step S503. It is determined whether or not the shape of the halo that is similar to the contour shape 408 is shown, and further includes an enlargement step S506 for deriving the contour shape 408 in plan view of the droplet 4 by enlarging the shape of the halo. It can also be.

  Furthermore, in the plan view contour derivation method of the present embodiment, in the determination step S504, each pixel P of the droplet plane image 400 is seen in the plan view of the droplet 4 in the droplet 4 based on the comparison result in the comparison step S503. It is determined whether or not the shape of the halo that is similar to the contour shape 408 is shown, and the shape of the halo is enlarged based on the width direction dimension d of the droplet 4 derived in the droplet width deriving step S302. Thus, it is possible to further include an enlargement step S506 for deriving the planar view contour shape 408 of the droplet 4.

  By adopting such a configuration, even when the liquid droplet planar image 400 is unclear, the planar view contour shape of the liquid droplet 4 may be derived with high accuracy.

  Further, in the planar view contour derivation method of the present embodiment, the droplet 4 on the sample 2 is imaged based on the calibration image (the calibration side image 200 and the calibration plane image 210) obtained by imaging the calibration standard sample 80. A pixel size calibration step S105 for calibrating the size of one pixel in the obtained image is further provided.

  With such a configuration, the actual dimensions can be easily obtained in the measurement of the contact angle θ and the contour shape 408 in plan view of the droplet 4, and more various evaluations are performed on the properties of the solid surface. be able to.

  Further, the planar view contour derivation method of the present embodiment is based on the calibration plane image 210 obtained by imaging the calibration standard sample 80 from above and the calibration side image 200 obtained by imaging the calibration standard sample 80 from the side. Further, there is further provided a positional relationship calibration step S106 for calibrating the correspondence between the positions of the image obtained by imaging the droplet 4 on the sample 2 from above and the image obtained by imaging the droplet 4 on the sample 2 from the side.

  For this reason, it is possible to efficiently perform image processing by linking the image captured by the first imaging device 30 and the image captured by the second imaging device 40, and the speed of measurement can be increased.

  The embodiment of the present invention has been described above, but the image processing device for contact angle meter and the method for deriving the contour shape of the droplet in plan view of the present invention are not limited to the above-described embodiment, and the present invention is not limited thereto. Of course, various changes can be made without departing from the scope of the present invention.

  The image processing apparatus for contact angle meter and the method for deriving the outline shape of a droplet in plan view according to the present invention can be used in the field of measurement and evaluation of surface properties of solids.

2 Solid Sample 4 Droplet 80 Standard Sample for Calibration 82 Flat Plate 84 Projection 120 Image Processing Device 130 Contact Angle Deriving Unit 140 Shape Deriving Unit 142 Comparing Unit 144 Judging Unit 146 Comparison Range Setting Unit 148 Enlarging Unit 150 Calibration Unit 152 Pixel Size Calibration Means 154 Positional calibration means 160 Droplet width deriving means 200 Calibration side image 210 Calibration plane image 300 Droplet side image 400 Droplet plane image 500 Reference plane image 408 Planar outline shape of droplet d Droplet width H No. 2 Clearance between illumination device and solid sample surface P Pixel S Optical axis of second imaging device θ Contact angle

Claims (17)

An image processing apparatus for processing an image obtained by imaging a droplet on the sample in a contact angle meter for measuring a contact angle of the droplet on the sample,
Shape deriving means for deriving a planar view contour shape of the droplet based on a droplet plane image obtained by imaging the droplet on the sample from above ;
Droplet width deriving means for deriving a width direction dimension of the droplet based on a droplet width deriving image obtained by imaging the droplet on the sample from a side , and
The shape deriving means includes
Comparison means for comparing each pixel of the droplet plane image with other pixels;
Determining means for determining whether or not each pixel of the liquid droplet planar image shows a planar view contour shape of the liquid droplet based on the comparison result of the comparing means;
Comparison range setting means for setting a range of pixels to be compared by the comparison means based on a width-direction dimension of the droplets derived by the droplet width deriving means ,
Image processing device for contact angle meter. It further comprises contact angle deriving means for deriving the contact angle of the droplet based on a droplet side image obtained by imaging the droplet on the sample from the side,
The image processing apparatus for a contact angle meter according to claim 1. The comparing means compares each pixel of the liquid drop planar image with a pixel at the same position in a reference flat image obtained by imaging a state where the liquid droplet is not present on the sample from above.
The image processing apparatus for a contact angle meter according to claim 1 or 2 . The comparing means compares each pixel of the droplet plane image with surrounding pixels in the droplet plane image,
The image processing apparatus for a contact angle meter according to claim 1 or 2 . Whether the determination means indicates, based on the comparison result of the comparison means, each pixel of the liquid drop planar image indicates the shape of the halo that is similar to the outline shape of the liquid drop in plan view in the liquid drop Determine whether or not
The shape deriving means further comprises an enlarging means for deriving the contour shape of the droplet in plan view by enlarging the shape of the halo.
Contact angle meter image processing apparatus according to any one of claims 1 to 4. The expansion means, the liquid droplet width deriving means to enlarge the shape of the halo on the basis of the width dimension of the droplets led out, and characterized in that you derive the plan view outline shape of the droplet To
The image processing apparatus for a contact angle meter according to claim 5 . It further comprises calibration means for performing calibration based on a calibration image obtained by imaging a calibration standard sample,
Contact angle meter image processing apparatus according to any one of claims 1 to 6. The calibration means includes pixel size calibration means for calibrating the size of one pixel in an image obtained by imaging the droplet on the sample based on the calibration image.
The image processing device for a contact angle meter according to claim 7 . The calibration means is configured to detect the liquid droplets on the sample from above based on a calibration plane image obtained by imaging the calibration standard sample from above and a calibration side image obtained by imaging the calibration standard sample from the side. It is characterized by comprising positional relationship calibration means for calibrating the correspondence between the positions in the captured image and the image captured from the side of the droplet on the sample,
The image processing apparatus for a contact angle meter according to claim 7 or 8 . The calibration standard sample is composed of a flat plate and a partial spherical protruding portion protruding from the surface of the flat plate,
Contact angle meter image processing apparatus according to any one of claims 7 to 9. A method for deriving a contour shape in plan view of the droplet by processing an image obtained by imaging the droplet on the sample in a contact angle meter for measuring a contact angle of the droplet on the sample,
A droplet width deriving step for deriving a width direction dimension of the droplet based on a droplet width deriving image obtained by imaging the droplet on the sample from a side;
A comparison range setting step of setting a comparison range based on the width direction dimension of the droplet derived in the droplet width deriving step;
A comparison step of comparing each pixel in the comparison range of the droplet plane image obtained by imaging the droplet on the sample from above with other pixels;
A determination step of determining whether or not each pixel of the liquid droplet planar image indicates a planar view outline shape of the droplet based on the comparison result of the comparison step,
A method for deriving a contour shape of a droplet in plan view. In the comparison step, each pixel of the liquid droplet planar image is compared with a pixel at the same position in a reference planar image obtained by imaging a state where the liquid droplet is not present on the sample from above.
The method of deriving a contour shape in plan view of a droplet according to claim 11 . In the comparison step, each pixel of the droplet plane image is compared with surrounding pixels in the droplet plane image.
The method of deriving a contour shape in plan view of a droplet according to claim 11 . In the determining step, whether each pixel of the liquid drop planar image shows the shape of the halo that is similar to the contour shape of the liquid drop in plan view based on the comparison result of the comparing step And determine whether or not
The method further comprises an enlarging step of deriving a contour shape of the droplet in plan view by enlarging the shape of the halo.
The method for deriving a contour shape in plan view of a droplet according to any one of claims 11 to 13 . Wherein in enlargement step, to enlarge the shape of the halo on the basis of the width dimension of the droplets derived in the droplet width derivation step, and characterized in that you derive the plan view outline shape of the droplet To
The method for deriving a contour shape of a liquid droplet in plan view according to claim 14 . The method further comprises a pixel size calibration step of calibrating the size of one pixel in an image obtained by imaging the droplet on the sample based on a calibration image obtained by imaging the calibration standard sample.
Plan view contour shape derivation process of a droplet according to any one of claims 11 to 15. Based school Tadashiyo standard sample for calibration plane image captured from above, and the calibration standard samples for calibration side image taken from the side, the image and the captured the droplets on the sample from above The method further comprises a positional relationship calibration step of calibrating a correspondence relationship between positions in an image obtained by imaging the droplet on the sample from the side,
Plan view contour shape derivation process of a droplet according to any one of claims 11 to 15.

Images