Patent Publication Number: US-2023140945-A1

Title: Surface performance evaluation device, surface performance evaluation method, and surface performance evaluation program

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2021-181371 filed on Nov. 5, 2021, the disclosure of which is incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a surface performance evaluation device, a surface performance evaluation method, and a surface performance evaluation program. 
     Related Art 
     Non-patent document JIS R 3257:1999 discloses a testing method of wettability of glass substrate. This test evaluates the contact angle of a liquid adhered to a substrate glass by image analysis. 
     The evaluation method of the Non-patent document JIS R 3257:1999 is not suitable for data-driven material development because evaluation of surface performance, such as wettability, takes time or varies depending on the evaluator. In data-driven material development, it is necessary to acquire quantitative values of surface performance quickly and independent of the evaluator. 
     SUMMARY 
     The present disclosure provides a surface performance evaluation device capable of evaluating surface performance independent of an evaluator by quantifying a degree of diffusion of a liquid diffused from a test object that is exposed to the liquid. 
     A surface performance evaluation device according to a first aspect of the present disclosure includes: an acquisition section configured to acquire a captured image, which is a moving image of a test object on which a liquid is dispersed, and which is captured by an image capture section; a quantification section configured to quantify, based on the captured image that is acquired by the acquisition section, a degree of diffusion of the liquid that is dispersed on the test object and diffuses; and an evaluation section configured to evaluate a surface performance of the test object based on an index quantified by the quantification section. 
     In the surface performance evaluation device according to the first aspect of the present disclosure, when the acquisition section acquires, as a captured image, a moving image of a test object on which a liquid is dispersed, the quantification section quantifies the degree of diffusion of the liquid based on the captured image, and the evaluation section evaluates the surface performance of the test object based on the index quantified by the quantification section. According to the surface performance evaluation device, surface performance can be evaluated independent of an evaluator by quantifying the degree of diffusion of a liquid diffused from a test object that is exposed to the liquid. 
     A surface performance evaluation device according to a second aspect of the present disclosure is the surface performance evaluation device according to the first aspect of the present disclosure, wherein: the quantification section is configured to calculate the index based on a frequency distribution for each direction in which the liquid diffuses in a predetermined period of time; and the evaluation section is configured to evaluate the surface performance based on whether or not the index exceeds a threshold value. 
     In the surface performance evaluation device according to the second aspect of the present disclosure, the evaluation section evaluates the surface performance based on whether or not the index calculated by quantification by the quantification section exceeds a threshold value. The index in the surface performance evaluation device is calculated based on the frequency distribution for each direction in which the liquid diffuses in a predetermined period of time. Namely, according to the surface performance evaluation device, surface performance during a continuous period can be evaluated by quantification based on the frequency distribution in a predetermined period of time. 
     A surface performance evaluation device according to a third aspect of the present disclosure is the surface performance evaluation device according to the second aspect of the present disclosure, wherein the captured image is captured from a position directly horizontal to the test object. 
     In the surface performance evaluation device according to the third aspect of the present disclosure, the diffusion direction of the liquid on the test object and the movement direction of the liquid on the captured image can be aligned by capturing an image of the test object from a position directly horizontal to the test object. As a result, according to the surface performance evaluation device, in a case of illustrating the diffusion state of the liquid in a radar chart, the appearance of the radar chart and the captured image can be correlated. 
     A surface performance evaluation method according to a fourth aspect of the present disclosure includes a computer executing processing, the processing including: acquiring a captured image, which is a moving image of a test object on which a liquid is dispersed, and which is captured by an image capture section; quantifying, based on the captured image that is acquired, a degree of diffusion of the liquid that is dispersed on the test object and diffuses; and evaluating a surface performance of the test object based on a quantified index. 
     In the surface performance evaluation method according to the fourth aspect of the present disclosure, when a computer acquires, as a captured image, a moving image of a test object on which a liquid is dispersed, the degree of diffusion of the liquid is quantified based on the captured image, and the surface performance of the test object is evaluated based on the quantified index. According to the surface performance evaluation method, surface performance can be evaluated independent of an evaluator by quantifying the degree of diffusion of a liquid diffused from a test object that is exposed to the liquid. 
     A surface performance evaluation program according to a fifth aspect of the present disclosure is executable by a computer to perform processing, the processing including: acquiring a captured image, which is a moving image of a test object on which a liquid is dispersed, and which is captured by an image capture section; quantifying, based on the captured image that is acquired, a degree of diffusion of the liquid that is dispersed on the test object and diffuses; and evaluating a surface performance of the test object based on a quantified index. 
     The surface performance evaluation program according to the fifth aspect of the present disclosure causes a computer to execute the following processing. When a computer acquires, as a captured image, a moving image of a test object on which a liquid is dispersed, the degree of diffusion of the liquid is quantified based on the captured image, and the surface performance of the test object is evaluated based on the quantified index. According to the surface performance evaluation program, surface performance can be evaluated independent of an evaluator by quantifying the degree of diffusion of a liquid diffused from a test object that is exposed to the liquid. 
     According to the present disclosure, surface performance can be evaluated independent of an evaluator by quantifying the degree of diffusion of a liquid diffused from a test object that is exposed to the liquid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present disclosure will be described in detail based on the following figures, wherein: 
         FIG.  1    is a diagram illustrating a schematic configuration of an evaluation system according to a first exemplary embodiment; 
         FIG.  2    is a block diagram illustrating a hardware configuration of an evaluation system of the first exemplary embodiment; 
         FIG.  3    is a block diagram illustrating a configuration of ROM of the first exemplary embodiment; 
         FIG.  4    is a block diagram illustrating a configuration of storage of the first exemplary embodiment; 
         FIG.  5    is a block diagram illustrating a functional configuration of a CPU of the first exemplary embodiment; 
         FIG.  6    is a flowchart illustrating a flow of quantification processing of the first exemplary embodiment; 
         FIG.  7    is an example of a captured image of a test object in the first exemplary embodiment; 
         FIG.  8 A  is a captured image subjected to color tone conversion in the first exemplary embodiment, and is an example of a case in which adsorption properties are highly evaluated; 
         FIG.  8 B  is a captured image subjected to color tone conversion in the first exemplary embodiment, and is an example of a case in which adsorption properties are lowly evaluated; 
         FIG.  9 A  is a radar chart illustrating the degree of diffusion of an oil droplet in the first exemplary embodiment, and is an example of a case in which adsorption properties are highly evaluated; 
         FIG.  9 B  is a radar chart illustrating the degree of diffusion of an oil droplet in the first exemplary embodiment, and is an example of a case in which adsorption properties are lowly evaluated; 
         FIG.  10    is a flowchart illustrating a flow of evaluation processing according to the first exemplary embodiment; 
         FIG.  11    is a diagram illustrating the relationship between the number of frames and the vertical/horizontal component ratio; and 
         FIG.  12    is a diagram illustrating a schematic configuration of an evaluation system according to a second exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     First Exemplary Embodiment 
     (Configuration) 
       FIG.  1    illustrates an evaluation system  10  of a first exemplary embodiment. The evaluation system  10  of the present exemplary embodiment is a device that evaluates the surface performance of a wall surface C in a case in which an oil droplet D, which is a liquid, is dispersed on the wall surface C, which is a test object. The surface performance evaluated in the present exemplary embodiment is the adsorption properties of the wall surface C with respect to the oil droplet D. These adsorption properties are performance that comprehensively incorporate lipophilicity, oil repellency, oil-proof property, hydrophilicity, surface performance, waterproof property, and the like. 
     As illustrated in  FIG.  1   , the evaluation system  10  of the present exemplary embodiment includes a processing device  20  serving as a surface performance evaluation device, a camera  22  serving as an image capture section, and a monitor  24  serving as a display section. The camera  22  is fixed in an arrangement that enables the wall surface C to be imaged. 
     As illustrated in  FIG.  2   , the processing device  20  includes a central processing unit (CPU)  20 A, read only memory (ROM)  20 B, random access memory (RAM)  20 C, storage  20 D, a communication interface (I/F)  20 E, and an input/output I/F  20 F. The CPU  20 A, the ROM  20 B, the RAM  20 C, the storage  20 D, the communication I/F  20 E, and the input/output I/F  20 F are communicably connected to each other via a bus  20 G. 
     The CPU  20 A is a central processing unit that executes various programs and controls various components. Namely, the CPU  20 A reads a program from the ROM  20 B or the storage  20 D, and executes the program using the RAM  20 C as a workspace. 
     The ROM  20 B stores various programs and various data. As illustrated in  FIG.  3   , the ROM  20 B of the present exemplary embodiment stores a surface performance evaluation program  100  and setting data  110 . The surface performance evaluation program  100  is a program that executes analysis processing which is described later. The setting data  110  is data that defines values such as the number of frames, which becomes an integration period, and threshold values in the analysis processing. Note that the surface performance evaluation program  100  and the setting data  110  may be stored in the storage  20 D. 
     As illustrated in  FIG.  2   , the RAM  20 C serves as a workspace to temporarily store programs and data. 
     The storage  20 D is configured by a hard disk drive (HDD) or a solid state drive (SSD), and stores various programs and various data. As illustrated in  FIG.  4   , the storage  20 D of the present exemplary embodiment stores moving image data  120  and evaluation result data  130 . The moving image data  120  stores image data of a moving image, which is a captured image M captured by the camera  22 . The evaluation result data  130  stores data relating to evaluation results of surface performance of the wall surface C. Note that the moving image data  120  and the evaluation result data  130  may be stored in the ROM  20 B. 
     As illustrated in  FIG.  2   , the communication I/F  20 E is an interface for connecting to external devices. 
     The input/output I/F  20 F is an interface for communicating with the camera  22  and the monitor  24 . Note that the camera  22  and the monitor  24  may be directly connected to the bus  20 G. 
     As illustrated in  FIG.  5   , in the processing device  20  of the present exemplary embodiment, the CPU  20 A functions as an acquisition section  200 , a quantification section  210 , an evaluation section  220 , and an output section  230  by executing the surface performance evaluation program  100 . 
     The acquisition section  200  has a function of acquiring the captured image M captured by the camera  22 . More specifically, the acquisition section  200  acquires a moving image, as the captured image M, in which an oil droplet D is dispersed onto the wall surface C, from the camera  22 . 
     The quantification section  210  has a function of quantifying the degree of diffusion of the oil droplet D that is dispersed on the wall surface C and diffuses. The quantification section  210  vectorizes the diffused oil droplet D in the captured image M, and based on this vectorized information, obtains a histogram that is a frequency distribution for each direction in which the oil droplet D diffuses during predetermined frames. The quantification section  210  then generates a radar chart from the histogram, and calculates a vertical/horizontal component ratio of the wall surface C, as an evaluation index, from the information in the radar chart. Note that the vertical/horizontal component ratio is a ratio of the frequency of a portion (i.e., a vertical component) of the oil droplet D on the wall surface C which has moved in a direction away from or in a direction approaching the wall surface C, with respect to the frequency of a portion (i.e., a horizontal component) of the oil droplet D on the wall surface C which has moved along the wall surface C. 
     The evaluation section  220  has a function of evaluating the surface performance of the wall surface C based on the evaluation index that is quantified by the quantification section  210 . The evaluation section  220  determines that the adsorption properties are “low adsorption properties” in a case in which the evaluation index exceeds a threshold value, and determines that the adsorption properties are “high adsorption properties” in a case in which the evaluation index is equal to or less than the threshold value. 
     The output section  230  has a function of outputting, to the monitor  24 , the captured image M of the oil droplet D that has been vectorized by the quantification section  210 . 
     (Flow of Control) 
     Explanation follows regarding a flow of analysis processing executed by the processing device  20  of the present exemplary embodiment, with reference to the flowcharts of  FIG.  6    and  FIG.  10   . Processing performed by the processing device  20  is implemented by the CPU  20 A functioning as the acquisition section  200 , the quantification section  210 , the evaluation section  220 , and the output section  230  described above. The analysis processing includes acquisition processing, quantification processing, and evaluation processing. 
     When the analysis processing is started in the processing device  20 , the CPU  20 A executes the acquisition processing, and starts acquisition of the captured image M obtained by capturing the wall surface C from the camera  22 . The captured image M is a moving image in which the oil droplet D that is dispersed on the wall surface C diffuses on the wall surface C. 
     Note that during the analysis processing in the present exemplary embodiment, the wall surface C is disposed at an inclination of 45 degrees with respect to a floor surface, and the camera  22  captures images from a position directly horizontal to the wall surface C. Further, the oil droplet D is dispersed in a direction perpendicular to the wall surface C. Namely, as illustrated in  FIG.  7   , in the captured image M, the wall surface C is disposed along the horizontal direction H from the upper left to the lower right, and the oil droplet D is dispersed on the wall surface C from the upper right along the vertical direction V. 
     The CPU  20 A then executes the quantification processing and the evaluation processing together with the acquisition processing. In the quantification processing, based on the captured image M obtained by capturing the oil droplet D that has collided against the wall surface C, the CPU  20 A quantifies the movement frequency of the vertical component (a direction including the vertical direction V) of the oil droplet D with respect to the movement frequency of the horizontal component (horizontal direction H) of the oil droplet D as a vertical/horizontal component ratio. Moreover, in the evaluation processing, the adsorption properties are evaluated based on the vertical/horizontal component ratio. 
     First, explanation follows regarding the quantification processing illustrated in  FIG.  6   . 
     At step S 100  in  FIG.  6   , the CPU  20 A extracts points on the oil droplet D from the first frame of the acquired captured image M as feature points. 
     At step S 101 , the CPU  20 A vectorizes the movement of the oil droplet D between the current frame and the next frame of the captured image M. The CPU  20 A thereby extracts the movement direction and the movement distance of each feature point in the oil droplet D. 
     At step S 103 , the CPU  20 A causes display of the vectorized captured image M at the monitor  24 .  FIG.  8 A  and  FIG.  8 B  are examples in which a state in which the oil droplet D that has collided with the wall surface C moves in the captured image M, illustrated in  FIG.  7   , is vectorized. Arrows on the captured image M in  FIG.  8 A  and  FIG.  8 B  indicate vectors of respective feature points. 
     Note that the CPU  20 A may convert the color tone of the vectors obtained at step S 101 , and at step S 103 , may indicate the movement direction and the movement distance of each feature point of the oil droplet D with respect to the captured image M by hue and brightness. In this case, the CPU  20 A converts the vectors of the respective feature points of the oil droplet D into a hue and a brightness in HSV format. Namely, the direction in which the oil droplet D moves is replaced by a hue represented by a range of from 0 to 360 degrees, and the distance traveled by the oil droplet D is replaced by a brightness represented by a range of from 0 to 100%. 
     At step S 104 , the CPU  20 A generates a histogram for each direction in a case in which the movement of the feature points of the vectorized oil droplet D has been integrated during predetermined frames. 
     At step S 105 , the CPU  20 A generates a radar chart based on the histogram. As a result, the radar charts as illustrated in  FIG.  9 A  and  FIG.  9 B  are generated. In each of the drawings, a direction of from 45 degrees to 225 degrees corresponds to the horizontal direction H on the wall surface C, and a direction of from 135 degrees to 315 degrees corresponds to the vertical direction V with respect to the wall surface C. 
     At step S 106 , the CPU  20 A calculates a vertical/horizontal component ratio as an evaluation index. Then, the processing returns to step S 100 . 
     As described above, during execution of the analysis processing, the CPU  20 A repeats the quantification processing of step S 100  to step S 106 . 
     Next, explanation follows regarding the evaluation processing illustrated in  FIG.  10   . 
     At step S 200  in  FIG.  10   , the CPU  20 A determines whether or not the vertical/horizontal component ratio serving as the evaluation index exceeds 1.1. In a case in which the CPU  20 A determines that the vertical/horizontal component ratio exceeds 1.1 (in a case of Y at step S 200 ), the processing proceeds to step S 201 . On the other hand, in a case in which the CPU  20 A determines that the vertical/horizontal component ratio does not exceed 1.1, namely, that the vertical/horizontal component ratio is 1.1 or less (in a case of N at step S 200 ), the processing proceeds to step S 202 . 
     At step S 201 , the CPU  20 A determines the surface performance as “low adsorption properties”, and stores the determination result in the evaluation result data  130 . The evaluation processing then ends. 
     At step S 202 , the CPU  20 A determines the surface performance as “high adsorption properties”, and stores the determination result in the evaluation result data  130 . The evaluation processing then ends. 
     SUMMARY OF EXEMPLARY EMBODIMENT 
     In the processing device  20  of the present exemplary embodiment, when the acquisition section  200  acquires, as the captured image M, a moving image in which the oil droplet D is dispersed on the wall surface C, the quantification section  210  quantifies the degree of diffusion of the oil droplet D based on the captured image M, and the evaluation section  220  evaluates the adsorption properties of the test object based on the quantified index. More specifically, when the oil droplet D dispersed on the wall surface C diffuses on the wall surface C, based on the captured image M of the wall surface C captured by the camera  22 , the quantification section  210  vectorizes the movement of the oil droplet D in the captured image M, and generates a histogram for each direction between the captured frames. Moreover, the quantification section  210  generates a radar chart based on the histogram, and calculates the vertical/horizontal component ratio of the radar chart as an evaluation index. The evaluation section  220  then determines whether or not the adsorption properties are favorable, based on whether or not the vertical/horizontal component ratio exceeds a threshold value of 1.1. 
       FIG.  9 A  is an example in which the adsorption properties are determined to be high adsorption properties, the rebound of the oil droplet D from the wall surface C was small, and the vertical/horizontal component ratio was less than 1.1.  FIG.  8 A  is an example in which, in the example of  FIG.  9 A , one frame in the captured image M serving as the basis for calculation of the vertical/horizontal component ratio is vectorized and displayed at the monitor  24 . As illustrated in  FIG.  8 A , the lower right approximately ⅔ of the oil droplet D is occupied by vectors in the horizontal direction H, and vectors having a component in the vertical direction V are present only in the upper left approximately ⅓ of the oil droplet D. This enables the situation in which the oil droplet D is diffused widely in the horizontal direction H and is easily adsorbed by the wall surface C to be visually observed. 
       FIG.  9 B  is an example in which the adsorption properties are determined to be low adsorption properties, the rebound of the oil droplet D from the wall surface C was large, and the vertical/horizontal component ratio exceeded 1.1.  FIG.  8 B  is an example in which, in the example of  FIG.  9 B , one frame in the captured image M serving as the basis for calculation of the vertical/horizontal component ratio is vectorized and displayed at the monitor  24 . As illustrated in  FIG.  8 B , although vectors in the horizontal direction H are present near the wall surface C, the oil droplet D is occupied by vectors having a component in the vertical direction V at a position away from the wall surface C. This enables the situation in which the oil droplet D is not diffused in the horizontal direction H and is not adsorbed by the wall surface C to be visually observed. 
     As described above, according to the processing device  20  of the present exemplary embodiment, the degree of diffusion of the oil droplet D diffused from the wall surface C that is exposed to the oil droplet D is quantified as a vertical/horizontal component ratio, which is the evaluation index, enabling surface performance to be evaluated independent of an evaluator. In particular, since the evaluation index is calculated based on a histogram for each direction in which the oil droplet D diffuses during predetermined frames, according to the present exemplary embodiment, the surface performance of successive periods can be evaluated. Moreover, the movement and state of diffusion of the oil droplet D can be better visually observed by vectorizing the oil droplet D in the captured image M compared to a case in which the movement of the oil droplet D is simply visually observed. In addition, according to the present exemplary embodiment, subtle differences in adsorption properties (more specifically, lipophilicity, oil repellency, oil-proof property, hydrophilicity, surface performance, waterproof property, and the like) of the wall surface C can be evaluated without human evaluation, and therefore, the present exemplary embodiment is suitable for data-driven material development. 
     Note that the processing device  20  uses vectors of the oil droplet during predetermined frames as an integration period for creating a histogram and a radar chart. However, there is no limitation thereto, and an arbitrary period of time which is suitable for evaluation can be set as the integration period. For example, as illustrated in  FIG.  11   , setting an integration period of around 8 to 13 frames from the start of the analysis processing enables the quality of the surface performance to be clearly determined. 
     In the present exemplary embodiment, whether or not the adsorption properties are favorable as surface performance is determined based on whether or not the vertical/horizontal component ratio exceeds a threshold value of 1.1; however, there is no limitation thereto, and any value may be set according to analysis needs. 
     Moreover, in the present exemplary embodiment, the vertical/horizontal component ratio of the radar chart is used as the evaluation index; however, there is no limitation thereto, and an area or the like calculated from the radar chart may be used as the evaluation index. In this case, the surface performance can be determined based on whether or not the evaluation index, which is the area, exceeds a predetermined threshold value. 
     Second Exemplary Embodiment 
     The second exemplary embodiment differs from the first exemplary embodiment in the configuration of the evaluation system  10 . Explanation follows regarding differences from the first exemplary embodiment. Note that the other configurations are the same as those of the first exemplary embodiment, and detailed explanation thereof is omitted. 
     As illustrated in  FIG.  12   , the evaluation system  10  of the present exemplary embodiment includes a processing device  20 , a collection device  40 , and plural terminals  42 . The processing device  20 , the collection device  40 , and the terminals  42  are connected together through a network N. The processing device  20  of the present exemplary embodiment can be, for example, a cloud server. At least the camera  22  is connected to the collection device  40  of the present exemplary embodiment. The terminals  42  are, for example, personal computers. 
     In the evaluation system  10  of the present exemplary embodiment, the collection device  40  collects the captured image M of the wall surface C captured by the camera  22  and uploads the captured image M such that the processing device  20  performs evaluation of surface performance. The terminals  42  can display the evaluation results acquired from the processing device  20  and the captured image M of the vectorized oil droplet D. This enables the evaluation work of the wall surface C to be performed at a location away from the test location. 
     Otherwise, the present exemplary embodiment exhibits operation and effects similar to those of the first exemplary embodiment. 
     Notes 
     Note that in each of the above-described embodiments, any of various types of processors other than CPU may execute the processing that the CPU  20 A executes by reading software (programs). Examples of such processors include a Programmable Logic Device (PLD) in which the circuit configuration can be modified post-manufacture, such as a Field-Programmable Gate Array (FPGA), or a specialized electric circuit that is a processor with a specifically-designed circuit configuration for executing specific processing, such as an Application Specific Integrated Circuit (ASIC). Further, each of the above-described processing may be executed by one of these various types of processors, or may be executed by combining two or more of the same type or different types of processors (e.g., plural FPGAs, or a combination of a CPU and an FPGA, or the like). Further, a hardware configuration of the various processors is specifically formed as an electric circuit combining circuit elements such as semiconductor elements. 
     Moreover, explanation has been given regarding an aspect in which the respective programs are stored (installed) in advance on a non-transitory recording medium that is readable by a computer in each of the above-described exemplary embodiments. For example, the surface performance evaluation program  100  in the processing device  20  is stored in advance in the ROM  20 B. However, there is no limitation thereto, and the respective programs may be provided in a format recorded on a non-transitory recording medium such as a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), or universal serial bus (USB) memory. Alternatively, the programs may be provided in a format downloadable from an external device over a network. 
     The flow of processing described in the above exemplary embodiments is also one example, and unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged within a range not departing from the gist of the present disclosure.