JP2021196452A - Propriety determination device, propriety determination method, and propriety determination program - Google Patents

Abstract

To provide a propriety determination device, a propriety determination method, and a propriety determination program that allow the optical states of dimming sheets to be evaluated using a new evaluation index.SOLUTION: A propriety determination device for determining the suitability of a photographing target in the state evaluation of a dimming sheet includes: a calculation unit that calculates the degree of blurring of an image by a dimming sheet 10 by analyzing the image of the photographing target taken via the dimming sheet 10; and a determination unit that determines that the photographing target is suitable for evaluation of the optical state on the condition that the degree of blurring by the dimming sheet 10 when a predetermined optical state of the dimming sheet 10 is reflected is in an appropriate range and the degree of blurring calculated by the calculation unit is in the appropriate range.SELECTED DRAWING: Figure 1

Description

The present invention relates to a suitability determination device for determining whether or not an imaging object is suitable for evaluating the optical state of a dimming sheet, a suitability determination method, and a suitability determination program.

The visibility of an object through a dimming sheet having liquid crystal molecules between the transparent electrodes changes according to the voltage change between the transparent electrodes. The normal type dimming sheet that keeps opaque when not energized is applied to digital signage screens and store exteriors that are required to be opaque for a long time. The reverse type dimming sheet that keeps transparency when not energized is applied to glass partitions and windows of moving objects that are required to be transparent in an emergency.

Stabilization of the optical state of the light control sheet and improvement of reproducibility will expand the use of the light control sheet in various fields and accelerate the spread of the light control sheet. The haze conforming to JIS K 7136: 2000 is adopted as an evaluation index of the optical state of the dimming sheet. For example, setting the haze of the dimming sheet to a predetermined range of 95% or more as an opaque control item and setting the haze of the dimming sheet to a predetermined range of 12% or less as a transparent control item. Has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 6493598

By the way, a transparent body such as a glass plate or an acrylic plate to which a dimming sheet is attached is installed in a building or a moving body. Being able to evaluate the optical state of the dimming sheet while it is installed in a building or moving object can further accelerate the spread of the dimming sheet. However, haze measurement, in which a dedicated optical device such as an integrating sphere is placed to measure the amount of light in a dark place, makes it rather troublesome to evaluate the optical state. There is an urgent need for a new technology that can evaluate the optical state of the dimming sheet over time even when the sheet is installed.

The request for new technology for evaluating the optical state of the light control sheet over time is not limited to the device of the light control sheet, but also handles the light control sheet at the time of development of the light control sheet and at the time of shipment of the light control sheet. It is common in various situations.

An object of the present invention is to provide a suitability judgment device, a suitability judgment method, and a suitability judgment program that enable evaluation of the optical state of a dimming sheet using a new evaluation index.

The suitability judgment device for solving the above-mentioned problems is a suitability judgment device for judging the suitability of the shooting target in the state evaluation of the light control sheet, and is an image of the image of the shooting target taken through the light control sheet. The calculation unit that calculates the degree of blurring of the image by the dimming sheet by analysis and the degree of blurring by the dimming sheet when reflecting a predetermined optical state in the dimming sheet are within an appropriate range. A determination unit for determining that the imaging target is suitable for evaluation of the optical state is provided, provided that the degree of blurring calculated by the calculation unit is within the appropriate range.

The suitability determination method for solving the above problems is a suitability determination method for determining the suitability of a shooting target in the state evaluation of the light control sheet, and is an image of the image of the shooting target taken through the light control sheet. The degree of blurring of the image by the dimming sheet is calculated by analysis, and the degree of blurring by the dimming sheet when reflecting a predetermined optical state in the dimming sheet is within an appropriate range. It includes determining that the imaged object is suitable for the evaluation of the optical state, provided that the calculated degree of blurring is within the appropriate range.

In the suitability determination program for solving the above problems, the suitability determination device for determining the suitability of the shooting target in the state evaluation of the light control sheet causes the image of the shooting target taken through the light control sheet to be image-analyzed. By doing so, the degree of blurring of the image by the dimming sheet is calculated, the degree of blurring when reflecting a predetermined optical state in the dimming sheet is within an appropriate range, and the calculated degree of blurring is the appropriateness. On condition that it is within the range, it is determined that the imaged object is suitable for the evaluation of the optical state.

According to each of the above configurations, the degree of blurring of an image taken through the light control sheet by the light control sheet is calculated by using image analysis of the image. The shooting of such images is realized not by a dedicated optical device such as an integrating sphere, but by a general-purpose shooting device such as a smartphone or a tablet terminal. The degree of blurring of such an image is calculated by using various image analyzes such as frequency component analysis and edge intensity analysis. The degree of blurring by the dimming sheet includes the degree of blurring of an image taken without passing through the dimming sheet, the degree of blurring of an image taken with the dimming sheet transparent, and a predetermined value estimated to correspond to these. Can be calculated based on. The degree of blurring by the dimming sheet tends to increase as the haze of the dimming sheet increases, and tends to change in synchronization with the haze change of the dimming sheet. Therefore, if the above configuration determines that the shooting target is suitable on condition that the degree of blurring of the shooting target by the dimming sheet is within the appropriate range, a new evaluation index of the degree of blurring of the optical state of the light control sheet is used. It can be evaluated using it.

In the suitability determination device, the degree of blurring calculated by the calculation unit is a value in which the first degree of blurring is standardized by the degree of second blurring, and the appropriate range reflects a predetermined optical state in the dimming sheet. It is the range of the standardized value at the time of the operation, and the first degree of blurring is the degree of blurring by the dimming sheet in the image to be photographed taken through the opaque dimming sheet. The second degree of blurring may be the degree of blurring by the dimming sheet in the image to be photographed taken through the transparent dimming sheet.

In shooting an object to be photographed through a dimming sheet, the external light condition in which the object to be photographed is placed may vary depending on the opportunity of photography. The external light condition in which the object to be photographed is placed includes the illuminance and the illumination angle in the external light such as the illumination light of the lighting device and the natural light. In this regard, according to the suitability determination device, since the degree of blurring when the dimming sheet is transparent is used as a reference, the influence of the external light condition on the calculation of the degree of blurring is reduced. As a result, it becomes possible to improve the accuracy of evaluation using a new evaluation index called the degree of blurring.

In the suitability determination device, the photographing target may be a scene seen from the place where the dimming sheet is installed. According to this configuration, it is possible to evaluate the optical state of the dimming sheet when the dimming sheet is attached to the transparent body as the exterior or interior of various facilities or when monitoring.

In the suitability determination device, in the image analysis, the magnitude of the frequency component in the predetermined frequency band in the radial distribution obtained from the Fourier transform of the image may be calculated as the degree of blurring.

The short-period repeat sharpness in an image is detected as the magnitude of the frequency component in the high frequency band. On the other hand, the sharpness of repetition in a long period in an image is detected as the magnitude of a frequency component in a low frequency band. In this respect, in the case of the suitability determination device, since the degree of blurring is calculated through frequency analysis of the image, it is possible to express the optical state of the light control sheet in detail by the degree of blurring.

Further, since the magnitude of the frequency component in the radial distribution is calculated as the degree of blurring, dimming is performed regardless of whether the spatial frequency component appears in the one-dimensional direction or the spatial frequency component appears in the two-dimensional direction. It is possible to calculate the frequency component of the size according to the optical state of the sheet. That is, the restrictions related to spatial anisotropy are alleviated in the object to be photographed. Therefore, it is possible to expand the situations in which the suitability determination device is applied in various fields, and to increase the versatility of the suitability determination device.

In the suitability determination device, the calculation unit performs image analysis of an evaluation image, which is an image taken after the imaging target determined by the determination unit to be suitable for evaluation of the optical state through the dimming sheet. The dimming sheet is used to calculate the degree of blurring of the evaluation image by the dimming sheet, and the determination unit determines that the dimming sheet is provided with the condition that the degree of blurring of the evaluation image by the dimming sheet is within the appropriate range. It may be judged to be normal.

According to the suitability determination device, it is possible to detect that the optical state of the light control sheet is normal.
In the suitability determination device, the light control sheet is applied so that the degree of blurring of the evaluation image is within the appropriate range, provided that the degree of blurring of the evaluation image by the light control sheet is outside the appropriate range. Further, a control unit that makes it possible to change the drive voltage to be used may be provided.

According to the suitability determination device, the drive voltage can be changed so that the optical state of the light control sheet is normal, provided that the degree of blurring by the light control sheet is out of the appropriate range. As a result, it is also possible to drive the dimming sheet so that the optical state is normal.

The suitability determination device, the suitability determination method, and the suitability determination program according to the present invention make it possible to evaluate the optical state of the dimming sheet using a new evaluation index.

The block diagram which shows the structure of the suitability judgment device together with a dimming sheet. A block diagram functionally showing the configuration of the index calculation unit. A power spectrum diagram showing an example of sampling of a sample group for calculating an evaluation index. A flowchart showing a process flow in the evaluation index calculation method. The apparatus block diagram which shows the photographing apparatus of the evaluation image. The figure which shows the image of the image | subject of the test example 1. FIG. The figure which shows the image of the image | subject of the test example 2. The figure which shows the image of the image | subject of the test example 3. The graph which shows the radial direction distribution obtained from the FFT conversion image of Test Example 1. The graph which shows the radial direction distribution obtained from the FFT conversion image of Test Example 2. The graph which shows the radial direction distribution obtained from the FFT conversion image of Test Example 3. A graph showing the relationship between the standard value of the sample integrated value obtained from the radial distribution of each test example and the drive voltage together with the haze.

A suitability determination device, a suitability determination method, and a suitability determination program will be described with reference to FIGS. 1 to 12. First, the configuration of the dimming sheet to be evaluated will be described, and then the suitability determination device, the suitability determination method, and the suitability determination program will be described.

[Dimming sheet 10]
The light control sheet 10 is configured so that the light transmittance can be changed. The light transmittance of the light control sheet 10 is changed by changing the drive voltage applied to the light control sheet 10. The type of the light control sheet 10 includes an electrochromic sheet in addition to the liquid crystal light control sheet. The transmittance of the liquid crystal dimming sheet is controlled by controlling the orientation of the liquid crystal molecules by applying the driving voltage V. The transmittance of the electrochromic sheet is controlled by controlling the charge of the electrochromic material by applying the drive voltage V.

The dimming sheet 10 projects windows provided in various buildings such as commercial facilities and public facilities, partitions installed in offices and medical facilities, show windows installed in exhibition facilities and cultural facilities, and images. It is attached to various transparent bodies 11 such as a base material of a screen and a window provided in a moving body such as a vehicle or an aircraft. The light control sheet 10 is attached to the surface of a transparent body 11 such as a window glass, or sandwiched between two transparent bodies such as laminated glass.

The shape of the dimming sheet 10 is not only a flat surface that follows the outer shape of the transparent body 11, but also a two-dimensional curved surface such as a cylinder or an ellipsoid, and a three-dimensional curved surface such as a spherical surface or an ellipsoid. , And irregular shapes other than geometric shapes. The color of the dimming sheet 10 in a state of having high transmittance is colorless and transparent or colored transparent. The color of the dimming sheet 10 in a state of having low transmittance is achromatic color or chromatic color.

The model of the dimming sheet 10 is a normal type or a reverse type. The normal type dimming sheet has a relatively high light transmittance when the dimming sheet 10 is energized, while it has a relatively low light transmittance when the dimming sheet 10 is not energized. The reverse type dimming sheet has a relatively low light transmittance when the dimming sheet 10 is energized, while it has a relatively high light transmittance when the dimming sheet 10 is not energized.

The light control sheet 10 includes a first transparent electrode, a second transparent electrode, and a light control layer that extend in the plane direction of the light control sheet 10. In the light control sheet 10, the first transparent electrode, the light control layer, and the second transparent electrode are laminated in this order, and the light control layer is sandwiched between the first transparent electrode and the second transparent electrode. The first transparent electrode and the second transparent electrode are electrically connected to the dimming control device 30.

The first transparent electrode and the second transparent electrode have light transmission through which visible light is transmitted. The light transmittance of the first transparent electrode enables visual recognition of an object through the dimming sheet 10. The light transmittance of the second transparent electrode also enables visual recognition of an object through the dimming sheet 10. The material constituting each transparent electrode is, for example, any one selected from the group consisting of indium tin oxide, fluorine-doped tin oxide, tin oxide, zinc oxide, carbon nanotubes, and poly (3,4-ethylenedioxythiophene). Is.

The light control layer included in the liquid crystal light control sheet contains a liquid crystal composition. Examples of liquid crystal molecules contained in the liquid crystal composition include Schiff base type, azo type, azoxi type, biphenyl type, terphenyl type, benzoic acid ester type, trans type, pyrimidine type, cyclohexanecarboxylic acid ester type, phenylcyclohexane type, and the like. It is at least one selected from the group consisting of dioxane systems. The holding type of the liquid crystal composition is a polymer dispersion type or a capsule type. The polymer-dispersed type holds the liquid crystal composition in a large number of voids dispersed in the polymer layer. The polymer-dispersed type includes a polymer network type having a polymer network having a three-dimensional network. The polymer network type holds the liquid crystal composition in the mesh-like voids. The capsule type holds the liquid crystal composition having a capsule shape in the polymer layer.

The reverse type liquid crystal light control sheet further includes an alignment film between the light control layer and the first transparent electrode, and between the light control layer and the second transparent electrode. The material constituting the alignment film is, for example, an organic compound such as polyimide, polyamide, polyvinyl alcohol, and a cyanide compound, an inorganic compound such as silicone, silicon oxide, and zirconium oxide, or a mixture thereof.

The alignment film is, for example, a vertical alignment film or a horizontal alignment film. The vertical alignment film is oriented in the major axis direction of the liquid crystal molecules so as to be perpendicular to the surface opposite to the surface in contact with the first transparent electrode and the surface opposite to the surface in contact with the second transparent electrode. Align. The horizontal alignment film is in the major axis direction of the liquid crystal molecules so as to be substantially parallel to the surface opposite to the surface in contact with the first transparent electrode and the surface opposite to the surface in contact with the second transparent electrode. To orient.

The dimming layer included in the electrochromic sheet contains an electrochromic material and an electrolyte. An example of an electrochromic material is one selected from organic compounds such as polyaniline derivatives, viologens, metallic phthalocyanines and phenanthroline complexes, and inorganic compounds such as tungsten trioxide and indium dioxide. An example of the electrolyte is a liquid electrolyte such as a lithium salt or a potassium salt, or a polymer solid electrolyte.

[Dimming system]
As shown in FIG. 1, the dimming system includes a dimming sheet 10, a photographing unit 12, an index calculation device 20 which is an example of a suitability determination device, and a dimming control device 30.

The dimming control device 30 receives a drive command NS from the index calculation device 20 or receives an input signal MC of the operation unit to drive the dimming sheet 10 for calculating the evaluation index Qe. The photographing unit 12 photographs the photographing object 13 via the dimming sheet 10 to generate an evaluation image PE of the photographing object 13. The photographing unit 12 transmits the evaluation image PE generated by the photographing unit 12 to the index calculation device 20. The index calculation device 20 calculates the degree of blurring of the evaluation image PE by the dimming sheet 10 by using the image analysis of the evaluation image PE.

The degree of blurring calculated by the index calculation device 20 is the evaluation index Qe of the dimming sheet 10. The degree of blurring by the light control sheet 10 is a value for repeatedly evaluating whether or not the light control sheet 10 has a stable optical state over time, and whether the light control sheet 10 has an optical state, which is an evaluation item. It is a value indicating whether or not. The optical state, which is an evaluation item, is, for example, having a haze of a predetermined value or more, having a clarity of a predetermined value or less, and the like.

For example, the degree of blurring by the light control sheet 10 is a value indicating whether or not the light control sheet 10 has a high haze such that the presence or absence of an object is not visually recognized through the light control sheet 10. On the contrary, the degree of blurring by the dimming sheet 10 is a value indicating whether or not the dimming sheet 10 has a haze low enough to visually recognize the existence or nonexistence of the object through the dimming sheet 10.

For example, the degree of blurring by the light control sheet 10 is a value indicating whether or not the light control sheet 10 has a high haze such that the contour of an object is not visually recognized through the light control sheet 10. On the contrary, the degree of blurring by the light control sheet 10 is a value indicating whether or not the light control sheet 10 has a low haze such that the contour of the object is visually recognized through the light control sheet 10.

For example, the degree of blurring by the dimming sheet 10 is a value indicating whether or not the dimming sheet 10 has a low clarity such that the type of the object is not visually recognized through the dimming sheet 10. On the contrary, the degree of blurring by the dimming sheet 10 is a value indicating whether or not the dimming sheet 10 has a high degree of clarity such that the details of the object can be visually recognized through the dimming sheet 10.

The index calculation device 20 is suitable for the evaluation index Qe calculated by the index calculation device 20 and the imaging target 13 for evaluating the optical state of the light control sheet 10, for example, at the time of manufacturing or construction of the light control sheet 10. Compare with the index threshold value Qm, which is the evaluation index of the time. The index calculation device 20 determines whether or not the photographing target 13 is suitable for evaluating the optical state of the light control sheet 10 based on the comparison between the evaluation index Qe and the index threshold value Qm. The fact that the evaluation index Qe is equal to or higher than the index threshold value Qm means that the degree of blurring of the image by the dimming sheet 10 is within an appropriate range.

The photographing unit 12 and the index calculation device 20 are configured to enable transmission of the evaluation image PE by the photographing unit 12 and reception of the evaluation image PE by the index calculation device 20 through wired communication or wireless communication. The index calculation device 20 may include, for example, a maintenance device that is communicably connected to the photographing unit 12 without a network, a server device that is communicably connected to the photographing unit 12 via a network, or a photographing unit 12. It is a device built into the installed user terminal. The index calculation device 20 is, for example, a server that receives an application for determining the suitability of a shooting target 13 from a user terminal equipped with a shooting unit 12 and receives an evaluation image PE shot via the dimming sheet 10 from the user terminal. It is a device.

The index calculation device 20 and the dimming control device 30 can transmit a drive command NS by the index calculation device 20 and receive a drive command NS by the dimming control device 30, for example, through wired communication or wireless communication. It is configured. The index calculation device 20 is, for example, a maintenance device that is communicably connected to the dimming control device 30 without going through a network, a server device that is communicably connected to the dimming control device 30 via a network, or It is an electronic device provided with hardware common to a part of the dimming control device 30.

The photographing unit 12 receives a two-dimensional image sensor in which photographing elements such as CCD (Charged coupled devices) or CMOS (Complementary metal oxide semiconductor) are arranged in two dimensions, and the light emitted from the photographing target 13 is received by the image sensor. It is equipped with a photographing optical system that forms an image on a surface. The photographing unit 12 forms an image of the light emitted from the photographing object 13 on the light receiving surface of the image sensor, and records the still image of the photographing object 13 through the dimming sheet 10 as the evaluation image PE which is the image data. The photographing unit 12 is, for example, a camera mounted on a smartphone or a tablet terminal, a surveillance camera installed in various facilities such as commercial facilities and public facilities, and a general camera such as a digital camera.

The photographing unit 12 generates the evaluation image PE. The evaluation image PE is an image in which the photographing target 13 in a predetermined environment is photographed through the dimming sheet 10. The shooting of the shooting target 13 is performed through the dimming sheet 10 with the shooting unit 12 and the shooting target 13 placed in a predetermined environment.

The predetermined environment for shooting the evaluation image PE is the setting environment of the shooting unit 12, the lighting environment for the shooting unit 12, and the lighting environment for the shooting target 13. The setting environment of the shooting unit 12 is, for example, to set the manual focus distance at the time of shooting to a predetermined value, and to set the aperture value and the shutter speed to a predetermined value. The lighting environment for the shooting unit 12 is such that, for example, the lighting is turned on at the place where the shooting unit 12 is placed, or the amount of solar radiation at the place where the shooting unit 12 is placed is estimated to be a predetermined amount. be. The lighting environment for the shooting target 13 is, for example, that the lighting is turned on at the place where the shooting target 13 is placed, or the amount of solar radiation at the place where the shooting target 13 is placed is estimated to be a predetermined amount. be. Estimating that the amount of solar radiation is a predetermined amount means that, for example, the shooting date and time is a predetermined date and time, and the type of weather at the time of shooting is fine. As described above, the shooting of the evaluation image PE is realized not by a dedicated optical device such as an integrating sphere but by a general-purpose shooting device such as a smartphone or a tablet terminal.

The shooting target 13 is a target for which suitability is judged, and is a shooting target used for calculating the evaluation index Qe. The photographing object 13 is prepared as a candidate for evaluating an artificial object such as a building or a building visually recognized through the dimming sheet 10, a natural landscape visually recognized through the dimming sheet 10, and an optical state of the dimming sheet 10. This is a test pattern for printed matter. The above-mentioned artifacts and natural landscapes are examples of scenes that can be seen from the place where the dimming sheet 10 is installed.

A test pattern is a printed matter used to evaluate physical performance such as contrast, resolution, noise, etc. by the degree of separation between black and white. The test pattern is, for example, a pattern in which white and black thin lines are arranged in parallel alternately, a pattern in which white and black thin lines are arranged radially, and white and black thin lines having different line widths are alternately arranged. Patterns arranged in parallel, patterns in which white and black fine lines having different linear densities are arranged, and the like. The test pattern is, for example, characters or alphanumericals having different sizes from each other. In addition, the test pattern is, for example, a test chart containing text such as characters and alphanumericals used for resolution measurement of digital cameras, a resolution chart compliant with ISO12233-2000, and JIS X 0527 used for performance evaluation of barcode readers. Compliant barcode test charts, etc.

[Index calculation device 20]
The index calculation device 20 is not limited to processing all kinds of processing by software. For example, the index calculation device 20 includes dedicated hardware such as an integrated circuit for a specific application (Graphics Processing Unit: GPU, Application Specific Integrated Circuit: ASIC) that executes at least a part of various processes. May be good. The index calculation device 20 is also configured as a circuit including one or more dedicated hardware circuits such as an ASIC, one or more processors operating according to a computer program, or a combination thereof. In the following, an example will be described in which the index calculation device 20 stores the evaluation index calculation program in a readable medium, reads out the evaluation index calculation program stored in the readable medium, executes the program, and performs various processes.

The index calculation device 20 includes a control unit 21, an image analysis unit 22, a storage unit 23, and a communication unit 24.
The storage unit 23 stores the evaluation index calculation program 23A for calculating the evaluation index and the index calculation information 23B used for executing the evaluation index calculation program. The evaluation index calculation program 23A is an example of a suitability determination program. The index calculation information 23B includes an evaluation voltage V0 and sampling conditions. The evaluation voltage V0 is a drive voltage V applied to the dimming sheet 10, and is used as an initial value applied for calculating the evaluation index Qe. The sample extraction condition is a condition for extracting the sample group used for the calculation of the evaluation index Qe from the distribution of the feature vector. The sampling conditions are set so that a sample group suitable for evaluation is extracted based on the results of tests conducted in advance.

For example, when it is an evaluation item of the optical state to have a high haze such that the presence or absence of an object cannot be visually recognized through the dimming sheet 10, a sample group suitable for evaluating whether or not the object has the high haze is selected. The conditions for extracting from the distribution of the feature vector are stored as sampling conditions. On the contrary, when the evaluation item is that the dimming sheet 10 has a low haze that allows the presence or absence of an object to be visually recognized through the dimming sheet 10, it is suitable for evaluating whether or not the dimming sheet 10 has the low haze. The conditions for extracting the sample group from the distribution of the feature vector are stored as the sample extraction conditions.

For example, when it is an evaluation item of the optical state to have a high haze such that the contour of the object is not visually recognized through the dimming sheet 10, a sample group suitable for evaluating whether or not the object has the high haze is selected. The conditions for extracting from the distribution of the feature vector are stored as sampling conditions. On the contrary, when it is an evaluation item that the dimming sheet 10 has a low haze such that the details of the object can be visually recognized through the dimming sheet 10, it is suitable for evaluating whether or not the dimming sheet 10 has the low haze. The conditions for extracting the sample group from the distribution of the feature vector are stored as the sample extraction conditions.

For example, when it is an evaluation item to have a low clarity such that the contour of an object is not visually recognized through the dimming sheet 10, a sample group suitable for evaluating whether or not the object has the low clarity is used as a feature vector. The conditions for extracting from the distribution are stored as sampling conditions. On the contrary, when it is an evaluation item that the dimming sheet 10 has a high clarity such that the details of the object can be visually recognized through the dimming sheet 10, it is suitable for evaluating whether or not the dimming sheet 10 has the high clarity. The conditions for extracting the sample group from the distribution of the feature vector are stored as the sample extraction conditions.

The index calculation information 23B may include data required for the process of determining suitability, such as the index threshold value Qm, the upper limit voltage Vmax, and the step voltage Vs. The index threshold value Qm is a threshold value of the evaluation index Qe obtained through the dimming sheet 10 satisfying the evaluation items. The index threshold value Qm is a threshold value of the evaluation index Qe obtained in advance using an imaging target suitable for evaluating the optical state. The upper limit voltage Vmax is the maximum value of the drive voltage applied to the dimming sheet 10 by the dimming control device 30. The step voltage Vs is a change amount of the drive voltage V that can be changed for each opportunity to calculate the evaluation index Qe in the suitability judgment.

The control unit 21 reads the evaluation index calculation program 23A from the storage unit 23, interprets the evaluation index calculation program 23A, and causes the image analysis unit 22, the storage unit 23, and the communication unit 24 to execute various processes. For example, the control unit 21 causes the communication unit 24 to acquire the evaluation image PE from the photographing unit 12, and causes the image analysis unit 22 to perform image analysis using the evaluation image PE acquired by the communication unit 24. The control unit 21 causes the image analysis unit 22 to calculate the evaluation index Qe using the result of the image analysis by the image analysis unit 22. The control unit 21 is an example of the determination unit, and determines the suitability of the imaging target 13 based on the comparison between the calculated evaluation index Qe and the index threshold value Qm.

[Image analysis unit 22]
The image analysis unit 22 executes image analysis of the evaluation image PE, and calculates the degree of blurring of the evaluation image PE by the dimming sheet 10 as the evaluation index Qe. The image analysis unit 22 is an example of a calculation unit.

As shown in FIG. 2, the image analysis unit 22 functions as a grayscale processing unit 22A, an FFT processing unit 22B, and a frequency analysis unit 22C. The gray scale processing 22A performs (i) gray scale conversion of the evaluation image PE. The FFT processing unit 22B performs (ii) a two-dimensional fast Fourier transform using the grayscaled image data. The frequency analysis unit 22C executes frequency analysis of the (iii) Fourier transform image using the processing result of the FFT processing unit 22B.

In the image analysis performed by the image analysis unit 22, the degree of blurring of the image indicates the degree of clarity of the evaluation image PE, that is, the optical density such as the brightness of the evaluation image PE and the optical density such as the brightness of the background image. It may be to calculate the difference between. Alternatively, the image analysis performed by the image analysis unit 22 may be to calculate the optical density of the pixel having the pixel value corresponding to the edge intensity in the contour of the evaluation image PE as the degree of blurring of the image. For example, it is also possible to determine each pixel corresponding to the contour of the evaluation image by using the average value of the edge strength obtained by the edge detection process based on the luminance value of the pixel.

(i) Grayscale conversion changes the image data in RGB space to the image data in YUV space. Grayscale is a process of performing an intermediate value method that outputs an intermediate value using RGB values as a result, a weighted averaging method that outputs an average value of RGB values weighted by each different coefficient as a result, and the like. Further, the gray scale may be a process in which a weighted averaging method and a correction are combined to output a value obtained by applying gamma correction to the weighted average value of the RGB values weighted by each different coefficient as a result. Further, the grayscale may be a process of performing a simple averaging method that outputs a simple average value of RGB values as a result, a median method that outputs a median value among RGB values as a result, and the like.

(Ii) The two-dimensional fast Fourier transform is performed using the grayscaled image data, and the distribution of the feature vectors in the two-dimensional Fourier transform image is calculated. The feature vector is at least one of a radial vector and an angular vector. The radial distribution p (r) is an example of a frequency component, and is the sum of power spectra on a concentric region existing at a distance r from the center of the two-dimensional Fourier transformed image. The angular distribution q (θ) is the sum of the power spectra on the linear region of the angle θ with respect to the horizontal axis. The distribution of the feature vector is determined by what spatial frequency the wave with is strongly included in the image data after grayscale, and in what direction the strong wave is included, that is, the radial direction and the angle. It shows the periodicity of shading in the image in the direction.

(Iii) In the frequency analysis, a sample group satisfying the sample extraction condition is extracted from the distribution of the feature vector. In the frequency analysis, the evaluation index Qe is calculated from the feature vector of the extracted sample group. As described above, the sampling condition is a condition for extracting the sample group used for calculating the evaluation index from the distribution of the feature vector. In the frequency analysis, for example, the sum of the feature vectors of all the samples satisfying the sampling conditions is calculated as the sample integration value SumV. In the frequency analysis, the evaluation index Qe is calculated using the calculated sample integrated value SumV and the reference value for standardizing the sample integrated value SumV.

[Sampling]
Next, an example of extracting a sample group in the above frequency analysis will be described below. FIG. 3 shows the sample group extracted in the power spectrum of the Fourier transformed image with dots.

As shown in FIG. 3, for example, when the distribution of the feature vector is the distribution in the radial direction, one example of the sampling condition is that the distance r is within a predetermined range, that is, the frequency is in a predetermined frequency band. Is. When it is an evaluation item that the contour of the object has a high haze that cannot be visually recognized, one example of the sampling condition is that the distance r is equal to or larger than the sampling threshold value rx. An example of the sample threshold value rx satisfies the following conditions 1 and 2 in the radial distribution.

(Condition 1)
Specimen threshold rx> Extraction reference distance rs
(Condition 2)
Sample threshold energy p (rx) <extraction reference energy p (rs) x 10%
Here, the extraction reference energy (rs) is, for example, the maximum value p (r) max indicating the largest energy in the radial direction distribution p (r). The extraction reference distance rs is a distance r that gives the maximum value p (r) max.

In the grayscaled image, the light and shade wave corresponding to the maximum value p (r) max is likely to be a wave indicating the existence or nonexistence of the object. On the other hand, in the grayscaled image, the light and shade wave corresponding to the energy smaller than the maximum value p (r) max is likely to be a wave showing the contour of an object or the like. Then, the extraction of the sample group based on the above conditions 1 and 2 excludes the waves that are likely to indicate the existence of the object from the sample group, and evaluates that the contour of the object is not visually recognized. A suitable sample group can be extracted.

As described above, the setting of the above condition 1 and the condition 2 excludes the low frequency wave below the shade wave corresponding to the feature vector by setting the extraction reference energy (rs) to the specific feature vector. It makes it possible to extract a sample group suitable for evaluating whether or not a high frequency wave is visually recognized. That is, the setting of the sampling condition is a condition that enables the calculation of the magnitude of the frequency component in the predetermined frequency band. In the frequency analysis, the sum of the feature vectors of all the samples extracted based on these sampling conditions is calculated as the sample integration value SumV (regions marked with dots in FIG. 3). Then, in the frequency analysis, the sample integration value SumV is divided by the reference value, and the evaluation index Qe standardized by the reference value is calculated. The sample integrated value SumV is the first degree of blurring, and the reference value is the second degree of blurring.

When the evaluation item is to have a high haze such that the contour of the object is not visually recognized, the reference value is the sample integrated value of the evaluation image PE taken under a predetermined environment without passing through the dimming sheet 10. SumV, the sample integrated value SumV of the evaluation image PE taken with the dimming sheet 10 transparent, and a predetermined value estimated to correspond to these.

On the contrary, when the evaluation item is to have a haze low enough for the contour of the object to be visually recognized, the reference value is taken under a predetermined environment through a dimming sheet 10 to which the contour of the object is not visually recognized. It is a sample integrated value SumV of the evaluated evaluation image PE, or a predetermined value estimated to correspond to the sample integrated value SumV. In this case as well, the reference value may be separately calculated by the index calculation device 20 or may be stored in advance in the index calculation device 20.

When the optical state when the drive voltage V is applied to the dimming sheet 10 is an evaluation item, the reference value is, for example, the sample integration value when the drive voltage V is not applied to the dimming sheet 10. It is SumV or a predetermined value estimated to correspond to this.

On the contrary, when the optical state when the drive voltage V is not applied to the dimming sheet 10 is an evaluation item, the reference value is, for example, the sample integration when the drive voltage V is applied to the dimming sheet 10. It is a value SumV or a predetermined value estimated to correspond to the value SumV.

In any case, the reference value may be separately calculated by the index calculation device 20 or may be stored in advance in the index calculation device 20.
Further, when the distribution of the feature vector is the angular distribution q (θ), it is a sampling condition that the angle θ is within a predetermined range. Further, when the distribution of the feature vector is the angular distribution q (θ), the reference value is also taken from the angular distribution q (θ) of the evaluation image PE taken under a predetermined environment without passing through the dimming sheet 10. It is a sample integrated value obtained. When the distribution of the feature vector is the angular distribution q (θ), the reference value is the sample integrated value obtained from the angular distribution q (θ) of the evaluation image PE taken with the dimming sheet 10 transparent. Or, a predetermined value estimated to correspond to these.

The communication unit 24 executes to acquire the evaluation image PE from the photographing unit 12 in response to the command from the control unit 21. The communication unit 24 transmits, for example, a drive command NS required for calculating the evaluation index Qe to the dimming control device 30 in response to a command from the control unit 21, and determines the suitability for the image shooting target 13. It is possible to send to an output unit such as a display unit. Further, the communication unit 24 may transmit the result of the suitability determination for the photographing target 13 to the user terminal in response to the command from the control unit 21.

[Dimming control device 30]
Returning to FIG. 1, the dimming control device 30 is not limited to processing all kinds of processing by software. For example, the dimming control device 30 may include dedicated hardware such as an application specific integrated circuit (ASIC) that executes at least a part of various processes. The dimming control device 30 is also configured as a circuit including one or more dedicated hardware circuits such as an ASIC, one or more processors operating according to a computer program, or a combination thereof. In the following, an example will be described in which the dimming control device 30 stores a drive program in a readable medium, reads out the drive program stored in the readable medium, executes the drive program, and performs various processes.

The dimming control device 30 includes a control unit 31, a storage unit 32, and a drive unit 33. The storage unit 32 stores a drive program for driving the dimming sheet 10 and various data used for executing the drive program. The control unit 31 reads the drive program from the storage unit 32, interprets the drive program, and causes the drive unit 33 to generate the drive voltage V.

For example, the control unit 31 receives a drive command NS from the index calculation device 20 or receives an input signal MC of the operation unit, and causes the drive unit 33 to generate a drive voltage V for calculating the evaluation index Qe. The drive unit 33 applies the generated drive voltage V to the dimming sheet 10.

For example, the control unit 31 stores the drive voltage V corrected at the time of the suitability determination in the storage unit 32. The control unit 31 receives the drive command NS from the index calculation device 20 or receives the input signal MC of the operation unit, reads the corrected drive voltage V from the storage unit 32, and drives the corrected drive voltage V. It is generated by the unit 33. The drive unit 33 applies the generated corrected drive voltage V to the dimming sheet 10 at the time of calculating the next evaluation index Qe to be executed after the suitability determination.

[Appropriateness judgment]
Next, the suitability determination method executed by the index calculation device 20 will be described. In the following, an example will be shown in which a reverse type liquid crystal dimming sheet is used, and whether or not the dimming sheet 10 has a high haze to the extent that the contour of an object is not visually recognized through the dimming sheet 10 is used as an evaluation item. ..

As shown in FIG. 4, the index calculation device 20 first transmits a drive command NS for generating the evaluation voltage V0 as the drive voltage V to the dimming control device 30. The dimming control device 30 generates an evaluation voltage V0 in response to the drive command NS, and applies an evaluation voltage V0 for making the dimming sheet 10 opaque. As a result, the dimming sheet 10 changes to an optical state for determining the suitability of the photographing target 13 (step S11).

The index calculation device 20 may be configured to store a separate evaluation voltage V0 for each evaluation item. For example, as for the evaluation voltage V0, the evaluation voltage V0 corresponding to the evaluation item is selected by the index calculation device 20 according to the evaluation item selected by the user. For example, it is an evaluation item to have a high haze such that the presence or absence of an object is not visually recognized through the dimming sheet 10 and to have a high haze such that the contour of the object is not visually recognized through the dimming sheet 10. If so, the user selects one of the evaluation items. The index calculation device 20 reads out the evaluation voltage V0 corresponding to the evaluation item selected by the user, and transmits a drive command NS for setting the evaluation voltage V0 to the drive voltage V to the dimming control device 30.

Next, the photographing unit 12 photographs the evaluation image PE of the imaging target 13 via the light control sheet 10 to which the evaluation voltage V0 is applied. The index calculation device 20 acquires the evaluation image PE of the photographing target 13 photographed through the dimming sheet 10 from the photographing unit 12 (step S12).

Next, the index calculation device 20 executes image analysis of the acquired evaluation image PE, and calculates the degree of blurring of the evaluation image PE by the dimming sheet 10 as the evaluation index Qe. The image analysis performed by the index calculation device 20 is to calculate the degree of blurring of the evaluation image PE by the dimming sheet 10, and as described above, for example, grayscale, two-dimensional fast Fourier transform, and frequency analysis. (Step S13).

Next, the index calculation device 20 determines whether or not the calculated evaluation index Qe is equal to or greater than the index threshold value Qm. At this time, the index threshold value Qm is a lower limit value of the evaluation index Qe obtained from an image of an appropriate image to be photographed through a dimming sheet 10 having an appropriate optical state. The dimming sheet 10 having an appropriate optical state has a high haze such that the contour of the object is not visually recognized through the dimming sheet 10 (step S14).

When the index calculation device 20 determines that the evaluation index Qe is equal to or greater than the index threshold value Qm (YES in step S14), the index calculation device 20 stores the evaluation index Qe as the initial index Q0 (step S15). Then, the index calculation device 20 notifies the outside that the shooting target 13 is appropriate as a subject for calculating the evaluation index Qe prior to the evaluation of the optical state of the light control sheet 10 over time (adequacy determination). : Step S16).

On the other hand, when the index calculation device 20 determines that the evaluation index Qe does not meet the index threshold value Qm (NO in step S14), the index calculation device 20 determines whether or not the current drive voltage V is the upper limit voltage Vmax (step S17). .. Next, when the index calculation device 20 determines that the current drive voltage V is not the upper limit voltage Vmax (NO in step S17), the index calculation device 20 generates a new drive voltage V by adding the step voltage Vs to the evaluation voltage V0. The drive command NS is transmitted to the dimming control device 30.

The dimming control device 30 generates a new drive voltage V in response to the drive command NS, and applies the generated drive voltage to the dimming sheet 10. As a result, the light transmittance of the dimming sheet 10 is further reduced. Then, by repeating the processes from step S12 to step S18, the index calculation device 20 grasps the drive voltage V when the evaluation index Qe becomes the index threshold value Qm or more.

The index calculation device 20 notifies the dimming control device 30 of the drive voltage V when the evaluation index Qe is equal to or higher than the index threshold value Qm. The dimming control device 30 stores the notified drive voltage V as a drive voltage V that satisfies the evaluation item, that is, a drive voltage V that can be used by the photographing target 13 in the evaluation of the optical state over time, and is executed thereafter. The stored drive voltage V is used in the evaluation of the optical state over time.

On the other hand, when the index calculation device 20 determines that the current drive voltage V is the upper limit voltage Vmax (YES in step S17), the index calculation device 20 sets the evaluation index Qe prior to the temporal evaluation of the optical state of the light control sheet 10. Notify the outside that the shooting target 13 is inappropriate as the subject for calculation (step S19).

[Test example]
Next, FIGS. 5 to 12 show test examples showing that the optical state of the dimming sheet 10 can be evaluated by image analysis and whether or not the photographing target 13 is appropriate as a subject for calculating the evaluation index Qe. It will be explained with reference to. In the following, an example in which a polymer network type liquid crystal dimming sheet driven as a normal type is used as the dimming sheet 10 will be shown.

First, a photographing device for photographing the evaluation image PE will be described.
As shown in FIG. 5, the dark room 51 included in the photographing apparatus includes a bottom portion 51B that functions as a surface light source. The bottom portion 51B of the dark room 51 is an LED table that irradiates light toward the top of the dark room 51. The bottom of the dark room 51 supports the image target 13 inside the dark room 51. The top portion 51T of the dark room 51 is equipped with a shooting unit 12 such as a smartphone so that the inside of the dark room 51 can be photographed directly above the shooting target 13. The inner surface of the dark room 51 is black so as to prevent the photographing unit 12 from being irradiated with external light and the photographing unit 12 from being reflected.

The inside of the dark room 51 is provided with a mounting portion for mounting the dimming sheet 10 between the photographing unit 12 and the photographing target 13. The mounting portion is a flat plate-shaped partition plate that partitions the space in which the photographing target 13 is arranged and the space other than the space. A rectangular hole-shaped through hole is formed in the mounting portion at a position facing the photographing target 13. The dimming sheet 10 is placed so as to close the through hole formed in the mounting portion. The photographing unit 12 photographs the photographing target 13 through the dimming sheet 10 and the through hole of the mounting portion.

The light control sheet 10 is placed on the mounting portion in a state of being attached to a colorless and transparent glass plate. The dimming sheet 10 has a rectangular sheet shape, has a short side of 100 mm and a long side of 112 mm. The glass plate to which the dimming sheet 10 is attached also has a rectangular plate shape, the short side is 105 mm, and the long side is 126 mm. When the drive voltage V is 0 V, the dimming sheet 10 has the lowest transmittance, and when the drive voltage V is the upper limit voltage Vmax, the dimming sheet 10 has the highest transmittance.

The inside of the dark room 51 includes target LEDs 54R and 54L that irradiate the photographing target 13 with light L. The target LEDs 54R and 54L irradiate the entire bottom portion 51B from the lower surface of the mounting portion with light L inside the dark room 51. The target LEDs 54R and 54L irradiate daylight of the same color with each other. The illuminance of the object 13 to be photographed by the object LEDs 54R and 54L is 2690 lpx.

The inside of the dark room 51 includes sheet LEDs 53R and 53L that irradiate the dimming sheet 10 with light L. The sheet LEDs 53R and 53L irradiate the entire mounting portion from the top 51T of the dark room 51 with light L inside the dark room 51. The seat LEDs 53R and 53L irradiate daylight of the same color with each other. The illuminance on the dimming sheet 10 by the sheet LEDs 53R and 53L is 532 lpx.

The distance H1 in the vertical direction between the photographing unit 12 and the photographing object 13 is 350 mm. The distance H2 in the vertical direction between the photographing object 13 and the mounting portion is 100 mm. That is, the vertical distance between the photographing target 13 and the light control sheet 10 is 100 mm, and the vertical distance between the light control sheet 10 and the photographing unit 12 is 200 mm.

FIG. 6 shows an example of the evaluation image PE of Test Example 1 in which a natural landscape photograph is used as the photographing target 13. As shown in FIG. 6, a substantially monochromatic "sky" is located in a region of more than half of the evaluation image PE of Test Example 1, and a single tree is located in a region other than the "sky".

FIG. 7 shows an example of the evaluation image PE of Test Example 2 in which a landscape photograph including a building or the like is used as the photographing target 13. As shown in FIG. 7, a "cityscape" in which a large number of large buildings and a large number of small buildings are lined up is located in more than half of the area of the evaluation image PE of Test Example 2, and is located in an area other than the "cityscape". , The "sky" where multiple "clouds" float is located.

FIG. 8 shows an example of the evaluation image PE of Test Example 3 in which the test pattern is used as the imaging target 13. As shown in FIG. 8, the evaluation image PE of Test Example 3 has a pattern in which white and black fine lines are alternately arranged in parallel, a pattern in which black fine lines are arranged in a radial pattern, and different line widths. A pattern in which white and black fine lines are arranged alternately in parallel, a pattern in which white and black fine lines having different linear densities are arranged, and the like are located.

6 to 8 are evaluation image PEs when the drive voltage V is set to 30 V. Further, the evaluation image PE is an image obtained by the following processing. That is, after trimming the portion of the image taken by the photographing unit 12 through the dimming sheet 10 so that the vertical / horizontal size is 600 cps × 600 cps, the trimmed image is trimmed to have a vertical / horizontal size of 256 cps × 256 cps. It is compressed so that it becomes.

FIG. 9 is a graph showing the dependence of the drive voltage V on the radial distribution p (r), and is the radial distribution p of Test Example 1 obtained from the FFT conversion image of the evaluation image PE of Test Example 1. r) is shown. FIG. 10 is a graph showing the dependence of the drive voltage V in the radial distribution p (r), and is the radial distribution p of Test Example 2 obtained from the FFT conversion image of the evaluation image PE of Test Example 2. r) is shown. FIG. 11 is a graph showing the dependence of the drive voltage V on the radial distribution p (r), and is the radial distribution p of Test Example 3 obtained from the FFT conversion image of the evaluation image PE of Test Example 3. r) is shown.

In addition, in each of FIGS. 9 to 11, the value obtained by normalizing the radial distribution p (r) with the maximum value p (r) max is shown for each drive voltage V. In addition, each FFT (i) grayscaled using processing according to the ITU-R Rec BT.601 standard, and using the grayscaled image data, (ii) two-dimensional fast Fourier transform, and (ii) iii) Frequency analysis was performed in order.

As shown in FIG. 9, in the frequency analysis result of Test Example 1, when the drive voltage V is 0V, that is, when the light transmittance of the dimming sheet 10 is the lowest, the distance r is 1 in the range of 8 or less. There are two large radial distributions p (r), and no radial distribution p (r) is found in the other ranges. When the drive voltage is 30 V, that is, when the light transmittance of the dimming sheet 10 is the highest, there are two large radial distributions p (r) in the range where the distance r is 16 or less, and the distance r is. Four small radial distributions p (r) are observed in the range of 16 or more and 64 or less.

As shown in FIG. 10, in the frequency analysis result of Test Example 2, when the drive voltage V is 0V, that is, when the light transmission rate of the dimming sheet 10 is the lowest, the distance r is 1 in the range of 8 or less. There are one large radial distribution p (r) and one small radial distribution p (r), and no radial distribution p (r) is observed in the other range.

On the other hand, in the frequency analysis result of Test Example 2, when the drive voltage is 30 V, that is, when the light transmittance of the dimming sheet 10 is the highest, the distance r is in the range of 8 or more and 16 or less, and three large radii are used. There is a directional distribution p (r). Further, a large number of small radial distributions p (r) are observed over a wide range of distance r of 16 or more and 96 or less, which is sufficiently larger than that of Test Example 1.

As shown in FIG. 11, in the frequency analysis result of Test Example 3, when the drive voltage V is 0V, that is, when the light transmittance of the dimming sheet 10 is the lowest, the distance r is in the range of 16 or less, 2 There are two large radial distributions p (r), and three small radial distributions p (r) are recognized in the range where the distance r is 16 or more and 40 or less.

On the other hand, in the frequency analysis result of Test Example 3, when the drive voltage is 30 V, that is, when the light transmittance of the dimming sheet 10 is the highest, Test Example 1 and Test Example have a distance r of 128 or less over almost the entire range. A large number of large radial distributions p (r) are observed, which is sufficiently larger than that of 2.

In this way, the range where the distance r is relatively small, that is, the range where the spatial frequency in the real space is relatively large, is distributed in the radial direction due to the difference in the drive voltage V in both Test Example 1 and Test Example 3. p (r) is hard to change. On the other hand, in the range where the distance r is relatively large, that is, the range where the spatial frequency in the real space is relatively high, in Test Example 2 and Test Example 3, the radial distribution p (r) is increased due to the difference in the drive voltage V. It changes a lot.

The range where the spatial frequency in the real space is high is a fine shade in the image after grayscale, and indicates, for example, the surface shape of the object or the outline of the object. On the other hand, the range where the spatial frequency in the real space is low is a coarse shade in the grayscaled image, and indicates, for example, the existence or nonexistence of an object. As described above, the difference in the spatial frequency in the real space appears as the difference in the radial distribution p (r) due to the difference in the drive voltage V. For example, the difference between fine shades such as "cityscapes" and test patterns of many buildings of different sizes and coarse shades such as "trees" against the background of "sky" is the difference in drive voltage V. It appears as a difference in the radial distribution p (r) due to.

As a result, for example, whether or not the dimming sheet 10 to which a predetermined drive voltage V is applied is in an optical state to the extent that the surface shape and contour of the object are not visually recognized, or the surface shape and contour of the object. It can be said that whether or not the optical state is such that such things are visually recognized appears as a difference in the radial distribution p (r). For example, whether or not the dimming sheet 10 to which a predetermined drive voltage V is applied is in an optical state such that the existence or nonexistence of an object is not visually recognized, or the optical state is such that the existence or nonexistence of an object is visually recognized. It can be said that whether or not the state is present appears as a difference in the radial distribution p (r).

In other words, whether or not the photographing target 13 is suitable as a subject is determined based on the sum of the radial distribution p (r) satisfying the sampling conditions, prior to the evaluation of the optical state of the dimming sheet 10 over time. It can be said that it can be judged.

FIG. 12 shows the dependence of the evaluation index Qe obtained from the radial distribution p (r) of Test Example 1 to Test Example 3 on the drive voltage V, and the dependence of the haze of the dimming sheet 10 on the drive voltage V. Is shown. Note that FIG. 12 shows the evaluation index Qe standardized by the reference value by dividing the sample integration value SumV calculated at each drive voltage V by the reference value. At this time, the sample integrated value SumV when the drive voltage V is 30 V, that is, the sample integrated value SumV when the dimming sheet 10 has the highest light transmittance was used as a reference value. Further, in FIG. 12, the haze of the dimming sheet 10 shows a value standardized with 100% as 1.

As shown in FIG. 12, in the range where the drive voltage V is 0 V or more and 10 V or less, the haze of the dimming sheet 10 gradually decreases from the vicinity of 100% to 90%. Further, in the range where the drive voltage V is 0 V or more and 10 V or less, the evaluation index Qe of Test Example 1 gradually increases from the vicinity of 0.3 to the vicinity of 0.4. Each evaluation index Qe of Test Examples 2 and 3 gradually increases from the vicinity of 0 toward 0.1.

On the other hand, in the range where the drive voltage V is 10 V or more and 20 V or less, the haze of the dimming sheet 10 drops sharply from 90% to 30%. In the range where the drive voltage V is 10 V or more and 20 V or less, each evaluation index Qe of Test Examples 2 and 3 also sharply increases from the vicinity of 0.1 to the vicinity of 0.7. On the other hand, in the range where the drive voltage V is 10 V or more and 13 V or less, the evaluation index Qe of Test Example 1 sharply increases from around 0.3 to around 1.0, and when the drive voltage V is 13 V or more, it is almost 1. Maintain 0.0. That is, in the range where the drive voltage V is 13 V or more, the evaluation index Qe of Test Example 1 does not follow the haze of the dimming sheet 10.

In the range where the drive voltage V is 20 V or more and 30 V or less, the haze of the dimming sheet 10 gradually decreases from 30% to 10%. In addition, each evaluation index Qe of Test Examples 2 and 3 also gradually increases from 0.7 to 1.0.

As described above, in the entire range where the drive voltage V is 0 V or more and 30 V or less, the evaluation index Qe of Test Examples 2 and 3 changes following the change in haze in the dimming sheet 10. On the other hand, the evaluation index Qe of Test Example 1 does not follow the change in haze in the dimming sheet 10. As a result, it can be said that the evaluation index Qe of Test Examples 2 and 3 represents the optical state of the dimming sheet 10. Then, it can be said that it can be determined whether or not the photographing target 13 is suitable as the subject of the evaluation index Qe by setting the index threshold value Qm for the evaluation index Qe of the test examples 2 and 3.

As described above, according to the above embodiment, the effects listed below can be obtained.
(1) The degree of blurring of the evaluation image PE taken by the light control sheet 10 by the light control sheet 10 is calculated by using the image analysis of the evaluation image PE. Since the shooting of the evaluation image PE is realized not by a dedicated optical device such as an integrating sphere but by a general-purpose shooting device such as a smartphone or a tablet terminal, the general-purpose image PE is used when evaluating the optical state of the dimming sheet 10. It is possible to enhance the sex.

(2) The evaluation index Qe by the dimming sheet 10 tends to be larger as the haze of the dimming sheet 10 is larger, and tends to change in synchronization with the haze change of the dimming sheet 10. Therefore, if the above configuration determines that the photographing target 13 is suitable on condition that the evaluation index Qe is within an appropriate range, the optical state of the dimming sheet 10 can be evaluated using the new evaluation index Qe. It will be possible.

(3) In the shooting of the shooting target 13 through the dimming sheet 10, the external light condition in which the shooting target 13 is placed may change variously depending on the shooting opportunity. The external light condition in which the photographing object 13 is placed includes the illuminance and the illumination angle in the external light such as the illumination light of the lighting device and the natural light. In this respect, if the dimming sheet 10 is configured with the sample integrated value SumV as a reference value when it is transparent, the influence of the external light condition on the calculation of the evaluation index Qe is reduced. As a result, it becomes possible to improve the accuracy of evaluation using the new evaluation index Qe.

(4) Since it is possible to set the scene seen from the installation location of the dimming sheet 10 as the shooting target 13, the device of the dimming sheet 10 attached to the transparent body 11 as the exterior or interior of various facilities is used or monitored. At times, it becomes possible to evaluate the optical state of the dimming sheet 10.

(5) The sharpness of repetition in a short cycle in the evaluation image PE is detected as the magnitude of the frequency component in the high frequency band. On the other hand, the sharpness of repetition in a long period in the evaluation image PE is detected as the magnitude of the frequency component in the low frequency band. In this respect, if the evaluation index Qe is calculated from a predetermined frequency band in the radial distribution p (r), the optical state of the dimming sheet 10 can be expressed in detail by the evaluation index Qe.

(6) Since the evaluation index Qe is calculated from the sample integrated value SumV in the radial distribution p (r), the spatial frequency component appears in the two-dimensional direction even in the evaluation image PE in which the spatial frequency component appears in the one-dimensional direction. Even if it is an evaluation image PE, it is possible to calculate an evaluation index Qe having a size according to the optical state of the dimming sheet 10. That is, the restrictions related to spatial anisotropy are alleviated in the photographing target 13. Therefore, it is possible to expand the scenes to which the suitability determination of the photographing target 13 is applied in various fields, and to increase the versatility of the dimming system.

The above embodiment can also be modified and implemented as follows.
The evaluation index Qe is not limited to the value in which the sample integrated value SumV is standardized by the reference value, and may be, for example, the sample integrated value SumV itself. If the configuration is such that the evaluation index Qe when the dimming sheet 10 is transparent is calculated and the other evaluation index Qe is standardized using the evaluation index Qe as a reference value, the difference in lighting at the time of shooting and the shooting target The error due to the difference of 13 can be reduced in the evaluation index Qe. Since it is possible to calculate the degree of blurring by the dimming sheet 10 with high accuracy, it is also possible to improve the accuracy of determining the suitability of the object to be photographed.

The index calculation device 20 may separately calculate the evaluation index Qe from the evaluation image PE after the determination of the imaging target 13 used for the determination of the suitability after determining that the index calculation device 20 is suitable for the evaluation of the optical state. .. Then, the index calculation device 20 may determine that the dimming sheet 10 is normal on condition that the evaluation index Qe calculated after the suitability determination is equal to or higher than the index threshold value Qm. That is, the index calculation device 20 executes the processes from step S11 to step S14 after determining the suitability, and the optical state of the dimming sheet 10 is maintained on condition that the evaluation index Qe is equal to or higher than the index threshold value Qm. You may judge.

Further, the index calculation device 20 may correct the drive voltage V so that the evaluation index Qe becomes equal to or higher than the index threshold Qm on condition that the evaluation index Qe calculated after the suitability determination is less than the index threshold Qm. good. That is, the index calculation device 20 executes the processes from step S12 to step S18 after determining the suitability, and drives the evaluation index Qe to be equal to or higher than the index threshold Qm on condition that the evaluation index Qe does not reach the index threshold Qm. The voltage V may be corrected to maintain the optical state of the dimming sheet 10.

p (r) ... Radial radial distribution PE ... Evaluation image Qe ... Evaluation index 10 ... Dimming sheet 12 ... Imaging unit 13 ... Imaging target 20 ... Index calculation device 21 ... Control unit 22 ... Image analysis unit 23A ... Evaluation index calculation program 30 ... Dimming control device 31 ... Control unit

Claims (8)

It is a suitability judgment device that judges the suitability of the shooting target in the condition evaluation of the dimming sheet.
A calculation unit that calculates the degree of blurring of the image by the dimming sheet by image analysis of the image of the image to be photographed taken through the dimming sheet.
The blurring degree by the dimming sheet when reflecting a predetermined optical state in the dimming sheet is within the appropriate range, and the blurring degree calculated by the calculation unit is within the appropriate range. A suitability determination device including a determination unit for determining that the object to be imaged is suitable for evaluating the optical state. The degree of blurring calculated by the calculation unit is a value in which the first degree of blurring is standardized by the degree of second blurring.
The appropriate range is a range of the standardized values when reflecting a predetermined optical state in the dimming sheet.
The first degree of blurring is the degree of blurring by the dimming sheet in the image to be photographed taken through the dimming sheet which is opaque.
The suitability determination device according to claim 1, wherein the second degree of blurring is the degree of blurring by the dimming sheet in the image to be photographed taken through the transparent dimming sheet. The suitability determination device according to claim 1 or 2, wherein the photographing target is a scene seen from the place where the dimming sheet is installed. The image analysis is described in any one of claims 1 to 3 in which the magnitude of a frequency component in a predetermined frequency band in the radial distribution obtained from the Fourier transform of the image is calculated as the degree of blurring. Appropriateness judgment device. The calculation unit uses image analysis of an evaluation image, which is an image taken after the image pickup target determined by the determination unit to be suitable for evaluation of the optical state through the dimming sheet. Calculate the degree of blurring of the evaluation image by
The determination unit according to any one of claims 1 to 4 for determining that the dimming sheet is normal, provided that the degree of blurring of the evaluation image by the dimming sheet is within the appropriate range. The suitability judgment device described. The drive voltage applied to the dimming sheet can be changed so that the degree of blurring of the evaluation image is within the appropriate range, provided that the degree of blurring of the evaluation image by the dimming sheet is outside the appropriate range. The suitability determination device according to claim 5, further comprising a control unit. It is an appropriateness judgment method for judging the suitability of the shooting target in the condition evaluation of the dimming sheet.
To calculate the degree of blurring of the image by the dimming sheet by image analysis of the image to be photographed taken through the dimming sheet, and
The subject to be photographed, provided that the degree of blurring by the dimming sheet when reflecting a predetermined optical state in the dimming sheet is within the appropriate range and the calculated degree of blurring is within the appropriate range. Is a suitability determination method including determining that is suitable for the evaluation of the optical state. For the suitability judgment device that judges the suitability of the shooting target in the condition evaluation of the dimming sheet,
By image analysis of the image to be photographed taken through the dimming sheet, the degree of blurring of the image by the dimming sheet is calculated.
The subject to be photographed, provided that the degree of blurring by the dimming sheet when reflecting a predetermined optical state in the dimming sheet is within the appropriate range and the calculated degree of blurring is within the appropriate range. Is a suitability judgment program that makes it judged that is suitable for the evaluation of the optical state.

Images