Applicability judgment device, suitability judgment method, and suitability judgment program

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

[Technical field]

[0001] The present invention relates to a suitability judgment device, a suitability judgment method, and a suitability judgment program for judging whether or not a subject to be photographed is suitable for evaluating the optical state of a light adjusting sheet. [Background technology]

[0002] The visibility of objects through a light-control sheet, which has liquid crystal molecules between transparent electrodes, changes according to the change in voltage between the transparent electrodes. Normal-type light-control sheets, which remain opaque when not energized, are used in digital signage screens and store exteriors, which are required to remain opaque for long periods of time. Reverse-type light-control sheets, which remain transparent when not energized, are used in glass partitions and windows of moving objects, which are required to be transparent in emergencies.

[0003] Stabilization of the optical state and improvement of reproducibility of the light-adjusting sheet will broaden the applications of the light-adjusting sheet and accelerate the spread of the light-adjusting sheet. Haze according to JIS K 7136:2000 is adopted as an evaluation index of the optical state of the light-adjusting sheet. For example, it has been proposed to set a specified range of haze of 95% or more as a control item for opacity, and a specified range of haze of 12% or less as a control item for transparency (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6493598 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, transparent bodies such as glass plates and acrylic plates on which light-controlling sheets are attached are installed in buildings and moving objects. Being able to evaluate the optical state of light-controlling sheets when installed in buildings and moving objects can further accelerate the spread of light-controlling sheets. However, haze measurement, which measures the amount of light in a dark place using a dedicated optical device such as an integrating sphere, makes the evaluation of the optical state rather troublesome, so there is a strong demand in fields that use light-controlling sheets for new technology that can evaluate the optical state of light-controlling sheets over time even when the sheets are installed.

[0006] Furthermore, the demand for new technology to evaluate the optical state of light-adjusting sheets over time is not limited to when the light-adjusting sheets are installed, but is common in various situations where light-adjusting sheets are handled, such as when they are developed and when they are shipped.

[0007] The present invention aims to provide a suitability judgment device, a suitability judgment method, and a suitability judgment program that make it possible to evaluate the optical state of a light adjusting sheet using a new evaluation index. [Means for solving the problem]

[0008] The suitability judgment device for solving the above problem is a suitability judgment device that judges the suitability of a subject to be photographed in evaluating the condition of a light-adjusting sheet, and includes a calculation unit that calculates the degree of blurring of the image caused by the light-adjusting sheet by image analysis of the image of the subject to be photographed through the light-adjusting sheet, and a judgment unit that judges that the subject to be photographed is suitable for evaluating the optical condition, provided that the degree of blurring caused by the light-adjusting sheet when reflecting a specified optical state of the light-adjusting sheet is within an appropriate range and the degree of blurring calculated by the calculation unit is within the appropriate range.

[0009] A suitability judgment method for solving the above problem is a suitability judgment method for judging the suitability of a subject to be photographed in evaluating the condition of a light-adjusting sheet, and includes calculating the degree of blurring of the image caused by the light-adjusting sheet by performing image analysis of the image of the subject to be photographed through the light-adjusting sheet, and judging that the subject is suitable for evaluating the optical condition, provided that the degree of blurring caused by the light-adjusting sheet when reflecting a specified optical state of the light-adjusting sheet is within an appropriate range and the calculated degree of blurring is within the appropriate range.

[0010] A suitability judgment program for solving the above problem causes a suitability judgment device, which judges the suitability of a subject to be photographed in evaluating the condition of a light-adjusting sheet, to calculate the degree of blurring of the image caused by the light-adjusting sheet by performing image analysis of the image of the subject to be photographed through the light-adjusting sheet, and judges that the subject is suitable for evaluating the optical condition, provided that the degree of blurring when reflecting a specified optical condition of the light-adjusting sheet is within an appropriate range and the calculated degree of blurring is within the appropriate range.

[0011] According to each of the above configurations, the degree of blurring caused by the light-adjusting sheet of an image photographed through the light-adjusting sheet is calculated using image analysis of the image. Such images are photographed not by a dedicated optical device such as an integrating sphere, but by a general-purpose photographing device such as a smartphone or a tablet terminal. The degree of blurring of such images is calculated using various image analyses such as frequency component analysis and edge intensity analysis. The degree of blurring caused by the light-adjusting sheet can be calculated based on the degree of blurring of an image photographed without passing through the light-adjusting sheet, the degree of blurring of an image photographed with the light-adjusting sheet made transparent, or a predetermined value estimated to correspond to these. The degree of blurring caused by the light-adjusting sheet tends to be greater as the haze of the light-adjusting sheet increases, and is likely to change in sync with the change in haze of the light-adjusting sheet. Therefore, with the above configuration in which the subject is judged to be suitable on the condition that the degree of blurring of the subject by the light-adjusting sheet is within an appropriate range, it becomes possible to evaluate the optical state of the light-adjusting sheet using a new evaluation index called the degree of blurring.

[0012] In the above-mentioned suitability judgment device, the degree of blur calculated by the calculation unit is a value obtained by normalizing the first degree of blur by the second degree of blur, the appropriate range is a range of the normalized values ​​when a specified optical state of the light-adjusting sheet is reflected, the first degree of blur is the degree of blur caused by the light-adjusting sheet in an image of the subject photographed through the light-adjusting sheet which is opaque, and the second degree of blur is the degree of blur caused by the light-adjusting sheet in an image of the subject photographed through the light-adjusting sheet which is transparent.

[0013] When photographing a subject through a light-adjusting sheet, the external light conditions in which the subject is placed may vary depending on the occasion of the photograph. The external light conditions in which the subject is placed include the illuminance and lighting angle of external light such as the illumination light of a lighting device or natural light. In this regard, according to the suitability determination device, the degree of blurring when the light-adjusting sheet is transparent is used as the standard, so the influence of the external light conditions on the calculation of the degree of blurring is reduced. As a result, it is possible to improve the accuracy of the evaluation using the new evaluation index, the degree of blurring.

[0014] In the above suitability judgment device, the subject to be photographed may be a view seen from a location where the light controlling sheet is installed. With this configuration, it is possible to evaluate the optical state of the light controlling sheet when it is installed or monitored and the light controlling sheet is attached to a transparent body as the exterior or interior of various facilities.

[0015] In the suitability determination device, the image analysis may calculate, as the degree of blurring, a magnitude of a frequency component in a predetermined frequency band in a radial distribution obtained by a Fourier transform of the image.

[0016] The sharpness of short-period repetition in an image is detected as the magnitude of frequency components in a high frequency band. On the other hand, the sharpness of long-period repetition in an image is detected as the magnitude of frequency components in a low frequency band. In this regard, the suitability determination device calculates the degree of blurring through frequency analysis of the image, making it possible to express the optical state of the light-control sheet in detail by the degree of blurring.

[0017] In addition, since the magnitude of the frequency components in the radial distribution is calculated as the degree of blurring, whether the spatial frequency components appear in a one-dimensional direction or in a two-dimensional direction, the frequency components having a magnitude corresponding to the optical state of the light-control sheet can be calculated. In other words, the constraints related to spatial anisotropy are alleviated in the subject to be photographed. Therefore, it is possible to expand the scope of application of the suitability judgment device to many areas, and ultimately to increase the versatility of the suitability judgment device.

[0018] In the above-mentioned suitability judgment device, the calculation unit calculates the degree of blurring of the evaluation image caused by the light-adjusting sheet using image analysis of an evaluation image, which is an image of the subject that the judgment unit has judged to be suitable for evaluating the optical state, taken after the judgment was made through the light-adjusting sheet, and the judgment unit may judge that the light-adjusting sheet is normal, provided that the degree of blurring of the evaluation image caused by the light-adjusting sheet is within the appropriate range.

[0019] The suitability determination device also makes it possible to detect whether the optical state of the light adjusting sheet is normal. The above-mentioned suitability judgment device may further include a control unit that, provided that the degree of blurring of the evaluation image caused by the light-adjusting sheet is outside the appropriate range, can change the driving voltage applied to the light-adjusting sheet so that the degree of blurring of the evaluation image is within the appropriate range.

[0020] According to the suitability determination device, it is possible to change the driving voltage so that the optical state of the light controlling sheet is normal, provided that the degree of blurring caused by the light controlling sheet is outside the appropriate range. As a result, it is possible to drive the light controlling sheet so that the optical state is normal. Effect of the Invention

[0021] The suitability judgment device, suitability judgment method, and suitability judgment program according to the present invention make it possible to evaluate the optical state of a light controlling sheet using a new evaluation index. [Brief description of the drawings]

[0022] [Figure 1] FIG. 4 is a block diagram showing the configuration of the suitability determination device together with a light controlling sheet. [Diagram 2] FIG. 4 is a block diagram functionally showing the configuration of an index calculation unit. [Diagram 3] FIG. 11 is a power spectrum diagram showing an example of extraction of a sample group for calculating an evaluation index. [Figure 4] 1 is a flowchart showing the flow of steps in an evaluation index calculation method. [Diagram 5] FIG. 2 is a diagram showing the configuration of an evaluation image capturing device. [Figure 6] FIG. 13 shows an image of a subject in Test Example 1. [Figure 7] FIG. 13 shows an image of a subject in Test Example 2. [Figure 8] FIG. 13 shows an image of a subject in Test Example 3. [Figure 9] 13 is a graph showing a radial distribution obtained from an FFT transformed image of Test Example 1. [Figure 10] 13 is a graph showing a radial distribution obtained from an FFT transformed image of Test Example 2. [Figure 11] 13 is a graph showing a radial distribution obtained from an FFT transformed image of Test Example 3. [Figure 12] 13 is 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 driving voltage, together with the haze. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The suitability judgment device, the suitability judgment method, and the suitability judgment program will be described with reference to Fig. 1 to Fig. 12. First, the configuration of the light adjusting sheet to be evaluated will be described, and then the suitability judgment device, the suitability judgment method, and the suitability judgment program will be described.

[0024] [Light control sheet 10] The light controlling sheet 10 is configured to be able to change its light transmittance. The light transmittance of the light controlling sheet 10 is changed by changing the driving voltage applied to the light controlling sheet 10. In addition to liquid crystal light controlling sheets, types of light controlling sheets 10 include electrochromic sheets. The transmittance of liquid crystal light controlling sheets is controlled by controlling the orientation of liquid crystal molecules through the application of a driving voltage V. The transmittance of electrochromic sheets is controlled by controlling the charge of the electrochromic material through the application of a driving voltage V.

[0025] The light controlling sheet 10 is attached to various transparent bodies 11 such as windows 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, the base material of a screen for projecting images, and windows in moving objects such as vehicles and aircraft. The light controlling sheet 10 is attached by attaching it to the surface of the transparent body 11 such as window glass, or by sandwiching it between two transparent bodies such as laminated glass.

[0026] The shape of the light-adjusting sheet 10 includes a planar shape that follows the outer shape of the transparent body 11, a two-dimensional curved shape such as a cylindrical shape or an elliptical cylindrical shape, a three-dimensional curved shape such as a spherical shape or an ellipsoidal shape, and an indefinite shape other than a geometric shape. The color of the light-adjusting sheet 10 in a state of high transmittance is colorless and transparent, or colored and transparent. The color of the light-adjusting sheet 10 in a state of low transmittance is achromatic or chromatic.

[0027] The light-adjusting sheet 10 is of a normal type or a reverse type. A normal type light-adjusting sheet has a relatively high light transmittance when the light-adjusting sheet 10 is energized, but has a relatively low light transmittance when the light-adjusting sheet 10 is not energized. A reverse type light-adjusting sheet has a relatively low light transmittance when the light-adjusting sheet 10 is energized, but has a relatively high light transmittance when the light-adjusting sheet 10 is not energized.

[0028] The light-adjusting sheet 10 includes a first transparent electrode, a second transparent electrode, and a light-adjusting layer that extend in the surface direction of the light-adjusting sheet 10. In the light-adjusting sheet 10, the first transparent electrode, the light-adjusting layer, and the second transparent electrode are laminated in this order, and the light-adjusting 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 light control device 30.

[0029] The first transparent electrode and the second transparent electrode have optical transparency that transmits visible light. The optical transparency of the first transparent electrode allows visual recognition of an object through the light-adjusting sheet 10. The optical transparency of the second transparent electrode also allows visual recognition of an object through the light-adjusting 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).

[0030] The light control layer of the liquid crystal light control sheet contains a liquid crystal composition. An example of the liquid crystal molecules contained in the liquid crystal composition is at least one selected from the group consisting of Schiff base type, azo type, azoxy type, biphenyl type, terphenyl type, benzoic acid ester type, tolan type, pyrimidine type, cyclohexane carboxylate ester type, phenylcyclohexane type, and dioxane type. The retention type of the liquid crystal composition is a polymer dispersion type, a capsule type, and the like. The polymer dispersion type retains the liquid crystal composition in a large number of voids dispersed in a polymer layer. The polymer dispersion type includes a polymer network type having a polymer network having a three-dimensional mesh shape. The polymer network type retains the liquid crystal composition in mesh-shaped voids. The capsule type retains a capsule-shaped liquid crystal composition in a polymer layer.

[0031] 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, or a cyanide compound, an inorganic compound such as silicone, silicon oxide, or zirconium oxide, or a mixture thereof.

[0032] The alignment film is, for example, a vertical alignment film or a horizontal alignment film. The vertical alignment film aligns the long axis direction of the liquid crystal molecules so that it is 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. The horizontal alignment film aligns the long axis direction of the liquid crystal molecules so that it is approximately 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.

[0033] The light control layer of the electrochromic sheet includes an electrochromic material and an electrolyte. An example of the electrochromic material is one selected from organic compounds such as polyaniline derivatives, viologens, metal 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.

[0034] [Dimming system] As shown in FIG. 1, the light adjusting system includes a light adjusting sheet 10, an image capturing unit 12, an index calculating device 20 which is an example of a suitability determining device, and a light adjusting control device 30.

[0035] The light control device 30 receives a drive command NS from the index calculation device 20 or an input signal MC from an operation unit, and drives the light controlling sheet 10 to calculate the evaluation index Qe. The photographing unit 12 photographs the subject 13 through the light controlling sheet 10 and generates an evaluation image PE of the subject 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 caused by the light controlling sheet 10 using image analysis of the evaluation image PE.

[0036] The degree of blurring calculated by the index calculation device 20 is the evaluation index Qe of the light-adjusting sheet 10. The degree of blurring caused by the light-adjusting sheet 10 is a value for repeatedly evaluating whether or not the light-adjusting sheet 10 has a stable optical state over time, and is a value indicating whether or not the light-adjusting sheet 10 has the optical state that is an evaluation item. The optical state that is an evaluation item is, for example, having a haze of a predetermined value or more, or having a clarity of a predetermined value or less, etc.

[0037] For example, the degree of blurring provided by the light-adjusting sheet 10 is a value indicating whether or not the light-adjusting sheet 10 has a high level of haze that prevents the presence or absence of an object from being visually recognized through the light-adjusting sheet 10. Conversely, the degree of blurring provided by the light-adjusting sheet 10 is a value indicating whether or not the light-adjusting sheet 10 has a low level of haze that allows the presence or absence of an object to be visually recognized through the light-adjusting sheet 10.

[0038] For example, the degree of blurring provided by the light-adjusting sheet 10 is a value indicating whether or not the light-adjusting sheet 10 has a high level of haze such that the contours of objects cannot be visually recognized through the light-adjusting sheet 10. Conversely, the degree of blurring provided by the light-adjusting sheet 10 is a value indicating whether or not the light-adjusting sheet 10 has a low level of haze such that the contours of objects can be visually recognized through the light-adjusting sheet 10.

[0039] For example, the degree of blurring provided by the light-adjusting sheet 10 is a value indicating whether the light-adjusting sheet 10 has low clarity such that the type of object cannot be visually recognized through the light-adjusting sheet 10. Conversely, the degree of blurring provided by the light-adjusting sheet 10 is a value indicating whether the light-adjusting sheet 10 has high clarity such that the details of the object can be visually recognized through the light-adjusting sheet 10.

[0040] For example, during the manufacture or application of the light-adjusting sheet 10, the index calculation device 20 compares the evaluation index Qe calculated by the index calculation device 20 with an index threshold Qm, which is an evaluation index when the photographed subject 13 is suitable for evaluating the optical state of the light-adjusting sheet 10. Based on the comparison between the evaluation index Qe and the index threshold Qm, the index calculation device 20 determines whether or not the photographed subject 13 is suitable for evaluating the optical state of the light-adjusting sheet 10. When the evaluation index Qe is equal to or greater than the index threshold Qm, it means that the degree of image blurring by the light-adjusting sheet 10 is within an appropriate range.

[0041] The photographing unit 12 and the index calculation device 20 are configured to enable the photographing unit 12 to transmit an evaluation image PE and the index calculation device 20 to receive the evaluation image PE through wired communication or wireless communication. The index calculation device 20 is, for example, a maintenance device connected to the photographing unit 12 so as to be able to communicate without going through a network, a server device connected to the photographing unit 12 so as to be able to communicate through a network, or a device built into a user terminal equipped with the photographing unit 12. The index calculation device 20 is, for example, a server device that accepts an application for suitability judgment of the photographing target 13 from a user terminal equipped with the photographing unit 12 and receives the evaluation image PE photographed through the light controlling sheet 10 from the user terminal.

[0042] The index calculation device 20 and the dimming control device 30 are configured to enable the index calculation device 20 to transmit a drive command NS and the dimming control device 30 to receive the drive command NS, for example, through wired communication or wireless communication. The index calculation device 20 is, for example, a maintenance device connected to the dimming control device 30 so as to be able to communicate without going through a network, a server device connected to the dimming control device 30 so as to be able to communicate via a network, or an electronic device having hardware common to part of the dimming control device 30.

[0043] The photographing unit 12 includes a two-dimensional image sensor in which photographing elements such as CCDs (Charged Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors) are arranged two-dimensionally, and a photographing optical system that forms an image of light emitted from the photographing target 13 on the light receiving surface of the image sensor. The photographing unit 12 forms an image of the light emitted from the photographing target 13 on the light receiving surface of the image sensor, and records a still image of the photographing target 13 through the light controlling sheet 10 as an evaluation image PE, which is image data. The photographing unit 12 is, for example, a general camera such as a camera mounted on a smartphone or tablet terminal, a surveillance camera installed in various facilities such as commercial facilities or public facilities, or a digital camera.

[0044] The photographing unit 12 generates an evaluation image PE. The evaluation image PE is an image of a photographing target 13 in a predetermined environment photographed through the light controlling sheet 10. The photographing target 13 is photographed through the light controlling sheet 10 in a state where the photographing unit 12 and the photographing target 13 are placed in a predetermined environment.

[0045] The predetermined environment for photographing the evaluation image PE is the setting environment of the photographing unit 12, the lighting environment for the photographing unit 12, and the lighting environment for the photographing target 13. The setting environment of the photographing unit 12 is, for example, setting the manual focus distance at the time of photographing to a predetermined value, and setting the aperture value and the shutter speed to predetermined values. The lighting environment for the photographing unit 12 is, for example, that the lighting is turned on at the place where the photographing unit 12 is placed, or that the amount of solar radiation at the place where the photographing unit 12 is placed is estimated to be a predetermined amount. The lighting environment for the photographing target 13 is, for example, that the lighting is turned on at the place where the photographing target 13 is placed, or that the amount of solar radiation at the place where the photographing target 13 is placed is estimated to be a predetermined amount. The amount of solar radiation is estimated to be a predetermined amount when, for example, the photographing date and time is a predetermined date and time, or the weather type at the time of photographing is clear. In this way, the photographing of the evaluation image PE is realized by a general-purpose photographing device such as a smartphone or a tablet terminal, rather than a dedicated optical device such as an integrating sphere.

[0046] The photographed subject 13 is an object to be judged as to suitability, and is a photographed subject used to calculate the evaluation index Qe. The photographed subject 13 is an artificial object such as a building or structure visible through the light-adjusting sheet 10, a natural landscape visible through the light-adjusting sheet 10, or a test pattern such as a printed matter prepared as a candidate for evaluating the optical state of the light-adjusting sheet 10. The above-mentioned artificial objects and natural landscapes are examples of views that can be seen from the installation location of the light-adjusting sheet 10.

[0047] The test pattern is a printed matter used to evaluate physical performance such as contrast, resolution, and noise based on 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 alternately in parallel, a pattern in which white and black thin lines are arranged radially, a pattern in which white and black thin lines having different line widths are arranged alternately in parallel, a pattern in which white and black thin lines having different line densities are arranged, and the like. The test pattern is, for example, letters or alphanumeric characters having different sizes. The test pattern is, for example, a test chart including text such as letters or alphanumeric characters used for measuring the resolution of a digital camera, a resolution chart conforming to ISO12233-2000, a barcode test chart conforming to JIS X 0527 used for evaluating the performance of a barcode reader, and the like.

[0048] [Indicator calculation device 20] The index calculation device 20 is not limited to a device that processes various processes entirely by software. For example, the index calculation device 20 may include dedicated hardware such as an application specific integrated circuit (Graphics Processing Unit: GPU, Application Specific Integrated Circuit: ASIC) that executes at least some of the various processes. The index calculation device 20 may also be configured as a circuit including one or more dedicated hardware circuits such as an ASIC, one or more processors that operate according to a computer program, or a combination of these. In the following, an example will be described in which the index calculation device 20 stores an evaluation index calculation program in a readable medium that can be read, reads out and executes the evaluation index calculation program stored in the readable medium, and performs various processes.

[0049] 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 an evaluation index calculation program 23A for calculating the evaluation index, and index calculation information 23B used to execute 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 sample extraction conditions. The evaluation voltage V0 is a driving voltage V applied to the light controlling sheet 10, and is used as an initial value applied for calculating the evaluation index Qe. The sample extraction conditions are conditions for extracting a sample group used for calculating the evaluation index Qe from the distribution of feature vectors. The sample extraction conditions are determined based on the results of a test performed in advance, etc., so that a sample group suitable for evaluation is extracted.

[0050] For example, when an evaluation item of the optical state is that the light-adjusting sheet 10 has a high haze such that the presence or absence of an object cannot be visually recognized through the light-adjusting sheet 10, conditions for extracting a sample group suitable for evaluating whether or not the light-adjusting sheet 10 has a high haze from the distribution of feature vectors are stored as sample extraction conditions. Conversely, when an evaluation item is that the light-adjusting sheet 10 has a low haze such that the presence or absence of an object can be visually recognized through the light-adjusting sheet 10, conditions for extracting a sample group suitable for evaluating whether or not the light-adjusting sheet 10 has a low haze from the distribution of feature vectors are stored as sample extraction conditions.

[0051] For example, when an evaluation item of the optical state is that the light-adjusting sheet 10 has a high haze such that the contours of an object cannot be visually recognized through the light-adjusting sheet 10, conditions for extracting a sample group suitable for evaluating whether or not the light-adjusting sheet 10 has a high haze from the distribution of feature vectors are stored as sample extraction conditions. Conversely, when an evaluation item is that the light-adjusting sheet 10 has a low haze such that the details of an object can be visually recognized through the light-adjusting sheet 10, conditions for extracting a sample group suitable for evaluating whether or not the light-adjusting sheet 10 has a low haze from the distribution of feature vectors are stored as sample extraction conditions.

[0052] For example, when an evaluation item is that the light-adjusting sheet 10 has low clarity such that the contours of an object cannot be visually recognized through the light-adjusting sheet 10, conditions for extracting a sample group suitable for evaluating whether or not the light-adjusting sheet 10 has low clarity from the distribution of feature vectors are stored as sample extraction conditions. Conversely, when an evaluation item is that the light-adjusting sheet 10 has high clarity such that the details of an object can be visually recognized through the light-adjusting sheet 10, conditions for extracting a sample group suitable for evaluating whether or not the light-adjusting sheet 10 has high clarity from the distribution of feature vectors are stored as sample extraction conditions.

[0053] The index calculation information 23B may include data required for the suitability judgment process, such as the index threshold Qm, the upper limit voltage Vmax, and the step voltage Vs. The index threshold Qm is a threshold of the evaluation index Qe obtained through the light controlling sheet 10 that satisfies the evaluation items. The index threshold Qm is a threshold of the evaluation index Qe obtained in advance using a photographing subject suitable for evaluating the optical state. The upper limit voltage Vmax is the maximum value of the driving voltage that the light controlling control device 30 applies to the light controlling sheet 10. The step voltage Vs is the amount of change in the driving voltage V that is changed each time the evaluation index Qe is calculated in the suitability judgment.

[0054] The control unit 21 reads out 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 an evaluation image PE from the photographing unit 12, and causes the image analysis unit 22 to execute 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 an evaluation index Qe using a result of the image analysis by the image analysis unit 22. The control unit 21 is an example of a judgment unit, and judges the suitability of the photographing target 13 based on a comparison between the calculated evaluation index Qe and an index threshold Qm.

[0055] [Image Analysis Section 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 caused by the light adjusting sheet 10 as an evaluation index Qe. The image analysis unit 22 is an example of a calculation unit.

[0056] 2, the image analysis unit 22 functions as a grayscale process 22A, an FFT process 22B, and a frequency analysis unit 22C. The grayscale process 22A performs (i) grayscaling of the evaluation image PE. The FFT process 22B performs (ii) two-dimensional fast Fourier transform using the grayscaled image data. The frequency analysis unit 22C performs (iii) frequency analysis of the Fourier transform image using the processing result of the FFT process 22B.

[0057] The image analysis performed by the image analysis unit 22 may be to calculate the degree of clarity of the evaluation image PE, i.e., the difference between the optical density such as the luminance of the evaluation image PE and the optical density such as the luminance of the background image, as the degree of blurring of the image. Alternatively, the image analysis performed by the image analysis unit 22 may be to calculate the optical density of a pixel having a 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 the degree of blurring of the image by using an average value of edge intensity obtained by edge detection processing based on the pixel luminance value for each pixel corresponding to the contour of the evaluation image.

[0058] (i) Grayscaling converts image data in RGB space into image data in YUV space. Grayscaling is a process that performs an intermediate value method that outputs an intermediate value using RGB values ​​as a result, or a weighted average method that outputs an average value of RGB values ​​weighted by each separate coefficient as a result. Grayscaling may also be a process that combines a weighted average method that outputs a value obtained by applying gamma correction to the weighted average value of RGB values ​​weighted by each separate coefficient, and correction. Grayscaling may also be a process that performs a simple average method that outputs a simple average value of RGB values ​​as a result, or a median method that outputs a median value of RGB values ​​as a result.

[0059] (ii) A two-dimensional fast Fourier transform is performed using the grayscaled image data, and the distribution of feature vectors in the two-dimensional Fourier transformed 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 in a concentric region at a distance r from the center of the two-dimensional Fourier transformed image. The angular distribution q(θ) is the sum of power spectra in a linear region of an angle θ with respect to the horizontal axis. The distribution of feature vectors indicates what spatial frequency waves are strongly contained in the grayscaled image data, and in what direction strong waves are contained, i.e., the periodicity of the shading in the image in the radial and angular directions.

[0060] (iii) In the frequency analysis, a group of samples that satisfy the sample extraction conditions is extracted from the distribution of the feature vectors. In the frequency analysis, an evaluation index Qe is calculated from the feature vectors of the extracted group of samples. As described above, the sample extraction conditions are conditions for extracting a group of samples to be used for calculating the evaluation index from the distribution of the feature vectors. In the frequency analysis, for example, the sum of the feature vectors of all samples that satisfy the sample extraction conditions is calculated as the sample integrated value SumV. In the frequency analysis, the evaluation index Qe is calculated using the calculated sample integrated value SumV and a reference value for normalizing the sample integrated value SumV.

[0061] [Sample extraction] Next, an example of extracting a sample group in the above frequency analysis will be described below. Figure 3 shows the sample group extracted in the power spectrum of the Fourier transform image by adding dots.

[0062] As shown in Fig. 3, for example, when the distribution of the feature vector is a radial distribution, an example of the sample extraction condition is that the distance r is within a predetermined range, that is, the frequency is a predetermined frequency band. When the evaluation item is that the object has a high degree of haze that makes the contour of the object unrecognizable by the eye, an example of the sample extraction condition is that the distance r is equal to or greater than a sample threshold value rx. An example of the sample threshold value rx satisfies the following conditions 1 and 2 in the radial distribution.

[0063] (Condition 1) Sample threshold rx>Extraction reference distance rs (Condition 2) Sample threshold energy p(rx) < Extraction reference energy p(rs) × 10% Here, the extraction reference energy (rs) is, for example, the maximum value p(r)max that indicates the largest energy in the radial distribution p(r), and the extraction reference distance rs is the distance r that gives the maximum value p(r)max.

[0064] In the grayscaled image, the grayscale waves corresponding to the maximum value p(r)max are highly likely to be waves indicating the presence or absence of an object. On the other hand, in the grayscaled image, the grayscale waves corresponding to energy smaller than the maximum value p(r)max are highly likely to be waves indicating the contour of an object. Then, the extraction of the sample group based on the above conditions 1 and 2 can exclude waves that are highly likely to indicate the presence or absence of an object from the sample group, and extract a sample group suitable for evaluating whether the contour of an object is not visually recognized.

[0065] In this way, the above conditions 1 and 2 are set to a specific feature vector as the extraction reference energy (rs), thereby excluding low-frequency waves equal to or lower than the shading waves corresponding to the feature vector, and making it possible to extract a group of samples suitable for evaluating whether high-frequency waves are visually recognized. In other words, the setting of the sample extraction conditions is a condition that makes it possible to calculate the magnitude of frequency components in a predetermined frequency band. The frequency analysis calculates the sum of the feature vectors of all samples extracted based on these sample extraction conditions as a sample integrated value SumV (the dotted area in FIG. 3). Then, the frequency analysis divides the sample integrated value SumV by a reference value to calculate an evaluation index Qe normalized by the reference value. The sample integrated value SumV is the first blurring degree, and the reference value is the second blurring degree.

[0066] In addition, when the evaluation item is having a high level of haze such that the contours of an object cannot be visually recognized, the reference value is the sample accumulated value SumV of the evaluation image PE photographed under a specified environment without passing through the light-adjusting sheet 10, or the sample accumulated value SumV of the evaluation image PE photographed with the light-adjusting sheet 10 made transparent, or a specified value estimated to correspond to these.

[0067] On the other hand, when the evaluation item is that the object has a low haze such that the contour of the object is visually recognized, the reference value is the sample integrated value SumV of the evaluation image PE photographed under a predetermined environment through the light adjusting sheet 10 such that the contour of the object is not visually recognized, or a predetermined value estimated to be equivalent thereto. Even in this case, the reference value may be calculated separately by the index calculation device 20, or may be stored in advance in the index calculation device 20.

[0068] In addition, when the evaluation item is the optical state when a driving voltage V is applied to the dimming sheet 10, the reference value is, for example, the sample accumulated value SumV when no driving voltage V is applied to the dimming sheet 10, or a predetermined value estimated to be equivalent thereto.

[0069] Conversely, if the evaluation item is the optical state when no driving voltage V is applied to the dimming sheet 10, the reference value is, for example, the sample accumulated value SumV when a driving voltage V is applied to the dimming sheet 10, or a predetermined value estimated to be equivalent thereto.

[0070] In either case, the reference value may be calculated separately by the index calculation device 20, or may be stored in advance in the index calculation device 20. Furthermore, when the distribution of the feature vector is an angular direction distribution q(θ), the sample extraction condition is that the angle θ is within a predetermined range. Furthermore, when the distribution of the feature vector is an angular direction distribution q(θ), the reference value is also a sample integrated value obtained from the angular direction distribution q(θ) of the evaluation image PE photographed under a predetermined environment without passing through the light adjusting sheet 10. Furthermore, when the distribution of the feature vector is an angular direction distribution q(θ), the reference value is a sample integrated value obtained from the angular direction distribution q(θ) of the evaluation image PE photographed with the light adjusting sheet 10 made transparent, a predetermined value estimated to be equivalent to these, or the like.

[0071] The communication unit 24 executes acquiring an evaluation image PE from the photographing unit 12 in response to a command from the control unit 21. Note that the communication unit 24 can execute, for example, sending 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 sending a result of the suitability judgment for the photographing target 13 to an output unit such as a display unit. In addition, the communication unit 24 may send a result of the suitability judgment for the photographing target 13 to a user terminal in response to a command from the control unit 21.

[0072] [Light control device 30] Returning to FIG. 1, the dimming control device 30 is not limited to a device that processes various processes entirely 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 some of the various processes. The dimming control device 30 may also be configured as a circuit that includes one or more dedicated hardware circuits such as an ASIC, one or more processors that operate according to a computer program, or a combination of these. In the following, an example will be described in which the dimming control device 30 stores a driving program in a readable medium that can be read, reads out and executes the driving program stored in the readable medium, and performs various processes.

[0073] The light 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 light adjusting sheet 10 and various data used to execute the drive program. The control unit 31 reads out the drive program from the storage unit 32, interprets the drive program, and causes the drive unit 33 to generate a drive voltage V.

[0074] For example, the control unit 31 receives a drive command NS from the index calculation device 20 or an input signal MC from 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 light adjusting sheet 10.

[0075] For example, the control unit 31 stores the corrected driving voltage V at the time of suitability judgment in the memory unit 32. Upon receiving a drive command NS from the index calculation device 20 or an input signal MC from the operation unit, the control unit 31 reads out the corrected driving voltage V from the memory unit 32 and causes the drive unit 33 to generate the corrected driving voltage V. The drive unit 33 applies the generated corrected driving voltage V to the light controlling sheet 10 when calculating the next evaluation index Qe, which is executed after the suitability judgment.

[0076] [Suitability judgment] Next, a method for determining suitability 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 light-adjusting sheet is used, and the evaluation item is whether the light-adjusting sheet 10 has a high level of haze that makes it impossible to visually recognize the contours of objects through the light-adjusting sheet 10.

[0077] 4, the index calculation device 20 first transmits a drive command NS for generating an evaluation voltage V0 as the drive voltage V to the light control device 30. The light control device 30 generates the evaluation voltage V0 in response to the drive command NS, and applies the evaluation voltage V0 for making the light controlling sheet 10 opaque. This causes the light controlling sheet 10 to change to an optical state for determining whether the subject 13 is suitable for imaging (step S11).

[0078] The index calculation device 20 may be configured to store a different evaluation voltage V0 for each evaluation item. For example, the evaluation voltage V0 is selected by the index calculation device 20 according to an evaluation item selected by a user. For example, in the case where the evaluation items are that the light-adjusting sheet 10 has a high level of haze such that the presence or absence of an object cannot be visually recognized, and that the light-adjusting sheet 10 has a high level of haze such that the contour of an object cannot be visually recognized, 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 to the light-adjusting control device 30 to set the evaluation voltage V0 to the drive voltage V.

[0079] Next, the photographing unit 12 photographs the evaluation image PE of the photographing target 13 through the light controlling sheet 10 to which the evaluation voltage V0 has been applied. The index calculation device 20 acquires the evaluation image PE of the photographing target 13 photographed through the light controlling sheet 10 from the photographing unit 12 (step S12).

[0080] Next, the index calculation device 20 performs image analysis of the acquired evaluation image PE to calculate the degree of blurring of the evaluation image PE caused by the light adjusting 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 caused by the light adjusting sheet 10, and as described above, for example, grayscaling, two-dimensional fast Fourier transform, and frequency analysis are performed in this order (step S13).

[0081] Next, the index calculation device 20 judges whether the calculated evaluation index Qe is equal to or greater than the index threshold Qm. At this time, the index threshold Qm is the lower limit of the evaluation index Qe obtained from an image of an appropriate subject through the light-adjusting sheet 10 having an appropriate optical state. The light-adjusting sheet 10 having an appropriate optical state has a high haze to the extent that the contour of an object cannot be visually recognized through the light-adjusting sheet 10 (step S14).

[0082] When the index calculation device 20 determines that the evaluation index Qe is equal to or greater than the index threshold Qm (YES in step S14), it stores the evaluation index Qe as an initial index Q0 (step S15). Then, prior to evaluating the optical state of the light adjusting sheet 10 over time, the index calculation device 20 notifies the outside that the subject 13 is appropriate as a subject for calculating the evaluation index Qe (appropriateness determination: step S16).

[0083] On the other hand, if the index calculation device 20 determines that the evaluation index Qe is less than the index threshold value Qm (NO in step S14), it determines whether the current drive voltage V is the upper limit voltage Vmax (step S17). Next, if the index calculation device 20 determines that the current drive voltage V is not the upper limit voltage Vmax (NO in step S17), it transmits a drive command NS to the dimming control device 30 so that a new drive voltage V is generated by adding the step voltage Vs to the evaluation voltage V0.

[0084] The light control device 30 generates a new drive voltage V in response to the drive command NS, and applies the generated drive voltage to the light controlling sheet 10. This further reduces the light transmittance of the light controlling sheet 10. 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 equal to or greater than the index threshold value Qm.

[0085] The index calculation device 20 notifies the dimming control device 30 of the driving voltage V when the evaluation index Qe is equal to or greater than the index threshold value Qm. The dimming control device 30 stores the notified driving voltage V as the driving voltage V that satisfies the evaluation item, i.e., the driving voltage V that can be used by the subject 13 in the evaluation of the optical state over time, and uses the stored driving voltage V when the evaluation of the optical state over time is subsequently performed.

[0086] On the other hand, when the index calculation device 20 determines that the current driving voltage V is the upper limit voltage Vmax (YES in step S17), it notifies the outside that the subject 13 is inappropriate as a subject for calculating the evaluation index Qe (step S19) prior to evaluating the optical state of the light-adjusting sheet 10 over time.

[0087] [Test example] Next, a test example showing that the optical state of the light controlling sheet 10 can be evaluated by image analysis and whether the subject 13 is suitable as a subject for calculating the evaluation index Qe will be described with reference to Fig. 5 to Fig. 12. Note that the following shows an example in which a polymer network type liquid crystal light controlling sheet driven as a normal type is used as the light controlling sheet 10.

[0088] First, the photographing device for photographing the evaluation image PE will be described. As shown in Fig. 5, the darkroom 51 of the imaging device has a bottom 51B that functions as a surface light source. The bottom 51B of the darkroom 51 is an LED table that irradiates light toward the top of the darkroom 51. The bottom of the darkroom 51 supports the subject 13 to be photographed inside the darkroom 51. The top 51T of the darkroom 51 is equipped with a photographing unit 12 such as a smartphone directly above the subject 13 so as to be able to photograph the inside of the darkroom 51. The inner surface of the darkroom 51 is black to prevent external light from being irradiated onto the photographing unit 12 and to prevent reflections from occurring on the photographing unit 12.

[0089] The interior of the darkroom 51 is provided with a placement section for placing the light-adjusting sheet 10 between the photographing unit 12 and the photographed object 13. The placement section is a flat partition plate that separates the space in which the photographed object 13 is placed from the other space. A rectangular through-hole is formed in the placement section at a position facing the photographed object 13. The light-adjusting sheet 10 is placed so as to cover the through-hole formed in the placement section. The photographing unit 12 photographs the photographed object 13 through the light-adjusting sheet 10 and the through-hole of the placement section.

[0090] The light controlling sheet 10 is placed on the placement section while being attached to a colorless and transparent glass plate. The light controlling sheet 10 has a rectangular sheet shape with a short side of 100 mm and a long side of 112 mm. The glass plate to which the light controlling sheet 10 is attached also has a rectangular plate shape with a short side of 105 mm and a long side of 126 mm. When the driving voltage V is 0 V, the light controlling sheet 10 has the lowest transmittance, and when the driving voltage V is the upper limit voltage Vmax, the light controlling sheet 10 has the highest transmittance.

[0091] The interior of the darkroom 51 is provided with object LEDs 54R, 54L that irradiate light L onto the subject 13. The object LEDs 54R, 54L irradiate light L from the lower surface of the placement portion onto the entire bottom portion 51B inside the darkroom 51. The object LEDs 54R, 54L irradiate daylight of the same color. The illuminance of the object LEDs 54R, 54L on the subject 13 is 2690 lx.

[0092] The darkroom 51 is provided with sheet LEDs 53R and 53L that irradiate light L onto the light controlling sheet 10. Inside the darkroom 51, the sheet LEDs 53R and 53L irradiate light L from the top 51T of the darkroom 51 onto the entire placement portion. The sheet LEDs 53R and 53L irradiate daylight of the same color. The illuminance on the light controlling sheet 10 by the sheet LEDs 53R and 53L is 532 lx.

[0093] The vertical distance H1 between the photographing unit 12 and the photographing target 13 is 350 mm. The vertical distance H2 between the photographing target 13 and the placement unit is 100 mm. In other words, the vertical distance between the photographing target 13 and the light adjusting sheet 10 is 100 mm, and the vertical distance between the light adjusting sheet 10 and the photographing unit 12 is 200 mm.

[0094] Fig. 6 shows an evaluation image PE of Test Example 1, which is an example in which a natural landscape photograph is used as the shooting subject 13. As Fig. 6 shows, more than half of the area in the evaluation image PE of Test Example 1 is occupied by a nearly monochromatic "sky," and a single tree is located in the area other than the "sky."

[0095] Fig. 7 shows an example of an evaluation image PE of Test Example 2, which uses a landscape photograph including buildings as the photographed object 13. As Fig. 7 shows, more than half of the area in the evaluation image PE of Test Example 2 is occupied by a "streetscape" with many large buildings and many small buildings lined up, and the area other than the "streetscape" is occupied by a "sky" with multiple "clouds" floating in it.

[0096] Fig. 8 shows an evaluation image PE of Test Example 3, in which a test pattern was used as the photographed object 13. As shown in Fig. 8, the evaluation image PE of Test Example 3 includes a pattern in which white and black thin lines are alternately arranged in parallel, a pattern in which black thin lines are radially arranged, a pattern in which white and black thin lines having different line widths are alternately arranged in parallel, and a pattern in which white and black thin lines having different line densities are arranged.

[0097] 6 to 8 are evaluation images PE when the driving voltage V is set to 30 V. The evaluation images PE are all images obtained by the following process: from the image captured by the image capture unit 12, the portion captured through the light adjusting sheet 10 is trimmed to a vertical and horizontal size of 600 cps x 600 cps, and then the trimmed image is compressed to a vertical and horizontal size of 256 cps x 256 cps.

[0098] Fig. 9 is a graph showing the dependency of the radial distribution p(r) on the driving voltage V, and shows the radial distribution p(r) of Test Example 1 obtained from the FFT-transformed image of the evaluation image PE of Test Example 1. Fig. 10 is a graph showing the dependency of the radial distribution p(r) on the driving voltage V, and shows the radial distribution p(r) of Test Example 2 obtained from the FFT-transformed image of the evaluation image PE of Test Example 2. Fig. 11 is a graph showing the dependency of the radial distribution p(r) on the driving voltage V, and shows the radial distribution p(r) of Test Example 3 obtained from the FFT-transformed image of the evaluation image PE of Test Example 3.

[0099] 9 to 11, the radial distribution p(r) normalized by the maximum value p(r)max is shown for each drive voltage V. In addition, for each FFT (i) grayscale conversion, processing conforming to the ITU-R Rec BT.601 standard was used, and using the image data after grayscale conversion, (ii) two-dimensional fast Fourier transform and (iii) frequency analysis were performed in that order.

[0100] 9, in the frequency analysis results of Test Example 1, when the driving voltage V is 0 V, i.e., when the light transmittance of the light-adjusting sheet 10 is the lowest, one large radial distribution p(r) exists in the range where the distance r is 8 or less, and no radial distribution p(r) is observed in other ranges. When the driving voltage is 30 V, i.e., when the light transmittance of the light-adjusting sheet 10 is the highest, two large radial distributions p(r) exist in the range where the distance r is 16 or less, and four small radial distributions p(r) are observed in the range where the distance r is 16 or more and 64 or less.

[0101] As shown in Figure 10, in the frequency analysis results of test example 2, when the driving voltage V is 0 V, i.e., when the light transmittance of the light-controlling sheet 10 is the lowest, one large radial distribution p(r) and one small radial distribution p(r) exist in the range where the distance r is 8 or less, and no radial distribution p(r) is observed in other ranges.

[0102] On the other hand, in the frequency analysis results of Test Example 2, when the driving voltage is 30 V, i.e., when the light transmittance of the light-controlling sheet 10 is the highest, three large radial distributions p(r) are present in the range of distance r from 8 to 16. Furthermore, over a wide range of distance r from 16 to 96, many small radial distributions p(r), which are sufficiently more than those of Test Example 1, are observed.

[0103] As shown in Figure 11, in the frequency analysis results of test example 3, when the driving voltage V is 0 V, i.e., when the light transmittance of the light-controlling sheet 10 is the lowest, two large radial distributions p(r) are present in the range where the distance r is 16 or less, and three small radial distributions p(r) are observed in the range where the distance r is 16 or more and 40 or less.

[0104] On the other hand, in the frequency analysis results of test example 3, when the driving voltage is 30 V, i.e., when the light transmittance of the light-controlling sheet 10 is the highest, a large number of large radial distributions p(r) are observed over almost the entire distance r of 128 or less, which is significantly more than in test examples 1 and 2.

[0105] Thus, in the range where the distance r is relatively small, i.e., where the spatial frequency in real space is relatively high, in all of Test Examples 1 to 3, the radial distribution p(r) is unlikely to change due to differences in the driving voltage V. On the other hand, in the range where the distance r is relatively large, i.e., where the spatial frequency in real space is relatively high, in Test Examples 2 and 3, the radial distribution p(r) changes significantly due to differences in the driving voltage V.

[0106] The range of high spatial frequency in real space is fine shading in the image after grayscaling, and indicates, for example, the surface shape or contour of an object. On the other hand, the range of low spatial frequency in real space is coarse shading in the image after grayscaling, and indicates, for example, the presence or absence of an object. As described above, the difference in spatial frequency in real space appears as a difference in radial distribution p(r) due to a difference in driving voltage V. For example, the difference between fine shading such as a "cityscape" of many buildings of different sizes or a test pattern and coarse shading such as "trees" against a "sky" background appears as a difference in radial distribution p(r) due to a difference in driving voltage V.

[0107] As a result, for example, whether the light-adjusting sheet 10 to which a predetermined driving voltage V is applied is in an optical state in which the surface shape, contour, etc. of an object is not visually recognizable, or whether the light-adjusting sheet 10 is in an optical state in which the surface shape, contour, etc. of an object is visually recognizable, can be said to appear as a difference in the radial distribution p(r). For example, whether the light-adjusting sheet 10 to which a predetermined driving voltage V is applied is in an optical state in which the presence or absence of an object is not visually recognizable, or whether the light-adjusting sheet 10 is in an optical state in which the presence or absence of an object is visually recognizable, can be said to appear as a difference in the radial distribution p(r).

[0108] In other words, prior to evaluating the optical state of the light-adjusting sheet 10 over time, whether the subject 13 is suitable as a photographic subject can be determined based on the sum of the radial distribution p(r) that satisfies the sample extraction conditions.

[0109] FIG. 12 shows the dependency of the evaluation index Qe obtained from the radial distribution p(r) of Test Examples 1 to 3 on the driving voltage V, and the dependency of the haze of the light-adjusting sheet 10 on the driving voltage V. Note that in FIG. 12, the sample integrated value SumV calculated at each driving voltage V is divided by a reference value, and the evaluation index Qe normalized by the reference value is shown. In this case, the sample integrated value SumV when the driving voltage V is 30 V, that is, the sample integrated value SumV when the light-adjusting sheet 10 has the highest light transmittance, is used as the reference value. Also, in FIG. 12, the haze of the light-adjusting sheet 10 is shown as a normalized value with 100% being 1.

[0110] 12, when the driving voltage V is in the range of 0 V or more and 10 V or less, the haze of the light controlling sheet 10 gradually decreases from near 100% to 90%. Furthermore, when the driving voltage V is in the range of 0 V or more and 10 V or less, the evaluation index Qe of Test Example 1 gradually increases from near 0.3 to near 0.4. The evaluation indexes Qe of Test Examples 2 and 3 gradually increase from near 0 to 0.1.

[0111] On the other hand, when the driving voltage V is in the range of 10V or more and 20V or less, the haze of the light-controlling sheet 10 drops sharply from 90% to 30%. When the driving voltage V is in the range of 10V or more and 20V or less, the evaluation indexes Qe of Test Examples 2 and 3 also increase sharply from around 0.1 to around 0.7. On the other hand, when the driving voltage V is in the range of 10V or more and 13V or less, the evaluation index Qe of Test Example 1 increases sharply from around 0.3 to around 1.0, and remains at approximately 1.0 when the driving voltage V is 13V or more. That is, when the driving voltage V is in the range of 13V or more, the evaluation index Qe of Test Example 1 does not follow the haze of the light-controlling sheet 10.

[0112] The haze of the light controlling sheet 10 gradually decreases from 30% to 10% when the driving voltage V is in the range of 20 V to 30 V. Moreover, the evaluation index Qe of each of Test Examples 2 and 3 also gradually increases from 0.7 to 1.0.

[0113] In this way, in the entire range of the driving voltage V from 0 V to 30 V, the evaluation index Qe of Test Examples 2 and 3 changes in accordance with the change in haze in the light-adjusting sheet 10. On the other hand, the evaluation index Qe of Test Example 1 does not follow the change in haze in the light-adjusting 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 light-adjusting sheet 10. And, by setting the index threshold Qm for the evaluation index Qe of Test Examples 2 and 3, it can be said that it is possible to determine whether or not the subject 13 is suitable as a subject for the evaluation index Qe.

[0114] As described above, according to the above embodiment, the following effects can be obtained. (1) The degree of blurring of the evaluation image PE photographed through the light-adjusting sheet 10 by the light-adjusting sheet 10 is calculated using image analysis of the evaluation image PE. The evaluation image PE is photographed not with a dedicated optical device such as an integrating sphere, but with a general-purpose photographing device such as a smartphone or tablet terminal, so that it is possible to increase the versatility of the evaluation of the optical state of the light-adjusting sheet 10.

[0115] (2) The evaluation index Qe of the light-adjusting sheet 10 tends to be larger as the haze of the light-adjusting sheet 10 increases, and is likely to change in sync with changes in the haze of the light-adjusting sheet 10. Therefore, with the above configuration in which the subject 13 to be photographed is determined to be suitable on the condition that the evaluation index Qe is within an appropriate range, it becomes possible to evaluate the optical state of the light-adjusting sheet 10 using the new evaluation index Qe.

[0116] (3) When photographing the subject 13 through the light-adjusting sheet 10, the external light conditions in which the subject 13 is placed may vary depending on the occasion of photographing. The external light conditions in which the subject 13 is placed include the illuminance and lighting angle of external light, such as the illumination light from a lighting device or natural light. In this regard, if the sample integrated value SumV when the light-adjusting sheet 10 is transparent is used as the reference value, the influence of the external light conditions on the calculation of the evaluation index Qe is reduced. As a result, it is possible to improve the accuracy of the evaluation using the new evaluation index Qe.

[0117] (4) Since the view seen from the installation location of the dimming sheet 10 can be used as the subject of photography 13, it is possible to evaluate the optical state of the dimming sheet 10 when it is installed or monitored and attached to the transparent body 11 as the exterior or interior decoration of various facilities.

[0118] (5) The sharpness of short-period repetition in the evaluation image PE is detected as the magnitude of frequency components in a high frequency band. On the other hand, the sharpness of long-period repetition in the evaluation image PE is detected as the magnitude of frequency components in a low frequency band. In this regard, if the evaluation index Qe is calculated from a predetermined frequency band in the radial distribution p(r), it is possible to express the optical state of the light controlling sheet 10 in detail by the evaluation index Qe.

[0119] (6) Since the evaluation index Qe is calculated from the sample integrated value SumV in the radial distribution p(r), it is possible to calculate the evaluation index Qe having a magnitude corresponding to the optical state of the light adjusting sheet 10, whether the evaluation image PE has spatial frequency components that appear in a one-dimensional direction or in a two-dimensional direction. In other words, the constraints related to spatial anisotropy are alleviated in the subject 13. This makes it possible to broaden the scope of situations in which the suitability judgment of the subject 13 can be applied, and ultimately to increase the versatility of the light adjusting system.

[0120] The above embodiment can be modified as follows. The evaluation index Qe is not limited to a value obtained by normalizing the sample integrated value SumV by a reference value, and may be, for example, the sample integrated value SumV itself. If the evaluation index Qe is calculated when the light adjusting sheet 10 is transparent, and other evaluation indexes Qe are normalized using the evaluation index Qe as a reference value, errors due to differences in lighting during shooting and differences in the subject 13 to be shot can be reduced in the evaluation index Qe. In addition, since it is possible to calculate the degree of blurring caused by the light adjusting sheet 10 with high accuracy, it is also possible to improve the accuracy of judging whether the subject is suitable for shooting.

[0121] After determining that the light controlling sheet 10 is suitable for evaluating the optical state, the index calculation device 20 may separately calculate an evaluation index Qe from the evaluation image PE of the subject 13 after the judgment used in the suitability judgment. Then, the index calculation device 20 may determine that the light controlling sheet 10 is normal on condition that the evaluation index Qe calculated after the suitability judgment is equal to or greater than the index threshold value Qm. In other words, the index calculation device 20 may execute the processes from step S11 to step S14 after the suitability judgment, and determine that the optical state of the light controlling sheet 10 is maintained on condition that the evaluation index Qe is equal to or greater than the index threshold value Qm.

[0122] Furthermore, the index calculation device 20 may correct the driving voltage V so that the evaluation index Qe becomes equal to or greater than the index threshold Qm, on condition that the evaluation index Qe calculated after the suitability determination does not satisfy the index threshold Qm. That is, the index calculation device 20 may execute the processes from step S12 to step S18 after the suitability determination, and correct the driving voltage V so that the evaluation index Qe becomes equal to or greater than the index threshold Qm, on condition that the evaluation index Qe does not satisfy the index threshold Qm, thereby maintaining the optical state of the light controlling sheet 10. [Explanation of symbols]

[0123] p(r)…radial direction distribution PE...Evaluation image Qe…Evaluation index 10. Light-adjusting sheet 12. Photography Department 13...Photography subject 20…Indicator calculation device 21...Control unit 22...Image analysis section 23A…Evaluation index calculation program 30...Light control device 31...Control unit

Claims

1. A suitability judgment device for judging suitability of a subject to be photographed in evaluating the state of a light adjusting sheet, A calculation unit that calculates a degree of blurring of the image by the light adjusting sheet by performing image analysis on the image of the object photographed through the light adjusting sheet; and a judgment unit that judges that the subject is suitable for evaluation of the optical state under the condition that the degree of blur caused by the light-adjusting sheet when a predetermined optical state of the light-adjusting sheet is reflected is within an appropriate range and the degree of blur calculated by the calculation unit is within the appropriate range; the degree of blurring calculated by the calculation unit is a value obtained by normalizing the first degree of blurring by the second degree of blurring, the appropriate range is a range of the normalized values ​​when a predetermined optical state of the light adjusting sheet is reflected, The first blurring degree is a blurring degree caused by the light controlling sheet in an image of the subject photographed through the light controlling sheet, which is opaque; The second blurring degree is a blurring degree caused by the light controlling sheet in an image of the subject photographed through the light controlling sheet, which is transparent. Suitability determination device.

2. A suitability judgment device for judging the suitability of a subject to be photographed in evaluating the state of a light-adjusting sheet, comprising: A calculation unit that calculates a degree of blurring of the image by the light adjusting sheet by performing image analysis on the image of the object photographed through the light adjusting sheet; and a judgment unit that judges that the subject is suitable for evaluation of the optical state under the condition that the degree of blur caused by the light-adjusting sheet when a predetermined optical state of the light-adjusting sheet is reflected is within an appropriate range and the degree of blur calculated by the calculation unit is within the appropriate range; The image analysis calculates, as the degree of blurring, the magnitude of a frequency component in a predetermined frequency band in a radial direction distribution obtained by a Fourier transform of the image. Suitability determination device.

3. The calculation unit calculates a degree of blurring of an evaluation image, which is an image of the subject that the determination unit has determined to be suitable for evaluating the optical state, photographed through the light adjusting sheet in an optical state different from the predetermined optical state; The determination unit determines that the light adjusting sheet is normal on condition that the degree of blurring of the evaluation image by the light adjusting sheet is within the appropriate range. The suitability determination device according to claim 1 or 2.

4. The present invention further includes a control unit that, on condition that the degree of blur calculated by the calculation unit is outside the appropriate range, changes a drive voltage applied to the light-adjusting sheet so that the degree of blur calculated by the calculation unit is within the appropriate range. The suitability determination device according to any one of claims 1 to 3.

5. A method for determining whether a subject is suitable for photography in evaluating the state of a light adjusting sheet, comprising: Calculating the degree of blurring of the image by the light adjusting sheet by performing image analysis on the image of the object photographed through the light adjusting sheet; and and determining that the subject is suitable for evaluation of the optical state, provided that the degree of blur caused by the light-adjusting sheet when reflecting a predetermined optical state of the light-adjusting sheet is within an appropriate range and the calculated degree of blur is within the appropriate range; the calculated blurring degree is a value obtained by normalizing the first blurring degree by the second blurring degree, the appropriate range is a range of the normalized values ​​when a predetermined optical state of the light adjusting sheet is reflected, The first blurring degree is a blurring degree caused by the light controlling sheet in an image of the subject photographed through the light controlling sheet, which is opaque; The second blurring degree is a blurring degree caused by the light controlling sheet in an image of the subject photographed through the light controlling sheet, which is transparent. How to determine suitability.

6. A method for determining the suitability of a subject to be photographed in evaluating the condition of a light-adjusting sheet, comprising: Calculating the degree of blurring of the image by the light adjusting sheet by performing image analysis on the image of the object photographed through the light adjusting sheet; and and determining that the subject is suitable for evaluation of the optical state, provided that the degree of blur caused by the light-adjusting sheet when reflecting a predetermined optical state of the light-adjusting sheet is within an appropriate range and the calculated degree of blur is within the appropriate range; The image analysis calculates, as the degree of blurring, the magnitude of a frequency component in a predetermined frequency band in a radial direction distribution obtained by a Fourier transform of the image. How to determine suitability.

7. A suitability judgment device for judging suitability of a subject to be photographed in evaluating the state of a light-adjusting sheet, Calculating the degree of blurring of the image by the light adjusting sheet by performing image analysis on the image of the object photographed through the light adjusting sheet; On the condition that the degree of blur caused by the light-adjusting sheet when a predetermined optical state of the light-adjusting sheet is reflected is within an appropriate range and the calculated degree of blur is within the appropriate range, the subject to be photographed is judged to be suitable for evaluation of the optical state; the calculated blurring degree is a value obtained by normalizing the first blurring degree by the second blurring degree, the appropriate range is a range of the normalized values ​​when a predetermined optical state of the light adjusting sheet is reflected, The first blurring degree is a blurring degree caused by the light controlling sheet in an image of the subject photographed through the light controlling sheet, which is opaque; The second blurring degree is a blurring degree caused by the light controlling sheet in an image of the subject photographed through the light controlling sheet, which is transparent. Suitability assessment program.

8. A suitability judgment device for judging suitability of a subject to be photographed in evaluating the state of a light-adjusting sheet, comprising: Calculating the degree of blurring of the image by the light adjusting sheet by performing image analysis on the image of the object photographed through the light adjusting sheet; On the condition that the degree of blur caused by the light-adjusting sheet when a predetermined optical state of the light-adjusting sheet is reflected is within an appropriate range and the calculated degree of blur is within the appropriate range, the subject to be photographed is judged to be suitable for evaluation of the optical state; The image analysis calculates, as the degree of blurring, the magnitude of a frequency component in a predetermined frequency band in a radial direction distribution obtained by a Fourier transform of the image. Suitability assessment program.

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