Transmission-type color gray scale card and color correction method for image pickup apparatus

Abstract

The invention provides a transmission-type color gray scale card and a color correction method of an image pickup apparatus. A transmission-type color gradation card is provided with: a color card member having at least one color bar in which transmitted light is colored; and a gray-scale card member having a plurality of transmissive regions in which transmitted light is achromatic and differing in brightness, the color card member and the gray-scale card member being laminated so as to have a repeating transmissive region in which the color bar and the plurality of transmissive regions overlap in plan view.

Description

[0001] This application is a divisional application of the PCT international application with application number 202080083129.7 (international application number: PCT / JP2020 / 038510), invention name “Transmissive color grayscale card, transmissive color grayscale card device and gray grayscale card”, and international application date of October 12, 2020 (priority date of 2019 / 10 / 15). Technical Field

[0002] The present disclosure relates to a transmissive color grayscale card, and in particular to a transmissive color grayscale card for an imaging device, a transmissive color grayscale card device, and a gray grayscale card. Background Art

[0003] In the field of imaging equipment, the output image is being pushed to a higher resolution. For color, high color reproduction is also required to faithfully reproduce the color tone, and the color gamut is expanded. In other words, the color reproduction in the imaging equipment is being widened. Here, "color gamut" refers to a specific range in the visible area, such as Figure 13 As shown, the color gamut can be represented using the xy chromaticity diagram of the XYZ color system (CIE1931-XYZ color system) specified by the CIE (International Commission on Illumination). The color gamut can be represented by a triangle with the chromaticity coordinates of the vertices of the R, G, and B colors defined in the xy chromaticity diagram and connected by straight lines.

[0004] The color gamut is determined by various existing color gamut standards. In the imaging industry, including camera equipment, for example, Figure 13 As shown, it includes wide color gamut standards such as BT.709 and BT.2020. Figure 13 In the xy chromaticity diagram shown, the CIE standard illuminant D65, which serves as the white point, is plotted as 0.

[0005] In order to display output images with accurate reproduced colors, the imaging device uses a color chart such as that disclosed in Patent Document 1, compares the reproduced colors in the imaging device with those in the color chart, and performs correction based on the color chart if there is a difference in the reproduced colors.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2004 / 044639 Summary of the Invention

[0009] -Problems to be solved by the invention-

[0010] Here, the conventional color grayscale card is a card that designs swing colors based on the RGB values ​​(0, 0, 0) to (255, 255, 255) obtained by dividing the lightness and darkness of each RGB color step by step. Therefore, a color card ( Figure 14 (A)).

[0011] However, a detailed analysis of a color card designed and produced using RGB values ​​reveals that even in a design that only reduces brightness, there is a problem of color shift in the actual product. Figure 13 If the brightness is reduced ( Figure 13 ), the chromaticity position on the xy chromaticity diagram shifts (the chromaticity shifts). Therefore, a transmissive color grayscale chart that can perform more accurate color correction is needed.

[0012] The present disclosure has been made in view of the above-mentioned problems, and a main object of the present disclosure is to provide a transmissive color grayscale card capable of performing accurate color calibration of an imaging device or the like.

[0013] -Methods for solving the problem-

[0014] That is, the present disclosure provides a transmissive color grayscale card comprising: a color card component having at least one color stripe through which light is transmitted in a color; and a gray grayscale card component having a plurality of transmissive areas through which light is transmitted in a colorless manner and having different brightnesses. The color card component and the gray grayscale card component are stacked to form an overlapping transmissive area in which the color stripe and the plurality of transmissive areas overlap when viewed from above.

[0015] According to the present disclosure, it is possible to precisely adjust colors including brightness, and to perform accurate color correction of an imaging device.

[0016] Furthermore, in the present disclosure, it is preferable that the covering portions of the plurality of transmissive regions be formed using a black colorant or metal, because this allows for precise color adjustment compared to the case of using multiple colors.

[0017] Furthermore, in the present disclosure, it is preferred that the plurality of transmissive regions be composed of transmissive dot regions in which light-shielding dots are randomly arranged, because this allows for more accurate brightness adjustment.

[0018] Furthermore, in the present disclosure, it is preferred that a spacer be disposed between the color card member and the grayscale card member, wherein the spacer has an opening in the overlapping transmission region. This is because a gap corresponding to the thickness of the spacer is created between the color card member and the grayscale card member, thereby suppressing the occurrence of Newton rings.

[0019] Furthermore, in the present disclosure, it is preferred that a viewing angle determining mark for determining the viewing angle of an imaging device calibrated using the transmissive color grayscale card is formed on a principal surface of the color card member that is different from the principal surface on the gray grayscale card member side. This allows the color card member side to be used as the imaging device side during imaging device calibration. As described above, by focusing on the color card member surface, chromatic aberration can be suppressed.

[0020] In the present disclosure, it is preferred that the distance between adjacent transmissive regions among the plurality of transmissive regions is at least half the width of the transmissive region, because this can prevent the intrusion of light leakage from adjacent transmissive regions and enable more accurate correction.

[0021] Furthermore, the present disclosure provides a transmissive color grayscale card device comprising two protective substrates and the transmissive color grayscale card sandwiched between the two protective substrates. This device prevents solvents, etc., from adhering to or physically contacting the color card member and the gray grayscale card member, thereby preventing undesirable effects such as reduced color density or pigment changes in the color stripes of the color card member.

[0022] In addition, the present disclosure provides a gray grayscale card, characterized in that it is composed of a gray grayscale card structure with multiple transmissive areas of different brightness stacked together so that the above-mentioned multiple transmissive areas overlap when viewed from above, and the above-mentioned multiple transmissive areas are composed of transmissive dot areas, in which dots with light-blocking properties are randomly arranged.

[0023] According to the present disclosure, there is an effect that brightness, that is, light transmittance can be set to a gray scale that can be accurately and easily corrected.

[0024] In the present disclosure, it is preferable that the distance between adjacent dot regions is at least half the width of the dot region, because this can prevent the intrusion of leaked light from adjacent dot regions and enable more accurate correction.

[0025] -Effects of the Invention-

[0026] The transmissive color grayscale card disclosed herein has the following effects: it enables precise and easy adjustment of color including brightness, and enables accurate color calibration of imaging equipment and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 (A) is a schematic diagram showing an example of a transmissive color grayscale card disclosed herein. Figure 1 (B) is a schematic top view of the transmissive color grayscale card of the present disclosure.

[0028] Figure 2(A) is a schematic plan view showing an example of a color card member in the present disclosure, Figure 2 (B) means Figure 2 (A) Schematic diagram of the transmittance at each wavelength shown by the color card member.

[0029] Figure 3 (A) is a schematic plan view showing an example of a grayscale card member in the present disclosure. Figure 3 (B) is Figure 3 (A) Schematic diagram of the transmittance at each wavelength shown by the grayscale card member.

[0030] Figure 4 This is an xy chromaticity diagram showing the color gamut of the transmissive color grayscale card disclosed herein.

[0031] Figure 5 It is the transmittance for each wavelength shown on the transmission type color grayscale card of the present disclosure.

[0032] Figure 6 This is a schematic plan view showing an example of a transmissive color grayscale card disclosed herein.

[0033] Figure 7 This is a schematic diagram showing an example of a transmissive color grayscale card device disclosed herein.

[0034] Figure 8 (A) and (B) are photographs showing interference fringes produced when a conventional grayscale card member is used. Figure 8 (C) is a graph showing the transmittance of a conventional grayscale card member for each wavelength.

[0035] Figure 9 (A) is a schematic diagram showing an example of a grayscale card structure of the present disclosure. Figure 9 (B) is Figure 9 Magnified photo of the dot area in (A), Figure 9 (C) is used Figure 9 (A) is a schematic top view of a transmissive color grayscale card structure.

[0036] Figure 10 This is a graph showing the transmittance for each wavelength shown on the grayscale chart of the present disclosure.

[0037] Figure 11 This is a graph showing the brightness of transmitted light in each transmission area of ​​the gray scale chart disclosed herein.

[0038] Figure 12 This is an explanatory diagram for explaining how to use the transmissive color grayscale card disclosed herein.

[0039] Figure 13This is an xy chromaticity diagram showing the color gamut of a color card member designed and produced using conventional RGB values.

[0040] Figure 14 (A) is a schematic top view showing a conventional color card member. Figure 14 (B) is a schematic diagram showing an example of transmittance for each wavelength shown by a conventional color card member.

[0041] Figure 15 This is a light intensity diagram that measures the degree of light leakage when light is irradiated to the transmission area.

[0042] Figure 16 It is a schematic plan view showing an example of a covering portion in the transmission region. DETAILED DESCRIPTION

[0043] As described above, in recent years, the color gamut of reproduced colors in imaging devices has been widened, and higher accuracy is required for color correction of imaging elements.

[0044] On the other hand, the present inventors have discovered that a detailed analysis of color card members designed and manufactured using conventional RGB values ​​based on RGB shades reveals that, when a design is made with only the lightness reduced using the same color, the actual product exhibits a problem of shifting in chroma.

[0045] That is, the present inventors have found that the transmission spectrum of the conventional color card member is as follows Figure 14 As shown in (B), as the transmittance decreases, the peak wavelength shifts, generating noise. In other words, it was found that the color card member designed based on RGB values ​​has a chromaticity shift, especially at low brightness.

[0046] To address the aforementioned issues, the inventors of the present disclosure conducted extensive research and discovered that by combining and overlaying a color card component with a grayscale card component, it is possible to simultaneously adjust both brightness and chroma, resulting in a transmissive color grayscale card capable of accurate color calibration for imaging equipment. The transmissive color grayscale card of the present disclosure is described below.

[0047] A. Transmissive Color Grayscale Card

[0048] The transmissive color grayscale card disclosed herein is characterized in that it comprises: a color card component having at least one color stripe through which light is transmitted in a color; and a gray grayscale card component having multiple transmissive areas through which light is transmitted in a colorless manner and of different brightnesses. The color card component and the gray grayscale card component are stacked to form overlapping transmissive areas in which the color stripe and the multiple transmissive areas overlap when viewed from above.

[0049] The transmissive color grayscale card disclosed herein will be described with reference to the accompanying drawings. Figure 1 (A) is an explanatory diagram for explaining the transmissive color grayscale card of the present disclosure. Figure 1 (B) is a schematic top view of the transmissive color grayscale card of the present disclosure.

[0050] like Figure 1 As shown in (A), the transmissive color grayscale card 10 of the present disclosure is characterized in that it comprises: a color card member 1 having a transparent substrate 5 and at least one colored color stripe 3 formed on the transparent substrate 5; and a gray grayscale card member 2 having a plurality of transmissive areas 4 that are achromatic and have different light transmittances, the color card member 1 and the gray grayscale card member 2 being configured to have at least one overlapping transmissive area, which is an area where one or more color stripes 3 in the color card member 1 and the plurality of transmissive areas 4 with different transmittances in the gray grayscale card member 2 overlap when viewed from above.

[0051] exist Figure 1 (A) and (B) show a case where three transmissive regions 4 are arranged so that they overlap with each color stripe when viewed from above, and a total of nine transmissive regions 4 are arranged so that they overlap with three color stripes 3 when viewed from above. In this case, the transmissive color grayscale chart 10 has nine calibration patches.

[0052] Hereinafter, each structure of the transmissive color grayscale card of the present disclosure will be described.

[0053] 1. Color card components

[0054] The color card component of the present disclosure has at least one color stripe that transmits light in a color. The transmissive color grayscale card of the present disclosure will be described with reference to the accompanying drawings. Figure 2 (A) is a schematic plan view showing an example of a color card member in the present disclosure. Figure 2 (B) means Figure 2 (A) Schematic diagram of an example of transmittance for each wavelength shown in a color card member.

[0055] like Figure 2 As shown in (A) of FIG. 1 , the color card member 1 in the present disclosure includes a transparent substrate (not shown) and a color stripe 3 having at least one color formed on the transparent substrate. Figure 2 In (A), four color stripes are formed: red stripes 3R, green stripes 3G, blue stripes 3B, and white stripes 3W. Color stripe group 33 is configured by arranging these four color stripes in a pattern in a different order. Color card light shielding portions 6 are provided around each color stripe on a transparent substrate 5. A color card holding frame 7 is disposed around the color stripe group 33 and the color card light shielding portions 6. White stripe 3W is normally transparent.

[0056] Hereinafter, such a color card member will be described in detail.

[0057] (1) Color bars

[0058] The color stripes in the present disclosure are components that transmit light in various colors, and are formed in at least one form. When multiple color stripes are formed, a group of color stripes is formed, which are arranged in a pattern in different orders.

[0059] Such color stripes are not particularly limited, and are usually formed on a transparent substrate.

[0060] (a) Types of color bars

[0061] As the color strips configured in the color card member used in the present disclosure, for example, the above-mentioned Figure 2 As shown in (A), a total of four color bars (color bar group) including three primary colors and white may be used, or a single color bar may be used. In the color card member of the present disclosure, the number and type of color bars can be appropriately selected according to the application.

[0062] For example, when calibrating an imaging element capable of expressing a wide color gamut, such as BT.709 or BT.2020, it is preferable to use a color card component that corresponds to these standards. Specifically, the color bar group described in Japanese Patent Application Laid-Open No. 2017-187756 can be used. The following describes a color card component used for such applications.

[0063] The transmissive color card member splits the light incident from the back side based on the selective transmittance of the colored color stripes other than the white (W) color stripe group, and the transmission spectrum of each color appears in the visible light region. As the color stripe group of the color card member in the present disclosure, it is preferred that the transmission spectrum of each color stripe has a separate peak. The so-called "the transmission spectrum of each color stripe has a separate peak" means, for example, Figure 2 As shown in (B), the transmission spectra of each color bar (red (R), green (G), and blue (B)) have independent mountain-shaped waveforms. This is because by making the transmission spectra of each color bar that makes up the color bar group have a mountain-shaped waveform, the brightness of the color bar group can be made uniform.

[0064] The transmission spectrum of each color bar can be obtained by measuring the transmittance in the visible light region of 380 nm to 780 nm using an Olympus Corporation microspectrometer OSP-SP200 or a Topcon Techno House Co., Ltd. 2D spectroradiometer SR-5000 (optional light source) with an achromatic (transparent) white color bar as a background.

[0065] Furthermore, in the present disclosure, it is preferable that the transmission spectra of the color stripes other than W constituting the color stripe group have peaks at desired intervals within the visible light region and are arranged in a well-balanced manner.

[0066] Specifically, the following color card member described in Japanese Patent Application Laid-Open No. 2017-187756 can be used.

[0067] That is, a color card member can be used, which includes a transparent substrate and a color bar group formed on the transparent substrate, wherein the color bar group is composed of color bars of at least six colors, namely, red, green, blue, a first color, a second color, and white, arranged in a pattern in different orders, and the coordinate point of the first color is located in an area surrounded by four points, namely, (0.351, 0.649), (0.547, 0.453), (0.380, 0.506), and (0.433, 0.464) on the xy chromaticity diagram, and the coordinate point of the second color is located in an area surrounded by four points, namely, (0.125, 0.489), (0.112, 0.22 9), (0.270, 0.407), (0.224, 0.242), the peak wavelength of the transmission spectrum of the red color bar is greater than 600nm and less than 680nm, the peak wavelength of the transmission spectrum of the green color bar is greater than 495nm and less than 570nm, the peak wavelength of the transmission spectrum of the blue color bar is greater than 430nm and less than 490nm, the peak wavelength of the transmission spectrum of the first color bar (yellow (Ye) color bar) is greater than 540nm and less than 595nm, and the peak wavelength of the transmission spectrum of the second color bar (blue (Cy) color bar) is greater than 470nm and less than 515nm.

[0068] The transmission spectra of the first color stripe and the transmission spectra of the second color stripe have separate peaks and can be formed into a mountain-shaped waveform. In addition, the transmission spectra of the R, G, and B color stripes also have separate peaks and can be formed into a mountain-shaped waveform.

[0069] When forming each color stripe, the peak wavelength position of the transmission spectrum of the color stripe can be adjusted according to the type of color stripe and its formation method.

[0070] For example, when a dyed substrate using one type of dye is used as a color stripe, the peak wavelength of the transmission spectrum of the color stripe can be adjusted by adjusting the concentration of the dye.

[0071] Furthermore, if a dyed substrate formed by blending two or more dyes is used as a color stripe, the peak wavelength of the color stripe's transmission spectrum can be adjusted by varying the blending ratio of the two dyes. Specifically, a green (G) color stripe can be formed using a dyeing method using two dyes: a yellow dye and a blue dye. However, the peak wavelength can be adjusted by increasing the blending ratio of the yellow dye to shift the peak wavelength toward longer wavelengths, and by increasing the blending ratio of the blue dye to shift it toward shorter wavelengths.

[0072] (b) Size of color bars

[0073] The size of the color bars is not particularly limited and can be appropriately designed based on the intended use of the transmissive color grayscale card of the present disclosure to facilitate the desired effect. For example, the size of the transmissive color grayscale card of the present disclosure can be designed based on the image it is intended for. Specifically, when the transmissive color grayscale card of the present disclosure is used for color evaluation and color correction of output images of measurement specimens captured by a microscope in pathology imaging equipment, it can be configured as a micro-imaging color card with a color bar group of a size corresponding to the magnification of the microscope's objective lens.

[0074] Furthermore, when the transmissive color grayscale chart of the present disclosure is used for color evaluation and color correction of output images of measurement samples photographed at equal magnification by an imaging device, for example, it can be a color chart for macro photography having a color bar group having a size corresponding to the size of the photographed image.

[0075] Specifically, the length of the color bar in the long axis direction can be 250 mm to 3.5 mm, and the length in the short axis direction can be 190 mm to 0.8 mm.

[0076] (c) Other

[0077] In the color bar group disclosed in the present invention, each color bar is arranged in a pattern in a different order. As the arrangement pattern of each color bar, it can be as follows Figure 1 as well as Figure 2 As shown in (A), the color bars can be arranged in a row in a linear pattern. Although not shown, they can also be arranged in a grid pattern or a circular pattern. Furthermore, the order in which the color bars are arranged is not particularly limited and can be appropriately designed to facilitate the desired effect, depending on the intended use of the transmissive color grayscale card disclosed herein.

[0078] like Figure 1 As shown in (A) of FIG. 1 , in each color bar, each transmission area 4 of the gray scale card member 2 described later is divided into a plurality of areas 3 a that overlap in a plan view, but may not be divided.

[0079] As described above, when the color bar is divided into a plurality of parts, it is generally preferred that a light shielding portion for a color card described later be arranged in the divided parts.

[0080] Each color stripe can be formed using any method that exhibits a desired transmission spectrum, such as vapor deposition, dyeing, printing, transfer, or inkjet. In particular, dyeing can be used to form color stripes. For example, a silver salt emulsion prepared by adding a solution of potassium bromide and silver nitrate to gelatin can be used. This silver salt emulsion is then applied to a chip substrate such as a glass plate. The dried silver salt photographic plate is then desilvered and dyed with a dye corresponding to the color of the color stripe. Alternatively, a dyed substrate can be formed by pre-mixing a dye in gelatin (solution) and applying the resulting material to a chip substrate such as a glass plate.

[0081] The color stripe group can be formed by, for example, arranging the color stripes formed by the above-described method in a desired pattern on one surface of a transparent substrate described later, and sandwiching the color stripes between the transparent substrate and a cover glass.

[0082] (2) Transparent substrate

[0083] The color stripes disclosed herein are not particularly limited, but are preferably formed on a transparent substrate. The transparent substrate used in the present disclosure is not particularly limited, as long as it can support the color stripe group and the color card light shielding portion and has the desired light transmittance. It can be the same transparent substrate used in conventionally known color card components. Specifically, inorganic substrates such as glass substrates and resin substrates can be used. Besides being in the form of plates, resin substrates can also be films or sheets.

[0084] (3) Shading part for color cards

[0085] The color card member in the present disclosure is generally provided with a color card light shielding portion for partitioning the transmission area of ​​the color stripe.

[0086] As such a light shielding portion for a color card, for example, if a color stripe is formed on the transparent substrate, a light shielding portion arranged on the transparent substrate so as to surround the color stripe can be cited. Figure 2 The color card shown in (A) has a light shielding portion 6 .

[0087] In addition, if Figure 7 As shown, a light shielding mask provided separately from the color stripes may be used as a light shielding portion for a color card.

[0088] The color card light shielding portion may be any portion having a desired light shielding property, and examples thereof include a metal film such as a chromium thin film, and a printed layer formed of black ink.

[0089] As for the method of forming the light-shielding portion for the color card, a conventionally known method can be used depending on the material used.

[0090] Furthermore, as described above, the color card light shielding portion in the present disclosure is, for example, Figure 1 As shown in (A), when the color stripes 3 are divided and formed, the divided color stripes 3 a may be arranged to be divided.

[0091] (4) Perspective-determined signs

[0092] The transmissive color grayscale card disclosed herein is configured so that the color card member is located on the imaging device side when in use. Therefore, a viewing angle determination mark for determining the viewing angle of the imaging device is formed on the surface of the color card member opposite to the gray grayscale card member. Figure 6 As an example of a mark for determining an angle of view, the mark for determining an angle of view of the imaging element 11 is provided on the surface of the color card member opposite to the grayscale card member so as to indicate the boundary between the color card light shielding portion 6 and the color bar holding frame 7 .

[0093] The shape and size of the image sensor angle determining mark 11 are not particularly limited as long as they are recognizable as marks indicating the image sensor angle of view, and can be appropriately adjusted according to the design of the transmissive color grayscale chart.

[0094] On the other hand, the grayscale card member is arranged to be located on the light source side, and therefore such a viewing angle determination mark is usually not provided.

[0095] (5) Others

[0096] Furthermore, the color card components disclosed herein may also include IR-cut filters. When the color stripes are formed using a dyeing method, the dye's properties tend to easily transmit light in the wavelength range above 650nm, resulting in high light transmittance. In particular, the dyes used for the yellow (Ye), orange (O), and red (R) color stripes tend to have a low absorption rate towards the long wavelength range around 650nm. Consequently, the transmission spectra of the individual colors overlap in the long wavelength range.

[0097] In contrast, by adding an IR cut filter that removes a predetermined area from the color stripe, the transmission spectrum of each color can be separated, thereby preventing color mixing.

[0098] The IR cut filter can be selected by considering the wavelength region to be cut off according to the transmission spectrum characteristics of each color bar.

[0099] In addition to the above-mentioned structure, the color card member in the present disclosure may also have an alignment mark, an identification code, a cover glass, a color bar holding frame, a transparent protective plate with a light shielding portion, and the like.

[0100] The identification code may be, for example, a code recording information on the test card. Furthermore, the alignment marks can be marks recording position information, but may also function as identification codes recording information on the test card. These may also be provided on a transparent protective plate with a light-shielding portion.

[0101] 2. Grayscale card component

[0102] The gray scale card member in the present disclosure will be described with reference to the accompanying drawings. Figure 3 (A) is a schematic plan view showing an example of a grayscale card member. Figure 3 (B) means Figure 3 (A) Schematic diagram of the transmittance spectrum of each transmission area of ​​the grayscale card member.

[0103] like Figure 3 As shown in (A), the gray card member 2 in the present disclosure has a plurality of transmissive regions 4 that are achromatic and have different brightness. Figure 3 In (A), eight lightness grayscale regions are formed, each having multiple transmissive regions 4 of varying lightness. A grayscale card light shielding portion 6' is provided around the lightness grayscale regions. A grayscale card holding frame 7' is disposed around the outer periphery of the grayscale card light shielding portion 6'.

[0104] Such grayscale components will be described in detail below.

[0105] (1) Multiple transmission areas

[0106] like Figure 3 As shown in (A), the gray card member of the present disclosure has a plurality of transmissive regions 4 with different light transmittances. The plurality of transmissive regions in the gray card member are arranged to have at least one region overlapping with one color stripe in the color card member in a plan view.

[0107] (a) Shapes of multiple transmission regions

[0108] The arrangement of the transmissive regions for each grayscale with different transmittances is not particularly limited, and they can be arranged in a row or in a grid pattern so that the transmittance changes stepwise. For example, the transmittance can be arranged so that the transmittance decreases from the maximum light transmittance portion (the whitest portion) to the minimum light transmittance portion (the darkest portion).

[0109] exist Figure 1In FIG. 1 , one color stripe 3 of the color card member 1 and three transmission areas 4 of the grayscale card member 2 are arranged to overlap when viewed from above. Figure 2 Color card components and Figure 3 When overlapping grayscale card members, each color bar 3 and the corresponding grayscale card member 2, comprising two horizontally arranged brightness grayscale regions, are arranged so as to overlap in a plan view, totaling 16 transmissive regions. Thus, the number of transmissive regions of a grayscale card member that overlaps a color bar in a plan view is not particularly limited, as long as it is plural; for example, it can be set to 2 or more and 256 or less.

[0110] The planar shape of each transmission region is not particularly limited, and can generally be a rectangular shape.

[0111] The size of each transmissive area can be appropriately designed according to the application of the transmissive color grayscale card of the present disclosure so as to easily exhibit the desired effect, and can be set to, for example, 250 mm×190 mm to 3.5 mm×0.8 mm.

[0112] While multiple transmissive regions with different light transmittances that overlap a single color stripe when viewed from above may be formed continuously, it is preferable to form the transmissive regions with different transmittances separately. This is because forming the transmissive regions with different transmittances separately prevents the influence of light leakage from adjacent transmissive regions, thereby enabling accurate correction.

[0113] Figure 15 It is an HDR (High Dynamic Range) grayscale chip with a transmission area of ​​10mm×10mm (equivalent to a transmission area of ​​the grayscale card component mentioned above), with a brightness of 4500cd / m 2 The results of the measurement using the 2D spectroradiometer SR-5000 manufactured by Topcon Techno House Co., Ltd. (the results of the brightness distribution are shown in a two-dimensional map) when the light source is irradiated. Figure 15 As shown in FIG. 1 , the amount of light leaking out of the transmission area is approximately 10% of the transmission area at a distance of 5 mm, and is almost nonexistent at a distance of 10 mm.

[0114] That is, the brightness in use is 4500cd / m 2 When illuminated by a light source, light leakage outside the transmissive area is approximately 10% of the transmissive area at a distance half the width of the transmissive area from the end of the area, and is virtually nonexistent at a distance equal to the width of the transmissive area. The luminance ratio shown on the vertical axis of the graph in the figure represents the luminance ratio of the surrounding area when the luminance of the transmissive area is set to 1.

[0115] According to the above experimental results, when the transmissive regions having different transmittances are separated and formed, the distance between adjacent transmissive regions having different transmittances is preferably at least half the width of the transmissive region, and more preferably at least the same width as the transmissive region.

[0116] The width of the transmission region refers to the distance from a side on the transmission region side adjacent to the transmission region, among sides that divide the transmission region, to a side facing the side.

[0117] This is because, by setting the value to be greater than the above value, light leakage between adjacent transmissive regions can be avoided. In addition, when the transmissive regions are formed separately, a light shielding portion for a gray scale card described later is usually formed between adjacent transmissive regions.

[0118] (b) Structure of multiple transmission regions

[0119] The grayscale card component is not particularly limited as long as it has multiple transmission areas with different light transmittances. Examples include components having multiple metal films of different thicknesses formed on a transparent support with light transmittance such as glass or film, components having striped or dot-shaped covering parts formed on a transparent support, silver halide films, and stacks thereof.

[0120] Figure 16 An example of a covering portion is shown, and an example in which a covering portion 41 having a halftone dot pattern is formed in the transmission region 4 is shown in enlarged form.

[0121] The covering portions of the plurality of transmissive regions are preferably formed using a black colorant or black-colored paper, film, glass, or metal. This is because using multiple colors as light-shielding regions within the plurality of transmissive regions may cause chromatic noise in the transmitted light.

[0122] The grayscale card member disclosed herein is preferably a grayscale card structure comprising a transmissive dot region and a grayscale card light-shielding portion disposed therearound, or a stack of such grayscale card structures, wherein light-shielding dots are randomly disposed in the dot region. This allows for accurate brightness adjustment and prevents the generation of moiré patterns when stacking grayscale card structures to ensure accurate brightness adjustment.

[0123] The gray scale card structure will be described in detail in the section "C. Gray scale card" described later.

[0124] (c) Other

[0125] As a method for forming a gray grayscale card component, for example, there can be cited a sputtering method for forming a plurality of metal films of different thicknesses on a transparent support such as glass or film, a printing method for forming stripe-shaped or dot-shaped covering portions with different coverage areas on a transparent support, an inkjet method, a photolithography method, etc.

[0126] (2) Gray grayscale card light shielding part

[0127] The grayscale card member in the present disclosure preferably has a grayscale card light shielding portion provided on the periphery of the plurality of transmission regions or the periphery of each transmission region. By providing the grayscale card light shielding portion, it is possible to prevent the backscatter of light from the lateral direction. As an example of the grayscale card light shielding portion, the same light shielding portion as that described in "1. Color card member (3) Color card light shielding portion" above can be exemplified.

[0128] In addition, if Figure 7 As shown, a light shielding mask provided separately from the plurality of transmission regions may be used as a light shielding portion for a gray scale card.

[0129] In the present disclosure, it is preferable that the area of ​​the opening of the color chart light shielding portion is smaller than the area of ​​the opening of the gray scale chart light shielding portion.

[0130] In the transmissive color grayscale chart disclosed herein, a color card member and a gray card member are stacked so that the color card light shield and the gray card light shield overlap when viewed from above, forming an overlapping transmissive region. When using such a transmissive color grayscale chart for calibration with an imaging device, an illumination device is pre-installed on the gray card member side of the transmissive color grayscale chart, and an imaging device is positioned on the color card member side. This is because when the imaging device focuses on the transmissive color grayscale chart, chromatic aberration can be suppressed by aligning the focal point with the color card member surface. In this case, if the area of ​​the opening of the color card light shield in the overlapping transmissive region is equal to or larger than the area of ​​the gray card light shield in the overlapping transmissive region, both the ends of the color card light shield and the ends of the gray card light shield will be captured by the imaging device during calibration, potentially causing problems in focus adjustment and other issues.

[0131] (3) Transparent support

[0132] The plurality of transmissive regions and the grayscale card light shielding portion in the grayscale card member are not particularly limited and are preferably formed on a transparent support. Such a transparent support is not particularly limited, as long as it can support the plurality of transmissive regions and the grayscale card light shielding portion and has the desired light transmittance, and can be the same as any conventionally known transparent substrate for grayscale. Specifically, inorganic substrates such as glass substrates and resin substrates can be used. The resin substrate may be in the form of a plate, a film, or a sheet.

[0133] (4) Others

[0134] Furthermore, the grayscale card member in the present disclosure may also have an alignment mark, a cover glass, a grayscale card holding frame, and a transparent protective plate with a light shielding portion, in addition to the above-mentioned structure.

[0135] 3. Isolation

[0136] The transmissive color grayscale card disclosed herein preferably includes a spacer disposed between the color card member and the gray grayscale card member. The spacer preferably has an opening at least in the region that overlaps with the color stripes in the color card member when viewed from above. This is because the spacer creates a gap corresponding to the thickness of the spacer between the color card member and the gray grayscale card member, thereby suppressing the appearance of Newton rings. Examples of the spacer include thick paper, film, and the like that have an opening at least in the region that overlaps with the color stripes when viewed from above.

[0137] The thickness of the spacer is appropriately adjusted based on the size of the gap to be provided between the color card member and the grayscale card member, and is not particularly limited. Specifically, it can be 10 μm or greater, preferably 20 μm or greater. By setting the spacer thickness within the above range, a gap can be provided to a degree that suppresses the occurrence of Newton rings.

[0138] In the present disclosure, the spacer may also be the light shield described in the section "B. Transmissive Color Grayscale Card Device 2. Light Shield" below. In this case, the light shield may function as both the color card light shield and the gray scale card light shield, and may be provided independently of the color card light shield and the gray scale card light shield.

[0139] 4. Others

[0140] The transmissive color grayscale card disclosed herein is formed by overlapping the color card component described in the above-mentioned item "1. Color card component" and the gray grayscale card component described in the item "2. Gray grayscale card component", and is characterized in that it is configured to have a repeated transmissive area in which at least one color strip in the color card component and multiple transmissive areas in the gray grayscale card component overlap when viewed from above.

[0141] The color card member and the grayscale card member are superimposed as needed by fixing them with an adhesive while sandwiching the above-mentioned spacers, fixing them with a jig for the process, or using a solid adhesive that can have gaps.

[0142] As described above, the transmission type color grayscale chart of the present disclosure includes a plurality of calibration patches by overlapping "1. color chart member" and "2. gray chart member."

[0143] The transmissive color grayscale card disclosed herein can adjust the color by using the color card component and adjust the brightness by using the gray grayscale card component, and can adjust the brightness without changing the chroma. Specifically, the xy chromaticity diagram obtained by the transmissive color grayscale card disclosed herein is shown in FIG. Figure 4 In addition, the transmission spectra of each correction patch obtained by the transmission type color grayscale card disclosed in this invention are shown in Figure 5 .exist Figure 4 In the figure, it can be seen that even if the brightness is reduced, the chromaticity position on the xy chromaticity diagram remains almost unchanged. Figure 5 It can be seen that even when the brightness is set to low, the peak wavelength of the transmitted light does not deviate and there is no noise.

[0144] 5. Color correction method using a transmissive color grayscale card

[0145] The transmissive color grayscale card disclosed herein can be used for calibration of imaging equipment such as cameras, that is, for evaluating color reproducibility. Figure 12 As shown, a lighting fixture 12 is arranged on one surface side of a transmissive color grayscale card 10 .

[0146] Next, while the transmissive color grayscale card is illuminated from one side by an illumination device 12, an image of the transmissive color grayscale card is captured from the other side by a camera 13. After capturing the transmissive color grayscale card, the camera's computational circuit compares the calibration patch on the captured image with a reference color patch pre-stored in the camera's memory unit, calculating an evaluation value for the camera's color reproducibility based on the chromaticity of the two patches. After calculating the color reproducibility evaluation value, the camera's color correction circuit calibrates the camera by correcting camera parameters related to color reproducibility to minimize color deviation, thereby performing camera calibration.

[0147] Here, the transmissive color grayscale card disclosed herein is preferably used with the color card member disposed on the camera side and the grayscale card member facing the lighting device side. This is because when the camera focuses on the card, the color difference can be suppressed by focusing on the color card member surface.

[0148] 6. Purpose

[0149] The transmissive color grayscale card disclosed herein can be used in all imaging devices, video equipment, and peripheral devices that require color correction, and is particularly suitable for pathology imaging devices.

[0150] B. Transmissive color grayscale card device

[0151] The transmissive color grayscale card device disclosed herein is characterized by comprising two protective substrates and the transmissive color grayscale card sandwiched between the two protective substrates.

[0152] The transmissive color grayscale card device of the present disclosure will be described with reference to the accompanying drawings. Figure 7 Schematic diagram showing an example of a transmissive color grayscale card device disclosed herein. Figure 7 As shown, the transmissive color grayscale card apparatus 100 of the present disclosure includes a transmissive color grayscale card 10, a protective substrate 101 (hereinafter referred to as a first protective substrate) disposed on the color card member 1 side of the transmissive color grayscale card, and a protective substrate 102 (hereinafter referred to as a second protective substrate) disposed on the gray grayscale card member 2 side of the transmissive color grayscale card. The first protective substrate 101 and the second protective substrate 102 are disposed so as to face each other with the color stripes of the color card member and the plurality of transmissive regions of the gray grayscale card member interposed therebetween. The first protective substrate 101 and the second protective substrate 102 have at least a transmissive portion in the region overlapping with the color stripes of the color card member when viewed from above.

[0153] In this way, by having a structure in which the above-mentioned transmissive color grayscale card is clamped between a pair of protective substrates (i.e., a first protective substrate and a second protective substrate), it is possible to suppress the adhesion and physical contact of solvents and the like to the color card components and the gray grayscale card components, and it is possible to suppress the occurrence of adverse conditions such as a decrease in the color concentration of the color bars of the color card components or a change in pigment.

[0154] Hereinafter, each structure of the transmissive color grayscale card device of the present disclosure will be described.

[0155] 1. Protect the substrate

[0156] The two protective substrates disclosed herein are arranged to face each other across a transmissive color grayscale card. The protective substrate preferably includes a transmissive portion at least in an area that overlaps with the color stripes of the color card member when viewed from above. Here, the "transmissive portion" refers to an area that transmits at least visible light.

[0157] The size of the protective substrate is appropriately selected according to the size of the transmission-type color grayscale card device of the present disclosure and is not particularly limited.

[0158] The material used for the protective substrate is preferably a material that can protect the color card component and the gray grayscale card component clamped by a pair of protective substrates from damage and dust. As specific protective substrates, for example, transparent substrates such as glass and plastic can be cited. In the case where the transmission type color grayscale card device disclosed herein is used for a microscope with a camera device, glass is generally used as the material for the protective substrate. In addition, as the above-mentioned protective substrate, a transparent protective plate with a light shielding portion having the same pattern as the light shield described later can also be used.

[0159] 2. Lens hood

[0160] like Figure 7 As shown, the transmissive color grayscale card device of the present disclosure is preferably provided with light shielding masks 103 and 104 between the first protective substrate 101 and the transmissive color grayscale card 10 , and between the second protective substrate 102 and the transmissive color grayscale card 10 .

[0161] Hereinafter, the light shielding mask 103 between the first protective substrate 101 and the transmissive color grayscale card 10 is referred to as a first light shielding mask, and the light shielding mask 104 between the second protective substrate 102 and the transmissive color grayscale card 10 is referred to as a second light shielding mask.

[0162] In this case, the third light shielding mask 105 can constitute a spacer of the above-mentioned transmissive color grayscale card.

[0163] Examples of the first to third light shielding masks include thick paper, film, and the like having at least an opening in a region of the color card member that overlaps with the color stripe in a plan view.

[0164] The openings of each light shield only need to be formed at the predetermined positions described above. For example, the positions and widths of the openings of each light shield can be the same or different. In the present disclosure, the positions and widths of the openings of each light shield can be made the same. This allows for a clearer outline of the color bars, resulting in a higher-quality transmissive color grayscale card device.

[0165] Furthermore, when the position and width of the opening in the light shield are different, it is preferable that the area of ​​the spacer (third light shield) and the second light shield cannot be seen from the viewing side (camera side) of the transmissive color grayscale card device. Figure 7 As shown in , when the width of the opening of the first light shield 103 is set to w1, the width of the opening of the spacer (third light shield 105) is set to w2, and the width of the opening of the second light shield 104 is set to w3, the relationship w1 < w2 < w3 is preferably satisfied. This prevents leakage of obliquely incident light.

[0166] In the above Figure 7In the example shown, the first and second light shields 103 and 104 also function as spacers, suppressing Newton rings caused by contact between the protective substrate and the transmissive color grayscale card. Furthermore, the third light shield 105 also functions as a spacer, suppressing Newton rings caused by contact between the color card member and the gray grayscale card member.

[0167] The specific size of the light shield and the width of the opening are appropriately adjusted according to the design of the transmissive color grayscale card device and are not particularly limited.

[0168] 3. Transmissive color grayscale card

[0169] The transmissive color grayscale card used in the transmissive color grayscale card device of the present disclosure can be the same as that described in the above-mentioned "A. Transmissive Color Grayscale Card", and therefore description thereof is omitted here.

[0170] C. Grayscale card

[0171] In recent years, image output devices capable of capturing dynamic range information on subjects with large differences in brightness and darkness at high resolution have been developed. Advances in display technology have increased peak brightness and expanded dynamic range. Specifically, while conventional SDR (Smooth Dynamic Range) displays have a brightness ratio of 1:1000, High Dynamic Range (HDR) displays achieve a brightness ratio of 1:100,000. Consequently, there is a demand for grayscale charts capable of finely adjusting transmittance in increments of 0.0001% at low brightness levels.

[0172] However, conventional grayscale charts adjust brightness within a single grayscale chart, and therefore it is extremely difficult to obtain brightness that enables accurate correction at low brightness.

[0173] The present inventors have studied this point and have found that by stacking gray scale cards, it is possible to obtain brightness that enables accurate correction at low brightness, and have conducted further research.

[0174] The results of the research revealed that conventional grayscale charts used regular patterns of dots, lines, and spaces. Therefore, a new issue was discovered: if grayscale charts using such regular patterns were overlapped to adjust transmittance, interference fringes (moiré) would occur.

[0175] Figure 8 (A) indicates the case of using regular dots. Figure 8(B) shows interference fringes produced when a line-and-space pattern is used. These interference fringes may exhibit subtle variations in transmittance. Furthermore, since transmittance varies for each wavelength, the grayscale card member used as the transmissive color grayscale card described above may cause problems when used in combination with a color card member. Figure 8 (C) shows Figure 8 (A) The transmittance of the gray scale card at each wavelength.

[0176] The present invention is a grayscale card structure configured with multiple transmissive areas of different brightness. The above-mentioned multiple transmissive areas use a grayscale card structure composed of transmissive dot areas with randomly arranged light-shielding dots, and solve the above-mentioned problems by stacking them.

[0177] That is, the gray grayscale card disclosed herein is characterized in that a gray grayscale card structure having multiple transmissive areas of different brightness is stacked so that the multiple transmissive areas overlap when viewed from above, and the multiple transmissive areas are composed of transmissive dot areas, in which dots with light-blocking properties are randomly arranged.

[0178] Hereinafter, the grayscale card of the present disclosure will be described in detail.

[0179] Figure 9 (A) is a schematic plan view of each layer (gray scale card structure) of a gray scale card in which four gray scale card structures 21 from the first layer to the fourth layer are stacked. Figure 9 (B) is an enlarged view of a dot region with randomly arranged light-blocking dots. The grayscale card structure 21 consists of a transmissive dot region 22 with randomly arranged light-blocking dots and a grayscale card structure light-blocking portion 23 without these dots. By overlapping these grayscale card structures 21, a grayscale card with multiple transmissive regions of varying light transmittance is formed.

[0180] Figure 10 The transmittance of each transmission area of ​​the gray grayscale card disclosed in the present invention is shown in FIG. Figure 10 As shown, the transmittance of the grayscale card disclosed herein is substantially constant for each wavelength. Therefore, when used in combination with a color card member, that is, when used as a grayscale card member of the aforementioned transmissive color grayscale card, chroma and brightness can be adjusted simultaneously, enabling quick and accurate adjustments. Figure 9 (C) is a schematic plan view of a transmissive color grayscale card obtained by overlaying the gray grayscale card of the present disclosure with a color card member.

[0181] 1. Gray grayscale card structure

[0182] In the present disclosure, the gray scale card structure comprises: a dot region having transmissive properties in which dots having light-shielding properties are randomly arranged and a gray scale card structure light-shielding portion having light-shielding properties. The gray scale card structure is as follows: Figure 9 As shown in (A), a plurality of dot areas are divided by light-shielding portions of a grayscale card structure.

[0183] Such a grayscale card structure is used as a grayscale card by stacking multiple layers of grayscale card structures in which the aforementioned dot regions are arranged in parallel. In this case, it is preferred that each stacked grayscale card structure has different lengths in a direction perpendicular to the direction in which the aforementioned dot regions are arranged in parallel, and each grayscale card structure has a different number of dot regions.

[0184] With this structure, when used as a grayscale chart, multiple dot regions are stacked to form transmissive regions. By varying the number of stacked dot regions and the transmittance of each dot region, the transmittance in each transmissive region can be varied. In particular, since transmittance at low brightness levels is extremely difficult to adjust using a single layer, this method of adjusting transmittance by stacking dot regions is extremely effective.

[0185] As a stacking method of the gray scale card structure, it is preferable to stack the gray scale card structure in such a way that the length in the direction perpendicular to the parallel direction of the dot areas, that is, the number of dot areas in the gray scale card structure, changes in sequence. As a stacking method in this case, for example, the following can be cited: Figure 9 As shown in (A), the grayscale card structures are stacked so that one end side in the longitudinal direction is aligned.

[0186] exist Figure 9 In the example shown in (A), the grayscale card structure on the right side of the figure has a large number of stacked layers, and the transmittance in the transmissive area of ​​the grayscale card is low. On the other hand, the grayscale card structure on the left side of the figure has a small number of stacked layers, and the transmittance in the transmissive area of ​​the grayscale card is high.

[0187] (1) Point area

[0188] The dot region in this disclosure is a transmissive region in which light-shielding dots are randomly arranged. Random refers to a state in which the arrangement is not periodic, such as a perfect arrangement. Specifically, the arrangement can be randomized using the Meier-Bernoulli or error diffusion methods.

[0189] In particular, randomization is preferably performed so that the random arrangement does not repeat within the dot area or between stacked dot areas.

[0190] By randomly arranging the dots in this manner, it is possible to suppress the occurrence of interference fringes when the grayscale card structures are overlapped. Figure 9(B) shows an enlarged view of the dot area.

[0191] The transmittance of a dot region can be adjusted by adjusting the density of the included dots. Preferably, each grayscale card structure includes multiple dot regions. In this case, the multiple dot regions within a grayscale card structure may have the same dot density (same transmittance) or different dot densities (or different transmittances).

[0192] The planar shape of the dot is not particularly limited, but is preferably a substantially quadrilateral shape, a substantially circular shape, a rectangular shape, or a shape including a circle.

[0193] The dot size is not particularly limited, but it is preferably a size that does not cause resolution even when shooting at 8K resolution. Specifically, at a distance of 50 cm from the camera relative to the effective surface of a 230mm × 170mm test chart, even when shooting at 8K resolution (pixel count, horizontal 7680 × vertical 4320), it is preferably not resolved. Therefore, it is preferably 30μm (230mm / 7680) × 40μm (170mm / 4320) or less. The lower limit is not particularly limited, but it is preferably 2μm or more, which does not cause wavelength shift even in the near-infrared wavelength.

[0194] The dot region can be obtained by forming a random dot pattern on a light-transmitting support such as a substrate or a film by a printing method, a photolithography method (drawing method), or the like.

[0195] The top view shape of the point area is not particularly limited, for example Figure 9 As shown in (A), it is preferred to arrange the dots in a linear manner so that the brightness changes in sequence. Specifically, it is preferred that the dot regions be arranged in parallel in a rectangular, elliptical, or oblong shape when viewed from above. Figure 3 As shown, it can also be configured in multiple columns.

[0196] In each dot area of ​​the grayscale card structure, if light irradiated to the adjacent dot area is mixed, accurate correction cannot be performed. Therefore, in order to prevent light from leaking to the adjacent dot area, the distance between the adjacent dot area ( Figure 9 (d)) is preferably at least half the width of the dot region, and particularly preferably at least the same width as the dot region.

[0197] The reasons why such a range is preferred and the definition of the width of the dot region are the same as those described in "A. Transmissive Color Grayscale Card 2. Gray Grayscale Card Component (1) Multiple Transmissive Regions (a) Shapes of Multiple Transmissive Regions" and are therefore omitted here. In the above description, the dot region is described as the transmissive region.

[0198] (2) Gray grayscale card structure shading part

[0199] In addition, in order to avoid light circling, the grayscale card structure in the present disclosure preferably has a grayscale card structure light shielding portion around the above-mentioned point area, and the grayscale card structure light shielding portion has light shielding properties. In addition, it is preferred to form a light shielding area on the end face of the grayscale card structure.

[0200] As the light shielding portion of the gray scale card structure, the same structure as that in the above-mentioned "A. Transmissive color gray scale card 2. Gray scale card member (2) Light shielding portion for gray scale card" is exemplified.

[0201] 2. Gray Grayscale Card

[0202] The grayscale chart disclosed herein is constructed by superimposing grayscale chart structures so that the dot regions of the multiple grayscale chart structures overlap when viewed from above. The transmittance of each transmissive region can be adjusted based on the dot density of the dot regions within each grayscale chart structure, the number of overlapping grayscale chart structures, and the method of superposition. This allows precise adjustment of the brightness of transmitted light, making it easy to manufacture a grayscale chart having multiple transmissive regions with varying brightness, or light transmittance.

[0203] exist Figure 11 In the figure, the horizontal axis represents the number (gray scale) of each transmission area of ​​the gray scale card disclosed herein, and the vertical axis represents the brightness of the transmitted light shown in each transmission area. Figure 11 As shown, in the gray scale card of the present disclosure, 0.005 cd / m 2 brightness.

[0204] In addition, for example, as the minimum brightness difference between the plurality of transmission areas in the low brightness area, as long as it is 0.005 cd / m 2 , it can be formed.

[0205] 3. Others

[0206] Furthermore, the grayscale card of the present disclosure may further include a cover glass, a grayscale card structure holding frame, and a transparent protective plate with a light shielding portion, in addition to the above-mentioned structure.

[0207] 4. Purpose

[0208] The grayscale card disclosed herein can be used for imaging equipment that requires fine adjustment of brightness, ultra-high-resolution (4K, 8K with HDR) compatible cameras, and the like.

[0209] Furthermore, it can also be used as the above-mentioned "A. Transmissive color grayscale card 2. Gray grayscale card member".

[0210] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any technical solution having substantially the same structure and exhibiting the same function and effect as the technical concept described in the claims of the present invention is within the technical scope of the present invention.

[0211] -Explanation of symbols-

[0212] 1 ... Color card component

[0213] 2 … Grayscale Card widget

[0214] 3 … Color Bars

[0215] 4 … Transmission area

[0216] 10… Transmissive Color Grayscale Card

[0217] 21… Gray Grayscale Card Construct

[0218] 22… point area

[0219] 100… Transmissive color grayscale card device

[0220] 101, 102…protect the substrate

[0221] 103, 104, 105…Lens hood.

Claims

1. A transmissive color grayscale card, characterized in that: have: a color card member having at least one color stripe that transmits light in a color; and The gray grayscale card component has multiple transmission areas where the transmitted light is achromatic and has different brightness. The transmissive color grayscale card is formed by stacking the color card member and the gray grayscale card member, so as to have repeated transmissive areas where the color stripes and the plurality of transmissive areas overlap when viewed from above. A distance between adjacent ones of the plurality of transmissive regions is greater than or equal to half of a width of the transmissive region.

2. The transmissive color grayscale card according to claim 1, wherein: The covering portions in the plurality of transmission areas are formed using a black colorant or metal.

3. The transmissive color grayscale card according to claim 1 or 2, wherein: The plurality of transmissive regions are composed of transmissive dot regions, in which dots having light-shielding properties are randomly arranged.

4. The transmissive color grayscale card according to claim 1 or 2, wherein: A spacer is arranged between the color card member and the grayscale card member. The spacer has an opening in the repeated transmission area.

5. The transmissive color grayscale card according to claim 1 or 2, characterized in that: A viewing angle determination mark for determining the viewing angle of an imaging device calibrated based on the transmission type color grayscale card is formed on a main surface of the color card member that is different from the main surface on the grayscale card member side.

6. A color correction method for a camera device, characterized in that: A transmissive color grayscale card, a lighting fixture, and an imaging device are prepared. The transmissive color grayscale card comprises: a color card member having at least one color stripe that transmits colored light; and a gray grayscale card member having a plurality of transmissive regions that transmit achromatic light and have different brightnesses. The transmissive color grayscale card is formed by stacking the color card member and the gray grayscale card member so as to have overlapping transmissive regions in which the color stripe and the plurality of transmissive regions overlap when viewed from above, and the distance between adjacent transmissive regions in the plurality of transmissive regions is at least half the width of the transmissive region. irradiating light using the lighting fixture as a light source from one side of the transmissive color grayscale card, and capturing an image of the transmissive color grayscale card from the other side of the transmissive color grayscale card using the imaging device; Color correction of the imaging device is performed based on a photographic image captured by the imaging device.

7. The color correction method of the imaging device according to claim 6, characterized in that: The color card member of the transmission-type color grayscale card is arranged on the imaging device side.

Images