WO2021149445A1 - Optical characteristic evaluation device - Google Patents

Optical characteristic evaluation device Download PDF

Info

Publication number
WO2021149445A1
WO2021149445A1 PCT/JP2020/048131 JP2020048131W WO2021149445A1 WO 2021149445 A1 WO2021149445 A1 WO 2021149445A1 JP 2020048131 W JP2020048131 W JP 2020048131W WO 2021149445 A1 WO2021149445 A1 WO 2021149445A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
optical characteristic
characteristic measuring
measuring device
illumination
Prior art date
Application number
PCT/JP2020/048131
Other languages
French (fr)
Japanese (ja)
Inventor
拓史 宇田
良隆 寺岡
阿部　芳久
Original Assignee
コニカミノルタ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by コニカミノルタ株式会社 filed Critical コニカミノルタ株式会社
Publication of WO2021149445A1 publication Critical patent/WO2021149445A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/46—Measurement of colour; Colour measuring devices, e.g. colorimeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration

Definitions

  • the present invention relates to an optical characteristic measuring device used for measuring the subsurface diffusion of light incident on the surface of a measurement object.
  • subsurface scattering may be used to correct "edge loss,” which has often been a problem in the field of colorimeters. This is because edge loss is a problem caused by the illuminated light seeping out to the outside of the detection area. This problem has become a major problem especially in compatibility between measuring instruments having different optical geometries, and there is a certain demand for its correction.
  • CCM Computer Color Matching
  • the subsurface scattering measurement is a wavelength decomposition measurement.
  • Non-Patent Document 1 illuminates an object to be measured from a specific direction so that a point light source focuses on the sample, and the illuminated sample is fixed at a different angle. It is described that the subsurface scattering is measured by measuring with a camera and analyzing one dimension orthogonal to the camera angle passing through the focus point.
  • Non-Patent Document 2 describes spatial information in which light is laterally diffused by using a plurality of fibers, and further connects the fibers on the exit side to a spectroscopic imaging unit. A method of performing spectroscopy has been proposed.
  • Non-Patent Document 1 uses an RGB camera, it is not possible to acquire spectroscopic data of surface diffused light, and even if a spectroscopic camera is used instead of the RGB camera, the measurement time is long. There is a problem that there is a concern about an increase in the number of devices and an increase in the size of the device.
  • Non-Patent Document 2 the resolution and measurement range of the diffusion length are determined by the size and number of fibers, and it is difficult to perform a spatially detailed measurement. There is a problem.
  • the present invention has been made in view of such a technical background, and has problems that it can image at a high spatial resolution but cannot acquire spectroscopic data, or it can acquire spectroscopic data but cannot acquire data at a high spatial resolution. It is an object of the present invention to provide an optical characteristic measuring device that can solve the problem while suppressing an increase in the size of the device and an increase in measurement time.
  • An optical characteristic measuring device for measuring subsurface scattering of light inside an object, for locally illuminating the surface of an object to be measured with illumination light having intensity in a wavelength band including a visible light region.
  • illumination light having intensity in a wavelength band including a visible light region.
  • An imaging means capable of unilaterally spatially decomposing a measurement range including both of the light from a location and imaging, and a spectrum that disperses the light captured from each spatially decomposed measurement location on the upstream side of the imaging means.
  • An optical characteristic measuring device comprising means, and the imaging means receives light for each wavelength dispersed by the spectroscopic means.
  • the number of the lighting means is two or more, and each lighting means is arranged symmetrically with respect to the lighting location of the measurement object.
  • Locally illuminated is the optical characteristic measuring apparatus according to any one of the above items 1 to 4, wherein the spatial distribution of the illumination intensity on the surface of the object to be measured is a rectangle or a shape close to a rectangle.
  • the optical characteristic measuring apparatus according to any one of the above items 1 to 5 wherein the wavelength region dispersed by the spectroscopic means is a region within a range of 300 to 800 nm.
  • the optical characteristic measuring apparatus according to any one of the above items 1 to 8, wherein the resolution of the one-dimensionally spatially decomposed measurement range is finer than 0.1 mm.
  • the one-dimensional direction in the one-dimensional spatial decomposition means the vertical surface of the object to be measured, including the optical axis of the irradiation light from the illuminating means to the illuminating portion, and intersecting the surface of the object to be measured.
  • the optical characteristic measuring apparatus according to any one of the preceding items 1 to 10, further comprising a specularly reflected light removing mechanism for preventing the capture of specularly reflected light from the surface of the object to be measured.
  • the specularly reflected light removing mechanism sets the positional relationship between the illuminating means and the imaging means so as not to angularly detect the incident light on the surface of the object to be measured and the specularly reflected light.
  • the specular light removing mechanism is configured by a mechanism that changes the illumination means side to linearly polarized light and extracts only those perpendicular to the polarized light on the light receiving side.
  • the optical characteristic measuring apparatus according to any one of items 1 to 13 above, wherein the number of times of imaging by the imaging means is the same as or less than the number of the lighting means.
  • the optical characteristic measurement according to any one of items 1 to 14 above which includes a calculation unit that calculates one or more parameters related to subsurface scattering of light from the pixel values of each pixel obtained by the imaging means. Device.
  • the parameter is a value that characterizes the scattering length of subsurface scattering.
  • the optical characteristic measuring device according to item 15 or 16 above, wherein the parameter is an input value for rendering in computer graphics.
  • the parameter is an edge loss correction coefficient.
  • the optical characteristic measuring device according to item 15 or 16 above, wherein the parameter is an input value for computer color matching.
  • the arithmetic unit is configured by an external personal computer.
  • a housing for accommodating the illumination means, an imaging means, and a spectroscopic means is provided, and the housing irradiates the surface of the measurement object with illumination light and emits light emitted from the surface of the measurement object.
  • the optical characteristic measuring apparatus according to any one of the preceding items 1 to 20, further comprising an opening for taking in and a display means for displaying the measurement result.
  • the optical characteristic measuring device according to any one of the preceding items 1 to 21, which is built in the color measuring device.
  • the illumination light having intensity in the wavelength band including the visible light region is emitted from the surface of the measurement object when the surface of the measurement object is locally illuminated.
  • the measurement range including both the light from a part or all of the illuminated area and the light from the unilluminated area near the illuminated area was spatially decomposed in a one-dimensional manner. Since the light captured from each measurement point is separated and received by the imaging means for imaging, the state of subsurface scattering of light can be quickly acquired with high spatial resolution and in a state of wavelength decomposition. Further, since a large-scale configuration is not required, it is possible to prevent the device from becoming large in size.
  • the state of subsurface scattering of light can be measured using one lighting means.
  • each lighting means is arranged symmetrically with respect to the lighting point of the object to be measured.
  • the symmetry can be offset, and more accurate measurement becomes possible.
  • the local illumination is directly illuminated with the illuminated portion because the spatial distribution of the illumination intensity on the surface of the object to be measured is a rectangle or a shape close to a rectangle.
  • the boundary with the non-existent part becomes clear, and it becomes possible to measure the subsurface scattering of light with high accuracy.
  • the measurement is performed in the wavelength region within the range of 300 to 800 nm.
  • a measurement range larger than 1 mm is unilaterally spatially decomposed for imaging.
  • the resolution of the one-dimensionally spatially decomposed measurement range is finer than 0.1 mm, so that highly accurate measurement can be performed.
  • the positional relationship between the illuminating means and the imaging means is set so as not to detect the incident light on the surface of the measurement object and the specularly reflected light from an angle. Specularly reflected light can be removed by a simple method.
  • specularly reflected light can be reliably removed by a mechanism that changes the illumination means side to linearly polarized light and extracts only those perpendicular to the polarized light on the light receiving side.
  • the number of times of imaging by the imaging means is the same as or less than the number of the lighting means, so that high-speed measurement is possible.
  • one or more parameters related to subsurface scattering of light can be calculated from the pixel values of each pixel obtained by the imaging means.
  • a value that characterizes the scattering length of subsurface scattering can be calculated from the pixel value of each pixel obtained by the imaging means.
  • the input value for rendering in computer graphics can be calculated from the pixel value of each pixel obtained by the imaging means.
  • the edge loss correction coefficient can be calculated from the pixel value of each pixel obtained by the imaging means.
  • the input value of computer color matching can be calculated from the pixel value of each pixel obtained by the imaging means.
  • one or more parameters related to subsurface scattering of light can be calculated by an external personal computer.
  • FIG. 1 It is a block diagram which shows the structure of the optical characteristic measuring apparatus which concerns on one Embodiment of this invention.
  • (A) and (B) are diagrams for explaining the relationship between the illuminated portion and the measurement range. It is a figure which shows the actual arrangement relation of the lighting means, the spectroscopic means, the imaging means, etc. of the optical characteristic measuring apparatus shown in the block diagram of FIG.
  • (A) is the top view of the object to be measured
  • (B) is the figure which shows the pixel plane of a two-dimensional photoelectric conversion element
  • (C) is It is a figure which shows an example of the light intensity with respect to wavelengths 500nm and 700nm for each spatial resolution when a one-dimensional spatial decomposition direction is X direction.
  • (A) is the top view of the object of measurement
  • (B) is the figure which shows the pixel plane of a two-dimensional photoelectric conversion element be.
  • FIG. 1 is a block diagram showing a configuration of an optical characteristic measuring device according to an embodiment of the present invention.
  • the optical characteristic measuring device includes one illuminating unit 1, and collects the light from the illuminating unit 1 through the lens 2 to illuminate the surface of the object to be measured 100.
  • the illumination light by the illumination unit 1 is illumination light having intensity in the wavelength band including the visible light region, and together with the action of the lens 2, locally illuminates the surface of the measurement object 100.
  • Locally illuminating means that the difference between the illuminated portion on the surface of the object to be measured 100 and the unilluminated portion in the vicinity of the illuminated portion is clear.
  • the spatial distribution of the illumination intensity on the surface of the measurement object 100 is a rectangle or a shape close to a rectangle that falls at the boundary between the illuminated portion and the portion that is not directly illuminated. Is desirable. This enables highly accurate measurement of subsurface scattering of light.
  • the spatial appearance in which the light illuminated on the irradiated portion on the surface of the measurement object 100 penetrates under the surface of the measurement object 100 and the light is diffused is wavelength-resolved by the spectroscopic unit 4 through the lens 3.
  • the two-dimensional photoelectric conversion element 5 as an image pickup means receives light and takes an image to acquire data.
  • the light receiving range (measurement range) of the two-dimensional photoelectric conversion element 5 is not limited, but is preferably 1 mm or more on the surface of the measurement object 100, and the light from the measurement object 100 is emitted in this measurement range. It is spatially decomposed in one dimension and receives light.
  • the spatial resolution is preferably smaller than 0.1 mm in order to improve the measurement accuracy, but this is not the case.
  • the illumination location 11 Both the light from all and the light from the non-illuminated portion 13 near the illuminated portion that is not directly illuminated are included.
  • both the light from a part of the illuminated portion 11 and the light from the non-illuminated portion 13 near the illuminated portion that is not directly illuminated are included. That is, the light from the illuminated portion 11 may be a part or the entire portion of the illuminated portion 11, but in either case, the light from the non-illuminated portion 13 near the illuminated portion is not directly illuminated. It is included in the measurement range 12.
  • the spectroscopic unit 4 decomposes wavelengths so that the spectral direction on the two-dimensional photoelectric conversion element 5 is perpendicular to the measurement direction.
  • the spectroscopic unit 4 may be a diffraction grating or a filter method using a linear variable filter (LVF) or the like, but has a wavelength region in the range of 300 to 800 nm, particularly a visible light region. It is desirable that the wavelength region in the range of about 400 to 700 nm can be resolved with a wavelength resolution finer than 30 nm. With such wavelength resolution, highly accurate measurement can be performed.
  • the electrical signal as the imaging data obtained by receiving the dispersed light of each wavelength by each pixel of the two-dimensional photoelectric conversion element 5 and performing photoelectric conversion is a current-voltage conversion circuit (IV conversion circuit) and analog-to-digital conversion (not shown). It is converted into a digital signal through a circuit (AD conversion circuit) and is subjected to arithmetic processing by the arithmetic unit 6.
  • the display unit 7 displays the calculation result. The arithmetic processing in the arithmetic unit 6 will be described later.
  • the spatial resolution is preferably 0.1 mm or less, and the measurement range is preferably 1.0 mm or more.
  • the imaging range is 1.0 mm or more only in the non-illuminated portion 13 other than the illuminated portion 11 directly illuminated by the light source. Further, it is desirable that the spatial distribution of the illumination intensity is close to a rectangle, and it is desirable that the amount of blurring when compared with the rectangular shape is 0.1 mm or less.
  • the optical characteristic measuring device can quickly acquire the state of subsurface scattering of light with high spatial resolution and in a state of wavelength decomposition. Further, since a large-scale configuration is not required, it is possible to prevent the device from becoming large in size.
  • FIG. 3 shows an example of the actual arrangement relationship of the illumination unit 1, the spectroscopic unit 4, the two-dimensional photoelectric conversion element 5, and the like of the optical characteristic measuring device shown in the block diagram of FIG.
  • the illumination side is tilted from the normal line of the measurement object 100, and the light receiving side is in the normal direction, but the arrangement is not limited to this.
  • the lens is designed so that the measurement object 100 and the two-dimensional photoelectric conversion element 5 are conjugated.
  • the illumination light from the illumination unit 1 having intensity in the visible light region is focused on the surface of the measurement object 100 by the lens 2 and locally irradiated, and the irradiation portion 11 and its vicinity are irradiated.
  • the light output from the surface of the non-illuminated portion 13 is spatially acquired one-dimensionally, separated by a spectroscopic unit 4 such as a one-dimensional diffraction grid, and then converted into an electric signal by a two-dimensional photoelectric conversion element 5.
  • a spectroscopic unit 4 such as a one-dimensional diffraction grid
  • the illumination unit 1 (illumination side) is prevented from detecting the specularly reflected light 30 from an angle. )
  • the two-dimensional photoelectric conversion element 5 (light receiving side) are set. In the example of FIG. 3, the illumination side is tilted from the sample normal and the light receiving side is in the normal direction, but the arrangement is not limited to this.
  • the one-dimensional direction in the one-dimensional spatial decomposition in other words, the extending direction of the measurement range 12, includes the optical axis of the irradiation light emitted from the illumination unit 1 to the illumination location 11, and vertically intersects the surface of the measurement object 100.
  • the direction is parallel or perpendicular to the surface of the object to be measured 100.
  • the left-right direction of the pixel surface in the two-dimensional photoelectric conversion element 5 shown in FIG. 4 (B) is The X direction and the vertical direction are the wavelength ⁇ directions, and the direction parallel to the vertically intersecting planes is the X direction.
  • FIG. 4A shows that the measurement range 12 extends in the X direction.
  • the direction of the measurement range 12 may be an in-plane direction or an out-plan direction.
  • FIG. 4C shows an example of light intensity at wavelengths of 500 nm and 700 nm for each spatial resolution when the one-dimensional spatial decomposition direction is the X direction.
  • FIG. 5 shows a state when the one-dimensional spatial decomposition direction is the Y direction.
  • FIG. 5A is a top view of the object to be measured 100
  • FIG. 5B is a two-dimensional photoelectric conversion element.
  • the pixel planes in No. 5 are shown respectively.
  • the directions of the pixel planes of the object 100 to be measured and the two-dimensional photoelectric conversion element 5 are the same as the directions shown in FIGS. 4 (A) and 4 (B), but in FIG. 5 (A), the measurement range 12 is the Y direction. Extends to.
  • a polarizing beam splitter 81 is interposed between the lens 3 and the spectroscopic unit 4, and the illumination light from the illumination unit 1 is guided to the illumination point 11 by the polarization beam splitter 81, and the measurement object 100 is used.
  • Light is directed to the two-dimensional photoelectric conversion element 5 via the lens 3, the polarizing beam splitter 81, and the spectroscopic unit 4.
  • a polarized beam splitter 81 that reflects P-polarized light and transmits S-polarized light is used, it will be illuminated with P-polarized light. , Only diffuse reflection can be detected.
  • a beam splitter 83 is arranged instead of the polarizing beam splitter 81, and deflectors 82 and 82 are arranged between the lens 2 and the beam splitter 83 and between the beam splitter 83 and the spectroscopic unit 4, respectively. ing. Further, the specularly reflected light may be removed by using circular polarization.
  • FIG. 8 is a diagram showing a configuration of an optical characteristic measuring device according to another embodiment of the present invention.
  • the two illuminating units 1a and 1b are arranged symmetrically with respect to the illuminating portion 11 of the measurement object 100, and the illuminating portion 11 is simultaneously irradiated with the illuminating light through different lenses 2a and 2b, respectively. It has become like.
  • the number of lighting units 1 may be three or more instead of two. Further, instead of arranging a plurality of illumination units 1, the position of one illumination unit 1 is changed to a position symmetrical with respect to the illumination location 11 of the measurement object 100, and the measurement data acquired at each position is changed.
  • the anisotropy may be offset from. However, it is preferable to use a plurality of illumination units 1 to simultaneously illuminate and take an image because the number of times of imaging by the two-dimensional photoelectric conversion element 5 is the same as or less than the number of the illumination units 1.
  • FIG. 9 is a diagram showing a configuration of an optical characteristic measuring device according to still another embodiment of the present invention.
  • the two illuminating units 1c and 1d are arranged at different angles with respect to the illuminating portion 11 of the measurement object 100, and the illuminating light has different angles at the illuminating portion 11 via different lenses 2c and 2d, respectively. It is designed to be irradiated with.
  • the transmittance of the illumination light on the surface of the object 100 depends on the aspecular angle (the angle indicating the inclination of the optical path of the reflected light from the specular reflection direction), it is often measured by changing the irradiation angle of the illumination light. Angle information can be obtained, and a lot of information can be obtained.
  • FIG. 9 shows the case of two different angles, but three or more may be used. Further, although the case where a plurality of lighting units 1c and 1d are arranged at different angles is shown, one lighting unit 1 may be moved and arranged at different angles. Further, as shown in FIG. 8, a plurality of illumination units 1a and 1b are arranged symmetrically with respect to the illumination portion 11 of the measurement object 100 to perform measurement, and the angles of the respective illumination units 1a and 1b are changed. It may be configured to perform further measurement.
  • the parameters calculated by the arithmetic processing are not limited, but some of the following can be exemplified.
  • the arithmetic processing by the arithmetic unit 6 is executed by operating a processor such as a CPU in a computer provided in the arithmetic unit 6 according to an application stored in a storage unit (none of which is shown).
  • a processor such as a CPU in a computer provided in the arithmetic unit 6 according to an application stored in a storage unit (none of which is shown).
  • the state of subsurface scattering of the measurement object 100 can be acquired for each wavelength.
  • FIG. 12A among the light illuminated by the illumination light 41 and entering under the surface of the measurement object 100a according to the size of the mask 42 (the size of the light receiving area), the light stays in the light receiving area and is detected. Since the ratio of the light Q and the light P that is not detected because the light is diffused outside the measurement range due to the edge loss changes, as shown in the left and right figures of FIG. 12B, a transparent measurement object Then, when the size of the mask 42 (light receiving area L and S area) changes, the color measurement value is also measured differently. Therefore, there is a problem that the color measurement values cannot be compatible with measuring instruments having different illumination systems and light receiving systems.
  • reference numeral 43 is an illumination area and 44 is an edge loss band.
  • the measurement of subsurface scattering may be useful as one of the features of the teacher data of computer color matching (CCM). Until now, CCM had only input color information, but adding subsurface scattering information to the input data may enable accurate mixed color estimation with a smaller number of teacher samples. Alternatively, more accurate color mixing estimation may be possible.
  • CCM computer color matching
  • FIG. 13 is a perspective view showing the appearance of the optical characteristic measuring device according to the embodiment of the present invention.
  • the optical characteristic measuring device is configured to be a portable handy type. Of course, it may be a bench top type.
  • the illumination unit 1, the lenses 2 and 3, the spectroscopic unit 4, the two-dimensional photoelectric conversion element 5, and the calculation unit 6 are housed in the housing 200. Further, the upper surface of the housing 200 is provided with a grip portion 202 for carrying, a display unit 7 for displaying a measurement result (calculation result) by the calculation unit 6, and a lower surface of the housing 200. Is formed with an opening 201 for irradiating the measurement object 100 with illumination light and taking in the light from the measurement object 100.
  • the optical characteristic measuring device shown in FIG. 13 grips the grip portion 202 and positions the opening 201 on the lower surface at the measurement target portion of the measurement object 100. Then, in this state, the illumination light is irradiated to the measurement object 100 from the illumination unit 1 housed inside the housing 200, and the light from the irradiation point 11 and its vicinity is separated by the spectroscopic unit 4 for two-dimensional photoelectric conversion.
  • the state of subsurface scattering of light is measured by receiving light from the element 5 and calculating with the calculation unit 6 using the imaging data output from the two-character photoelectric conversion element 5, and the measurement result is displayed on the measurement result display unit 7. It is designed to be displayed.
  • the state of subsurface scattering of light can be measured regardless of the location by carrying the housing 200.
  • the calculation unit 6 uses an external personal computer different from the housing 200, and transmits the imaging data output from the two-dimensional photoelectric conversion element 5 in the housing 200 to the external computer for measurement. It may be configured to be performed.
  • optical characteristic measuring device is not configured as a single measuring device, but may be built in an existing or new color measuring device.
  • the present invention can be used for measuring the subsurface diffusion of light incident on the surface of a measurement object.

Abstract

According to the present invention, among light emitted from a surface of a measurement subject (100) when the surface of the measurement subject (100) is illuminated in a localized manner with illumination light from an illumination means (1), the illumination light having an intensity in a wavelength band that includes the visible light region, a measurement range (12) that includes both light from all or part of an illumination location (11) and light from a location (13) that is near the illumination location but is not directly illuminated is one-dimensionally spatially resolved, spatially resolved light captured from each measurement location is split and received by an imaging means (5), and an image is captured.

Description

光学特性評価装置Optical characterization device
　この発明は、測定対象物の表面に入射した光の表面下拡散の測定に用いられる光学特性測定装置に関する。 The present invention relates to an optical characteristic measuring device used for measuring the subsurface diffusion of light incident on the surface of a measurement object.
　プラスチックや肌などの半透明物質では、物体に入射した光が表面下で散乱・拡散し、光が物体内に入射した箇所から離れた位置で出射する表面下散乱が起こる。この現象は透明度といったものの見え方に影響を与えるため、その表面下散乱の長さといった物理は、色空間におけるL*a*b*等の情報と同様に、物質のアピアランス特性を明らかにする上で重要である。 For translucent substances such as plastic and skin, light incident on an object is scattered and diffused under the surface, and subsurface scattering occurs in which light is emitted at a position away from the location where the light is incident on the object. Since this phenomenon affects the appearance of things such as transparency, physics such as the length of subsurface scattering reveals the appearance characteristics of matter as well as information such as L * a * b * in the color space. Is important.
　上記表面下散乱は、ものの見え方をヴァーチャルに再現するレンダリングの分野でよく研究されている。透明度を有する材料は身の回りに溢れており(大理石、肌、プラスチックなど)、そのアピアランスを正確に再現するためには表面下散乱の情報が必要となる。 The above subsurface scattering is well studied in the field of rendering that virtually reproduces the appearance of things. Transparent materials are everywhere around us (marble, skin, plastic, etc.), and subsurface scattering information is needed to accurately reproduce their appearance.
　また、表面下散乱は測色計の分野で度々問題となってきた”エッジロス”の補正に使える可能性がある。エッジロスは照明した光が検出領域の外側まで染み出してしまうことで生じる問題であるためである。この問題は特に異なる光学ジオメトリを有する測定器間の互換性において大きな問題となってきておりその補正には一定の需要がある。 In addition, subsurface scattering may be used to correct "edge loss," which has often been a problem in the field of colorimeters. This is because edge loss is a problem caused by the illuminated light seeping out to the outside of the detection area. This problem has become a major problem especially in compatibility between measuring instruments having different optical geometries, and there is a certain demand for its correction.
　さらに、表面下散乱の測定はコンピュータカラーマッチング（Computer Color Matching (CCM)）の教師データの特徴量の一つとして有用である可能性がある。これまでCCMは色情報の入力しかなかったが、表面下散乱の情報を入力データに追加することで、より少ない教師サンプル数で正確な混合色推定が可能になる可能性がある。もしくはより正確な混色推定が可能となる可能性がある。 Furthermore, the measurement of subsurface scattering may be useful as one of the features of the teacher data of Computer Color Matching (CCM). Until now, CCM had only input color information, but adding subsurface scattering information to the input data may enable accurate mixed color estimation with a smaller number of teacher samples. Alternatively, more accurate color mixing estimation may be possible.
　表面下散乱の測定において、その特性は材料により異なるため、幅広い材料で検知するためには、十分に広い空間測定レンジと十分に高い空間分解能を、同時に有することが望ましい。加えて、サンプル内を拡散する光は、色素による吸収や微粒子によるレイリー散乱など光の波長に依存した過程を経るため、表面下散乱測定は波長分解測定であることが望ましい。 In the measurement of subsurface scattering, its characteristics differ depending on the material, so it is desirable to have a sufficiently wide spatial measurement range and a sufficiently high spatial resolution at the same time in order to detect with a wide range of materials. In addition, since the light diffused in the sample undergoes a process depending on the wavelength of light such as absorption by a dye and Rayleigh scattering by fine particles, it is desirable that the subsurface scattering measurement is a wavelength decomposition measurement.
　従来、表面下拡散長を検出するために、非特許文献１には、被測定物を特定方向から点光源がサンプル上でフォーカスするよう照明し、照らされたサンプルを別角度に固定されたRGBカメラで測定し、フォーカス点を通過するカメラ角度に直行した一次元を解析することで表面下散乱を測定することが記載されている。 Conventionally, in order to detect the subsurface diffusion length, Non-Patent Document 1 illuminates an object to be measured from a specific direction so that a point light source focuses on the sample, and the illuminated sample is fixed at a different angle. It is described that the subsurface scattering is measured by measuring with a camera and analyzing one dimension orthogonal to the camera angle passing through the focus point.
　また、別の表面下散乱の測定方法として、非特許文献２には、複数のファイバーを利用することで光が横拡散する空間情報を捉え、さらに出射側のファイバーを分光イメージングユニットに接続することで分光まで行う方法が提案されている。 Further, as another method for measuring subsurface scattering, Non-Patent Document 2 describes spatial information in which light is laterally diffused by using a plurality of fibers, and further connects the fibers on the exit side to a spectroscopic imaging unit. A method of performing spectroscopy has been proposed.
　しかし、非特許文献１に記載の技術では、RGBカメラを利用しているため、表面拡散光の分光データを取得できず、また仮にRGBカメラの代わりに分光カメラを使用した場合でも、測定時間の増加や装置大型化が懸念される、という課題がある。 However, since the technique described in Non-Patent Document 1 uses an RGB camera, it is not possible to acquire spectroscopic data of surface diffused light, and even if a spectroscopic camera is used instead of the RGB camera, the measurement time is long. There is a problem that there is a concern about an increase in the number of devices and an increase in the size of the device.
　また非特許文献２に記載の技術での表面下散乱測定では、ファイバーの大きさ・個数により拡散長さの解像度・測定範囲が決まり、空間的に細かい測定を行うことが困難である、
という課題がある。 Further, in the subsurface scattering measurement by the technique described in Non-Patent Document 2, the resolution and measurement range of the diffusion length are determined by the size and number of fibers, and it is difficult to perform a spatially detailed measurement.
There is a problem.
　この発明は、このような技術的背景に鑑みてなされたものであって、高い空間解像度で撮像できるが分光データを取得できないとか、分光データを取得できるが高い空間解像度でデータを取得できないという課題を、装置の大型化と測定時間の増加を抑えた上で解決できる光学特性測定装置の提供を目的とする。 The present invention has been made in view of such a technical background, and has problems that it can image at a high spatial resolution but cannot acquire spectroscopic data, or it can acquire spectroscopic data but cannot acquire data at a high spatial resolution. It is an object of the present invention to provide an optical characteristic measuring device that can solve the problem while suppressing an increase in the size of the device and an increase in measurement time.
　上記目的は、以下の手段によって達成される。
（１）物体内部における光の表面下散乱を測定する光学特性測定装置であって、可視光領域を含む波長帯に強度を持った照明光で、測定対象物の表面を局所的に照明するための少なくとも１つの照明手段と、前記照明光で照明された前記測定対象物の表面より出射される光のうち、照明箇所の一部もしくは全部からの光と、照明箇所付近の直接照明されていない箇所からの光のどちらをも含む測定範囲を一次元的に空間分解して撮像できる撮像手段と、前記撮像手段の上流側において、前記空間分解された各測定箇所から取り込んだ光を分光する分光手段と、を備え、前記撮像手段は、前記分光手段で分光された波長毎の光を受光する光学特性測定装置。
（２）前記照明手段は１つである前項１に記載の光学特性測定装置。
（３）前記照明手段は２つ以上であり、各照明手段が前記測定対象物の照明箇所に対して対称に配置されている前項１に記載の光学特性測定装置。
（４）前記照明手段により異なる角度から前記測定対象物の表面を照明し、前記撮像手段は、異なる角度で照明されたときの光をそれぞれ受光して撮像する前項１に記載の光学特性測定装置。
（５）局所的に照明とは、測定対象物の表面上での照明強度の空間分布が矩形もしくは矩形に近い形である前項１～４のいずれかに記載の光学特性測定装置。
（６）前記分光手段が分光する波長領域は、３００－８００ｎｍの範囲内の領域である前項１～５のいずれかに記載の光学特性測定装置。
（７）前記分光手段が分光する波長分解能は３０ｎｍよりも細かい前項１～６のいずれかに記載の光学特性測定装置。
（８）一次元的に空間分解された測定範囲は１ｍｍよりも大きい前項１～７のいずれかに記載の光学特性測定装置。
（９）一次元的に空間分解された測定範囲の分解能は０．１ｍｍよりも細かい前項１～８のいずれかに記載の光学特性測定装置。
（１０）一次元的な空間分解における一次元方向とは、前記照明手段から前記照明箇所への照射光の光軸を含み測定対象物の表面と交差する鉛直面に対して、測定対象物の表面上で平行もしくは垂直な方向である前項１～９のいずれかに記載の光学特性測定装置。
（１１）測定対象物の表面からの正反射光の取り込みを防止する正反射光除去機構を備えている前項１～１０のいずれかに記載の光学特性測定装置。
（１２）前記正反射光除去機構は、測定対象物の表面への入射光とその正反射光とを、角度的に検出しないように、前記照明手段と前記撮像手段の位置関係が設定されることによるものである前項１１に記載の光学特性測定装置。
（１３）前記正反射光除去機構は、照明手段側を直線偏光に変更し、受光側にその偏光と垂直なもののみを抽出する機構により構成されている前項１１に記載の光学特性測定装置。
（１４）前記撮像手段による撮像回数は、前記照明手段の数と同じかもしくはそれ以下の回数である前項１～１３のいずれかに記載の光学特性測定装置。
（１５）前記撮像手段により得られた各画素の画素値より、光の表面下散乱に関する一つ以上のパラメーターを算出する演算部を備えている前項１～１４のいずれかに記載の光学特性測定装置。
（１６）前記パラメーターは、表面下散乱の散乱長を特徴づける値である前項１５に記載の光学特性測定装置。
（１７）前記パラメーターは、コンピュータグラフィックにおけるレンダリングの入力値である前項１５または１６に記載の光学特性測定装置。
（１８）前記パラメーターは、エッジロスの補正係数である前項１５または１６に記載の光学特性測定装置。
（１９）前記パラメーターは、コンピュータカラーマッチングの入力値である前項１５または１６に記載の光学特性測定装置。
（２０）前記演算部は、外部のパーソナルコンピュータによって構成されている前項１５～１９のいずれかに記載の光学特性測定装置。
（２１）前記照明手段、撮像手段及び分光手段を収容する筐体を備え、前記筐体には、前記測定対象物の表面に照明光を照射し、測定対象物の表面より出射される光を取り込むための開口と、測定結果を表示するための表示手段を備えている前項１～２０のいずれかに記載の光学特性測定装置。
（２２）測色装置に内蔵されている前項１～２１のいずれかに記載の光学特性測定装置。 The above object is achieved by the following means.
(1) An optical characteristic measuring device for measuring subsurface scattering of light inside an object, for locally illuminating the surface of an object to be measured with illumination light having intensity in a wavelength band including a visible light region. Of the light emitted from the surface of the measurement object illuminated by the illumination light and at least one of the illumination means, the light from a part or all of the illumination portion and the light not directly illuminated in the vicinity of the illumination portion. An imaging means capable of unilaterally spatially decomposing a measurement range including both of the light from a location and imaging, and a spectrum that disperses the light captured from each spatially decomposed measurement location on the upstream side of the imaging means. An optical characteristic measuring device comprising means, and the imaging means receives light for each wavelength dispersed by the spectroscopic means.
(2) The optical characteristic measuring device according to item 1 above, wherein the lighting means is one.
(3) The optical characteristic measuring device according to item 1 above, wherein the number of the lighting means is two or more, and each lighting means is arranged symmetrically with respect to the lighting location of the measurement object.
(4) The optical characteristic measuring apparatus according to item 1 above, wherein the lighting means illuminates the surface of the object to be measured from different angles, and the imaging means receives and captures light when illuminated at different angles. ..
(5) Locally illuminated is the optical characteristic measuring apparatus according to any one of the above items 1 to 4, wherein the spatial distribution of the illumination intensity on the surface of the object to be measured is a rectangle or a shape close to a rectangle.
(6) The optical characteristic measuring apparatus according to any one of the above items 1 to 5, wherein the wavelength region dispersed by the spectroscopic means is a region within a range of 300 to 800 nm.
(7) The optical characteristic measuring apparatus according to any one of the above items 1 to 6, wherein the wavelength resolution dispersed by the spectroscopic means is finer than 30 nm.
(8) The optical characteristic measuring apparatus according to any one of the above items 1 to 7, wherein the one-dimensionally spatially decomposed measuring range is larger than 1 mm.
(9) The optical characteristic measuring apparatus according to any one of the above items 1 to 8, wherein the resolution of the one-dimensionally spatially decomposed measurement range is finer than 0.1 mm.
(10) The one-dimensional direction in the one-dimensional spatial decomposition means the vertical surface of the object to be measured, including the optical axis of the irradiation light from the illuminating means to the illuminating portion, and intersecting the surface of the object to be measured. The optical characteristic measuring apparatus according to any one of the above items 1 to 9, which is in a parallel or vertical direction on the surface.
(11) The optical characteristic measuring apparatus according to any one of the preceding items 1 to 10, further comprising a specularly reflected light removing mechanism for preventing the capture of specularly reflected light from the surface of the object to be measured.
(12) The specularly reflected light removing mechanism sets the positional relationship between the illuminating means and the imaging means so as not to angularly detect the incident light on the surface of the object to be measured and the specularly reflected light. The optical characteristic measuring apparatus according to item 11 above.
(13) The optical characteristic measuring apparatus according to item 11, wherein the specular light removing mechanism is configured by a mechanism that changes the illumination means side to linearly polarized light and extracts only those perpendicular to the polarized light on the light receiving side.
(14) The optical characteristic measuring apparatus according to any one of items 1 to 13 above, wherein the number of times of imaging by the imaging means is the same as or less than the number of the lighting means.
(15) The optical characteristic measurement according to any one of items 1 to 14 above, which includes a calculation unit that calculates one or more parameters related to subsurface scattering of light from the pixel values of each pixel obtained by the imaging means. Device.
(16) The optical characteristic measuring apparatus according to item 15 above, wherein the parameter is a value that characterizes the scattering length of subsurface scattering.
(17) The optical characteristic measuring device according to item 15 or 16 above, wherein the parameter is an input value for rendering in computer graphics.
(18) The optical characteristic measuring apparatus according to item 15 or 16 above, wherein the parameter is an edge loss correction coefficient.
(19) The optical characteristic measuring device according to item 15 or 16 above, wherein the parameter is an input value for computer color matching.
(20) The optical characteristic measuring device according to any one of items 15 to 19 above, wherein the arithmetic unit is configured by an external personal computer.
(21) A housing for accommodating the illumination means, an imaging means, and a spectroscopic means is provided, and the housing irradiates the surface of the measurement object with illumination light and emits light emitted from the surface of the measurement object. The optical characteristic measuring apparatus according to any one of the preceding items 1 to 20, further comprising an opening for taking in and a display means for displaying the measurement result.
(22) The optical characteristic measuring device according to any one of the preceding items 1 to 21, which is built in the color measuring device.
　前項（１）に記載の発明によれば、可視光領域を含む波長帯に強度を持った照明光で、測定対象物の表面を局所的に照明したときの、測定対象物の表面より出射される光のうち、照明箇所の一部もしくは全部からの光と、照明箇所付近の直接照明されていない箇所からの光のどちらもを含む測定範囲を一次元的に空間分解し、空間分解された各測定箇所から取り込んだ光を分光して撮像手段により受光し撮像するから、光の表面下散乱の様子を高い空間解像度で、しかも波長分解した状態で迅速に取得することができる。また、大がかりな構成は不要であるから、装置の大型化を防ぐことができる。 According to the invention described in the previous section (1), the illumination light having intensity in the wavelength band including the visible light region is emitted from the surface of the measurement object when the surface of the measurement object is locally illuminated. The measurement range including both the light from a part or all of the illuminated area and the light from the unilluminated area near the illuminated area was spatially decomposed in a one-dimensional manner. Since the light captured from each measurement point is separated and received by the imaging means for imaging, the state of subsurface scattering of light can be quickly acquired with high spatial resolution and in a state of wavelength decomposition. Further, since a large-scale configuration is not required, it is possible to prevent the device from becoming large in size.
　前項（２）に記載の発明によれば、１つの照明手段を用いて光の表面下散乱の様子を測定することができる。 According to the invention described in the preceding paragraph (2), the state of subsurface scattering of light can be measured using one lighting means.
　前項（３）に記載の発明によれば、照明手段は２つ以上であり、各照明手段が測定対象物の照明箇所に対して対称に配置されているから、照明箇所及びその付近の異方性を相殺でき、より精度の高い測定が可能となる。 According to the invention described in the preceding paragraph (3), there are two or more lighting means, and each lighting means is arranged symmetrically with respect to the lighting point of the object to be measured. The symmetry can be offset, and more accurate measurement becomes possible.
　前項（４）に記載の発明によれば、照明手段により異なる角度から測定対象物の表面を照明して撮像することで、多角度での情報を取得でき、さらに詳細な測定が可能となる。 According to the invention described in the preceding paragraph (4), by illuminating the surface of the object to be measured from different angles with an illuminating means and taking an image, information at multiple angles can be acquired and more detailed measurement becomes possible.
　前項（５）に記載の発明によれば、局所的に照明とは、測定対象物の表面上での照明強度の空間分布が矩形もしくは矩形に近い形であるから、照明箇所と直接照明されていない箇所との境界が明確になり、光の表面下散乱の精度の高い測定が可能となる。 According to the invention described in the previous section (5), the local illumination is directly illuminated with the illuminated portion because the spatial distribution of the illumination intensity on the surface of the object to be measured is a rectangle or a shape close to a rectangle. The boundary with the non-existent part becomes clear, and it becomes possible to measure the subsurface scattering of light with high accuracy.
　前項（６）に記載の発明によれば、３００－８００ｎｍの範囲内の波長領域で測定が行われる。 According to the invention described in the preceding paragraph (6), the measurement is performed in the wavelength region within the range of 300 to 800 nm.
　前項（７）に記載の発明によれば、３０ｎｍよりも細かい波長分解能で高精度な測定が行われる。 According to the invention described in the previous section (7), highly accurate measurement is performed with a wavelength resolution finer than 30 nm.
　前項（８）に記載の発明によれば、１ｍｍよりも大きい測定範囲を一次元的に空間分解して撮像が行われる。 According to the invention described in the preceding paragraph (8), a measurement range larger than 1 mm is unilaterally spatially decomposed for imaging.
　前項（９）に記載の発明によれば、一次元的に空間分解された測定範囲の分解能は０．１ｍｍよりも細かいから、精度の高い測定を行うことができる。 According to the invention described in the previous section (9), the resolution of the one-dimensionally spatially decomposed measurement range is finer than 0.1 mm, so that highly accurate measurement can be performed.
　前項（１０）に記載の発明によれば、照明手段から照明箇所への照射光の光軸を含み測定対象物の表面と交差する鉛直面に対して、測定対象物の表面上の平行もしくは垂直な方向において、測定が行われる。 According to the invention described in the preceding paragraph (10), parallel or perpendicular to the vertical surface of the object to be measured, including the optical axis of the irradiation light from the illuminating means to the illuminating portion and intersecting the surface of the object to be measured. Measurements are taken in different directions.
　前項（１１）に記載の発明によれば、測定対象物の表面からの正反射光の取り込みが防止されるから、正反射光による影響を受けることなく、光の表面下散乱の様子を測定することができる。 According to the invention described in the previous section (11), since the uptake of specularly reflected light from the surface of the object to be measured is prevented, the state of subsurface scattering of light is measured without being affected by the specularly reflected light. be able to.
　前項（１２）に記載の発明によれば、測定対象物の表面への入射光とその正反射光とを、角度的に検出しないように、照明手段と撮像手段の位置関係が設定されるから、簡易な方法で正反射光を除去できる。 According to the invention described in the previous section (12), the positional relationship between the illuminating means and the imaging means is set so as not to detect the incident light on the surface of the measurement object and the specularly reflected light from an angle. Specularly reflected light can be removed by a simple method.
　前項（１３）に記載の発明によれば、照明手段側を直線偏光に変更し、受光側にその偏光と垂直なもののみを抽出する機構により、正反射光を確実に除去できる。 According to the invention described in the preceding paragraph (13), specularly reflected light can be reliably removed by a mechanism that changes the illumination means side to linearly polarized light and extracts only those perpendicular to the polarized light on the light receiving side.
　前項（１４）に記載の発明によれば、撮像手段による撮像回数は、前記照明手段の数と同じかもしくはそれ以下の回数であるから、高速な測定が可能となる。 According to the invention described in the preceding paragraph (14), the number of times of imaging by the imaging means is the same as or less than the number of the lighting means, so that high-speed measurement is possible.
　前項（１５）に記載の発明によれば、撮像手段により得られた各画素の画素値より、光の表面下散乱に関する一つ以上のパラメーターを算出できる。 According to the invention described in the previous section (15), one or more parameters related to subsurface scattering of light can be calculated from the pixel values of each pixel obtained by the imaging means.
　前項（１６）に記載の発明によれば、撮像手段により得られた各画素の画素値より、表面下散乱の散乱長を特徴づける値を算出できる。 According to the invention described in the previous section (16), a value that characterizes the scattering length of subsurface scattering can be calculated from the pixel value of each pixel obtained by the imaging means.
　前項（１７）に記載の発明によれば、撮像手段により得られた各画素の画素値より、コンピュータグラフィックにおけるレンダリングの入力値を算出できる。 According to the invention described in the preceding paragraph (17), the input value for rendering in computer graphics can be calculated from the pixel value of each pixel obtained by the imaging means.
　前項（１８）に記載の発明によれば、撮像手段により得られた各画素の画素値より、エッジロスの補正係数を算出できる。 According to the invention described in the preceding paragraph (18), the edge loss correction coefficient can be calculated from the pixel value of each pixel obtained by the imaging means.
　前項（１９）に記載の発明によれば、撮像手段により得られた各画素の画素値より、コンピュータカラーマッチングの入力値を算出できる。 According to the invention described in the preceding paragraph (19), the input value of computer color matching can be calculated from the pixel value of each pixel obtained by the imaging means.
　前項（２０）に記載の発明によれば、外部のパーソナルコンピュータによって、光の表面下散乱に関する一つ以上のパラメーターを算出できる。 According to the invention described in the preceding paragraph (20), one or more parameters related to subsurface scattering of light can be calculated by an external personal computer.
　前項（２１）に記載の発明によれば、コンパクトな光学特性測定装置とすることができる。 According to the invention described in the preceding paragraph (21), a compact optical characteristic measuring device can be obtained.
　前項（２２）に記載の発明によれば、表面下拡散の測定を行うことができる測色装置を提供できる。 According to the invention described in the preceding paragraph (22), it is possible to provide a color measuring device capable of measuring subsurface diffusion.
この発明の一実施形態に係る光学特性測定装置の構成を示すブロック図である。It is a block diagram which shows the structure of the optical characteristic measuring apparatus which concerns on one Embodiment of this invention. （Ａ）（Ｂ）は、照明箇所と測定範囲の関係を説明するための図である。(A) and (B) are diagrams for explaining the relationship between the illuminated portion and the measurement range. 図１のブロック図に示した光学特性測定装置の照明手段、分光手段、撮像手段等の実際の配置関係を示す図である。It is a figure which shows the actual arrangement relation of the lighting means, the spectroscopic means, the imaging means, etc. of the optical characteristic measuring apparatus shown in the block diagram of FIG. 一次元的な空間分解における一次元方向を説明するための図で、（Ａ）は測定対象物の上面図、（Ｂ）は２次元光電変換素子の画素面を示す図、（Ｃ）は、一次元的な空間分解方向がＸ方向であるときの空間分解能毎の、波長５００ｎｍと７００ｎｍについての光の強度の一例を示す図である。It is a figure for demonstrating the one-dimensional direction in one-dimensional spatial decomposition, (A) is the top view of the object to be measured, (B) is the figure which shows the pixel plane of a two-dimensional photoelectric conversion element, (C) is It is a figure which shows an example of the light intensity with respect to wavelengths 500nm and 700nm for each spatial resolution when a one-dimensional spatial decomposition direction is X direction. 一次元的な空間分解における一次元方向についての他の例を説明するための図で、（Ａ）は測定対象物の上面図、（Ｂ）は２次元光電変換素子の画素面を示す図である。It is a figure for demonstrating another example about one-dimensional direction in one-dimensional spatial decomposition, (A) is the top view of the object of measurement, (B) is the figure which shows the pixel plane of a two-dimensional photoelectric conversion element be. 偏光により正反射光を除去する例を示す図である。It is a figure which shows the example which removes specularly reflected light by polarized light. 偏光により正反射光を除去する他の例を示す図である。It is a figure which shows another example which removes specularly reflected light by polarization. この発明の他の実施形態に係る光学特性測定装置の構成を示す図である。It is a figure which shows the structure of the optical characteristic measuring apparatus which concerns on other embodiment of this invention. この発明のさらに他の実施形態に係る光学特性測定装置の構成を示す図である。It is a figure which shows the structure of the optical characteristic measuring apparatus which concerns on still another Embodiment of this invention. 内部反射光の輝度分布の一例を示す図である。It is a figure which shows an example of the luminance distribution of the internally reflected light. （Ａ）は通常の測色(表面下散乱の効果を考慮しない測定)では表現できない測定対象物の表面状態の一例を示す図、（Ｂ）は質感をより忠実に再現した測定対象物の表面状態を示す図である。(A) is a diagram showing an example of the surface state of the measurement object that cannot be expressed by normal color measurement (measurement that does not consider the effect of subsurface scattering), and (B) is the surface of the measurement object that more faithfully reproduces the texture. It is a figure which shows the state. （Ａ）（Ｂ）はエッジロスを説明するための図である。(A) and (B) are diagrams for explaining edge loss. この発明の一実施形態に係る光学特性測定装置の外観を示す斜視図である。It is a perspective view which shows the appearance of the optical characteristic measuring apparatus which concerns on one Embodiment of this invention.
　以下、この発明の実施形態を図面に基づいて説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図１はこの発明の一実施形態に係る光学特性測定装置の構成を示すブロック図である。光学特性測定装置は、１つの照明部１を備え、照明部１からの光をレンズ２を介して集光し、測定対象物１００の表面を照明するようになっている。 FIG. 1 is a block diagram showing a configuration of an optical characteristic measuring device according to an embodiment of the present invention. The optical characteristic measuring device includes one illuminating unit 1, and collects the light from the illuminating unit 1 through the lens 2 to illuminate the surface of the object to be measured 100.
　照明部１による照明光は、可視光領域を含む波長帯に強度を持った照明光であり、レンズ２の作用とも相俟って測定対象物１００の表面を局所的に照明する。局所的に照明とは、測定対象物１００の表面における照明箇所と照明箇所付近の直接照明されていない箇所との差が明確であることを意味する。具体的には、限定はされないが、測定対象物１００の表面上での照明強度の空間分布が、照明箇所と直接照明されていない箇所との境界で立下がる矩形もしくは矩形に近い形であるのが望ましい。これにより、光の表面下散乱の精度の高い測定が可能となる。 The illumination light by the illumination unit 1 is illumination light having intensity in the wavelength band including the visible light region, and together with the action of the lens 2, locally illuminates the surface of the measurement object 100. Locally illuminating means that the difference between the illuminated portion on the surface of the object to be measured 100 and the unilluminated portion in the vicinity of the illuminated portion is clear. Specifically, although not limited, the spatial distribution of the illumination intensity on the surface of the measurement object 100 is a rectangle or a shape close to a rectangle that falls at the boundary between the illuminated portion and the portion that is not directly illuminated. Is desirable. This enables highly accurate measurement of subsurface scattering of light.
　測定対象物１００の表面の照射箇所に照明された光が、測定対象物１００の表面下に侵入し、光が拡散する空間的な様子を、レンズ３を介して分光部４により波長分解した形で、撮像手段としての２次元光電変換素子５により受光し撮像してデータを取得する。このとき測定対象物１００の表面と２次元光電変換素子５は共役関係にあることが望ましいが、限定はされない。また、２次元光電変換素子５の受光範囲（測定範囲）は、限定はされないが、測定対象物１００の表面上で１ｍｍ以上とするのが良く、この測定範囲で測定対象物１００からの光を一次元的に空間分解して受光する。空間分解能は測定精度を高くするため０．１ｍｍより小さいことが望ましいが、その限りではない。 The spatial appearance in which the light illuminated on the irradiated portion on the surface of the measurement object 100 penetrates under the surface of the measurement object 100 and the light is diffused is wavelength-resolved by the spectroscopic unit 4 through the lens 3. Then, the two-dimensional photoelectric conversion element 5 as an image pickup means receives light and takes an image to acquire data. At this time, it is desirable that the surface of the object to be measured 100 and the two-dimensional photoelectric conversion element 5 have a conjugated relationship, but the present invention is not limited. The light receiving range (measurement range) of the two-dimensional photoelectric conversion element 5 is not limited, but is preferably 1 mm or more on the surface of the measurement object 100, and the light from the measurement object 100 is emitted in this measurement range. It is spatially decomposed in one dimension and receives light. The spatial resolution is preferably smaller than 0.1 mm in order to improve the measurement accuracy, but this is not the case.
　図２（Ａ）に示すように、２次元光電変換素子５により撮像される測定範囲１２には、照明光で照明された測定対象物１００の表面より出射される光のうち、照明箇所１１の全部からの光と、照明箇所付近の直接照明されていない非照明箇所１３からの光のどちらもが含まれる。あるいは、図２（Ｂ）に示すように、照明箇所１１の一部からの光と、照明箇所付近の直接照明されていない非照明箇所１３からの光のどちらもが含まれる。つまり、照明箇所１１からの光は、照明箇所１１の一部であっても全部であっても良いが、いずれの場合も、照明箇所付近の直接照明されていない非照明箇所１３からの光が測定範囲１２に含まれる。 As shown in FIG. 2A, in the measurement range 12 imaged by the two-dimensional photoelectric conversion element 5, among the light emitted from the surface of the measurement object 100 illuminated by the illumination light, the illumination location 11 Both the light from all and the light from the non-illuminated portion 13 near the illuminated portion that is not directly illuminated are included. Alternatively, as shown in FIG. 2B, both the light from a part of the illuminated portion 11 and the light from the non-illuminated portion 13 near the illuminated portion that is not directly illuminated are included. That is, the light from the illuminated portion 11 may be a part or the entire portion of the illuminated portion 11, but in either case, the light from the non-illuminated portion 13 near the illuminated portion is not directly illuminated. It is included in the measurement range 12.
　分光部４は、２次元光電変換素子５上での分光方向が測定方向と垂直な方向となるように波長分解する。分光部４は、回折格子によってでも良いし、リニアバリアブルフィルター（Liner Variable Filter (LVF)）などを利用したフィルター方式であっても良いが、３００－８００ｎｍの範囲内の波長領域、特に可視光領域である４００－７００ｎｍ程度の範囲内の波長領域を３０ｎｍよりも細かい波長分解能で分解できることが望ましい。このような波長分解能により高精度な測定を行うことができる。 The spectroscopic unit 4 decomposes wavelengths so that the spectral direction on the two-dimensional photoelectric conversion element 5 is perpendicular to the measurement direction. The spectroscopic unit 4 may be a diffraction grating or a filter method using a linear variable filter (LVF) or the like, but has a wavelength region in the range of 300 to 800 nm, particularly a visible light region. It is desirable that the wavelength region in the range of about 400 to 700 nm can be resolved with a wavelength resolution finer than 30 nm. With such wavelength resolution, highly accurate measurement can be performed.
　分光された各波長の光を２次元光電変換素子５の各画素により受光して光電変換された撮像データとしての電気信号は、図示しない電流－電圧変換回路（IV変換回路）、アナログ－デジタル変換回路（AD変換回路)を通じてデジタル信号とされ、演算部６で演算処理に供される。表示部７は演算結果を表示する。演算部６での演算処理については後述する。 The electrical signal as the imaging data obtained by receiving the dispersed light of each wavelength by each pixel of the two-dimensional photoelectric conversion element 5 and performing photoelectric conversion is a current-voltage conversion circuit (IV conversion circuit) and analog-to-digital conversion (not shown). It is converted into a digital signal through a circuit (AD conversion circuit) and is subjected to arithmetic processing by the arithmetic unit 6. The display unit 7 displays the calculation result. The arithmetic processing in the arithmetic unit 6 will be described later.
　ここで、上記空間分解能と光の表面下散乱長との関係性について述べる。表面下散乱についての先行研究によれば、例えば試料が肌である場合、照明箇所から０．３ｍｍ程度で光量は１／２となり、１．０ｍｍ程度で１／４程度となる。そのため、空間分解能は０．１ｍｍ以下であることが望ましく、測定範囲は１．０ｍｍ以上であることが望ましい。 Here, the relationship between the above spatial resolution and the subsurface scattering length of light will be described. According to previous studies on subsurface scattering, for example, when the sample is skin, the amount of light is halved at about 0.3 mm from the illuminated area, and about 1/4 at about 1.0 mm. Therefore, the spatial resolution is preferably 0.1 mm or less, and the measurement range is preferably 1.0 mm or more.
　また、その撮像範囲は光源により直接照明されている照明箇所１１以外の非照明箇所１３だけで１．０ｍｍ以上であることが望ましい。また照明強度の空間分布は矩形に近いことが望ましく、矩形形状と比べたときのボケ量が０．１ｍｍ以下であることが望ましい。 Further, it is desirable that the imaging range is 1.0 mm or more only in the non-illuminated portion 13 other than the illuminated portion 11 directly illuminated by the light source. Further, it is desirable that the spatial distribution of the illumination intensity is close to a rectangle, and it is desirable that the amount of blurring when compared with the rectangular shape is 0.1 mm or less.
　このように、この実施形態に係る光学特性測定装置は、光の表面下散乱の様子を高い空間解像度で、しかも波長分解した状態で迅速に取得することができる。また、大がかりな構成は不要であるから、装置の大型化を防ぐことができる。 As described above, the optical characteristic measuring device according to this embodiment can quickly acquire the state of subsurface scattering of light with high spatial resolution and in a state of wavelength decomposition. Further, since a large-scale configuration is not required, it is possible to prevent the device from becoming large in size.
　図１のブロック図に示した光学特性測定装置の照明部１、分光部４、２次元光電変換素子５等の実際の配置関係の一例を図３に示す。図３では、照明側が測定対象物１００の法線より傾いており、受光側が法線方向にあるが、この配置に限定されることはない。また、測定対象物１００と２次元光電変換素子５とは共役となるようレンズが設計されている。 FIG. 3 shows an example of the actual arrangement relationship of the illumination unit 1, the spectroscopic unit 4, the two-dimensional photoelectric conversion element 5, and the like of the optical characteristic measuring device shown in the block diagram of FIG. In FIG. 3, the illumination side is tilted from the normal line of the measurement object 100, and the light receiving side is in the normal direction, but the arrangement is not limited to this. Further, the lens is designed so that the measurement object 100 and the two-dimensional photoelectric conversion element 5 are conjugated.
　図３に示した実施形態では、可視光領域に強度を持つ照明部１からの照明光を、レンズ２により測定対象物１００の表面にフォーカスさせ局所的に照射し、照射箇所１１とその付近の非照明箇所１３の表面から出力される光を空間一次元的に取得し、一次元回折格子等の分光部４により分光した後、２次元光電変換素子５により電気信号に変換する。直接照明されていない非照明箇所１３も測定することで、照明箇所１１に侵入した光が測定対象物１００の表面下で散乱する様子を測定することができる。従って、一度の撮像により、光の表面下散乱の様子を波長別に取得することが可能となる。 In the embodiment shown in FIG. 3, the illumination light from the illumination unit 1 having intensity in the visible light region is focused on the surface of the measurement object 100 by the lens 2 and locally irradiated, and the irradiation portion 11 and its vicinity are irradiated. The light output from the surface of the non-illuminated portion 13 is spatially acquired one-dimensionally, separated by a spectroscopic unit 4 such as a one-dimensional diffraction grid, and then converted into an electric signal by a two-dimensional photoelectric conversion element 5. By measuring the non-illuminated portion 13 that is not directly illuminated, it is possible to measure how the light that has entered the illuminated portion 11 is scattered under the surface of the measurement object 100. Therefore, it is possible to acquire the state of subsurface scattering of light for each wavelength by one imaging.
　また、測定対象物１００の表面への正反射光３０が検出されると、表面下散乱の測定精度が低下するため、正反射光３０を角度的に検出しないように、照明部１(照明側）と２次元光電変換素子５（受光側）の位置関係が設定されている。図３の例では、照明側がサンプル法線より傾いており、受光側が法線方向にあるが、その配置に限定されるものではない。 Further, when the specularly reflected light 30 on the surface of the object to be measured 100 is detected, the measurement accuracy of the subsurface scattering is lowered. Therefore, the illumination unit 1 (illumination side) is prevented from detecting the specularly reflected light 30 from an angle. ) And the two-dimensional photoelectric conversion element 5 (light receiving side) are set. In the example of FIG. 3, the illumination side is tilted from the sample normal and the light receiving side is in the normal direction, but the arrangement is not limited to this.
　一次元的な空間分解における一次元方向、換言すれば測定範囲１２の延びる方向は、照明部１から照明箇所１１へ照射される照射光の光軸を含み測定対象物１００の表面と鉛直に交差する面に対して、測定対象物１００の表面上で平行もしくは垂直な方向である。 The one-dimensional direction in the one-dimensional spatial decomposition, in other words, the extending direction of the measurement range 12, includes the optical axis of the irradiation light emitted from the illumination unit 1 to the illumination location 11, and vertically intersects the surface of the measurement object 100. The direction is parallel or perpendicular to the surface of the object to be measured 100.
　図４（Ａ）に示す測定対象物１００の上面図において、左右方向をＸ方向、上下方向をＹ方向とすると、図４（Ｂ）に示す２次元光電変換素子５における画素面の左右方向がＸ方向、上下方向が波長λ方向となり、上記鉛直に交差する面に対して平行な方向はＸ方向となる。図４（Ａ）では測定範囲１２がＸ方向に延びていることを示している。なお、測定範囲１２の方向は面内（in-plane）方向でも面外（out-plan）方向でも良い。一次元的な空間分解方向がＸ方向であるときの空間分解能毎の、波長５００ｎｍと７００ｎｍについての光の強度の一例を図４（Ｃ）に示す。 In the top view of the measurement object 100 shown in FIG. 4 (A), assuming that the left-right direction is the X direction and the up-down direction is the Y direction, the left-right direction of the pixel surface in the two-dimensional photoelectric conversion element 5 shown in FIG. 4 (B) is The X direction and the vertical direction are the wavelength λ directions, and the direction parallel to the vertically intersecting planes is the X direction. FIG. 4A shows that the measurement range 12 extends in the X direction. The direction of the measurement range 12 may be an in-plane direction or an out-plan direction. FIG. 4C shows an example of light intensity at wavelengths of 500 nm and 700 nm for each spatial resolution when the one-dimensional spatial decomposition direction is the X direction.
　図５は、一次元的な空間分解方向がＹ方向であるときの状態を示すものであり、同図（Ａ）は測定対象物１００の上面図、同図（Ｂ）は２次元光電変換素子５における画素面をそれぞれ示す。測定対象物１００及び２次元光電変換素子５の画素面の各方向は、図４（Ａ）（Ｂ）にそれぞれ示した方向と同じであるが、図５（Ａ）では測定範囲１２がＹ方向に延びている。 FIG. 5 shows a state when the one-dimensional spatial decomposition direction is the Y direction. FIG. 5A is a top view of the object to be measured 100, and FIG. 5B is a two-dimensional photoelectric conversion element. The pixel planes in No. 5 are shown respectively. The directions of the pixel planes of the object 100 to be measured and the two-dimensional photoelectric conversion element 5 are the same as the directions shown in FIGS. 4 (A) and 4 (B), but in FIG. 5 (A), the measurement range 12 is the Y direction. Extends to.
　ところで、測定対象物１００の照明箇所１１へ局所的に照射された照明光の正反射光３０が、２次元光電変換素子５に侵入すると、測定対象物１００の表面下での散乱を高精度に測定することができない。このため、図３の例では前述したように、測定対象物１００の表面からの正反射光３０を角度的に検出しないように、照明部１(照明側）と２次元光電変換素子５（受光側）の位置関係が設定されている構成としたが、図６及び図７のように、偏光により正反射光３０を除去しても良い。 By the way, when the specularly reflected light 30 of the illumination light locally applied to the illumination portion 11 of the measurement object 100 penetrates into the two-dimensional photoelectric conversion element 5, the scattering under the surface of the measurement object 100 is highly accurate. Cannot measure. Therefore, in the example of FIG. 3, as described above, the illumination unit 1 (illumination side) and the two-dimensional photoelectric conversion element 5 (light receiving light) so as not to detect the specularly reflected light 30 from the surface of the measurement object 100 from an angle. Although the positional relationship on the side) is set, the specularly reflected light 30 may be removed by polarization as shown in FIGS. 6 and 7.
　図６の例では偏光ビームスプリッター８１を、レンズ３と分光部４との間に介在させ、照明部１からの照明光を偏光ビームスプリッター８１で照明箇所１１へと導き、測定対象物１００からの光をレンズ３、偏光ビームスプリッター８１、分光部４を介して２次元光電変換素子５へと導くようになっている。具体的には、例えばＰ偏光を反射、Ｓ偏光を透過する偏光ビームスプリッター８１を使用すると、Ｐ偏光で照明することになるため、正反射光もＰ偏光のため偏光ビームスプリッター８１を透過せず、拡散反射のみを検出できる。 In the example of FIG. 6, a polarizing beam splitter 81 is interposed between the lens 3 and the spectroscopic unit 4, and the illumination light from the illumination unit 1 is guided to the illumination point 11 by the polarization beam splitter 81, and the measurement object 100 is used. Light is directed to the two-dimensional photoelectric conversion element 5 via the lens 3, the polarizing beam splitter 81, and the spectroscopic unit 4. Specifically, for example, if a polarized beam splitter 81 that reflects P-polarized light and transmits S-polarized light is used, it will be illuminated with P-polarized light. , Only diffuse reflection can be detected.
　図７の例では、偏光ビームスプリッター８１の代わりに、ビームスプリッター８３を配置し、レンズ２とビームスプリッター８３の間及びビームスプリッター８３と分光部４の間に、それぞれ偏向子８２、８２を配置している。また、円偏光を利用して正反射光を除去しても良い。 In the example of FIG. 7, a beam splitter 83 is arranged instead of the polarizing beam splitter 81, and deflectors 82 and 82 are arranged between the lens 2 and the beam splitter 83 and between the beam splitter 83 and the spectroscopic unit 4, respectively. ing. Further, the specularly reflected light may be removed by using circular polarization.
　図８は、この発明の他の実施形態に係る光学特性測定装置の構成を示す図である。この実施形態では、２つの照明部１ａ、１ｂが測定対象物１００の照明箇所１１に対して対称に配置され、それぞれ異なるレンズ２ａ、２ｂを介して、照明光が照明箇所１１に同時に照射されるようになっている。 FIG. 8 is a diagram showing a configuration of an optical characteristic measuring device according to another embodiment of the present invention. In this embodiment, the two illuminating units 1a and 1b are arranged symmetrically with respect to the illuminating portion 11 of the measurement object 100, and the illuminating portion 11 is simultaneously irradiated with the illuminating light through different lenses 2a and 2b, respectively. It has become like.
　このような構成によって、測定対象物１００の照明箇所１１及びその付近に異方性が存在してもこれを相殺でき、より精度の高い測定を行うことができる。なお、照明部１は２つでなく３つ以上であっても良い。また、複数の照明部１を配置するのではなく、１つの照明部１の位置を、測定対象物１００の照明箇所１１に対して対称となる位置に変更し、それぞれの位置で取得した測定データから異方性を相殺しても良い。ただし、複数の照明部１を使用して同時に照明し撮像した方が、２次元光電変換素子５による撮像回数が照明部１の数と同じかもしくはそれ以下の回数で済むことから望ましい。 With such a configuration, even if anisotropy exists in or near the illuminated portion 11 of the measurement object 100, it can be offset and more accurate measurement can be performed. The number of lighting units 1 may be three or more instead of two. Further, instead of arranging a plurality of illumination units 1, the position of one illumination unit 1 is changed to a position symmetrical with respect to the illumination location 11 of the measurement object 100, and the measurement data acquired at each position is changed. The anisotropy may be offset from. However, it is preferable to use a plurality of illumination units 1 to simultaneously illuminate and take an image because the number of times of imaging by the two-dimensional photoelectric conversion element 5 is the same as or less than the number of the illumination units 1.
　図９は、この発明のさらに他の実施形態に係る光学特性測定装置の構成を示す図である。この実施形態では、２つの照明部１ｃ、１ｄが測定対象物１００の照明箇所１１に対して角度を変えて配置され、それぞれ異なるレンズ２ｃ、２ｄを介して、照明光が照明箇所１１に異なる角度で照射されるようになっている。 FIG. 9 is a diagram showing a configuration of an optical characteristic measuring device according to still another embodiment of the present invention. In this embodiment, the two illuminating units 1c and 1d are arranged at different angles with respect to the illuminating portion 11 of the measurement object 100, and the illuminating light has different angles at the illuminating portion 11 via different lenses 2c and 2d, respectively. It is designed to be irradiated with.
　照明光の測定対象物１００の表面における透過率はアスペキュラー角（正反射方向からの反射光の光路の傾きを示す角度）に依存するため、照明光の照射角度を変えて測定することで多角度の情報を取得することができ、多くの情報を得ることができる。 Since the transmittance of the illumination light on the surface of the object 100 depends on the aspecular angle (the angle indicating the inclination of the optical path of the reflected light from the specular reflection direction), it is often measured by changing the irradiation angle of the illumination light. Angle information can be obtained, and a lot of information can be obtained.
　図９の例では２つの異なる角度の場合を示すが、３つ以上でもよい。また、複数の照明部１ｃ、１ｄを異なる角度に配置した場合を示したが、１つの照明部１を角度を変えて移動配置するようにしても良い。また、図８に示したように、複数の照明部１ａ、１ｂを測定対象物１００の照明箇所１１に対して対称に配置して測定を行うとともに、各照明部１ａ、１ｂの角度を変更してさらに測定を行う構成であっても良い。 The example of FIG. 9 shows the case of two different angles, but three or more may be used. Further, although the case where a plurality of lighting units 1c and 1d are arranged at different angles is shown, one lighting unit 1 may be moved and arranged at different angles. Further, as shown in FIG. 8, a plurality of illumination units 1a and 1b are arranged symmetrically with respect to the illumination portion 11 of the measurement object 100 to perform measurement, and the angles of the respective illumination units 1a and 1b are changed. It may be configured to perform further measurement.
　次に、２次元光電変換素子５によって得られた撮像データの演算部６での演算処理について説明する。演算処理によって算出されるパラメーターは限定はされないが、以下のいくつかを例示できる。 Next, the arithmetic processing in the arithmetic unit 6 of the imaging data obtained by the two-dimensional photoelectric conversion element 5 will be described. The parameters calculated by the arithmetic processing are not limited, but some of the following can be exemplified.
　演算部６による演算処理は、演算部６に備えられたコンピュータにおいて、ＣＰＵ等のプロセッサが記憶部(いずれも図示せず)に格納されたアプリケーションに従って動作することにより実行される。
（１）散乱長特有の係数の算出
　図１０に示すような内部反射光の輝度分布に対して、明るさ（輝度値）I(x, λ)を例えば、I(x, λ) = C1・exp(-C2・x)のような関数でフィッティングしたときの、散乱長特有の係数C2を算出する。
（２）レンダリング
   本実施形態によれば、測定対象物１００の表面下散乱の様子を波長別に取得することができる。そこで、取得されたデータを、コンピュータグラフィックにおけるレンダリングの入力データの一部として利用することで、図１１（Ａ）に示すような通常の測色(表面下散乱の効果を考慮しない測定)では表現できない測定対象物１００の質感を、図１１（Ｂ）にグレースケールで模式的に示したように、より忠実に再現することが可能となる。
（３）エッジロス補正
　照明光の一部が観測外(マスクの外に拡散)に拡散するエッジロス、が半透明材料の測色の際よく問題となる。 The arithmetic processing by the arithmetic unit 6 is executed by operating a processor such as a CPU in a computer provided in the arithmetic unit 6 according to an application stored in a storage unit (none of which is shown).
(1) Calculation of coefficient peculiar to scattering length For the brightness distribution of internally reflected light as shown in FIG. 10, the brightness (luminance value) I (x, λ) is, for example, I (x, λ) = C1 ·. Calculate the coefficient C2 peculiar to the scattering length when fitting with a function such as exp (-C2 · x).
(2) Rendering According to the present embodiment, the state of subsurface scattering of the measurement object 100 can be acquired for each wavelength. Therefore, by using the acquired data as a part of the input data for rendering in computer graphics, it is expressed by normal color measurement (measurement that does not consider the effect of subsurface scattering) as shown in FIG. 11 (A). As shown schematically in gray scale in FIG. 11B, the texture of the measurement object 100, which cannot be measured, can be reproduced more faithfully.
(3) Edge loss correction Edge loss, in which a part of the illumination light is diffused outside the observation (diffused out of the mask), is often a problem when measuring the color of a translucent material.
　即ち、図１２（Ａ）のように、マスク４２のサイズ (受光エリアのサイズ) により、照明光４１で照明され測定対象物１００ａの表面下に侵入した光のうち、受光エリアにとどまり検出される光Ｑと、エッジロスにより測定範囲外に光が拡散され検出されない光Ｐと、の割合が変化するため、図１２（Ｂ）の左図と右図に示すように、透明性のある測定対象物ではマスク４２の大きさ(受光エリアＬとＳ領域)が変化すると測色値も異なって測定されてしまう。そのため、異なる照明系・受光系を持つ測定器では測色値の互換性が取れない問題があった。なお、図１２（Ｂ）において、符号４３は照明域、４４はエッジロス帯である。 That is, as shown in FIG. 12A, among the light illuminated by the illumination light 41 and entering under the surface of the measurement object 100a according to the size of the mask 42 (the size of the light receiving area), the light stays in the light receiving area and is detected. Since the ratio of the light Q and the light P that is not detected because the light is diffused outside the measurement range due to the edge loss changes, as shown in the left and right figures of FIG. 12B, a transparent measurement object Then, when the size of the mask 42 (light receiving area L and S area) changes, the color measurement value is also measured differently. Therefore, there is a problem that the color measurement values cannot be compatible with measuring instruments having different illumination systems and light receiving systems. In FIG. 12B, reference numeral 43 is an illumination area and 44 is an edge loss band.
　本実施形態により測定結果から各波長の表面下散乱を測定することで、どのような波長の光がどの程度測定エリアの外に拡散するかの定量的な値を取得することができるため、その測定結果を解析することで、装置間におけるエッジロスによる互換性の問題を、補正することが可能である。
（４）コンピュータカラーマッチング
　表面下散乱の測定はコンピュータカラーマッチング（Computer Color Matching(CCM)）の教師データの特徴量の一つとして有用である可能性がある。これまでCCMは色情報の入力しかなかったが、表面下散乱の情報を入力データに追加することで、より少ない教師サンプル数で正確な混合色推定が可能になる可能性がある。もしくはより正確な混色推定が可能となる可能性がある。 By measuring the subsurface scattering of each wavelength from the measurement result according to the present embodiment, it is possible to obtain a quantitative value of what wavelength and how much light is diffused outside the measurement area. By analyzing the measurement results, it is possible to correct the problem of compatibility due to edge loss between devices.
(4) Computer color matching The measurement of subsurface scattering may be useful as one of the features of the teacher data of computer color matching (CCM). Until now, CCM had only input color information, but adding subsurface scattering information to the input data may enable accurate mixed color estimation with a smaller number of teacher samples. Alternatively, more accurate color mixing estimation may be possible.
　図１３は、この発明の実施形態に係る光学特性測定装置の外観を示す斜視図である。この実施形態では、光学特性測定装置は携行可能なハンディタイプのものに構成されている。勿論ベンチトップタイプのものであっても良い。 FIG. 13 is a perspective view showing the appearance of the optical characteristic measuring device according to the embodiment of the present invention. In this embodiment, the optical characteristic measuring device is configured to be a portable handy type. Of course, it may be a bench top type.
　図１３に示す光学特性測定装置は、照明部１、レンズ２及び３、分光部４、２次元光電変換素子５、演算部６が筐体２００内に収容されている。また、筐体２００の上面には、携行用の把持部２０２が備えられるとともに、演算部６による測定結果(演算結果)等を表示するための表示部７が備えられ、さらに筐体２００の下面には、測定対象物１００に照明光を照射し、測定対象物１００からの光を取り込むための開口２０１が形成されている。 In the optical characteristic measuring device shown in FIG. 13, the illumination unit 1, the lenses 2 and 3, the spectroscopic unit 4, the two-dimensional photoelectric conversion element 5, and the calculation unit 6 are housed in the housing 200. Further, the upper surface of the housing 200 is provided with a grip portion 202 for carrying, a display unit 7 for displaying a measurement result (calculation result) by the calculation unit 6, and a lower surface of the housing 200. Is formed with an opening 201 for irradiating the measurement object 100 with illumination light and taking in the light from the measurement object 100.
　図１３に示す光学特性測定装置は、使用に際して、把持部２０２を把持して下面の開口２０１を測定対象物１００の被測定部位に位置させる。そしてこの状態で、筐体２００の内部に収容されている照明部１から照明光を測定対象物１００に照射し、照射箇所１１及びその付近からの光を分光部４で分光し２次元光電変換素子５で受光し、２字光電変換素子５から出力された撮像データを用いて演算部６で演算することにより、光の表面下散乱の様子を測定し、測定結果を測定結果表示部７に表示するようになっている。 When used, the optical characteristic measuring device shown in FIG. 13 grips the grip portion 202 and positions the opening 201 on the lower surface at the measurement target portion of the measurement object 100. Then, in this state, the illumination light is irradiated to the measurement object 100 from the illumination unit 1 housed inside the housing 200, and the light from the irradiation point 11 and its vicinity is separated by the spectroscopic unit 4 for two-dimensional photoelectric conversion. The state of subsurface scattering of light is measured by receiving light from the element 5 and calculating with the calculation unit 6 using the imaging data output from the two-character photoelectric conversion element 5, and the measurement result is displayed on the measurement result display unit 7. It is designed to be displayed.
　このような光学特性測定装置によれば、筐体２００を持ち運ぶことにより、場所を問わず光の表面下散乱の様子を測定できる。 According to such an optical characteristic measuring device, the state of subsurface scattering of light can be measured regardless of the location by carrying the housing 200.
　なお、演算部６については筐体２００とは別の外部のパーソナルコンピュータを使用し、筐体２００内の２次元光電変換素子５から出力された撮像データを外部のコンピュータに送信して、測定を行う構成としても良い。 The calculation unit 6 uses an external personal computer different from the housing 200, and transmits the imaging data output from the two-dimensional photoelectric conversion element 5 in the housing 200 to the external computer for measurement. It may be configured to be performed.
　また、光学特性測定装置は単独の測定装置として構成されるのではなく、既存のあるいは新規な測色装置に内蔵されていてもよい。 Further, the optical characteristic measuring device is not configured as a single measuring device, but may be built in an existing or new color measuring device.
　本発明は、測定対象物の表面に入射した光の表面下拡散の測定に用いる際に利用可能である。 The present invention can be used for measuring the subsurface diffusion of light incident on the surface of a measurement object.
　１、１ａ～１ｄ　照明部
　４　分光部
　５　２次元光電変換素子
　６　演算部
　７　表示部
　１１　照明箇所
　１２　測定範囲
　１３　照明箇所付近の非照明箇所
　３０　正反射光
　８１　偏光ビームスプリッター
　８２　偏光子
　８３　ビームスプリッター
　２００　筐体
　２０１　開口部
　２０２　把持部 1, 1a to 1d Illumination unit 4 Spectroscopy unit 5 Two-dimensional photoelectric conversion element 6 Calculation unit 7 Display unit 11 Illumination location 12 Measurement range 13 Non-illumination location near illumination location 30 Specular reflection light 81 Polarized beam splitter 82 Splitter 83 Beam splitter 200 Housing 201 Opening 202 Grip

Claims (22)

  1. 　物体内部における光の表面下散乱を測定する光学特性測定装置であって、
    　可視光領域を含む波長帯に強度を持った照明光で、測定対象物の表面を局所的に照明するための少なくとも１つの照明手段と、
    　前記照明光で照明された前記測定対象物の表面より出射される光のうち、照明箇所の一部もしくは全部からの光と、照明箇所付近の直接照明されていない箇所からの光のどちらをも含む測定範囲を一次元的に空間分解して撮像できる撮像手段と、
    　前記撮像手段の上流側において、前記空間分解された各測定箇所から取り込んだ光を分光する分光手段と、
    　を備え、
    　前記撮像手段は、前記分光手段で分光された波長毎の光を受光する光学特性測定装置。     An optical property measuring device that measures the subsurface scattering of light inside an object.
    At least one illumination means for locally illuminating the surface of the object to be measured with illumination light having intensity in the wavelength band including the visible light region.
    Of the light emitted from the surface of the measurement object illuminated by the illumination light, both the light from a part or all of the illuminated portion and the light from the unilluminated portion near the illuminated portion. An imaging means that can image the including measurement range by spatially decomposing it in a one-dimensional manner.
    On the upstream side of the imaging means, a spectroscopic means that disperses the light captured from each of the spatially decomposed measurement points and
    With
    The imaging means is an optical characteristic measuring device that receives light for each wavelength dispersed by the spectroscopic means.
  2. 　前記照明手段は１つである請求項１に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 1, wherein the lighting means is one.
  3. 　前記照明手段は２つ以上であり、各照明手段が前記測定対象物の照明箇所に対して対称に配置されている請求項１に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 1, wherein the number of the lighting means is two or more, and each lighting means is arranged symmetrically with respect to the lighting location of the measurement object.
  4. 　前記照明手段により異なる角度から前記測定対象物の表面を照明し、前記撮像手段は、異なる角度で照明されたときの光をそれぞれ受光して撮像する請求項１に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 1, wherein the lighting means illuminates the surface of the object to be measured from different angles, and the imaging means receives and captures light when illuminated at different angles.
  5. 　局所的に照明とは、測定対象物の表面上での照明強度の空間分布が矩形もしくは矩形に近い形である請求項１～４のいずれかに記載の光学特性測定装置。 Locally illuminating is the optical characteristic measuring apparatus according to any one of claims 1 to 4, wherein the spatial distribution of the illuminating intensity on the surface of the object to be measured is a rectangle or a shape close to a rectangle.
  6. 　前記分光手段が分光する波長領域は、３００－８００ｎｍの範囲内の領域である請求項１～５のいずれかに記載の光学特性測定装置。 The optical characteristic measuring apparatus according to any one of claims 1 to 5, wherein the wavelength region dispersed by the spectroscopic means is a region within a range of 300 to 800 nm.
  7. 　前記分光手段が分光する波長分解能は３０ｎｍよりも細かい請求項１～６のいずれかに記載の光学特性測定装置。 The optical characteristic measuring apparatus according to any one of claims 1 to 6, wherein the wavelength resolution dispersed by the spectroscopic means is finer than 30 nm.
  8. 　一次元的に空間分解された測定範囲は１ｍｍよりも大きい請求項１～７のいずれかに記載の光学特性測定装置。 The optical characteristic measuring apparatus according to any one of claims 1 to 7, wherein the one-dimensionally spatially decomposed measuring range is larger than 1 mm.
  9. 　一次元的に空間分解された測定範囲の分解能は０．１ｍｍよりも細かい請求項１～８のいずれかに記載の光学特性測定装置。 The optical characteristic measuring apparatus according to any one of claims 1 to 8, wherein the resolution of the one-dimensionally spatially decomposed measuring range is finer than 0.1 mm.
  10. 　一次元的な空間分解における一次元方向とは、前記照明手段から前記照明箇所への照射光の光軸を含み測定対象物の表面と鉛直に交差する面に対して、測定対象物の表面上で平行もしくは垂直な方向である請求項１～９のいずれかに記載の光学特性測定装置。 The one-dimensional direction in the one-dimensional spatial decomposition is on the surface of the measurement object with respect to a surface that includes the optical axis of the irradiation light from the illumination means to the illumination location and vertically intersects the surface of the measurement object. The optical characteristic measuring apparatus according to any one of claims 1 to 9, wherein the direction is parallel or vertical.
  11. 　測定対象物の表面からの正反射光の取り込みを防止する正反射光除去機構を備えている請求項１～１０のいずれかに記載の光学特性測定装置。 The optical characteristic measuring device according to any one of claims 1 to 10, further comprising a specularly reflected light removing mechanism for preventing the capture of specularly reflected light from the surface of the object to be measured.
  12. 　前記正反射光除去機構は、測定対象物の表面への入射光とその正反射光とを、角度的に検出しないように、前記照明手段と前記撮像手段の位置関係が設定されることによるものである請求項１１に記載の光学特性測定装置。 The specularly reflected light removing mechanism is based on setting the positional relationship between the illuminating means and the imaging means so as not to detect the incident light on the surface of the object to be measured and the specularly reflected light from an angle. The optical characteristic measuring apparatus according to claim 11.
  13. 　前記正反射光除去機構は、照明手段側を直線偏光に変更し、受光側にその偏光と垂直なもののみを抽出する機構により構成されている請求項１１に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 11, wherein the specular light removing mechanism is configured by a mechanism that changes the illumination means side to linearly polarized light and extracts only those perpendicular to the polarized light on the light receiving side.
  14. 　前記撮像手段による撮像回数は、前記照明手段の数と同じかもしくはそれ以下の回数である請求項１～１３のいずれかに記載の光学特性測定装置。 The optical characteristic measuring device according to any one of claims 1 to 13, wherein the number of times of imaging by the imaging means is the same as or less than the number of the lighting means.
  15. 　前記撮像手段により得られた各画素の画素値より、光の表面下散乱に関する一つ以上のパラメーターを算出する演算部を備えている請求項１～１４のいずれかに記載の光学特性測定装置。 The optical characteristic measuring apparatus according to any one of claims 1 to 14, further comprising a calculation unit that calculates one or more parameters related to subsurface scattering of light from the pixel values of each pixel obtained by the imaging means.
  16. 　前記パラメーターは、表面下散乱の散乱長を特徴づける値である請求項１５に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 15, wherein the parameter is a value that characterizes the scattering length of subsurface scattering.
  17. 　前記パラメーターは、コンピュータグラフィックにおけるレンダリングの入力値である請求項１５または１６に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 15 or 16, wherein the parameter is an input value for rendering in computer graphics.
  18. 　前記パラメーターは、エッジロスの補正係数である請求項１５または１６に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 15 or 16, wherein the parameter is an edge loss correction coefficient.
  19. 　前記パラメーターは、コンピュータカラーマッチングの入力値である請求項１５または１６に記載の光学特性測定装置。 The optical characteristic measuring device according to claim 15 or 16, wherein the parameter is an input value for computer color matching.
  20. 　前記演算部は、外部のパーソナルコンピュータによって構成されている請求項１５～１９のいずれかに記載の光学特性測定装置。 The optical characteristic measuring device according to any one of claims 15 to 19, wherein the calculation unit is configured by an external personal computer.
  21. 　前記照明手段、撮像手段及び分光手段を収容する筐体を備え、
    　前記筐体には、前記測定対象物の表面に照明光を照射し、測定対象物の表面より出射される光を取り込むための開口と、測定結果を表示するための表示手段を備えている請求項１～２０のいずれかに記載の光学特性測定装置。     A housing for accommodating the lighting means, an imaging means, and a spectroscopic means is provided.
    The housing is provided with an opening for irradiating the surface of the measurement object with illumination light and taking in the light emitted from the surface of the measurement object, and a display means for displaying the measurement result. Item 4. The optical characteristic measuring apparatus according to any one of Items 1 to 20.
  22. 　測色装置に内蔵されている請求項１～２１のいずれかに記載の光学特性測定装置。 The optical characteristic measuring device according to any one of claims 1 to 21, which is built in the color measuring device.
PCT/JP2020/048131 2020-01-23 2020-12-23 Optical characteristic evaluation device WO2021149445A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020-009363 2020-01-23
JP2020009363A JP2023025303A (en) 2020-01-23 2020-01-23 Optical property evaluation device

Publications (1)

Publication Number Publication Date
WO2021149445A1 true WO2021149445A1 (en) 2021-07-29

Family

ID=76992284

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/048131 WO2021149445A1 (en) 2020-01-23 2020-12-23 Optical characteristic evaluation device

Country Status (2)

Country Link
JP (1) JP2023025303A (en)
WO (1) WO2021149445A1 (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014077739A (en) * 2012-10-11 2014-05-01 Shiseido Co Ltd Transparency measurement device
US20140267274A1 (en) * 2013-03-15 2014-09-18 Disney Enterprises, Inc. Normalized diffusion profile for subsurface scattering rendering
JP2015132509A (en) * 2014-01-10 2015-07-23 凸版印刷株式会社 Image data acquiring system, and image data acquiring method
WO2018012358A1 (en) * 2016-07-14 2018-01-18 コニカミノルタ株式会社 Colorimeter
US20180300945A1 (en) * 2017-04-17 2018-10-18 Intel Corporation Physically based shading via fixed-functionality shader libraries
EP3479756A1 (en) * 2017-11-02 2019-05-08 Koninklijke Philips N.V. Optical skin sensor and method for optically sensing skin parameters

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014077739A (en) * 2012-10-11 2014-05-01 Shiseido Co Ltd Transparency measurement device
US20140267274A1 (en) * 2013-03-15 2014-09-18 Disney Enterprises, Inc. Normalized diffusion profile for subsurface scattering rendering
JP2015132509A (en) * 2014-01-10 2015-07-23 凸版印刷株式会社 Image data acquiring system, and image data acquiring method
WO2018012358A1 (en) * 2016-07-14 2018-01-18 コニカミノルタ株式会社 Colorimeter
US20180300945A1 (en) * 2017-04-17 2018-10-18 Intel Corporation Physically based shading via fixed-functionality shader libraries
EP3479756A1 (en) * 2017-11-02 2019-05-08 Koninklijke Philips N.V. Optical skin sensor and method for optically sensing skin parameters

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
JENSEN, H. W. ET AL.: "A Practical Model for Subsurface Light Transport", SIGGRAPH '01 PROCEEDINGS OF THE 28TH ANNUAL CONFERENCE ON COMPUTER GRAPHICS AND INTERACTIVE TECHNIQUES, 2001, pages 511 - 518, XP001049924, DOI: https://dl.acm.org/ doi/10.1145/383259.383319 *
OGATA NORIHIRO ET AL.: "Computer-aided industrial design support system for cuticle material used in car seats", THE JOURNAL OF THE INSTITUTE OF IMAGE INFORMATION AND TELEVISION, vol. 60, no. 4, 1 April 2006 (2006-04-01), pages 637 - 640, XP055843715 *
TADAHIRO OZAWA, TATSUYA YATAGAWA, HIROYUKI KUBO, SHIGEO MORISHIMA: "Fast subsurface light transport evaluation for realtime rendering using single shortest optical paths", THE JOURNAL OF THE INSTITUTE OF IMAGE ELECTRONICS ENGINEERS OF JAPAN, vol. 46, no. 4, 2017, pages 533 - 546, XP055843716 *

Also Published As

Publication number Publication date
JP2023025303A (en) 2023-02-22

Similar Documents

Publication Publication Date Title
JP4476462B2 (en) Semiconductor electrical property evaluation system
JP5199539B2 (en) Multispectral technique for defocus detection
KR100875873B1 (en) Impurity concentration tester and test method of semiconductor
JP5204093B2 (en) Optical measuring device
JP3115162U (en) Angle measuring equipment for optical surface characteristics
JP4625716B2 (en) Defect inspection apparatus and defect inspection method
US7724362B1 (en) Oblique incidence macro wafer inspection
JP2016507752A (en) Surface topography interferometer with surface color
US8184294B2 (en) Apparatus and method for measuring haze of sheet materials or other materials
US20050274913A1 (en) Object data input apparatus and object reconstruction apparatus
JP2016080429A (en) Spectral measurement device
TW201107723A (en) Device for measuring optical characteristic of light source, measuring method, and examining device provided with the measuring device
JP5424108B2 (en) Raman imaging equipment
Cucci et al. Extending hyperspectral imaging from Vis to NIR spectral regions: A novel scanner for the in-depth analysis of polychrome surfaces
JP2009229239A (en) Particle size measuring device and method
CN109100337A (en) Multiband multi-orientation detection device and detection method
Chlebda et al. Assessment of hyperspectral imaging system for colour measurement
WO2021149445A1 (en) Optical characteristic evaluation device
WO2006134429A2 (en) Device for analysing the colour of a unhomogeneous material, like hair, and method thereof
Nishida et al. A high-resolution small-angle light scattering instrument for soft matter studies
US20160153915A1 (en) Surface Inspecting Method
JP2016206060A (en) Spectroscopic measurement device and spectroscopic measurement method
US11231375B2 (en) Apparatus for high-speed surface relief measurement
Cai et al. A compact line-detection spectrometer with a Powell lens
CN114061907A (en) Halo quantization system and method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20914998

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20914998

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP