JP2016038221A - Sample measurement device and sample measurement program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sample measurement device with which it is possible to execute at a time the overall quantitative evaluation of a paint including a luminous material that looks like a different color depending on a viewing angle.SOLUTION: A sample 61 is irradiated with light from a plurality of angles set in the range designated by a calculation formula by driving the lighting of illuminations 15f-15h on at a time. In this case, the light differentiated in wavelength by filters 91-93 are radiated. A two-dimensional spectrograph camera device 1 capable of obtaining spectrograph information captures the image of reflected light in one shot. Also, declination spectrograph information is obtained by utilizing a change in an opto-geometric condition in the illumination and image-capturing directions per pixel in the X and Y axis directions within the two-dimensional image of a sample 61. Then, with in-plane being assumed to be a uniform sample, declination spectrograph information, declination colorimetric information, and BRDF information in an angle range determined as a measurement range are obtained, and also a texture such as luminosity feeling, particle feeling, gloss, haze, image clarity, orange peel, etc., is calculated.SELECTED DRAWING: Figure 35

Description

  The present invention relates to a sample measurement device and a sample measurement program.

  Today, the color measurement method from multiple angles, which is defined in the ASTM standard (E2539-12), is known as an evaluation of paints containing glitter materials that look different colors depending on the viewing angle, such as pearl color or metallic color. It has been. ASTM is an abbreviation for “American Test Materials Association”. However, in the case of the color measurement method defined in the ASTM standard, the color measurement result and the visual evaluation may be inconsistent.

  Patent Document 1 (Japanese Patent Laid-Open No. 2013-238576) discloses a variable angle spectroscopic imaging measurement apparatus that is more accurate and practical. This variable angle spectroscopic imaging measurement apparatus includes an illumination apparatus that irradiates illumination light from two or more angular directions with respect to a measurement sample surface, an imaging optical lens, and a monochrome two-dimensional image sensor. Using the change in the optical geometric condition for each pixel in the X-axis and Y-axis directions in the image, the variable angle spectroscopic imaging information is measured. Thereby, the angle-of-change information and the spectral information can be accurately measured in a short time for every pixel in all the pixels of the two-dimensional image. Therefore, a more accurate and practical variable angle spectroscopic imaging measurement apparatus can be realized.

  Here, as the evaluation items of the paint including the bright material that looks different colors depending on the viewing angle, the evaluation items of “brightness” and “particle feeling” expressed from the distribution of the bright material such as the interference material are known. In addition, as an evaluation item of a paint including a luster material that looks different colors depending on the viewing angle, evaluation items of “orange peel” and “image clarity” representing gloss and gloss of the paint surface state are known.

  However, in the color measurement method from multiple angles defined in the ASTM standard (E2539-12), glitter, graininess, orange peel, and mapping in paints containing glitter materials that look different colors at different viewing angles. It is difficult to quantify the texture such as sex. For this reason, conventionally, texture such as glitter, grain, orange peel, and image clarity has often been visually evaluated. Since the color measurement method from multiple angles defined in the ASTM standard (E2539-12) is difficult to quantify the texture such as the above-mentioned glitter feeling, the brightness that looks different colors depending on the viewing angle. It was difficult to comprehensively quantify the quality of the paint containing the material.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a sample measurement device and a sample measurement program capable of comprehensively quantifying the quality of various paints.

  In order to solve the above-described problems and achieve the object, the present invention provides a light source device that irradiates illumination light at a time from an illumination unit having a plurality of illumination angles to a sample surface of a sample, and each illumination unit. A plurality of filters provided with spectral spectral transmittance characteristics that transmit illumination light of different wavelengths and a sample surface are arranged above the sample surface, and the reflected light corresponding to the illumination light of each wavelength from the sample surface is dispersed. Using a spectroscopic camera device that acquires two-dimensional spectroscopic information in one imaging operation and changes in optical geometric conditions in the illumination direction and imaging direction for each pixel in the X-axis direction and Y-axis direction of the spectral information And a calculation unit for calculating declination spectral information of the sample surface for measuring a measurement value of a predetermined evaluation item of the sample.

  According to the present invention, it is possible to comprehensively quantify the quality of various paints.

FIG. 1 is a block diagram of the sample measuring apparatus according to the first embodiment. FIG. 2 is a functional block diagram of the sample measuring apparatus according to the first embodiment. FIG. 3 is a diagram schematically showing a main part of the spectroscopic camera device provided in the sample measuring apparatus according to the first embodiment. FIG. 4 is a diagram illustrating the spectral transmittance of each color filter when the incident angle of the light beam is 0 degree in the spectroscopic camera device of the sample measuring apparatus according to the first embodiment. FIG. 5 is a diagram illustrating a geometric design example of the color filter of the spectroscopic camera device of the sample measuring apparatus according to the first embodiment. FIG. 6 is a characteristic diagram showing the incident angle dependence of the spectral transmittance of the color filter. FIG. 7 is a view of the lens array as viewed from the optical axis direction. FIG. 8 is a plan view of a captured image of the spectroscopic camera device. FIG. 9 is an enlarged view of a macro pixel constituting the image of FIG. FIG. 10 is a diagram illustrating an example of a color checker as a color sample. FIG. 11 is a plot of the color checker on the 24 color xy chromaticity diagram. FIG. 12 is a diagram schematically showing a main part of another spectroscopic camera device provided in the sample measuring apparatus according to the first embodiment. FIG. 13 is a diagram for explaining a spectral filter provided on a sensor surface of another spectral camera device. FIG. 14 is a diagram illustrating the positional relationship between the illumination units of the spectroscopic camera device and the light source device in the sample measurement apparatus according to the first embodiment. FIG. 15 is a diagram illustrating angles formed by the positional relationship between the illumination units of the spectroscopic camera device and the light source device in the sample measurement device according to the first embodiment. FIG. 16 is a diagram illustrating an example of a captured image captured by the spectroscopic camera device at the timing when light is emitted from the illumination unit. FIG. 17 is a diagram illustrating another positional relationship between the illuminating units of the spectroscopic camera device and the light source device in the sample measurement device according to the first embodiment. FIG. 18 is a flowchart for explaining an operation of acquiring calibration information of declination spectral information in the sample measurement apparatus according to the first embodiment. FIG. 19 is a flowchart for explaining an operation of acquiring declination spectral information in the sample measurement apparatus according to the first embodiment. FIG. 20 is a flowchart for explaining an operation of acquiring calibration information of image clarity and orange peel measurement information in the sample measurement apparatus of the first embodiment. FIG. 21 is a flowchart for explaining an operation of acquiring measurement information of image clarity and orange peel in the sample measurement apparatus according to the first embodiment. FIG. 22 is a diagram illustrating an example of an arithmetic expression for declination colorimetric information. FIG. 23 is a diagram illustrating another example of an arithmetic expression for declination colorimetric information. FIG. 24 is a diagram for explaining angles used for defining BRDF information. FIG. 25 is a diagram showing a region for calculating an intensity histogram with an aspecular angle of 10 degrees, 20 degrees, and 30 degrees. FIG. 26 is a diagram showing intensity histograms at an aspecular angle of 10 degrees, 20 degrees, and 30 degrees. FIG. 27 is a diagram showing an image of a metallic paint sample with fine particles and an intensity histogram. FIG. 28 is a diagram showing an image and an intensity histogram of a metallic paint sample with coarse particles. FIG. 29 is a diagram showing an image of a pearl paint sample and an intensity histogram. FIG. 30 is a diagram illustrating an example of an arithmetic expression used to calculate the measured value of haze. FIG. 31 is a diagram showing slit light having a predetermined wavelength projected when calculating the image clarity and the measured value of orange peel. FIG. 32 is a diagram for explaining an arithmetic expression for calculating the image clarity and the measured value of the orange peel. FIG. 33 is a diagram for explaining white noise projected by the sample measuring apparatus according to the second embodiment. FIG. 34 is a block diagram of a sample measuring apparatus according to the third embodiment. FIG. 35 is a diagram illustrating the position of a filter provided in the sample measuring apparatus according to the fourth embodiment. FIG. 36 is a diagram for explaining the spectral transmittance characteristics of a filter provided in the sample measuring apparatus according to the fourth embodiment.

  Hereinafter, a sample measuring apparatus according to an embodiment to which the present invention is applied will be described in detail with reference to the accompanying drawings.

(Overview)
First, the sample measuring apparatus according to the embodiment can acquire declination spectroscopic information, declination colorimetric information, and BRDF information (bidirectional reflection distribution function) with the following optical configuration. The BRDF information is a function specific to a reflection point that represents how much light is reflected in each direction when light enters the reflection point from a certain direction. BRDF information uses spectral information of the wavelengths of three types of light, red (R), green (G), and blue (B).

  Specifically, the sample is illuminated from two or more angles set in the range specified by the calculation formula, and one imaging operation (one-shot) is performed using a two-dimensional spectroscopic camera. Spectral information is acquired from the reflected light by performing imaging at. The declination spectral information is obtained by utilizing the change in the optical geometric condition in the imaging direction and the illumination direction for each pixel in the X-axis direction and the Y-axis direction in the two-dimensional image obtained from the two-dimensional spectral information of the sample. obtain. Accordingly, the in-plane of the two-dimensional image is regarded as a uniform sample, and declination spectroscopic information, declination colorimetric information, and BRDF information in an angle range determined as a measurement range can be obtained.

  Next, the sample measurement apparatus according to the embodiment has the following measurement methods for glitter, particle feeling, gloss, haze (turbidity (cloudiness)), image clarity, orange peel, and other textures. The texture is quantified by using. The orange peel is a phenomenon of spotted unevenness due to diffused reflection of light caused by the material of the display material (a phenomenon that looks like a citrus peel).

  1. “Brightness” is quantified as follows. That is, the optical configuration of the spectroscopic camera is set to an optical configuration in which the resolution of one pixel with respect to the sample is, for example, a resolution of 10 to 100 μm, and high dynamic range technology is used to capture an image with a dynamic range of 18 bits or more. Then, a brightness histogram for each illumination angle and each spectral wavelength is calculated, and a brightness area and brightness intensity for each angle and wavelength are calculated.

  2. The particle feeling is quantified as follows. That is, with the above-described spectral camera having the resolution, image reconstruction is performed using only pixels determined as diffused light that avoids regular reflection light of illumination in the particle image for each illumination angle. Then, from the reconstructed image, the uniformity of the light / dark area is quantified as a particle feeling. The uniformity may be obtained by using entropy or dispersion of an image or by Fourier analysis.

  3. Gloss is quantified using the spectral information around 555 nm, which is the human visual sensitivity, and the calibration result with a standard glass plate for the pixel that has captured regular reflection light.

  4). The haze (turbidity (cloudiness)) is a specular information near 555 nm, which is human visual sensitivity, and calibration with a standard glass plate for a sample surface deviated from regular reflection light and regular reflection light by 1.9 to 3 degrees. Digitize using the results.

  5. The image clarity is obtained by imaging a slit light having a short wavelength (slit pattern light) projected from a projector with a spectroscopic camera, using spectral information around 555 nm, which is human visibility, and a calibration result on a standard glass plate. Digitize.

  6). The orange peel is obtained by imaging a slit light having a short wavelength projected from a projector with a spectroscopic camera and digitizing it using spectral information around 555 nm, which is human visibility, and a calibration result on a standard glass plate.

  In addition, the sample measuring apparatus according to the embodiment acquires the three-dimensional shape of the sample using slit light projected from the projector. Alternatively, the sample measurement device according to the embodiment acquires the three-dimensional shape of the sample by the three-dimensional acquisition device. And the sample measuring apparatus of embodiment calibrates declination spectral information from the normal direction of the three-dimensional shape of the acquired sample. Thereby, the sample can be measured without being affected by the shape of the measurement target surface.

  In this way, the sample measuring apparatus according to the embodiment obtains declination spectral information, declination colorimetric information, and BRDF information, and paints such as glitter, particle feeling, gloss, haze, image clarity, and orange peel Quantify the texture of the material. For this reason, for example, a paint containing a bright material that looks different colors depending on the viewing angle, such as pearl or metallic, can be quantitatively evaluated at a time.

(First embodiment)
FIG. 1 shows a block diagram of the sample measuring apparatus according to the first embodiment. As shown in FIG. 1, the sample measuring device includes a spectroscopic camera device 1, a light source device 2, a projector 3, an information processing device 4, and a monitor device 5.

  As will be described in detail later, a multiband camera device can be used as the spectroscopic camera device 1. The multiband camera device is a spectral information acquisition unit that acquires two-dimensional spectral information, and uses a spectral filter group inserted in the main lens and a microlens array inserted between the main lens and the light receiving element for each microlens. Spectral information corresponding to the number of spectral filters is acquired. Further, as the spectroscopic camera device 1, a hyperspectral camera device including one or more sets of filters and a diffraction grating (or prism) may be used.

  The spectroscopic camera device 1 includes an imaging unit 11 and an image processing unit 12, and in synchronization with light irradiation by the illumination unit 15 of the light source device 2 fixed at each angle, the two-dimensional spectroscopic information is transmitted once. Obtained by the imaging operation (one-shot). For example, when the imaging unit 11 is a CMOS imaging sensor or a semiconductor imaging element such as a CCD sensor, imaging light received by each pixel (in this case, reflected from a sample) is an example. This means an operation until reading out the electric charge generated according to light. CMOS is an abbreviation for “Complementary Metal Oxide Semiconductor Image Sensor”. CCD is an abbreviation for “Charge Coupled Device”.

  The light source device 2 includes a plurality of lighting units 15 and a lighting control unit 16 that drives each lighting unit 15 to light. As the illumination unit 15, a point light source, line illumination, or parallel light illumination can be used. As the light source type, a tungsten lamp, a halogen lamp, a xenon lamp, a white LED, or the like can be used. LED is an abbreviation for “Light Emitting Diode”.

  As the projector 3, a projector device can be used. The projector 3 irradiates the sample with a striped projection pattern (projection pattern having a predetermined spatial frequency) when measuring the image clarity (sharpness) and orange peel of the sample.

  As the monitor device 5, for example, a liquid crystal monitor device can be used. As will be described in detail later, in addition to the setting menu and the operation menu, the monitor device 5 displays an intensity histogram and the like corresponding to each irradiation angle of light in the glitter parameter.

  A general computer device can be used as the information processing device 4. The information processing apparatus 4 includes a CPU 21, a ROM 22, a RAM 23, and an HDD (hard disk drive) 24. Further, the information processing apparatus 4 has various interfaces (I / F) 25 and an input / output interface (I / O) 26. The CPUs 21 to I / O 26 are connected to each other via a bus line 27. CPU is an abbreviation for “Central Processing Unit”. ROM is an abbreviation for “Read Only Memory”. RAM is an abbreviation for “Random Access Memory”.

  In the HDD 24, in order to measure the texture of the sample, the imaging control of the spectroscopic camera device 1, the light source lighting control of the light source device 2, the projection pattern projection control of the projector, and each of the sample using the acquired spectral information A sample measurement program for performing calculations corresponding to the measurement items is stored. FIG. 2 shows a functional block diagram of each function realized by the CPU 21 operating according to the sample measurement program. As illustrated in FIG. 2, the CPU 11 includes a light source control unit 31, an imaging control unit 32, a pattern control unit 33, a calibration information acquisition unit 34, an information calibration unit 35, and a measurement value calculation unit 36 that is an example of a calculation unit. Each function is realized by software.

  In this example, the light source control unit 31 to the measurement value calculation unit 36 will be described as being implemented as software. However, some or all of the light source control unit 31 to the measurement value calculation unit 36 are hardware. It may be realized by wear.

  Further, the sample measurement program may be provided as a file in an installable or executable format and recorded on a recording medium readable by a computer device such as a CD-ROM or a flexible disk (FD). Further, the program may be provided by being recorded on a computer-readable recording medium such as a CD-R, a DVD, a Blu-ray disc (registered trademark), or a semiconductor memory. DVD is an abbreviation for “Digital Versatile Disk”. Further, the sample measurement program may be provided by being installed via a network such as the Internet. The sample measurement program may be provided by being incorporated in advance in a ROM or the like in the device.

  The light source controller 31 controls lighting of the light source device 2. The imaging control unit 32 controls imaging of the spectral camera device 1. The pattern projection control unit 33 projects a predetermined projection pattern. The calibration information acquisition unit 34 acquires calibration information by reading a calibration member such as a standard white plate, standard black glass, or mirror at the start of measurement. The information calibration unit 35 calibrates measurement information such as image clarity and orange peel using the acquired calibration information. The measurement value calculation unit 36 calculates evaluation values of various measurement items using the calibrated measurement information.

  Next, the principle of the spectroscopic camera device 1 will be described with reference to FIG. Here, for easy understanding, the main lens 54 as an optical system is shown as a single lens, and the aperture position S of the main lens 54 is the center of the single lens. In the center of the main lens 54, a color filter 56 as an optical bandpass filter is disposed. The color filter 56 is a filter corresponding to a tristimulus value of a color having a spectral transmittance based on the color matching function of the XYZ color system. That is, the color filter 56 includes a plurality (three in this case) of color filters 56a, 56b, and 56c having different spectral transmittances based on the color matching functions of the XYZ color system.

  Such an optical bandpass filter may be configured by combining a plurality of filters having different spectral transmittances, or may be configured to vary the spectral transmittance for each region on one filter. For example, when 16 types of optical bandpass filters having a transmission wavelength peak in 20 nm increments are used in the wavelength range from 400 nm to 700 nm, spectral information in the wavelength range from 400 nm to 700 nm is acquired in 20 nm increments. It is possible.

  In practice, the color filter 56 is not positioned in the lens as shown in FIG. The color filter 56 is disposed near the stop of the main lens 54. “Near the aperture” means a portion including the aperture position through which light rays with various angles of view can pass. In other words, it means an allowable range in design of the color filter 56 with respect to the main lens 54.

FIG. 4 shows spectral transmittances of the color filters 56a, 56b, and 56c when the incident angle of the light beam is 0 degree. The solid line, the broken line, and the dotted line in FIG. 4 are the spectral transmittances T _X (λ) and T _{Y of} the color filters 56 a (F _X ), 56 b (F _Y ), and 56 c (F _Z ) based on the following color matching functions, respectively. (Λ), T _Z (λ).

FIG. 5 shows a geometric design example of the color filters 56a (F _X ), 56b (F _Y ), and 56c (F _Z ). In FIG. 5, the color filter 56 is roughly divided into three in a fan shape, but the whole may be circular or may be divided into rectangles. Also, the area ratio of each filter need not be equally divided.

  As shown in FIG. 4, the area surrounded by the color matching function lines for Z is smaller than the others. The size of this area correlates with the magnitude of the signal to noise ratio (S / N ratio). In order to increase the S / N ratio, the area of the color filter 56c corresponding to Z may be made larger than the others.

Next, the design of T _X (λ), T _Y (λ), and T _Z (λ) will be described. Each spectral transmittance in FIG. 6 includes the color matching function defined in the CIE-1931 color system, the spectral transmittance T _L (λ) of the optical system excluding the lens filter, and the spectral sensitivity S (λ) of the light receiving element. Designed from That is, it can be defined by the following equations 1 to 3.

In Equations 1 to 3, since the sensor itself has spectral sensitivity, it is divided by S (λ) in order to eliminate the non-uniformity. In Equations (1) to (3), the values obtained by standardizing each maximum value as the transmittance of 100% are T _X (λ), T _Y (λ), and T _Z (λ). By standardizing, the SN ratio can be improved particularly for color filters corresponding to x (λ) and y (λ). When a color filter designed in this way is used, when a light beam that has passed through the color filter is detected by a light receiving element, the normalization based on the maximum value is simply calculated backward, and the output value is directly converted to X, Y, Z (three (Stimulus value).

T _X (λ), T _Y (λ), and T _Z (λ) are complex waveforms, but can be generated with values close to design values. T _X (λ), T _Y (λ), and T _Z (λ) can be generated by a dielectric multilayer film as an example. The dielectric multilayer film functions as a band-pass filter by optical interference. The spectral transmittance of the color filter 56 has a dependency on the incident angle of light in principle because a band pass filter can be realized by interference action. FIG. 6 shows an example of the incident angle dependency in the color filter 56a (F _X ). A solid line, a broken line, and a dotted line are spectral transmittances of incident angles of 0 degrees, 20 degrees, and 30 degrees, respectively. It can be seen that the transmission band shifts to the short wavelength side as the incident angle increases.

  As shown in FIG. 3, a microlens array (MLA) 53 composed of a plurality of microlenses (small lenses) is disposed near the condensing position of the main lens 54. On the image plane, a light receiving element array 55 including a plurality of light receiving elements (sensors) that convert optical information collected by the main lens 54 into electronic information (electrical signals) is arranged. The diameter of the micro lens of the MLA 53 and each light receiving element constituting the light receiving element array 55 are in a relationship of a ratio of about “30: 1 to 2: 1”.

  FIG. 7 shows a view of MLA3 as seen from the optical axis direction. In FIG. 7, white circles indicate the respective lenses, and black portions indicate light shielding portions. In other words, light is shielded by the light shielding part except for the lens part constituting the lens array. Although it is an example, the light shielding part is formed by vapor-depositing chromium oxide. The light shielding portion is a flat portion having no curvature or a region where the curvature does not satisfy the design value specification in terms of manufacturing. Since light from these regions may cause a light beam that is not intended in the design to reach the light receiving element, an electrical signal that is assumed from the design can be obtained by shielding the light. Thereby, an accurate measured value can be obtained.

  The light receiving element array 55 is a monochrome sensor in which a color filter for each pixel is not mounted. Hereinafter, the light receiving element array is also referred to as a “monochrome sensor”. Of the light emitted from the object 57 shown in FIG. 3, the light beam that enters the aperture of the main lens 54 and passes through the aperture is the object of measurement. The light beam incident on the main lens is a collection of innumerable light beams, and each light beam passes through different positions of the stop of the main lens 54. In the case of the example of FIG. 3, since the three color filters 56a, 56b, and 56c are arranged at the stop position of the main lens 54, each light beam passes through three filters having different spectral transmittances. At this time, the angle of the light ray incident on the filter surface varies depending on the object height. This can also be seen from the fact that the chief rays of the light beams emitted from the points on the object indicated by the symbols P and Q in FIG. 3 pass through the diaphragm surface of the main lens 54 at different angles.

  The light rays that have passed through the color filter 56 once form an image in the vicinity of the MLA 53, but then reach a different position of the sensor by the MLA 53, respectively. That is, since the position of the sensor surface (light receiving position) corresponds to the filter surface through which the light beam has passed, a value obtained by decomposing light emitted from a certain point of the object into tristimulus values X, Y, and Z in terms of wavelength is measured. be able to.

  However, as described with reference to FIG. 6, the spectral transmittance of the color filter 56 has an incident angle dependency. Therefore, if the output of the light receiving element is simply used, the optical axis may be on the optical axis at best. It is difficult to measure accurate tristimulus values X, Y, and Z of the included two-dimensional surface.

  For this reason, the spectroscopic camera device 1 obtains an accurate tristimulus value of a two-dimensional surface corrected for each light receiving position using a reference value and a value calculated from the output value from the spectroscopic camera device 1. It has become. Generally, this is a technique called multiple regression analysis. In the multiple regression analysis, explanatory variables and objective variables are prepared in advance, and correction calculation is performed using a regression matrix obtained from them. The procedure is specifically described below. First, a procedure for calculating an output value from the spectroscopic camera device 1 will be described. This corresponds to an explanatory variable in the multiple regression analysis.

  The image photographed with the configuration of FIG. 3 is a series of small circles as shown in FIG. The reason for forming a circle is that the aperture shape of the single lens (main lens 54) is circular. Here, each small circle is called a “macro pixel”. Each macro pixel is formed directly under each small lens constituting the lens array. The internal structure of the macro pixel corresponds to the structure of the color filter shown in FIG. An enlarged view of the macro pixel is shown in FIG. Compared with FIG. 9 and FIG. 5, the top, bottom, left and right are inverted because of passing through the optical system. However, since this correspondence depends on the optical system, it is not limited to this example.

The macro pixel internal structures M _X , M _Y , and M _Z are the results of arrival of light that has passed through the color filters F _X , F _Y , and F _Z , respectively. _Assume that the output values of the light receiving elements M _X , M _Y , and M _Z are v = [v _X , v _Y , v _Z ] ^t . t means transposition of the matrix. How to take the output _value, M _X, M _Y, may take the average value of _{M Z, M X,} and selects one of the light receiving element from _M Y, M _Z, may be the output value as the representative value.

  Next, a method for obtaining a reference value will be described. This corresponds to the objective variable in the multiple regression analysis. A color sample that covers a wide range in the color space is measured by a device such as a spectroscope that measures the X, Y, and Z values, and these are used as reference values. As the color swatch, for example, a widely used 24-color rectangular color swatch called a “color checker” can be used. An example of a color checker is shown in FIG. FIG. 11 shows the results of plotting the measured values of 24 colors included in the color checker on the xy chromaticity diagram.

The color sample is not limited to the color checker, and if the object to be measured is known, a better correction result can be obtained by using a value close to that color as a reference value. A reference value of X, Y, Z (tristimulus values) for a color sample is assumed to be r = [r _X , r _Y , r _Z ] ^t .

Next, the flow of correction calculation will be described. First, a color sample is measured with a measuring instrument to obtain a reference value. When a 24 color checker is used for the color swatch, a number is given for convenience, and a reference value for the _first color is r ₁ = [r _1X r _1Y r _1Z ] ^t . That is, values from r _{1 to} r ₂₄ are obtained. Let R = [r ₁ ,..., R ₂₄ ]. R is a 3 × 24 matrix. This matrix R is an objective variable.

Next, a color sample is photographed with the spectral camera device 1 of FIG. 3 to obtain imaging information. At this time, it is arranged so that one color sample appears in the entire image. Get v from each macro pixel. Reference values as well as _{V = [v1, ···, v} 24] obtained. This V becomes an explanatory variable. A matrix G is obtained from R and V obtained so far.

G = RV ^t (VV ^t ) ⁻¹ (Expression 4)

  This matrix G is called a regression matrix and is used for correction calculation. Since the explanatory variable V has a different value for each macro pixel, the matrix G is also calculated for each macro pixel. The above is preparation for correction calculation.

The flow of actual measurement will be described. A sample to be measured is imaged by the spectroscopic camera device 1. An output value is calculated for each macro pixel included in the captured image. This is assumed to be “v _C = [v _CX , v _CY , v _CZ ] ^t ”. Next, the corrected tristimulus value r _C is calculated by performing the following equation (5). By obtaining r _C for each macro pixel, an accurate tristimulus value of a two-dimensional surface can be obtained.

r _C = Gv _C (Expression 5)

In the above flow, V or v _C using the output value as it is is used, but it can be expanded as shown in the following equation (6).

_{v = [v X, v Y} , v Z 1 v X 2 v Y 2 v Z 2 ···] t ( equation (6))

“...” in Equation 6 means higher-order terms such as v _X v _Y and v _X ³ . By performing such expansion, it is possible to improve the accuracy of correction and obtain a more accurate value. When the regression matrix G is obtained with the expanded V, it is preferable to use the expanded v _C even in the case of actually using the equation (5).

  Next, as the spectroscopic camera device 1, a spectroscopic camera device having the configuration shown in FIG. 12 may be used. In the case of the spectroscopic camera device 1 shown in FIG. 12, the microlens array 87 is provided so that the image position of the main lens 85 and the sensor surface 88 are in a conjugate relationship. Further, as shown in FIG. 13, by providing a plurality of spectral filters 89a to 89d on the sensor surface 88, the same effects as described above can be obtained.

  In the case of the spectral camera device 1 shown in FIG. 12, the number of lenses of the microlens array 87 and the number of spectral filters 89a to 89d are the same. Then, an image of the main lens 85 is formed at each sensor position by each microlens array 87. In the case of the spectroscopic camera device 1 shown in FIG. 12, complicated image processing is not required, so that high-speed computation is possible. Further, since each spectral image can be simultaneously captured in the adjacent imaging regions, the sensor surface 88 can be used effectively, and the spectral image with higher resolution than the above-described spectral camera device 1 described with reference to FIG. An image can be obtained.

  A field lens 86 may be provided between the main lens 85 and the microlens array 87. By providing the field lens 86, the parallax of the image formed by each microlens array 87 can be reduced. In the field lens 86, the exit pupil of the main lens 85 and the entrance pupil of the microlens array 87 are preferably in a conjugate relationship.

  Next, FIG. 14 shows a positional relationship between the illumination units 15 of the spectroscopic camera device 1 and the light source device 2 in the sample measurement device of the embodiment. FIG. 15 shows angles formed by the positional relationship between the illumination units 15 of the spectroscopic camera device 1 and the light source device 2.

  The sample measuring apparatus according to the embodiment irradiates the flat sample 61 with light from each of the illumination units 15a to 15e of the light source device 2 installed at two or more angles. Then, the two-dimensional spectroscopy of the sample 61 is performed with the spectroscopic camera device 1 installed, for example, in the vertical direction (directly above the sample 61) or above (obliquely above the sample 61) as shown in FIG. Information is acquired by one imaging operation (one shot) for each light irradiation angle of each of the illumination units 15a to 15e. In this case, the sample measuring device corresponds to the size of the sample 61, the subject distance, and the angle of view of the spectroscopic camera device 1, and the light irradiation angle and specular reflection angle at the right end 61a and the left end 61b of the sample 61, and the sample 61 The difference angle between the right end 61a and the left end 61b with respect to the viewing angle of the spectroscopic camera device 1 (aspecular angle: aspecular) is set under the following conditions. Then, the declination spectral information of the sample surface of the sample 61 in the declination range determined corresponding to the position of the spectroscopic camera device 1 is acquired without omission.

  For example, when acquiring declination spectral information in a range from −15 degrees to 110 degrees, the spectroscopic camera device 1 is installed at an angle of 45 degrees with respect to the sample 61 as shown in FIGS. 14 and 15. Further, as shown in FIG. 14 and FIG. 15, as the specular angle, “angle A ≦ −15 degrees ≦ angle C ≦ angle B ≦ angle E ≦ angle D ≦ angle G ≦ angle F ≦ angle I ≦ angle H ≦ 110 degrees ≦ Illumination is arranged so that the angle is “J”, and spectral information (declination spectral information) in a desired declination range is acquired without omission.

  FIG. 16 shows an example of a photographed image captured by the spectroscopic camera device 1 at the timing when light is emitted from the illumination unit 15d. In imaging performed using the illumination unit 15d, the light from the illumination unit 15d is applied to the sample 61 from the slightly right end 61a of the sample 61. Further, the spectroscopic camera device 1 captures the sample 61 by receiving the reflected light of the light irradiated on the sample 61 from the slightly left end 61 b side of the sample 61. For this reason, since the light irradiation direction and the imaging direction are opposite to each other, as shown in FIG. 16, a captured image of the sample 61 that is gradually darkened is captured from the left end 61b side of the sample 61 to the right end 61a side of the sample 61. The

  In the configuration of FIG. 14, as an example, the distance between the spectroscopic camera device 1 having a diameter of the sample 61 of 60 mm and an angle of view of 22.6 degrees and the sample 61 is 150 mm, and each illumination installed at each angle with the sample 61. The distance from the parts 15a to 15e is 150 mm. In this case, as shown in FIG. 15, the maximum declination range that can be acquired is −16 degrees to 121 degrees. Under the same conditions, when the number of illumination units is increased, the declination range is −54 degrees to 142 degrees at the maximum.

  On the other hand, when acquiring declination spectral information in the range from 0 degrees to 90 degrees, the spectroscopic camera device 1 is installed perpendicular to the sample 61 as shown in FIG. Further, as the aspecular angle, the illumination units 15f to 15h are installed so as to satisfy the condition of “angle N ≦ 0 degrees ≦ angle O ≦ angle K ≦ angle P ≦ angle L ≦ 90 degrees ≦ angle M”, and the deviation of the cover range is set. Make it possible to obtain all angular spectral information. In the example of FIG. 17, a total of three illumination units 15 f to 15 h are provided as illumination units. However, the illumination unit according to the size of the sample 61, the subject distance, the angle of view of the spectroscopic camera device 1, and the deflection angle range to be measured. What is necessary is just to provide a number.

  In the configuration shown in FIG. 17, the diameter of the sample 61 is 60 mm, the distance between the spectroscopic camera device 1 and the sample 61 is 150 mm, and the distance between the sample 61 and the illumination units 15 f to 15 h installed at the respective angles is 150 mm. In this case, the maximum declinable angle range that can be acquired is −23 degrees to 101 degrees. According to the ASTM standard (E2539), −15 to 110 degrees is recommended as a normal aspecular angle for pearl color. ASTM is an abbreviation for “American Society for Testing Materials”. However, depending on the sample, even when the a specular angle is 0 to 90 degrees, it may be possible to perform measurement capable of grasping the characteristics of the sample. For this reason, what is necessary is just to use properly the structure of the above-mentioned FIG. 14 and the structure of FIG. 17 according to a sample.

  Next, the measurement operation of the sample 61 and the calculation operation of the measurement value of each evaluation item will be described. First, an outline of the operation will be described. In FIG. 1, the information processing apparatus 4 performs imaging control of the spectral camera apparatus 1 by the imaging control unit 32 illustrated in FIG. 2. In the information processing apparatus 4, the light source control unit 31 controls the lighting unit 15 to be turned on, and the measurement value calculation unit 36 calculates the measurement value of each evaluation item. Each calculated measurement value is stored in a storage unit such as the HDD 24, the RAM 23, or the ROM 22.

  In addition, the information processing apparatus 4 reads a calibration member such as a standard white plate by the calibration information acquisition unit 34 before measuring the sample, and generates calibration information for calibrating the declination spectral information. Further, the information processing device 4 reads a calibration member such as uniform standard black glass or a standard mirror by the calibration information acquisition unit 34 at the time of measuring image clarity and orange peel, and calibration for calibrating the declination spectral information. Generate information. The calibration information acquisition unit 34 stores the generated calibration information in a storage unit such as the HDD 24, the RAM 23, or the ROM 22. The information calibration unit 35 calibrates the declination spectral information of the sample obtained by measurement using the calibration information. The measurement value calculation unit 36 calculates the measurement value of each evaluation item using the calibrated declination spectral information. The generation of the calibration information may be performed before the measurement of the sample, for example, at the time of factory shipment, or may be performed every time the sample is measured by providing a calibration member.

  This will be specifically described below. First, FIG. 18 is a flowchart showing a flow of normal calibration information acquisition operation other than calibration information corresponding to image clarity and orange peel. In the flowchart of FIG. 18, in step S <b> 1, the user manually or the calibration information acquisition unit 34 controls the moving mechanism of the standard white plate to install the sample 61 shown in FIG. 14 or FIG. A standard white plate is installed in the imaging range of the spectroscopic camera device 1.

  In step S2, the light source control unit 31 controls lighting of any one of the illumination units 15a to 15e or the illumination units 15f to 15h illustrated in FIG. In step S3, the imaging control unit 32 controls the imaging of the spectroscopic camera device 1 so that the standard white plate irradiated with light from the lighting unit whose lighting is controlled is captured in one shot. The calibration information acquisition unit 34 stores the imaging information of the standard white plate as calibration information in a storage unit such as the HDD 24 in FIG.

  The sample measuring apparatus according to the embodiment images the standard white plate one by one while sequentially controlling lighting of the illumination unit. In step S4, the CPU 21 determines whether imaging corresponding to all the illumination units has been completed. If the CPU 21 determines that imaging corresponding to all the illumination units has not been completed (step S4: No), the process returns to step S2. Then, the illumination unit that is next driven to be lit is turned on by the light source control unit 31, and the standard white plate is repeatedly imaged by the spectroscopic camera device 1 under the control of the imaging control unit 32. Thereby, each calibration information corresponding to each illumination unit is stored in the HDD 24.

  On the other hand, when it is determined that imaging corresponding to all the illumination units has been completed (step S4: Yes), the process of the flowchart of FIG. 18 ends.

  When the sample measurement apparatus according to the embodiment acquires calibration information in this way, as shown in the flowchart of FIG. 19, the sample measurement apparatus acquires polarization spectroscopy information for each illumination unit by imaging the sample, and each polarization spectroscopy information is obtained. Use to calculate the measured value of each evaluation item. In the flowchart of FIG. 19, in step S11, the user manually or the calibration information acquisition unit 34 controls the moving mechanism, and as shown in FIG. 14 or FIG. A sample 61 is installed.

  In Step S12, the light source control unit 31 controls lighting of any one of the illumination units 15a to 15e or the illumination units 15f to 15h illustrated in FIG. In step S13, the imaging control unit 32 controls imaging of the spectroscopic camera device 1 so that the sample 61 irradiated with light from the lighting unit whose lighting is controlled is imaged in one shot. The imaging control unit 32 stores the above-described declination spectral information, which is imaging information of the sample 61, in a storage unit such as the RAM 23 in FIG.

  Here, in the sample measurement device, the light source control unit 31 performs an operation for controlling lighting of each of the illumination units 15a to 15e so as to have a predetermined exposure time (an operation for changing the amount of light), and the imaging control unit 32 performs imaging. One or both of the operations for changing the exposure time are performed. And the measured value calculation part 36 synthesize | combines several two-dimensional spectroscopic information acquired according to the change of such light quantity or the change of exposure time. Thereby, two-dimensional spectroscopic information with an expanded dynamic range can be generated.

  Next, the sample measuring apparatus according to the embodiment images the sample 61 one by one while sequentially controlling lighting of the illumination unit. In step S <b> 14, the CPU 21 determines whether imaging corresponding to all illumination units has been completed. If the CPU 21 determines that imaging corresponding to all the illumination units has not been completed (step S14: No), the process returns to step S12. Then, the illumination unit that is next driven to be lit is turned on by the light source control unit 31, and the imaging of the sample 61 by the spectroscopic camera device 1 is repeatedly performed under the control of the imaging control unit 32. Thereby, each declination spectral information corresponding to each illumination unit is stored in the HDD 24.

  Next, when it is determined in step S14 that imaging corresponding to all the illumination units has been completed (step S14: Yes), when the process proceeds to step S15, the information calibration unit 35 is stored in the HDD 24. The declination spectroscopic information stored in the RAM 23 is corrected (calibrated) using the calibration information. In step S <b> 16, the measurement value calculation unit 36 uses the corrected declination spectral information to calculate the measurement value of each evaluation item as will be described later. Specifically, the measurement value calculation unit 36 calculates each measurement value of declination spectroscopic information, declination colorimetry information, BRDF information, glitter feeling, particle feeling, glossiness, and haze, and calculates the calculated measurement value. The data is stored in a storage unit such as the HDD 24, and the process of the flowchart in FIG.

  Next, FIG. 20 is a flowchart showing a flow of an operation for acquiring calibration information corresponding to image clarity and orange peel. In the flowchart of FIG. 20, in step S21, the user manually or the calibration information acquisition unit 34 controls the moving mechanism of the standard black glass or the mirror to install the sample 61 shown in FIG. 14 or FIG. Standard black glass or the like is installed at a position (within the imaging range of the spectroscopic camera device 1).

  In step S22, the light source control unit 31 performs lighting control on any one of the illumination units 15a to 15e or the illumination units 15f to 15h illustrated in FIG. In step S23, the imaging control unit 32 controls imaging of the spectroscopic camera device 1 so that the standard black glass or the like irradiated with light from the lighting unit whose lighting is controlled is imaged in one shot. The calibration information acquisition unit 34 stores imaging information such as standard black glass in a storage unit such as the HDD 24 in FIG. 1 as calibration information corresponding to image clarity and orange peel.

  The sample measuring apparatus according to the embodiment images standard black glass or the like one by one while sequentially controlling lighting of the illumination unit. In step S24, the CPU 21 determines whether imaging corresponding to all the illumination units has been completed. If the CPU 21 determines that imaging corresponding to all the illumination units has not been completed (step S24: No), the process returns to step S22. Then, the illumination unit that is next driven to be lit is driven to be lit by the light source control unit 31, and the imaging of the standard black glass or the like by the spectroscopic camera device 1 is repeatedly performed under the control of the imaging control unit 32. As a result, the HDD 24 stores each calibration information of image clarity and orange peel corresponding to each illumination unit.

  On the other hand, when it is determined that imaging corresponding to all the illumination units has been completed (step S24: Yes), the processing of the flowchart of FIG. 20 ends.

  Next, when each calibration information of image clarity and orange peel is acquired in this way, the sample measurement apparatus of the embodiment performs polarization spectroscopy for each illumination unit by imaging the sample as shown in the flowchart of FIG. Information is acquired, and using each polarization spectroscopic information, the measurement value of each evaluation item of image clarity and orange peel is calculated.

  In the flowchart of FIG. 21, in step S31, the user manually or the calibration information acquisition unit 34 controls the moving mechanism, so that the sample is within the imaging range of the spectroscopic camera device 1 as shown in FIG. 61 is installed. In step S32, the light source control unit 31 performs lighting control on any one of the illumination units 15a to 15e or the illumination units 15f to 15h illustrated in FIG. In step S33, the imaging control unit 32 controls imaging of the spectroscopic camera apparatus 1 so that the sample 61 irradiated with light from the lighting unit whose lighting is controlled is imaged in one shot. The imaging control unit 32 stores the above-described declination spectral information, which is imaging information of the sample 61, in a storage unit such as the RAM 23 in FIG.

  The sample measuring apparatus according to the embodiment images the sample 61 one by one while sequentially controlling lighting of the illumination unit. In step S34, the CPU 21 determines whether or not imaging corresponding to all the illumination units has been completed. If the CPU 21 determines that imaging corresponding to all the illumination units has not been completed (step S34: No), the process returns to step S32. Then, the illumination unit that is next driven to be lit is turned on by the light source control unit 31, and the imaging of the sample 61 by the spectroscopic camera device 1 is repeatedly performed under the control of the imaging control unit 32. Thereby, each declination spectral information corresponding to each illumination unit is stored in the HDD 24.

  Next, when it is determined in step S34 that imaging corresponding to all the illumination units has been completed (step S34: Yes), when the process proceeds to step S35, the information calibration unit 35 is stored in the HDD 24. The declination spectral information stored in the RAM 23 is corrected (calibrated) using the image clarity and the orange peel calibration information. In step S36, the measurement value calculation unit 36 uses the corrected declination spectral information to calculate the measurement value of the image clarity and the orange peel as described later, and stores the calculated measurement value in the storage unit such as the HDD 24. Then, the process of the flowchart of FIG.

  Next, a specific calculation operation of each evaluation item in the measurement value calculation unit 36 will be described. In the sample measuring apparatus of this embodiment, light is irradiated to the sample from a plurality of illumination units installed at different angles in a pre-calculated range. Then, the reflected light from the sample is photographed by the two-dimensional spectroscopic camera device 1 capable of acquiring spectral information in one shot, and the illumination direction of each pixel in the X-axis direction and the Y-axis direction of the captured two-dimensional image The variable angle spectroscopic information is obtained by utilizing the change in the optical geometric condition in the imaging direction.

  In the sample measurement apparatus of the embodiment, the in-plane is regarded as a uniform sample. The measurement value calculation unit 36 uses the declination spectral information of the angle range determined as the measurement range to obtain declination colorimetric information and BRDF information (Bi-directional Reflectance Distribution Function (BRDF)), Calculate as follows.

(Declination spectroscopy information)
The declination spectral information is a declination spectral reflection characteristic at a certain point x (i, j, θ, λ) on the sample surface. As described above, the spectroscopic camera device 1 uses the HDD 24 or the like as information on each wavelength. Saved in the storage unit. “I” is a coordinate on the light receiving element on the X axis, “j” is a coordinate on the light receiving element on the Y axis, “θ” is an a specular angle, and “λ” is a spectral wavelength.

(Declination colorimetric information)
When calculating the declination colorimetric information, the measurement value calculation unit 36 first uses the declination spectroscopic information described above as defined by the CIE (Commission Internationale de l'Eclairage). Tristimulus values XYZ are calculated. Then, by using the tristimulus values XYZ, the calculation shown in FIG. 22 is performed to convert to the L * a * b * colorimetric system, which is used as declination colorimetric information. Alternatively, the measurement value calculation unit 36 converts the tristimulus values XYZ into the L * u * v * color system by performing the calculation shown in FIG. 23, and uses this as the declination colorimetric information.

(BRDF information)
In FIG. 24, the BRDF at a certain point x (i, j) on the surface of the sample 61 depends on the two directions of incidence and reflection, and is a spectrum with respect to the intensity of incident light from the direction (θi, φi) of the illumination 15. It is defined as the ratio of the intensity of reflected light in the imaging direction (θr, φr) of the camera device 1. The angle Q shown in FIG. 24 is θi, the angle R is φi, the angle S is θr, and the angle T is φr. BRDF is defined for every three channels of red (R), green (G), and blue (B). Since it is common to use four angles QRST as parameters as in the following Expression 7, the measured value calculation unit 36 calculates BRDF information by the calculation of the following Expression 7.

∫ _BDRF (x, θi, φi, θr, φr,) (Expression 7)

(Get material parameters)
In addition, the measurement value calculation unit 36 calculates measurement values as follows for textures such as glitter, particle feeling, gloss, haze, image clarity, and orange peel.

(Glitter)
The spectroscopic camera device 1 has an optical configuration in which the resolution with respect to the sample 61 is 10 to 100 μm per pixel. Then, the spectroscopic camera device 1 images the sample 61 using a high dynamic range technique, for example, with a dynamic range of 18 bits or more.

  The measurement value calculation unit 36 calculates an intensity histogram for each illumination angle and each spectral wavelength, and calculates the glitter area, the glitter intensity, and the glitter variance for each angle and wavelength. Specifically, the measurement value calculation unit 36 calculates an intensity histogram for each range of angles of 10 ± 2.5 degrees at a wavelength of 555 nm, for example, and calculates an intensity histogram of a certain number of pixels or more. In this example, the calculation is performed every 10 degrees, but the intensity histogram may be calculated using another aspecular angle such as every 5 degrees.

  FIG. 25 shows regions for calculating intensity histograms at an aspecular angle of 10 degrees, 20 degrees, and 30 degrees. In addition, FIG. 26 shows intensity histograms at an aspecular angle of 10 degrees, 20 degrees, and 30 degrees. As shown in FIG. 25, the number of pixels at the peak at an a specular angle of 10 degrees is “bright area AR1”, the number of pixels at the peak at an a specular angle of 20 degrees is “bright area AR2,” and the number of pixels at the peak at an a specular angle of 30 degrees is “ It is referred to as “brightness area AR3”. Also, in FIG. 26, the peak brightness intensity at an a specular angle of 10 degrees is “brightness intensity K1”, the peak brightness intensity at an aspecular angle of 20 degrees is “brightness intensity K2”, and the peak brightness intensity at an aspecular angle of 30 degrees is “brightness”. Intensity K3 ". Further, the brightness dispersion of the histogram at an aspecular angle of 10 degrees is “brightness dispersion B1”, the brightness dispersion of the histogram at an aspecular angle of 20 degrees is “brightness dispersion B2”, and the brightness dispersion of the histogram at an aspecular angle of 30 degrees is “brightness dispersion B3”. To do.

  In this case, the brightness parameter S (θ) at the angle θ can be represented by three parameters of “S_area (θ)”, “S_strength (θ)”, and “S_variance (θ)” as an example. The parameters of “S_area (θ)” are represented by a bright area (the number of pixels at the peak) AR1, a bright area AR2, and a bright area AR3. The parameter of “S_strength (θ)” is expressed by peak brightness intensity K1, brightness intensity K2, and brightness intensity K3. The parameter of “S_variance (θ)” is represented by the brightness dispersion B1, the brightness dispersion B2, and the brightness dispersion B3.

  As an example, an image of a finely-painted metallic paint sample is shown in FIG. 27 (a), and a finely-painted metal paint sample is shown in FIG. 27 (b). The intensity histogram of is shown. FIG. 28A shows an image of a sample with a metallic coating with coarse particles, and FIG. 28B shows an image of a sample with a metallic coating with coarse particles. An intensity histogram is shown. Further, an image of the pearl-coated sample is shown in the figure with the reference numeral (a) in FIG. 29, and an intensity histogram of the pearl-coated sample is shown in the figure with the reference numeral (b) in FIG. 27 to 29 are images and intensity histograms when the sample is imaged from the vertical direction (see FIG. 17). The information processing device 4 illustrated in FIG. 1 displays the sample image captured by the spectral camera device 1 and the calculated intensity histogram on the monitor device 5.

(Particle feeling)
The spectroscopic camera device 1 has an optical configuration in which the resolution with respect to the sample 61 is 10 to 100 μm per pixel. Then, the spectroscopic camera device 1 images the sample 61 using a high dynamic range technique, for example, with a dynamic range of 18 bits or more.

  The measurement value calculation unit 36 reconstructs an image using only pixels determined to be diffused light other than the regular reflection light of the illumination of the particle image for each illumination angle. That is, using the example shown in the intensity histogram of FIG. 26, the measurement value calculation unit 36 uses only pixels excluding “bright area AR2” and “bright area AR3” of the number of pixels at the peak, and Perform reconfiguration.

  And the measured value calculation part 36 calculates the dispersion value of a bright location and a dark location from the reconfigure | reconstructed image, and makes the calculated dispersion value the measured value of a particle feeling. The regular reflection light is often noise, and the calculation of particle feeling may be inaccurate. However, by using only pixels corresponding to diffused light other than specularly reflected light and performing the above-described image reconstruction and calculation of the dispersion value, it is possible to accurately quantify the particle feeling. A small dispersion value indicates that the paint particles are uniformly dispersed on the painted surface, and a large dispersion value indicates that the paint particles are sparsely dispersed on the painted surface. Show. The numerical value of the uniformity may be calculated using image entropy or may be calculated by Fourier analysis.

(Glossy)
When calculating the measurement value of gloss, the measurement value calculation unit 36 uses spectral intensity information of 555 nm, which is a human visual sensitivity, for a pixel obtained by imaging specular reflection light. And the measured value calculation part 36 measures glossiness by calculating the following Formula 8 according to Japanese Industrial Standard (JIS) Z8741-1997 Specular glossiness Methods of measurement. Calculate the value.

  Gs (θ) = φs / φos * Gos (θ) (Expression 8)

  In Equation 8, “φs” indicates a specularly reflected light beam from the sample surface with respect to the specified incident angle θ. “Φos” indicates a specularly reflected light beam from the standard surface with respect to the specified incident angle θ. “Gos (θ)” indicates the glossiness (%) of the standard surface used. Note that standard black glass or a standard mirror may be used as the standard surface.

  Further, the measurement value calculation unit 36 calculates a flop index (Flop Index) from the above-described L * a * b * color system information obtained by converting the tristimulus values XYZ, and a flop characteristic (degree of change in brightness). Is calculated. The flop index is a relative change in the value of the L * a * b * color system information for each angle and the brightness seen between the highlight and the shade.

  As a calculation formula of the flop index, the measurement value calculation unit 36 uses the following formula (9) developed by DuPont.

Flop Index = 2.69 * (L * 15-L * 110) ^1.11 / (L * 45) ^0.85 (Expression 9)

  Instead of normalizing at 45 degrees, the difference between highlight (15 degrees) and shade (110 degrees) may be used as the flop index.

(Haze)
For example, “ASTM E--” shown in FIG. 30 is obtained from the spectroscopic intensity information of 555 nm, which is the human visual sensitivity, on the sample surface shifted from 1.9 degrees to 3 degrees from the specular reflected light and the specular reflected light. 430 Test Method B "is calculated, and the measured value of haze is calculated. The example of FIG. 30 is an example of specular reflected light of 20 degrees, but can be expanded according to the angle. For example, the example of FIG. 14 is an example of specular reflection light of 45 degrees.

  Next, when calculating the image clarity and the orange peel measurement value, as shown in FIG. 31, the spectroscopic camera device 1 images a predetermined short wavelength slit light 80 projected onto the sample from the projector 1. The measurement value calculation unit 36 performs, for example, ASTM D5767-95 Test Method B shown in Equation 10 below using spectral intensity information near 555 nm, which is human visibility, to measure image clarity and orange peel. Calculate the value.

  C = ((M−m) / (M + m)) × 100 (Expression 10)

  In Equation 10, “C” represents a measured value of image clarity, “M” represents a maximum value of spectral intensity information, and “m” represents a minimum value of spectral intensity information. An example of the spectral intensity information waveform is shown in FIG. 32A and FIG. 32B.

(Orange peel)
When the orange peel measurement value is calculated, the slit light 80 is projected from the projector 3 and imaged by the spectroscopic camera device 1 as shown in FIG. 31. When measuring the orange peel, a predetermined long wavelength is used. The slit light is projected to take an image. The measurement value calculation unit 36 calculates the orange peel measurement value using, for example, the above-described equation (10) using spectral intensity information around 555 nm, which is the human visual sensitivity. As for the orange peel, by using the slit light 80 having a long period, it is possible to evaluate the general unevenness characteristic having a longer period than the image clarity.

  The information processing apparatus 4 shown in FIG. 1 measures each of the declination spectral information, declination colorimetric information, BRDF information, glitter feeling, grain feeling, gloss, haze, image clarity, and orange peel calculated in this way. The value is displayed on the monitor device 5. The user can comprehensively evaluate the sample from each displayed measurement value.

  As is clear from the above description, the sample measuring apparatus of the first embodiment irradiates the sample 61 with illumination from a plurality of angles set in a range specified by the calculation formula, and the reflected light is one-shot. Thus, imaging is performed by the two-dimensional spectroscopic camera device 1 capable of acquiring spectroscopic information. Also, declination spectroscopic information is obtained by using the change in the optical geometric conditions of the illumination direction and the imaging direction for each pixel in the X-axis direction and the Y-axis direction in the two-dimensional image of the sample 61. Then, the in-plane is regarded as a uniform sample, and declination spectroscopic information, declination colorimetric information, and BRDF information in an angle range determined as a measurement range are obtained.

  Further, for the texture of the sample 61, measurement information quantified as follows is calculated. That is, the glitter feeling is calculated as follows. A spectroscopic camera device 1 having a resolution of 10 to 100 μm per pixel is used to photograph a sample with a dynamic range of 18 bits or more using a high dynamic range technique. The brightness histogram for each illumination angle and each spectral wavelength is calculated, and the brightness area and brightness intensity for each angle and wavelength are calculated.

  The particle feeling is calculated as follows. Using the spectroscopic camera device 1 having a resolution of 10 to 100 μm per pixel with respect to the sample, using only the pixels determined to be the diffused light that avoids the regular reflection light of the particle image illumination for each illumination angle, The image is reconstructed, and the uniformity of the bright / dark area is digitized from the image as a particle feeling. Uniformity may be obtained by using entropy or dispersion of an image or by Fourier analysis.

  The gloss is calculated as follows. Pixels that have captured regular reflection light are digitized using spectral information near 555 nm, which is the human visual sensitivity, and calibration results on a standard glass plate.

  Calculation of haze (turbidity (cloudiness)) is performed as follows. The sample surface deviated from regular reflection light and regular reflection light by 1.9 to 3 degrees is digitized using spectral information around 555 nm, which is human visibility, and calibration results on a standard glass plate.

  The image clarity is calculated as follows. The slit light (short wavelength) projected from the projector 3 is imaged by the spectroscopic camera device 1 and digitized using spectral information around 555 nm, which is human visibility, and a calibration result on a standard glass plate.

  The orange peel is calculated as follows. The slit light (wavelength is long) projected from the projector 3 is imaged by the spectroscopic camera device 1 and digitized using spectroscopic information around 555 nm, which is human visibility, and a calibration result on a standard glass plate.

  The sample measurement apparatus according to the first embodiment is provided with a declination spectroscopic information, declination color information, BRDF information, radiance, and the like of a paint containing a brilliant material that looks different colors depending on the viewing angle, such as pearl color or metallic color Measured values for each evaluation item can be calculated for grain feeling, gloss, haze, image clarity, and orange peel. For this reason, it is possible to perform comprehensive quantitative evaluation of a paint including a bright material that looks different colors depending on the viewing angle at a time.

(Second Embodiment)
Next, a sample measuring apparatus according to the second embodiment will be described. The sample measuring apparatus according to the first embodiment described above is configured to irradiate the slit light 81 and take an image when measuring the image clarity.

  On the other hand, in the sample measuring apparatus of the second embodiment, when the image clarity is measured, the pattern projection control unit 33, as shown in FIG. 33, reaches the imaging limit spatial frequency of the spectroscopic camera apparatus 1. The projector 3 is controlled so that the two-dimensional white noise 82 including the spatial frequency is projected onto the sample. Then, as described above, the light source control unit 31 sequentially drives the illumination unit to turn on, and the imaging control unit 32 controls the imaging of the spectral camera device 1 and images the white noise 82.

  White noise has the same intensity at all frequencies when Fourier transform is performed to obtain a power spectrum. The measurement value calculation unit 36 calculates a two-dimensional spatial frequency characteristic obtained by Fourier transform of a captured image of white noise as a measurement value of image clarity. A two-dimensional spatial frequency characteristic obtained by Fourier transforming a projected image of white noise that is projected is the spatial frequency response of the mapping to the spatial frequency of all incident images. For this reason, even if white noise is projected instead of the slit light 80 described above, the image clarity can be calculated and the same effects as those of the first embodiment described above can be obtained.

(Third embodiment)
Next, the sample measuring apparatus according to the third embodiment will be described. The sample measuring apparatus according to the third embodiment can perform measurement that is not affected by the shape of the measurement target surface by correcting the optical geometric condition of the three-dimensional shape at each position on the sample surface.

  Specifically, in the case of the sample measuring device according to the third embodiment, the slit light projected from the projector 3 or the three-dimensional shape of each position on the sample surface by the three-dimensional information acquisition device 90 shown in FIG. To get. The measurement value calculation unit 36 calculates the normal direction of each position of the sample from the acquired three-dimensional shape of each position of the sample surface. And the measured value calculation part 36 correct | amends the regular reflection direction of the light from an illumination part from the normal line direction of each position of the calculated sample, and the positional relationship of the spectroscopic camera apparatus 1, each illumination part, and a sample. Then recalculate the aspecular angle. Thereby, the optical geometric condition of the three-dimensional shape at each position on the sample surface can be corrected.

  When measuring the declination characteristic of a sample, the declination characteristic also shifts only when the sample is inclined by 1 degree from the horizontal direction. However, in the case of the sample measuring apparatus according to the third embodiment, calculation can be performed by calibrating the deviation of the declination characteristic tilted by 1 degree from the normal direction of the sample surface and its geometrical arrangement. . For this reason, the normal direction is calculated from the three-dimensional shape of each position of the sample, the specular angle of the illumination is corrected, and the aspecular angle is recalculated to perform measurement that is not affected by the shape of the measurement target surface. In addition to obtaining a more accurate measurement value of each evaluation item, the same effects of the above-described embodiments can be obtained.

(Fourth embodiment)
Next, a sample measuring apparatus according to the fourth embodiment will be described. In each of the above-described embodiments, for example, the spectroscopic camera device 1 performs imaging in one shot while controlling lighting of each of the illumination units 15f to 15h illustrated in FIG. 17 one by one.

  On the other hand, the sample measuring apparatus according to the fourth embodiment is provided with filters 91, 92, and 93 having different spectral transmittance characteristics on the front surfaces of the illumination units 15f to 15h as shown in FIG. . In addition, you may apply | coat the coating material from which each spectral transmittance characteristic differs to each illumination part 15f-15h. The spectral transmittance characteristics of the filters 91, 92, and 93 are as shown in FIG. In FIG. 36, the solid line graph indicates the spectral transmittance characteristic of the filter 91, the dotted line graph indicates the spectral transmittance characteristic of the filter 92, and the alternate long and short dash line graph indicates the spectral transmittance characteristic of the filter 93. As can be seen from FIG. 36, the wavelengths of light transmitted through the filters 91, 92, 93 are shifted by a predetermined amount.

  The light source control unit 31 controls lighting of all the illumination units 15f to 15h at the same time. In addition, when “simultaneous lighting control” is performed, the lighting timings of the lighting units 15f to 15h are matched to control lighting at a time, and the lighting units 15f to 15h are controlled to be turned on one or more at a time. Moreover, you may carry out lighting control of all the illumination parts 15f-15h simultaneously. That is, the lighting units 15f to 15h may be controlled to be lit so that there is a time during which the lighting units 15f to 15h are lit simultaneously.

  The imaging control unit 33 controls imaging of the spectroscopic camera device 1 so as to perform one imaging operation while all the illumination units 15f to 15h are controlled to be turned on simultaneously. Thereby, the declination spectroscopic information and declination colorimetric information corresponding to each illumination part 15f-15h can be acquired at once by one shot. For this reason, in addition to shortening the measurement time of the sample, the same effects as the above-described embodiments can be obtained.

  Each above-mentioned embodiment is shown as an example and is not intending limiting the range of the present invention. Each of the novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. Each embodiment and modifications of each embodiment are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Spectroscopic camera apparatus 2 Light source apparatus 3 Projector 4 Information processing apparatus 5 Monitor apparatus 11 Imaging part 12 Image processing part 15 Illumination part 16 Lighting control part 31 Light source control part 32 Imaging control part 33 Pattern projection control part 34 Calibration information acquisition part 35 Information calibration section 36 Measurement value calculation section 53 Micro lens array (MLA)
54 Main lens 56 Color filter 61 Sample 61a Right end of sample 61b Left end of sample 80 Slit light 90 3D information acquisition device 91 Filter 92 Filter 93 Filter

JP2013-238576A

Claims (15)

A light source device that irradiates illumination light at a time from an illumination unit having a plurality of illumination angles to the sample surface of the sample;
A plurality of filters each having a light spectral transmittance characteristic that is provided in each of the illumination units and transmits illumination light of different wavelengths;
A spectroscopic camera device that is disposed above the sample surface and that splits reflected light corresponding to the illumination light of each wavelength from the sample surface to obtain two-dimensional spectral information in a single imaging operation;
The sample for measuring a measurement value of a predetermined evaluation item of the sample by using a change in optical geometric conditions of an illumination direction and an imaging direction for each pixel in the X-axis direction and the Y-axis direction of the spectral information A sample measuring device comprising: a calculating unit that calculates declination spectral information of a surface. The optical geometric condition includes a measurement range of the sample surface, an angle of view of the spectroscopic unit, a distance between the sample surface and the illumination unit, a distance between the spectroscopic unit and the illumination unit, and the illumination unit At least one of the illumination angles of
The sample measuring apparatus according to claim 1, wherein the illumination unit and the spectroscopic unit are arranged so that a declination range to be measured can be continuously acquired under the optical geometric condition. The calculation unit calculates a brightness histogram for each illumination angle and each spectral wavelength using the two-dimensional spectral information acquired by the spectroscopic camera device, and calculates a luminous area and a luminous intensity for each illumination angle and each spectral wavelength. The sample measuring apparatus according to claim 1 or 2, wherein: The light source device changes at least one of the light amount and the exposure time at the time of imaging,
The spectroscopic camera device synthesizes a plurality of the two-dimensional spectroscopic information acquired in accordance with a change in a light amount by the light source device, an exposure time at the time of imaging, or a light amount and an exposure time at the time of imaging. The sample measurement apparatus according to any one of claims 1 to 3, wherein the enlarged two-dimensional spectral information is generated. The calculation unit determines a diffused light reflection angle range excluding a regular reflection angle from the two-dimensional spectral information acquired by the spectral camera device, and diffuses particles other than the regular reflected light of the particle image for each illumination angle. Reconstruct the image using only the pixels determined to be light, and calculate the uniformity of the area of the bright and dark areas from the reconstructed image as particle feeling using image entropy, dispersion, or Fourier analysis The sample measurement device according to claim 1, wherein the sample measurement device is a sample. The calculation unit uses the declination spectral information to calculate a gloss value from a regular reflection angle, and calculates a haze value from the regular reflection angle and a nearby angle. The sample measuring device according to any one of the above. A projector that projects a predetermined pattern of slit light on the imaging range of the spectroscopic camera device 1;
The calculation unit measures each measurement value of image clarity and orange peel of the sample using declination spectral information generated by imaging the slit light with the spectral camera device. The sample measuring device according to any one of claims 1 to 6. A three-dimensional information acquisition device for measuring and acquiring three-dimensional shape information of the sample surface of the sample;
The calculation unit calculates the normal direction of each position on the sample surface using the acquired three-dimensional shape information of the sample surface, and is acquired by the spectroscopic camera device using the calculated normal direction. The sample measurement apparatus according to any one of claims 1 to 7, wherein the deviation angle spectroscopic information is corrected. The calculation unit calculates measured values of declination color information, BRDF information, glitter feeling, grain feeling, gloss, haze, image clarity, and orange peel, respectively, using the declination spectral information. The sample measuring device according to any one of claims 1 to 8. The projector projects an image of white noise on the imaging range of the spectral camera device 1,
The calculation unit calculates a measured value of image clarity of the sample using the declination spectral information obtained by capturing the white noise image with a spectral camera device. The sample measuring device according to claim 9. The spectroscopic camera device includes:
A multi-band camera that includes a main lens, a spectral filter group, and a micro lens and acquires spectral information corresponding to the number of the spectral filters, or a hyperspectral camera including one or more sets of filters and a diffraction grating or a prism ,
The said two-dimensional spectral information is acquired by one imaging operation | movement synchronizing with irradiation of the illumination light of each illumination angle of the said illumination part, The any one of Claims 1-10 characterized by the above-mentioned. The sample measuring device according to 1. The multi-van camera includes a spectral filter group inserted into a main lens, and a micro lens array inserted between the main lens and a light receiving element, and the spectral filter passes through each micro lens of the micro lens array. The sample measurement apparatus according to claim 11, wherein spectroscopic information corresponding to the number of is acquired. The multi-van camera acquires spectral information according to the number of the spectral filters by providing the spectral filter group between the microlens array and the light receiving element. Sample measuring device. The sample measuring apparatus according to any one of claims 1 to 11, wherein the spectroscopic camera device includes an optical configuration in which a resolution of each pixel with respect to the sample is 10 μm to 100 μm. Computer
To illuminate the sample surface of the sample with different wavelengths of light through filters having optical spectral transmittance characteristics that match the lighting timings of the illumination units at a plurality of illumination angles and transmit light of different wavelengths. A light source control unit for controlling the light source device;
The spectroscopic camera device is imaged so as to disperse reflected light corresponding to the illumination light of each wavelength from the sample surface and obtain two-dimensional spectroscopic information in one imaging operation. An imaging control unit to control;
The sample for measuring a measurement value of a predetermined evaluation item of the sample by using a change in optical geometric conditions of an illumination direction and an imaging direction for each pixel in the X-axis direction and the Y-axis direction of the spectral information A sample measurement program that functions as a calculation unit that calculates declination spectral information of a surface.