Method for acquiring local gonio-reflection characteristics of an image which is aggregation of dots. Sensory glossiness (L) of the image determined by equation (1) is 1.0 or more. The sensory glossiness (L) is determined based on a height of a peak (H), a height of a base (B) and a half width of a peak (W) of a distribution information of lightness with respect to light receiving angle, obtained by measuring reflected light of a measuring light irradiated into the image. The local gonio-reflection characteristics is acquired with a spatial resolution (A) for acquiring the local gonio-reflection characteristics and a resolution (B) which represents a distribution information of the dots within a region where the sensory glossiness (L) being 1.0 or more, satisfying formula (2).

L=Log((H−B)/W)  Equation (1)

0.8<A/B<10  Formula (2)

Method for acquiring local gonio-reflection characteristics of an image which is aggregation of dots. Sensory glossiness (L) of the image determined by equation (1) is 1.0 or more. The sensory glossiness (L) is determined based on a height of a peak (H), a height of a base (B) and a half width of a peak (W) of a distribution information of lightness with respect to light receiving angle, obtained by measuring reflected light of a measuring light irradiated into the image. The local gonio-reflection characteristics is acquired with a spatial resolution (A) for acquiring the local gonio-reflection characteristics and a resolution (B) which represents a distribution information of the dots within a region where the sensory glossiness (L) being 1.0 or more, satisfying formula (2).

L=Log((H−B)/W)  Equation (1)

0.8<A/B<10  Formula (2)

An optical system comprising: a light source; a photodetector; a first light-receiving system for causing the photodetector to receive first reflected light with a first angle of reflection from a surface; and a second light-receiving system for causing the photodetector to receive second reflected light with a second angle of reflection, different from the first angle of reflection, from the surface is provided. Here, a first light-receiving area of the photodetector with respect to light, of reflected light from the surface, via the first light-receiving system is spaced apart from a second light-receiving area of the photodetector with respect to light, of the reflected light from the surface, via the second light-receiving system.

An optical system comprising: a light source; a photodetector; a first light-receiving system for causing the photodetector to receive first reflected light with a first angle of reflection from a surface; and a second light-receiving system for causing the photodetector to receive second reflected light with a second angle of reflection, different from the first angle of reflection, from the surface is provided. Here, a first light-receiving area of the photodetector with respect to light, of reflected light from the surface, via the first light-receiving system is spaced apart from a second light-receiving area of the photodetector with respect to light, of the reflected light from the surface, via the second light-receiving system.

A hand-held measurement device for appearance analyses includes a measurement array which comprises a number of illumination means for applying illumination light to a measurement field in at least three illumination directions and a number of pick-up means for capturing the measurement light in at least one observation direction. The illumination directions and the observation directions lie in a common system plane. At least one pick-up means is embodied to spectrally gauge the measurement light in a locally integral way, and at least one imaging pick-up means is embodied to gauge the measurement light in terms of color in a locally resolved way. The spectral pick-up means and the locally resolving pick-up means are arranged such that they receive the measurement light reflected by the measurement field under the same observation conditions and in particular from the same observation direction.

A hand-held measurement device for appearance analyses includes a measurement array which comprises a number of illumination means for applying illumination light to a measurement field in at least three illumination directions and a number of pick-up means for capturing the measurement light in at least one observation direction. The illumination directions and the observation directions lie in a common system plane. At least one pick-up means is embodied to spectrally gauge the measurement light in a locally integral way, and at least one imaging pick-up means is embodied to gauge the measurement light in terms of color in a locally resolved way. The spectral pick-up means and the locally resolving pick-up means are arranged such that they receive the measurement light reflected by the measurement field under the same observation conditions and in particular from the same observation direction.

A texture evaluation apparatus includes a projector, an imager, and an evaluator. The projector is configured to project a two-dimensional pattern having an edge element onto an object. The imager is configured to capture an image of a surface of the object. The evaluator is configured to calculate an amount of shape change of a virtual image of the two-dimensional pattern in the image, and evaluate texture of the object based on the amount of shape change and sensory evaluation information obtained in advance.

3D shape reconstruction of glossy objects includes separation of diffuse and specular components of reflection from the object. Multiple layers of E-glass arranged in spaced-apart relation with each other, together with a camera for capturing images of reflected light. A first polarizer is positioned to polarize incident light before it reaches the object and a second polarizer is configured as an analyzer to analyze the light reflected from the object. The degree of polarization is varied. Images are captured of a structured light pattern as reflected in both diffuse and specular reflection the surface of the glossy object. A diffuse component of reflection is extracted by using the captured images of the deformed patterns, and a specular component of reflection is extracted by using the diffuse component of reflection and the captured images under polarized illumination. Depth of the surface of the object is estimated by fusing the diffuse component and the specular component.

A pearl grading method includes the following steps: (1) determining the color type of the pearl to be graded; (2) generating a simulated three-dimensional graph of the pearl to be graded; (3) calculating roundness, so as to obtain a roundness grade; (4) calculating the diameter of the simulated three-dimensional graph, so as to obtain a diameter grade; (5) drawing an illumination-wavelength reflection spectrum; (6) changing a detected part, and drawing an illumination-wavelength reflection spectrum again; (7) repeating the step (6) for at least two times; (8) performing weighted average to obtain a correction curve; and (9) comparing the correction curve with each glossiness grade spectrum baseline, so as to determine a glossiness grade according to the spectrum baseline with the highest coincidence degree. The method has the beneficial effects of low cost, high speed, good result consistency and high detection precision.

A color tone quantification device for a glossy color, in which the correlation with the color tone of the glossy color visually perceived by humans is further enhanced, is provided. The device comprises a coefficient calculation unit that calculates a coefficient calculated in consideration of a spatial distribution which is to be used to correct the chromaticity measured by a method including a specular reflection component obtained by measuring the reflection light obtained by reflection of measurement light to an area of an object; a chromaticity calculation unit that calculates an effective chromaticity obtained by weighting the chromaticity measured by the method including the specular reflection component with the coefficient calculated by the coefficient calculation unit; and an output unit that outputs the effective chromaticity as a stimulus value representing a glossy color of the area in a color space.