Improved colorimetric analysis of liquid samples is provided. A sample holder is used that delivers predetermined volumes of sample individually to each of several colorimetric test patches at the same time with a sliding action. An opaque housing is employed to prevent ambient light from reaching the test patches when color images of the test patches are acquired. Preferably, a mobile electronic device including a camera is attached to the opaque housing to acquire the images. Optical microscopy can be performed in addition to the colorimetric analysis.

A color measuring device includes a color difference meter module. The color difference meter module includes: a main detecting unit having an optical detecting unit configured to receive light introduced from an incident lens to generate a first current depending on a color, a first measuring unit configured to measure the first current, a sub-detecting unit having a dark detecting unit disposed adjacent to the main detecting unit and blocking the light to generate a second current in a dark state, a second measuring unit configured to measure the second current, a leakage measuring unit including a charging unit provided in the second measuring unit and charged with a predetermined set current, and measures a third current leaking from the charging unit, and a control unit that corrects the first current by reflecting the second current and the third current.

A color calibration viewer used in color calibration, wherein: the relative intensity at a wavelength of 505 nm is 0.80 or more and 0.95 or less, and the relative intensity at a wavelength of 620 nm is 0.65 or more and 0.80 or less, where 1 designates the optical intensity of a peak top in a first wavelength region at a wavelength of 440 nm or more and 470 nm or less; and the ratio (A/B) of A and B is 1.00 or more and 1.46 or less, where A designates the optical intensity at a wavelength of 505 nm, and B designates the optical intensity at a wavelength of 620 nm.

A color calibration viewer used in color calibration, wherein: the relative intensity at a wavelength of 505 nm is 0.80 or more and 0.95 or less, and the relative intensity at a wavelength of 620 nm is 0.65 or more and 0.80 or less, where 1 designates the optical intensity of a peak top in a first wavelength region at a wavelength of 440 nm or more and 470 nm or less; and the ratio (A/B) of A and B is 1.00 or more and 1.46 or less, where A designates the optical intensity at a wavelength of 505 nm, and B designates the optical intensity at a wavelength of 620 nm.

A calculation device comprises a color evaluation unit that acquires a sensor color and four or more reference colors from photography data from a measurement time when an indication object was photographed in a second photography environment; determines coefficients for color conversion between a first and the second photography environments based on the amount of change from color information for the reference colors in the first photography environment, which has been read from a calculation device storage unit, to color information for the reference colors in the second photography environment, which has been acquired from the photography data; and uses the sensor color acquired from the photography data from the measurement time and the color conversion coefficients to correct the sensor color to the color that would have been photographed in the first photography environment by solving a conversion formula including terms representing an affine transformation consisting of translation.

A method of making a colorimeter colour standard, including determining print parameters required to achieve a desired colour for the colour standard, printing the desired colour on a colour-receiving face of a first transparent piece using the determined print parameters and permanently affixing the printed first piece to a second transparent piece such that the colour-receiving face of the first transparent piece and a joining face of the second transparent piece are positioned at the interface between the first transparent piece and the second transparent piece.

The present disclosure describes a method and apparatus that uses spectral reconstruction of detector sensitivity to solve the above and other problems. Specifically, light sources (e.g., of visible light, infrared light and/or ultraviolet light) may target the sensor and emit, in sequence, beams of different wavelength. Spectral output of multiple channels of the sensor is received, the output including intensity (e.g., peak intensity) for each channel. The output is compared with reference intensities for each of the light sources and difference values are calculated. Based on the difference values, a calibration matrix is calculated that can be used in calibrating the specific sensor. In addition, the present disclosure describes an apparatus that includes a plurality of light sources, a receiver for receiving sensor output, and circuitry configured to generate a calibration matrix using the light sources, the receiver using spectral reconstruction of detector sensitivity.

A transmission type color calibration chart includes a transparent substrate and a color bar group formed on the transparent substrate, wherein the color bar group is constituted by color bars of a plurality of colors containing at least a first color and a second color arranged in a pattern in no particular order, coordinate points of the first color are within a region encompassed by the four points (0.351, 0.649), (0.547, 0.453), (0.380, 0.506) and (0.433, 0.464) on an xy chromaticity diagram, coordinate points of the second color are within a region encompassed by the four points (0.125, 0.489), (0.112, 0.229), (0.270, 0.407) and (0.224, 0.242) on an xy chromaticity diagram, and the transmission spectrum of the first color's color bar and the transmission spectrum of the second color's color bar have peak tops that are respectively separated.

A transmission type color calibration chart includes a transparent substrate and a color bar group formed on the transparent substrate, wherein the color bar group is constituted by color bars of a plurality of colors containing at least a first color and a second color arranged in a pattern in no particular order, coordinate points of the first color are within a region encompassed by the four points (0.351, 0.649), (0.547, 0.453), (0.380, 0.506) and (0.433, 0.464) on an xy chromaticity diagram, coordinate points of the second color are within a region encompassed by the four points (0.125, 0.489), (0.112, 0.229), (0.270, 0.407) and (0.224, 0.242) on an xy chromaticity diagram, and the transmission spectrum of the first color's color bar and the transmission spectrum of the second color's color bar have peak tops that are respectively separated.

The invention relates to a system and a method for determining the color of teeth or tooth surfaces, wherein the system comprises a 2D or 3D camera and an attachment on said camera, which sets a geometry of a captured image in such a way that, compared to capturing an image without the attachment, the distance, spatial angle and orientation of tooth surfaces relative to the camera are restricted. The attachment according to the invention can in particular be fitted to the camera in a simple manner.