Abstract:
A scientifically explained color normalization process for producing image and information arrays which correspond to human color perception and description and are substantially invariant under varying conditions of illumination intensity and measurements geometry. New radiation measurements obtained by a three waveband sensor (10) are normalized by a computer or equivalent device using an individual waveband normalization algorithm (12) which divides each measurement by the mean of about ten thousand surrounding measurements, thus extracting the maximum resolution relational reflectance factor. The combined three waveband normalized array is presented as a color-coded alphanumeric array in terms of MUNSELL hue, value and chroma, using a cylindrical coordinate transformation algorithm (14) and a MUNSELL conversion algorithm (16). The normalized array is also presented using a balanced image display device (18), based on either additive or subtractive primaries.
Abstract:
A method for generating the characteristics of a set of colors involves selecting at least two, and typically more reference colors. Each of the selected reference colors is described by a set of color characteristic data indicating the reflectance of each color at each of a set of predetermined wavelengths; and descriptions of the intermediate color samples are generated by computer the relative proportions of each base color which characterizes each intermediate color and calculating a reflectance value at each wavelength for the color to be generated proportionate to the reflectance values for each base color at the corresponding wavelength. A set of color samples is created as a result of the method for generating the characteristics of the colors and arranged in a geometry indicative of the method. A system for generating the color samples data has storage for storing the photometric characteristics and other data; a central processor under software control for accessing the stored data, computing the relative proportion of each reference color comprising each color to be generated, and computing the reflectances at each wavelength for which color reflectance data is stored for each intermediate color; and an output for outputting the data generated by the central processor.
Abstract:
A method of determining the color difference between two similar colors including the steps of determining the tristimulus values for a reference color with which another color is to be compared, providing a planar chromaticity diagram for the values other than brightness in which the values for the reference colors are at the origin and the abscissa and ordinates of the diagram, determining the hue of the reference color and plotting in said diagram an equi-hue line, determining the tristimulus values for the other color to be compared to the reference color and plotting the values other than brightness on the diagram, plotting an equi-saturation line on the diagram perpendicular to the equi-hue line and extending through the origin, plotting lines parallel to the equi-hue and equi-saturation lines through the position of the plotted values for the other color and extending across the equi-hue and equi-saturation lines, so that the difference in the tristimulus values for the other color from the reference color are shown by measurements along said parallel lines. In addition, a brightness line is provided having the brightness value of the reference color at the center of the line with values of greater brightness on one side of the center and values of less brightness on the other side of the center, and plotting the brightness of the other color on the line, whereby the difference in brightness for the other color from the reference color is shown by measurement along the line.
Abstract:
In a data base of inventoried fabric pieces (e.g. rolls) having associated predetermined color parameter value data, a target fabric piece is initially selected having color parameter values which substantially deviate from a nominal center point within the color parameter space. Thereafter, a subset of the inventoried fabric pieces is identified having associated color parameters sufficiently near to those of the identified target piece as to be commonly usable therewith (e.g. in the construction of a garment). The color parameters may include red/green difference (da*), yellow/blue difference (db*) and lightness difference (dL*) values. Those defined points which fall within an ellipsoidal color space volume (having axes dimensioned to correspond to a predetermined acceptable variations in the color parameters within the desired subset and having a center selected so as to cause the color parameter values of the target piece to be located at the outer portion of such an ellipsoidal volume) are selected as a potentially usable subset. The result is an inverted or outside-toward-inside shade grouping selection process (in color space) of the inventoried fabric pieces--rather than vice versa--thus tending always to concentrate the color space values of remaining inventoried fabric pieces.
Abstract:
In a data base of inventoried fabric pieces (e.g. rolls) having associated predetermined color parameter value data, a target fabric piece is initially selected having color parameter values which substantially deviate from a nominal center point within the color parameter space. Thereafter, a subset of the inventoried fabric pieces is identified having associated color parameters sufficiently near to those of the identified target piece as to be commonly usable therewith (e.g. in the construction of a garment). The color parameters may include red/green difference (da*), yellow/blue difference (db*) and lightness difference (dL*) values. Those defined points which fall within an ellipsoidal color space volume (having axes dimensioned to correspond to a predetermined acceptable variations in the color parameters within the desired subset and having a center selected so as to cause the color parameter values of the target piece to be located at the outer portion of such an ellipsoidal volume) are selected as a potentially usable subset. The result is an inverted or outside-toward-inside shade grouping selection process (in color space) of the inventoried fabric pieces--rather than vice versa--thus tending always to concentrate the color space values of remaining inventoried fabric pieces.
Abstract:
The present invention discloses a set of dental color indicator devices and a method of selecting dental colors. Each indicator device has a number of color samples arranged in a regular array. Each of the samples corresponds to the color at a corresponding location in an identical array formed on one of a plurality of transverse parallel cuts through an elongate substantially elipsoid body which represents the possible range of dental colors when graphically represented on a color co-ordinate system, such as the CIELAB psycometric color system or the Munsell visual color system. The selected color is either the color of one of the samples or a mixture of the color of two adjacent samples.
Abstract:
A method for measuring the color difference between a sample dye and a standard dye by testing the color properties of both dyes, which comprises measuring the distribution curve of absorbance of individual components of the dye; determining the relationship between the color difference of dye solution and the color difference of dyeings with respect to the standard dye and representative samples arbitrarily selected plural lots of dyes; and predicting the color difference of dyeings from the color difference of solution between the standard dye and the sample dye.
Abstract:
A method for converting digital chrominance signals of a cartesian color coordinate system into digital color signals and saturation signals of a polar color coordinate system and including a transformation circuit for the transformation from cartesian to polar coordinates.
Abstract:
The invention relates to a method and to a circuit arrangement for the partial recorrection of color recognition spaces in color recognition. Before the color recognition, the color coordinates (color locations) of characteristic sample points are determined in the colors to be recognized and sample color numbers are allocated to them, said sample color numbers being deposited in a color recognition memory. All color numbers of the remaining color locations of the color space are determined from the sample color numbers and are likewise stored. The respective color locations or, respectively, memory locations occupied with the same color numbers form a color recognition space within the color space. For subsequent boundary correction of a color recognition space, at least one auxiliary color sample is taken from a color to be recognized in the area of the desired change and the necessary sample color number is allocated to it. The color numbers within a spatial cancel area around the color location of the auxiliary color sample are cancelled and, upon incorporation of all sample color locations and sample color numbers, new color numbers are instead calculated and stored for the cancel area.
Abstract:
A trichromatic colorimeter for obtaining the CIE chromaticity coordinates for an object to be measured. By utilizing a logarithmic compression type light measuring circuit, a higher accuracy and measuring range are obtainable in comparison to prior art linear light measuring type colorimeters.