Method and means for color detection and modification

Means for detecting and modifying color values in portions of a color image, said means comprising:

• a. input means for receiving input color signals which represent a colored image, and for converting said image into a plurality of pixel portions, each pixel having a discrete location;
• b. digital conversion means for converting the input color signal at each pixel into three digital coordinate values, said first coordinate value representing an approximation of luminance, said second and third coordinate values representing chromaticity;
• c. sampling means to selectively sample one or more of said pixels representing a color value for which detection and modification is desired;
• d. means for storing said second and third chromaticity coordinate values as a function of said luminance coordinate values for each pixel sampled by said sampling means, said means defining a three-dimensional curve in color space when said coordinate values are stored in a memory means, said luminous coordinate defining the longitudinal path of said curve while said second and third chromaticity values define the LOCl of said curve at each level of luminance sampled;
• e. function generator means for defining a three-dimensional color sub-space around said color curve, said function means defining a weighted value for each pixel having color coordinate values that fall within said three-dimensional color sub-spaces;
• f. comparator means for sequentially sampling each pixel in said image and comparing the color coordinate values of said pixel with the color coordinate values of the color sub-space defined by said function generator means;
• and
• g. means responsive to said comparator means to combine a second color signal with said input signal for each pixel having color coordinate values falling within said defined color sub-space.

Digital means for the automatic detection of color, said means comprising:

• a. means for generating a three-dimensional color curve for a sample color to be detected, said trajectory defining variations of hue and saturation throughout the luminous range of the sample;
• b. memory means for storing digital coordinate values of said sample color curve, wherein chromaticity coordinate values are stored as a function of said luminance coordinate values;
• c. function generating means to define a three-dimensional color sub-space around said color curve, the longitudinal dimensions of said sub-space being determined by said luminous coordinate values and the cross-section of said sub-space being determined by the chromaticity coordinate values;
• d. input means for receiving additional color signals to be evaluated and compared with said sample color, said input means converting said additional color signals to three digital coordinate values, the first coordinate value representing luminance, the second and third coordinate values representing chromaticity;
• e. comparator means to compare the coordinate values of said incoming additional color values to the coordinate value of said three-dimensional color sub-space defined by said function generating means;
• and
• f. threshold means for receiving the output of said comparator means and detecting any incoming color signal having coordinate values that are defined within the coordinate values defined by said function generating means.

A method of automatically detecting color with digital electronics, said method comprising,

• (a) generating a digital three-dimensional color trajectory for a first color to be detected, said trajectory defining chromaticity values as a function of luminance values, the first coordinate value of the three-dimensions representing luminance, and the second and third coordinate values representing chromaticity,
• (b) extending the digital coordinate values of the first color throughout the luminance range, and storing the chromaticity values as functions of the luminance value, for each value of luminance,
• (c) defining a three-dimensional color sub-space about the color trajectory, wherein the longitudinal values are defined by a function generator means beginning at the chromaticity values of the trajectory for that level of luminance,
• (d) converting incoming color signals to be detected into three digital coordinate values, wherein the first coordinate value represents luminance, and the second and third coordinate values represent chromaticity,
• (e) comparing the three coordinate values to the coordinate values of the color sub-space defined by the function generator means,
• (f) detecting each compared color signal having coordinate values that fall within the three-dimensional color sub-space.

A method of automatically detecting and modifying the color in a color image with digital electronics, said method comprising,

• (a) digitizing a color image as an X-Y array with a plurality of pixels, each pixel having a discrete location in the X-Y array,
• (b) converting the color values of each pixel into three digital coordinate values, with a first value representing luminance, and second and third values representing chromaticity,
• (c) storing the three digital coordinate values for each pixel, wherein the chromaticity values are stored as functions of luminance values;
• (d) identifying a color value for which detection and modification is desired by selectively sampling one or more of the pixels and generating a three-dimensional color trajectory for the color to be detected and modified,
• (e) defining a three dimensional color sub-space about the color trajectory, wherein the longitudinal values are defined by the luminance value, and the cross sectional values are defined by a function generator means beginning at the chromaticity values of the trajectory for that level of luminance,
• (f) comparing the three digital coordinate values of each pixel in the image array to the digital coordinants of the color sub-space defined by the function generator means,
• (g) identifying each pixel having color coordinate values that fall within said defined color sub-space,
• (h) modifying the digital coordinate values of each pixel identified in step (g).