Manual correction of an image color

A color correction system for correcting colors in a color image comprising:

• coordinates for registering points in a first color space of at least one standard point, the first color space having axes for specifying colors;
• a second set of coordinates for registering points in a second color space of at least one standard point, the second color space having axes that include at least one coordinate for specifying color hues;
• a translator to convert image data from at least one point in the first color space to coordinates in the second color space;
• a modifier for modifying at least hue within image data in the second color space to form corrected image data in the second color space, whereby the modifier is adapted to determine whether a user specified control point is within a threshold defined adjacent an original maximum or minimum color value and adapted to move outside the range of original maximum or minimum color values when the user specified control point is within such a threshold of the maximum or minimum limits of color values to create a conceptual maximum or minimum color value, the modifier also being adapted to generate a color correction curve using a specified control point, one of an original maximum or minimum color value and one of a conceptual maximum or minimum color value;
• a translator for transferring corrected image data in the second color space to corrected image data in the first color space.

A method for correcting colors in a color image comprising:

• providing image data of points in a first color space, the first color space having axes for specifying colors;
• converting image data points in the first color space into image data points in a second color space, the second color space having coordinates that include at least one coordinate for hue for specifying colors;
• modifying at least hue of at least some data points within image data in the second color space to form corrected image data in the second color space, whereby this modifying provides for determining whether a user specified control point is within a threshold defined adjacent an original maximum or minimum color value and for movement outside the range of original maximum or minimum color values when the user specified control point is within such a threshold of the maximum or minimum limits of color values to create a conceptual maximum or minimum color value, the modifying also providing for generating a color correction curve using a user specified control point, one of an original maximum or minimum color value and one of a conceptual maximum or minimum color value;
• transferring corrected image data in the second color space to the first color space as corrected data.

A computer readable medium having computer executable instructions for performing steps comprising:

• providing image data of points in a first color space, the first color space having axes for specifying colors;
• converting image data points in the first color space into image data points in a second color space, the second color space having coordinates that include at least one coordinate for hue for specifying colors;
• modifying at least hue of at least some data points within image data in the second color space to form corrected image data in the second color space, whereby this modifying provides for determining whether a user specified control point is within a threshold defined adjacent an original maximum or minimum color value and for movement outside the range of original maximum or minimum color values when the user specified control point is within such a threshold of the maximum or minimum limits of color values to create a conceptual maximum or minimum color value, the modifying also providing for generating a color correction curve using a user specified control point, one of an original maximum or minimum color value and one of a conceptual maximum or minimum color value;
• transferring corrected image data in the second color space to the first color space as corrected data.

A computer readable medium having computer executable instructions for performing steps comprising:

• providing a tone reproduction curve relating to a first image, the tone reproduction curve defined by at least three points selected from the group consisting of an original minimum color value, an original maximum color value, and a user specified control point (USCP) that represents a change in color value from an original color value in an image to a desired color value;
• defining at least one threshold color value, the threshold color value defining a threshold color value in relationship to at least one of the original minimum color value or the original maximum color value, the threshold color value defining a threshold where if the USCP lies either between an original minimum color value and a minimum threshold color value defined in relationship therewith or between an original maximum color value and a maximum threshold color value defined in relationship therewith, the original minimum or maximum color value associated with that threshold is conceptually moved farther from the position of that original minimum or maximum color value to form a conceptual minimum color value or conceptual maximum color value, and
• then creating a monotonic tone reproduction curve through:
• a) the conceptual minimum color value or conceptual maximum color value,
• b) the USCP, and
• c) the original minimum color value or original maximum color value that was not associated with the threshold.

A computer readable medium having computer executable instructions for performing steps comprising:

• establishing color range limits for a color image to be subjected to color modification, the color range limits including an original minimum color value and an original maximum color value;
• establishing a user specified control point (USCP) representative of a first color to be modified and a second color to replace the first color;
• defining at least one threshold color value, the threshold color value defining a threshold color value in relationship to at least one of the original minimum color value or the original maximum color value;
• determining whether the USCP lies either between an original minimum color value and a minimum threshold color value defined in relationship therewith or between an original maximum color value and a maximum threshold color value defined in relationship therewith,
• moving the original minimum color value or the original maximum color value conceptually farther from the position of that original minimum or maximum color value to form a conceptual minimum color value or conceptual maximum color value, if the USCP has been determined to be within the threshold of the determining step;
• and
• then creating a monotonic tone reproduction curve through:
• a) the conceptual minimum color value or conceptual maximum color value,
• b) the USCP, and
• c) the original minimum color value or original maximum color value that was not associated with the threshold.