Computer graphics processing and selective visual display system – Computer graphics processing – Attributes
Reexamination Certificate
1999-12-10
2002-09-24
Luu, Matthew (Department: 2672)
Computer graphics processing and selective visual display system
Computer graphics processing
Attributes
C345S590000, C345S600000, C345S604000, C348S645000, C348S650000, C358S518000, C358S519000, C358S520000, C382S162000, C382S167000
Reexamination Certificate
active
06456293
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color picker utilized in computer graphic art design.
2. Description of the Prior Art
Graphic art design software, such as desktop publishing software, uses advanced techniques for accurately reproducing colors. However, tools utilized by graphic art design software for editing colors, both single colors and sets of related colors, are still fairly primitive. This is true despite the existence of sophisticated color design principles in the graphic arts.
Graphic art design software for working with colors on a computer system is configured to maintain color fidelity between an input device and an output device. A color in such graphic art design software is specified as a set of coordinates in a color space. A color space is typically defined by three attributes, namely, source transform, destination transform and boundary. The source transform is an algorithm that converts a color from a first color space to a second device-neutral color space. The destination transform is an algorithm that converts a color in the second device-neutral color space into a third color space. The source transform and the destination transform coact to convert a color from the first color space to the third color space, and vice versa, via the second device-neutral color space. The most commonly used second device-neutral color space is CIE XYZ, a device-independent color space configured to represent every color perceivable by the human visual system. The boundary is an imaginary surface defining the limit of legal colors in the color space. The boundary of each color space is related to the range of colors producible by a device, such as a color monitor, color printer or color scanner, represented by the color space of the device or the limitation of human vision.
Graphic art design software includes a color picker which enables each color in an image to be adjusted. Preferably, the color picker includes an interface that displays a range of producible colors in terms of a perceptual color space. The perceptual color space can be depicted as a three-dimensional, double or dual-cone having the color white represented by a point of one cone and having the color black represented by a point of the other cone. The cone having the point representing the color white diverges conically therefrom toward the color black and the cone having the point representing the color black diverges conically therefrom toward the color white. The conical divergence of the two cones meet intermediate the points representing the colors white and black.
A color within the perceptual color space can be characterized in polar coordinates. Specifically, the perceptual color space has a central axis representing lightness which extends between the points at opposite ends of the dual-cone. The radial distance from the lightness axis represents saturation and the angle around the lightness axis represents hue.
A typical color picker enables an artist to work within the perceptual color space by providing a graphical interface that enables selection of a plane in the perceptual color space. For example, the graphical interface of one color picker enables the artist to select a desired hue by moving a slider on a hue color bar representing hue. Adjacent the hue color bar, the color picker displays the range of colors of the perceptual color space in a saturation-lightness plane for the selected hue. The artist then moves a computer icon in the saturation-lightness plane and selects a point therein corresponding to a color to be displayed in a select part of an image.
The graphical interface of another color picker includes a hue circle surrounding a triangle representing a saturation-lightness plane. In this color picker, the artist selects a desired hue by moving a computer icon to a desired position in the hue circle. Thereafter, the artist moves another computer icon in the saturation-lightness triangle and selects a point therein corresponding to a color to be displayed in a select part of the image.
The graphical interface of yet another color picker includes a slider on a lightness bar and an adjacent hue-saturation circle. In this color picker, the artist moves the slider to a desired position on the lightness bar. Then the artist moves a computer icon in the saturation-hue circle and selects a point therein corresponding to a color to be displayed in a select part of the image.
As discussed above, a second device-independent color space is utilized to transform colors from a first color space to a third color space. To change a color in the third color space utilizing a graphical interface in the first color space, two color transforms are required. Namely, a first color transform between the first color space and the second device-independent color space, and a second color transform between the second device-independent color space and the third color space. Moreover, in order to depict colors represented in the third color space in the user interface of the first color space, two additional color transforms are necessary between the third color space and the first color space. Hence, when editing colors in a third color space utilizing a graphic interface in a first color space, four color transforms are necessary between the various color spaces in order to affect a change of a color in a third color space based upon a graphical interface representation of this color in the first color space.
A problem with using prior art color pickers is that each color transform introduces numerical error into the color transformations. This error affects the fidelity of the colors displayed in the first color space or produced in the third color space. Another problem with using prior art color pickers is that they do not enable one color in a color space to be changed as a function of another color in the color space, thereby maintaining a desired relationship, i.e., hue, saturation and/or lightness, therebetween. Still another problem with prior art color pickers is that their graphical user interfaces do not permit visualization of relationships between colors in an image.
It is, therefore, an object of the present invention to overcome the above problems and others by providing a method for adjusting one or more colors in one or more color spaces utilizing techniques for modeling physical systems, e.g., a particle simulator. It is an object of the present invention to provide a method for reducing the number of color transforms over prior art color pickers. It is an object of the present invention to provide a method for relating two or more colors in one or more color spaces so that a change to one color produces a desired change to the other related colors. It is an object of the present invention to provide an apparatus for performing the foregoing methods. Still other objects of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description.
SUMMARY OF THE INVENTION
Accordingly, I have invented a method of adjusting color in a color space of a device. The method includes adjusting a first color to a second color in a first color space and subjecting the adjustment from the first color to the second color in the first color space to (i) one or more objectives for the adjustment of the first color in the first color space to the second color in the first color space; (ii) one or more constraints for the adjustment of the first color in the first color space to the second color in the first color space; and/or (iii) one or more constraints between the adjustment from the first color to the second color in the first color space and an adjustment of a corresponding first color in a second color space to a second color in the second color space.
The step of subjecting the adjustment can include the steps of converting the adjustment from the first color to the second color in the first color space to an adjustment of the first color to the second color in
Luu Matthew
Sajous Wesner
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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