Hewlett-packard Development Company, L.p.

Hewlett-packard Company

Michael Stokes

Mary Nielsen

Denise Zimmerman

Daniel R Tretter

Qian Lin

Steve A Jacob

Malcolm Stuart Rix

David A Keefer

The method of the invention adaptively assigns an image data color management action to a component of a computing system. The computing system includes control programs such as an application program and a peripheral driver program. The computing system further includes a peripheral device that may have both software color management capability and hardware color management capability. The method of the invention initially examines received image data to determine at least one characteristic thereof. The method then compares the characteristic with one or more decision parameters that enable an assessment of the complexity of the color management actions required for the image data. Thereafter, based upon the result of the comparing action, the image data is subjected to a color management action by a selected one of the control programs or by the peripheral device, dependent upon the determined complexity of the image data.

Method and apparatus for assigning color management actions within a computing system

A graphics language interpreter includes one or more color converters that accept input color values and that algorithmically convert such input color values to output color values. The color converters are specified by a standard that defines the predefined graphics language. The color converters use color conversion algorithms that are potentially specified by graphics commands during rendering. A lookup component is associated with the color converters. The lookup component indicates output color values corresponding respectively to selected input color values. The lookup component is initialized with output color values that are converted from the selected input color values by the converters. During rendering, the graphics language interpreter uses the lookup component rather than the one or more color converters to convert input color values to output color values.

Color conversion acceleration using lookup tables

A process and apparatus is described to improve the digital processing of scanned negative films by reducing the amount of time necessary to perform the process and by increasing the robustness and quality of the images produced. These benefits are achieved by a process of color inversion, white point and black point mapping, and midtone adjustment. White and black mapping increases the dynamic range of the image, as well as removes the color cast of the negative film. A backlit image postprocessing algorithm can be employed which uses heuristics to identify backlighted situations, which are then brightened using a nonlinear power mapping. A midtone adjustment can include the sub-steps of contrast reduction and color adjustment. Contrast reduction reverses the film exposure characteristics. Color adjustment removes the remaining color cast in the midtone region of the image, and obtains the correct brightness. Starting from images with poor contrast and color cast, the system automatically looks for the appropriate correction parameters to produce images with vivid color and good contrast. This is achieved without rescanning or retaking the picture. One implementation, using one dimensional look-up-tables, is very efficient.

Digital processing of scanned negative films

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Boise, ID, United States of America

Michael Stokes