System and method for enhancing scanned document images for color printing
AssigneeHewlett-Packard Development Company, L.P.
InventorsJian Fan, Daniel Tretter, Qian Lin, Neerja Raman
Life of this patent
Estimating the term…
Abstract
A system and method for enhancing scanned document images utilizes an estimated background luminance of a given digital image to remove or reduce visual “see-through” noise. The estimated background luminance is dependent on the luminance values of the edges pixels of detected text edges of the image. In one embodiment, the estimated background luminance is generated using only the edge pixels that are on the lighter side of the detected edges. In addition to the see-through removal, the system and method may further enhance the scanned document images by removing color fringes and sharpening and/or darkening edges of text contained in the images.
Claims25
A method of enhancing digital images comprising:
- receiving an input digital image containing visual noise;
- detecting edges of a feature within said input digital image;
- generating a background threshold based on an estimation of background luminance of said input digital image, said background threshold being dependent on luminance values of edge pixels of said edges;
- and
- selectively modifying pixel values of said input digital image using said background threshold to at least partially remove said visual noise from said input digital image.
A system for enhancing an input digital image containing visual noise comprising:
- means for detecting edges of a feature within said input digital image;
- means for generating a background threshold based on an estimation of background luminance of said input digital image, said background threshold being dependent on luminance values of edge pixels of said edges;
- and
- means for selectively modifying pixel values of said input digital image using said background threshold to at least partially remove said visual noise from said input digital image.
A program storage medium readable by a computer, tangibly embodying a program of instructions executable by said computer to perform method steps for enhancing an input digital image containing visual noise, said method steps comprising:
- detecting edges of a feature within said input digital image;
- generating a background threshold based on an estimation of background luminance of said input digital image, said background threshold being dependent on luminance values of edge pixels of said edges;
- and
- selectively modifying pixel values of said input digital image using said background threshold to at least partially remove said visual noise from said input digital image.
Dependencies are inferred from the claim text.