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1. (WO1997045809) METHOD OF IMPROVING A DIGITAL IMAGE

Pub. No.:    WO/1997/045809    International Application No.:    PCT/US1997/007996
Publication Date: Fri Dec 05 00:59:59 CET 1997 International Filing Date: Fri May 09 01:59:59 CEST 1997
IPC: G06T 5/20
Applicants: SCIENCE AND TECHNOLOGY CORP.
Inventors: RAHMAN, Zia-ur
JOBSON, Daniel, J.
WOODELL, Glenn, A.
Title: METHOD OF IMPROVING A DIGITAL IMAGE
Abstract:
A method of improving a digital image is provided. The image is initially represented by digital data indexed to represent positions on a display. The digital data is indicative of an intensity value Ii(x,y) for each position (x,y) in each i-th spectral band. The intensity value for each position in each i-th spectral band is adjusted to generate an adjusted intensity value for each position in equation (I), each i-th spectral band in accordance with where S is the number of unique spectral bands included in said digital data, Wn is a weighting factor and '*' denotes the convolution operator. Each surround function Fn(x,y) is uniquely scaled to improve an aspect of the digital image, e.g., dynamic range compression, color constancy, and lightness rendition. The adjusted intensity value for each position in each i-th spectral band is filtered with a common function and then presented to a display device. For color images, a novel color restoration step is added to give the image true-to-life color that closely matches human observation.