Browse Prior Art Database

Enhancement of Monochrome Images of Bank Checks and Other Documents

IP.com Disclosure Number: IPCOM000103462D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Dubil, JF: AUTHOR [+3]

Abstract

Prior art of pseudo-color enhancement of monochrome images includes histogram equalization and static mapping of the monochrome scale to a color scale. Generally, psuedo-color is achieved by setting values in the LUT (look up table) which drives the color values output from a display adapter card.

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Enhancement of Monochrome Images of Bank Checks and Other Documents

      Prior art of pseudo-color enhancement of monochrome images
includes histogram equalization and static mapping of the monochrome
scale to a color scale.  Generally, psuedo-color is achieved by
setting values in the LUT (look up table) which drives the color
values output from a display adapter card.

      Disclosed is a variety of techniques to improve upon prior art
using non-linear transformations and other techniques.
(1)  Localized histogram equalization:  The document is sectioned
into many smaller areas.  A histogram equalization is performed for
each area.  For each pel (picture element) interpolated values for
the nearest neighbor areas.
(2)  Tinting:  Increasing the output of one color (e.g., red LUT) by
a small, constant amount between two operator selected input ranges
will cause gray tones within that range to be tinted (e.g., turned
"pink").  The variability of gray tones within the selected range
will remain, as if a colored transparent filter were overlaid the
"tinted" pels. A variation of this technique is the addition of a
spectrum of tints over the full monochrome range.
(3)  Gradient based pseudo-color modifications:  The gradient of the
image (along a particular direction, say 30 degrees) is added to the
monochrome value of the image in addition to tinting.  The gradient
technique causes the image to have a three-dimensional appearance in
addition to the colorati...