Browse Prior Art Database

3X MAGNIFICATION METHOD

IP.com Disclosure Number: IPCOM000026482D
Original Publication Date: 1992-Apr-30
Included in the Prior Art Database: 2004-Apr-06
Document File: 4 page(s) / 164K

Publishing Venue

Xerox Disclosure Journal

Abstract

It is a generally known requirement of certain computer graphic output devices to convert the resolution of digital input images prior to outputting them at a predefined output resolution (pixel density or raster density). For example, many existing input scanners and personal computer software packages operate at a medium image resolution of 300 spi, resulting in either an incompatibility with higher resolution printers or an underutilization of the output capabilities of such printers. It is therefore an object of the present invention to magnify an input raster image while automatically modifying the output raster image in order to minimize abrupt edge effects, or jaggedness, caused by the digital encoding process and preserving single pixel structure therein.

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XEROX DISCLOSURE JOURNAL

3X MAGNIFICATION METHOD

Louis D. Mailloux

Proposed Classification
U.S. C1.382/047 Int. C1. G06k 9/42

A B

C

D

F

'y3 I ; 23

I I I I

W I I

1 G H

XEROX DISCLOSURE JOURNAL - Vol. 17, No. 2 MarcWAprill992 107

[This page contains 1 picture or other non-text object]

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3X MAGNIFICATION METHOD(Cont'd)

It is a generally known requirement of certain computer graphic output devices to convert the resolution of digital input images prior to outputting them at a predefined output resolution (pixel density or raster density). For example, many existing input scanners and personal computer software packages operate at a medium image resolution of 300 spi, resulting in either an incompatibility with higher resolution printers or an underutilization of the output capabilities of such printers. It is therefore an object of the present invention to magnify an input raster image while automatically modifying the output raster image in order to minimize abrupt edge effects, or jaggedness, caused by the digital encoding process and preserving single pixel structure therein.

In accordance with the present invention, the magnification of the image is accomplished in a pixel by pixel fashion based upon neighboring image pixel data. With reference to the 3 scanline by 3 pixel (3x3) array of original image pixels in the figure, denoted alphabetically as pixels A through I, a center pixel E may be magnified by an integral multiple based upon the relative binary states of neighboring pixels A,B,C,D,F,G,H and I. The default binary state for the output pixel is determined by the binary state of the center pixel. Alteration of the default state is based upon the binary states of neighboring pixels and the relationships between sub-groups of neighboring pixels. Definition of the 3x3 original image array allows the generation of specific rules which may be applied symmetrically to all pixels to be generated from center pixel E. The figure depicts the 3x magnification of a center pixel E into nine output pixels where three unique output pixel positions X, Y and Z are identified within the upper left quadrant of the magnified pixel array. When reflected about both horizontal and vertical axes passing through the center of original pixel E, the unique positions are further multiplied to form nine output pixels (Xc, Y1- Y4, and 21 - 24). The center output pixel Xc is common to all four rotated positions and therefore is treated in a unique manner when applying the binary state determination rules.

Specifically, the binar...