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COMBINED RASTER AND VECTOR DATA REPRESENTATION AND RESOLUTION CONVERSION ALGORITHM

IP.com Disclosure Number: IPCOM000026102D
Original Publication Date: 1990-Apr-30
Included in the Prior Art Database: 2004-Apr-05
Document File: 4 page(s) / 197K

Publishing Venue

Xerox Disclosure Journal

Abstract

Current bit mapped images, as displayed on personal computer monitors, are typically displayed in resolutions below 100 spots per inch (spi). The display resolution is much lower than characteristic resolutions of readily available output devices, such as laser and ink jet printers. Typically, the generation of hardcopy output of the computer display is accomplished by a simple 2-D magnification of the picture elements of the display screen. Unfortunately, this simple approach usually results in poor output image quality, manifested in jagged edges on slanted lines, commonly referred to as "jaggies". The following information relates to a method of converting/magnifying the displayed image to achieve a more desirable rendition of the displayed image.

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XEROX DISCLOSURE JOURNAL

COMBINED RASTER AND VECTOR DATA REPRESENTATION AND U.S. C1.382/047 RESOLUTION CONVERSION
ALGORITHM
Jeng-Nan Shiau
Henry
E. Mannella

Proposed Classification

Int. C1. G06k 9/42

j

FIG. 1

XEROX DISCLOSURE JOURNAL - Vol. 15, No. 2 MarcWApril 1990 105

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

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COMBINED RASTER AND VECTOR DATA REPRESENTATION AND RESOLUTION CONVERSION ALGORITHM(Cont'd)

X I

Y

FIG. 2

106 XEROX DISCLOSURE JOURNAL - Vol. 15, No. 2 MarchlApril 1990

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

Page 3 of 4

COMBINED RASTER AND VECTOR DATA REPRESENTATION AND RESOLUTION CONVERSION ALGORITHM(Cont'd)

Current bit mapped images, as displayed on personal computer monitors, are typically displayed in resolutions below 100 spots per inch (spi). The display resolution is much lower than characteristic resolutions of readily available output devices, such as laser and ink jet printers. Typically, the generation of hardcopy output of the computer display is accomplished by a simple 2-D magnification of the picture elements of the display screen. Unfortunately, this simple approach usually results in poor output image quality, manifested in jagged edges on slanted lines, commonly referred to as "jaggies". The following information relates to a method of converting/magnifying the displayed image to achieve a more desirable rendition of the displayed image.

The method implemented attempts to create a vector representation of the bit mapped display image, that is subsequently re-rasterized to create an image at the higher resolution of the output device. Traditionally, a bit mapped image is stored as a two dimensional matrix of single bits, representing a binary or black and white image. This storage method is also extended to multiple color images using overlapping matrices for each color. Simple data compressions schemes are capable of compressing the image matrix into a numeric representation of adjacent pixels of the same color, occurring in each raster. In a similar fashion, a storage method may be used to store the x-locations, along each scanline, of the j-th color transition point, hereinafter referred to as Xj, as well as the color of the region to the right of the transition, Cj.

Referring to Figure 1, the area illustrated by the cross-hatched pixel locations, reference numeral 10, represents the display image after simple magnification. For an image color boundary making an angle of 45 degrees...