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BINARY HARDWARE INTERPOLATION FOR 2X MAGNIFICATION

IP.com Disclosure Number: IPCOM000023851D
Original Publication Date: 1979-Feb-28
Included in the Prior Art Database: 2004-Apr-01
Document File: 2 page(s) / 292K

Publishing Venue

Xerox Disclosure Journal

Abstract

Color terminals Often use a repeat field technique for the display of binary image information. The initial approach to producing color hard copy is to repeat each scan line twice. This results in an image compatible with the interlaced repeat field. The image, however, may appear jaggered. An improved image with reduced jaggedness is obtained when the image expansion is done by interpolation rather than replication.

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XEROX DISCLOSURE JOURNAL

BINARY HARDWARE INTERPOLATION Proposed Classification rw~xMAGNIF1CA'rIow- U.S. Cl. 355/4

Keith T. Knox~ mt. CL G03g 15/01 Louis D. Mailloux

Color terminals Often use a repeat field technique for the display of binary image information. The initial approach to producing color hard copy is to repeat each

scan line twice. This results in an image compatible with the interlaced repeat field. The image, however, may appear jaggered. An improved image with reduced jaggedness is obtained when the image expansion is done by interpolation rather than replication.

As a specific example, consider a typical display memory having 512 horizontal binary pixels and 256 vertical lines per field, When printed on the Xerox 6500

Color Graphics Printer (CGP) by repeat scan, the above format results in an image that is 6.83 inches wide by 5.12 inches high. This is 75 image elements (pixels) per

inch horizontally by 50 pixels per inch vertically. The CGP has a spot size of about

10 mils, scans at 100 scans per inch vertically and has sufficient bandwidth to address 400 points per inch horizontally.

The 75 x 50 per inch binary image is bi-linearly interpolated up to 150 x 100 per inch and is then printed on the CGP. In bi~4inearinterpolation, each scan line is first linearly interpolated in x, then scan lines are linearly interpolated in y.

The following logic equations explain the implementation of the present idea. The symbol O=output pixel and Izinput pixel....