Browse Prior Art Database

Eliminating Optical Effects in Computer Printing

IP.com Disclosure Number: IPCOM000034871D
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 4 page(s) / 18K

Publishing Venue

IBM

Related People

Kling, CC: AUTHOR

Abstract

A technique is described whereby undesirable optical patterns of a printer output are eliminated through computer control on a collective basis. The concept is an improvement over previous techniques, in that it takes into consideration the undesirable attributes of implementing pattern elimination on an independent basis. Four patterns are discussed: Optical Illusion, Siamese Twin, Stutter and Moire patterns. It is quite common in computer printing applications to have justified right margins, with the justification being carried out by the extension of one or more inter-word spaces to fill out a line. In many situations, the optical appearance can be considered satisfactory.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 30% of the total text.

Page 1 of 4

Eliminating Optical Effects in Computer Printing

A technique is described whereby undesirable optical patterns of a printer output are eliminated through computer control on a collective basis. The concept is an improvement over previous techniques, in that it takes into consideration the undesirable attributes of implementing pattern elimination on an independent basis. Four patterns are discussed: Optical Illusion, Siamese Twin, Stutter and Moire patterns. It is quite common in computer printing applications to have justified right margins, with the justification being carried out by the extension of one or more inter-word spaces to fill out a line. In many situations, the optical appearance can be considered satisfactory. However, the line adjustments needed for justification can lead to the production of undesirable visual illusions, which can mar the appearance of a document. These illusions include patterns such as: vertical lines or diagonal lines of inter-word spaces; effects which look like lighting flashes; snakes or chevrons. They are collectively known as Moire patterns. Another illusion is the Widow pattern, which occurs whenever the text adjustments cause the last line of a paragraph to be a single word, or even the terminal fragment of a hyphenated word, called "Orphan or Grass Widow". Also, certain printing lines produce the effect known as Siamese Twin lines, where the same word or words appears in two consecutive lines. A common error made in typing is the Stutter pattern, where a typist erroneously repeats a word, such as "the the", which is a word which is never repeated, unless specifically flagged. Optical Illusion Patterns: Although prior art has proposed solutions for each of the previously mentioned undesirable optical effects, the elimination of one illusion may create another and even produce a worse set of undesirable optical patterns. Therefore, the concept described herein discusses the use of a hierarchy of test operations, which can be built into the hardware of the computer or implemented with programmed software. The user has the ability to select, for example, correction hierarchy, such as the following: 1) Correct Siamese Twin Pattern 2) Correct Widow Pattern

3) Correct Moire Pattern

4) Stop and prompt user review and revision

5) Print with Illusion Pattern The computer would operate to format the text by means of a program sequence which included the justification. It would then carry out the following correction steps: Test for Illusion pattern of rank 1. If rank 1 pattern is found, iterate jitter and retest

sequence to correct the selected Illusion pattern.

Test for Illusion pattern of rank 2.

If rank 2 pattern is found, iterate jitter and retest

sequence to correct the selected Illusion pattern.

Test for Illusion pattern of rank 3.

If rank 3 pattern is found, iterate jitter and retest

sequence to correct the selected Illusion pattern.

Retest for Illusion pattern of rank 1.

1

Page 2 of 4

If r...