Browse Prior Art Database

General Line Centering With Optional Video Consolidation

IP.com Disclosure Number: IPCOM000076014D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 57K

Publishing Venue

IBM

Related People

Rosen, EW: AUTHOR [+2]

Abstract

This system solves the problem of uncertainty in the position of a line inside a scanning raster. It also provides means for reducing high resolution video patterns to medium resolution patterns by video consolidation. Furthermore, it provides for the detection of the raster being partly off the line of characters, and the detection and correction of line skew.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 48% of the total text.

Page 1 of 3

General Line Centering With Optional Video Consolidation

This system solves the problem of uncertainty in the position of a line inside a scanning raster. It also provides means for reducing high resolution video patterns to medium resolution patterns by video consolidation. Furthermore, it provides for the detection of the raster being partly off the line of characters, and the detection and correction of line skew.

High resolution video is entered serially into a fifty-six bit video shift register (VR)1, which has been set to zero just prior to rescan. The bit leaving the shift register is combined with the entering bit at OR gate 2, so that at the end of each scan the shift register contains the OR of the current scan with the contents of the shift register on the previous scan to generate a profile of the character height.

When segmentation occurs after Minimum Character Requirement (MCR), the character is checked to determine whether it is out of the top or bottom of the scan by logic units 3. The video bits are advanced out of VR 1, and the Character Center Counter (CCC) 4 is advanced by one for each blank bit that is encountered before the bottom of the character is reached (character bottom is indicated by three black bits in succession). When the bottom of the character is reached, the contents or CCC 4 are transferred to the Temporary Character Bottom Store Register (TBS) 5, and CCC 4 is reset.

VR 1 continues to advance, and CCC 4 again counts the number of bit positions which have been displaced. CCC 4 counts the number of bits in the height of the character; the top of the character is determined by three successive white bits. When the top of the character is reached, CCC 4 stops advancing and Character Height Store (CHS) 6 checks for height count between thirteen and twenty-two.

Valid character logic (VC) 7 becomes active if the height count is between thirteen and twenty-two, and a skew error was not detected during character center collect (a skew error is indicated if the character bits run all the way to the top or bottom of VR 1). VR 1 advances until all fifty-six bits are moved out. Since this is the first valid character of the line, the contents of TBS 5 are saved in the Final Character Bottom Store Register (FBS) 8. The count becomes the standard to compare with the next valid character.

As the scanner advances to the second character, the video bits are combined at OR 2. CCC 4 counts the number of blank bits encountered before the bottom of the character is reached (indicated by three successive black bits). While the blank bits are being counted, the count in CCC 4 is compared with the count for the last valid height character which is stored in FBS 8. If the counts compare before the bottom of the character is reached, the Character Count up- down Counter (CUC) 9 is set to count down. (This counter is used later to check that the two counts are within five of each other.) If they do not compare, CDC 9 wil...