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EP0703696A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Skew correction in line scanned images

Assignee: International Business Machines Corp
•
Filing: 1995-09-21
•
Granted: —
•
Expires: 2015-09-21
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Abstract

Abstract A method of correcting for skew in a line scanning system, comprises receiving image information from a line scanner, the image information having background elements and image elements, and storing the elements as a map representing the image. Every kth line is selected and for each such line the location of a left-most image element is determined (105). This location is either the actual location of the left-most element on the line or the location of the left-most element in a search area surrounding that location, if more to the left. A best-fit line is generated (109, 111) through the locations of the left-most elements and the map is rotated (113, 115) through an angle which is the difference between the best-fit line and a line perpendicular to the scan lines.

Inventors

  • 👤 Robert Grover Baker
  • 👤 Paul Richard Swingle

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 12:09
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/60; G06T3/608; G06V; G06V30/00; G06V30/10; G06V30/14; G06V30/146; G06V30/1475; G06V30/1478; H; H04; H04N; H04N1/00; H04N1/387; H04N1/3877; H04N1/3878

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 126 words
A method of correcting for skew in a line scanning system, comprising the steps of: (a) receiving image information from a line scanner, the image information having background elements and image elements, (b) storing the elements as they are received from the scanner, the elements being stored in a form preserving a record of the location of each element in the image, (c) determining the location of a left-most image element for each of a plurality of scan lines, (d) generating a best-fit line through the locations thus determined, and (e) changing the record of the locations of the image elements so as to rotate the image through an angle which is the difference between the best-fit line and a line perpendicular to the scan lines.
Claim 2
Dependent Claim 59 words
The method of claim 2 wherein step (c) comprises determining the location of the left-most image element on each of the plurality of scan lines, establishing a search area surrounding each such location, determining the location of the left-most image element within the search area, and substituting the last determined location as the location of the left-most image element.
Claim 3
Dependent Claim 23 words
The method of claim 1 or 2 wherein step (c) commences only after the scanner has scanned a predetermined portion of the image.
Claim 4
Dependent Claim 43 words
The method of claim 1, 2 or 3 wherein step (d) comprises generating an initial best-fit line, discarding those locations that deviate from the initial best-fit line by more than a predetermined amount, and calculating a new best-fit line through the remaining locations.
Claim 5
Independent Claim 14 words
The method of any preceding claim wherein step (e) performs a shear rotation algorithm.

References Cited (Backward Citations)

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