Method and system for fast rotation of run-length encoded images
US5581635A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1995 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Jul 25, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T3/606
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and system including a high speed computer algorithm for rotating images stored in a computer memory, such as those captured by a CCD array. The method and system may be used with an over-the-belt optical character recognition (OCR) reader that captures a pixelized image of the surface of a parcel as it moves along a conveyor. A run-length encoded output image is obtained from a run-length encoded input image, wherein the output image is a rotated version of the input image. A predefined pixel mapping sequence for a rotation angle with a rational tangent is used to map image pixel data. Mapping image pixel data using a predefined pixel mapping sequence allows rotation without floating point computations, and allows the use of a reverse pixel mapping technique to map output runs from an input image in order to avoid the creation of holes or artifacts in the output image. Mapped output runs are scaled to preserve the aspect ratio of the rotated image. The order of processing the elements of the input run-length input table is selected so as to directly create a run-length encoded output table.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.