Method and apparatus for simplifying runlength data from scanning of images
US4821336A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 19, 1987 |
| Grant date | Apr 11, 1989 |
| Priority date | — |
| Expiry date | Feb 19, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/413
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Serial runlength data obtained by scanning an image includes "slices" that each include the length and an ending pixel number of a successive string of connected black pixels. The runlength data is operated upon, line-by-line, by a decision tree classifier that creates a software "object" including a first linked list of a plurality of further linked lists each of which contains all of the slices of a simple shape of the image. The slices of the object are entered into a "frame" in the same order in which they are scanned and are "filtered" to delete insignificant horizontal and vertical gaps between slices. The slopes of edges of the shapes are tested for linearity to determine which shapes can be represented as trapezoids that can be represented by four corner points and which must be represented as irregular blobs containing all of their slices. The resulting greatly compacted frame data representing the object is fed into a decision tree classifier that recognizes and assigns identifiers to divergences, convergences, and open ends of the object and creates a new linked list of linked lists representing the object in the form of blob records, trapezoid records, divergence record…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.