System and method for analyzing a contour of an image by applying a Sobel operator thereto
US7116823B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 2002 |
| Grant date | Oct 3, 2006 |
| Priority date | — |
| Expiry date | Jul 26, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/20132
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention includes a method for analyzing an image wherein elements defining a path within a two-dimensional image are received from a prescreener. A Sobel operator may be applied to the region around each of the elements of the chain to obtain a corresponding array of gradient directions. An angle correction may be applied to any of the gradient directions that goes beyond the highest value (in radian measure; the Pi −Pi transition), to obtain an array of gradient directions free of any artificial jumps in value. The gradient direction array (Sobel chaincode) can have its bandwidth taken to determine a single number of straightness so as to identify extremely straight edges, (manmade objects) from less straight edges (natural objects). A similar process can be used to analyze contours for straight sections, which are also parallel. These two and other filters applied to the gradient array can be part of a feature suite, for feature space analysis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.