Accurate estimation of surface normals in 3-D data sets
US5283837A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 27, 1991 |
| Grant date | Feb 1, 1994 |
| Priority date | — |
| Expiry date | Aug 27, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S378/901
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A CT scanner or other medical diagnostic imager (A) generates data which is reconstructed (B) into a three-dimensional image representation that is stored in an image memory (C). Points on a surface (10) of a selected subregion, such as the surface of an internal organ, in the three-dimensional image representation are determined (12) which are visible from and correspond to pixels on a viewing plane (14). For each viewable point on the surface, a mean variation along an x, y, and z-coordinate system with its origin at the surface point in question is determined (20). A covariance matrix whose matrix elements along the diagonal are indicative of a rate of variance along each axis and whose other matrix values are indicative of a rate of variance relative to pairs of axes is defined (20). A rate of most rapid change through the 3D data is determined (22), by eigenvalue decomposition (24) of the covariance matrix. A vector along the rate of most rapid change is normalized (26). Gray scale shading for a pixel of a man-readable display (E) corresponding to the surface point is determined (28). In the preferred embodiment, the gray scale shading is proportional to the cosine of the angl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.