Apparatus for reduction of filtration truncation errors
US4606004A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 21, 1984 |
| Grant date | Aug 12, 1986 |
| Priority date | — |
| Expiry date | Mar 21, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S378/901
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Apparatus for reduction of filtration truncation errors caused by convolving a plurality of input signals, such as line-integral projection data obtained in a computerized tomography (CT) scan of an object, with a common kernel function in a finite precision machine using Fourier transform techniques. The resulting convolved output signals contain correlated noise which, in the case of reconstructed CT images, manifests itself as structured noise in the form of rings and center spots in the image. The correlated noise can be reduced by randomly shifting the data prior to convolving it. The random shift can be achieved by a rotational permutation scheme. Another scheme for shifting the data is to prepend or append zeros to the data by using a random number generator or a deterministic function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.