Method for determining the shape and location of an irradiation field
US5764791A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 4, 1993 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Feb 4, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30004
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An image signal is obtained from a recording medium, on which a radiation image has been recorded with an irradiation field being limited. A prospective contour point of the irradiation field is detected from signal components corresponding to positions on the recording medium located along each of lines radiating from a predetermined point in the region inside of the irradiation field towards edges of the recording medium. Differentiation processing is carried out on the signal components corresponding to positions on the recording medium located along each radial line in order to obtain differentiated values. If both the differentiated values, which are respectively negative and positive and the absolute values of which are larger than a predetermined value, occur while the differentiation processing proceeds from a signal component corresponding to the predetermined point in the region inside of the irradiation field towards a signal component corresponding to each edge of the recording medium, the region extending between the points on the recording medium associated with the two differentiated values is removed from the region surrounded by lines connecting the prospective con…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.