Non-uniformity energy correction method and apparatus
US4323977A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 20, 1979 |
| Grant date | Apr 6, 1982 |
| Priority date | — |
| Expiry date | Nov 20, 1999 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B6/4258
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A method and apparatus are disclosed for correcting energy (Z) signal non-uniformities in the response of an Anger-type scintillation camera to image events occurring at different (X, Y) positions on the camera face. Energy correction factors f(P)' corresponding to deviations of up to .+-.12.8% from a reference pixel area are determined off-line for 4,096 camera face pixel areas from a uniform flood field source Z-map. The correction factors f(P)' are stored in a 64.times.64 array of a correction factor memory, addressable by image event (X, Y) position coordinates. During on-line operation, for each image event the correction factor f(P)' corresponding to the image event (X, Y) position is retrieved, scaled in a multiplying digital to analog converter by the actual energy Z.sub.IN of the event, and added to the event Z.sub.IN signal to provide a corrected energy signal Z.sub.c =Z.sub.IN (1+f(P)') which is proportional to the incoming signal. The corrected energy signal is then applied to a fixed energy window analyzer to determine acceptance or rejection of the event. The invention is especially advantageous for correcting energy non-linearities in the detection of single source w…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.