X-Ray image digital subtraction system
US4399457A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1981 |
| Grant date | Aug 16, 1983 |
| Priority date | — |
| Expiry date | Jun 8, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05G1/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a digital fluoroscopy system, analog video signals representative of successive x-ray image frames are converted to digital pixel values that are used as addresses, respectively. A digital memory stores at its respective locations a digital value corresponding to the logarithm of an address value so that when a digital pixel value represented by an address is fed from the analog-to-digital converter to the memory the memory will output the logarithm of the pixel value in digital form. Pixel values for successive x-ray images are subtracted in-phase on a pixel-by-pixel basis to produce digital difference pixel signals which are converted to analog video signals for driving a television monitor that displays an image representative of the difference between x-ray images.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.