Image processing apparatus using recursive filters
US5296937A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1992 |
| Grant date | Mar 22, 1994 |
| Priority date | — |
| Expiry date | May 15, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05G1/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a diagnostic X-ray apparatus, an image signal output from a TV camera connected to an image intensifier tube is supplied to a noise reducer through an A/D converter. The noise reducer comprises a first recursive filter for adding a value which is (1-a) times the input to the noise reducer and a value which is a times an output of the first recursive filter (a factor a is fixed to a value close to 1), a second recursive filter for adding a value which is (1-k) times the output of said fluoroscopy means and a value which is k times the output of the first recursive filter, a subtracter for subtracting the output of the second recursive filter from the input to the noise filter for every pixel, and a factor table for setting the factor k of the second recursive filter in accordance with the difference obtained by the subtracter such that the factor k and the difference have an inverse proportional relationship if the difference has a positive value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.