Geometric distortion-free image intensifier system
US5065238A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1989 |
| Grant date | Nov 12, 1991 |
| Priority date | — |
| Expiry date | Oct 16, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A patient (12) is irradiated with x-rays (10) from an x-ray tube (A). X-rays that have passed through a region of interest of the patient are converted to a light image by a phosphor screen (14) on the dome shaped input face (16) of an image intensifier (B). The dome shaped input face causes the output optical image (20) of the image intensifier to be distorted with pin cushion distortion. The sweep pattern of the electron beam of a video pick up tube (24) of a video camera (C) is controlled by deflection plates (26a, 26b, 26c, 26d). A sweep control circuit (D) alters the sweep pattern such that electronic image representations generated by the video camera are distorted in a manner that is complementary to and cancels the image intensifier tube distortion. In this manner, the two distortions cancel and a man-readable image (28) displayed on a video monitor (22) is substantially distortion-free. The sweep control circuit alters conventional vertical sweep control voltage ramps (V) and horizontal control voltage ramps (H) by adding third order, parabolic terms: EQU V.sub.T =V+V+kV(V.sup.2 +H.sup.2) EQU H.sub.T =H+kH(V.sup.2 +H.sup.2) Amplifiers (50a, 50b50c, 50d) boost the voltage o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.