Diagnostic X-ray installation comprising a control loop for the exposure control
US4423521A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1982 |
| Grant date | Dec 27, 1983 |
| Priority date | — |
| Expiry date | Jan 28, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/32
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An exemplary embodiment comprises an image intensifier television chain which includes an X-ray image intensifier, an optical coupler, a camera tube, a video amplifier, and a monitor, and also has a control loop for exposure control which includes a control circuit for the formation of a control voltage for controlling the dose rate of the x-ray tube. A dominant-field-responsive circuit evaluates the video signal and includes a device for blanking-out portions of the video signal for the formation of a dominant field. An actual value transmitter is connected in circuit between the photocathode of the X-ray image intensifier and a high voltage generator therefor, so as to supply to the control circuit an actual value signal corresponding to the mean image brightness. In the control circuit, the actual value signal and the output signal of the dominant-field-responsive circuit are combined as a correction for the dose rate setpoint value signal, so that the dose rate is controlled in accordance with a selected portion of the video signal corresponding with a desired dominant portion of the image field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.