The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 27, 1987
Filed:
Jan. 22, 1987
Thomas V Meccariello, Waukesha, WI (US);
Gary F Relihan, Nashotah, WI (US);
General Electric Company, Schenectady, NY (US);
Abstract
A voltage signal proportional to the brightness of an x-ray image is derived. In a mA loop the ratio of a reference voltage to brightness is determined. If the brightness ratio does not equal 1 it causes the x-ray tube current controller to adjust current (mA) to eliminate the error. A command proportionate to the ratio is stored until the next image frame. In a kV loop a ratio of the last mA command and a set limit for mA is taken. This error ratio is multiplied by the brightness ratio to provide a kV control ratio indicative of how much of the brightness error the kV loop is obliged to correct. The kV control ratio is corrected for nonlinearity between kV change and brightness change and the resulting command is used to adjust the kV applied to the x-ray tube anode. In a video gain control loop a ratio is taken between the stored last brightness ratio or mA command and maximum mA command limit and the brightness change resulting from the last kV control command is ratioed to the maximum brightness factor limit. The result of multiplying the last two mentioned ratios and the brightness ratio is the new video gain (VG) control signal. The VG signal is used to adjust the f-stop of the video camera and the electronic gain to change brightness.