An x-ray imaging system provides automatic adjustment of x-ray tube voltage and current based on an identification and removal of background pixels in the image and a calculation of the functional relationship between voltage and current and dose for the particular imaged object as deduced from two exposures at different voltages. Real-time image distortion removal and image rotation are accomplished by computer processing using a generalized image transformation polynomial. Scatter in the image is reduced by calculating a scatter map based on a blurring of the received image and normalizing the scatter map to point scatter measurements made with an x-ray occluder eliminating direct exposure of certain areas of the image. Improved signal to noise ratio in a moving x-ray image is provided by averaging stationary portions of the image over a longer time than the moving portions of the image. A non-linear white compression function further reduced image noise by transforming the raw image to a gray scale having equal noise intervals.
申请公布号
EP0882275(A1)
申请公布日期
1998.12.09
申请号
EP19970906730
申请日期
1997.02.21
申请人
LUNAR CORPORATION
发明人
ERGUN, DAVID;STRAIT, DAVID, R.;SLUMP, CORENLIS, H.;LAANSTRA, GERT, JAN;KUIPERS, HENDRIK;DIJKEMA, MARCEL, JACOB;VAN DER SCHAAR, HANS, SJOERD, PETER