Scanning equalization radiography

摘要

A radiographic machine in which the exposure is equalized as between different areas of the image plane so as to enhance high spatial frequency features of the image and suppress low spatial frequency features and achieve other benefits as well. A fan beam which is wide enough to encompass the object being imaged is swept across the object and segments of that beam are individually pulse width modulated at each of a number of sampling intervals during the sweep by monostable or bistable shutter pins which either completely block or completely uncover the sectors which they control. An alternate embodiment adds beam width modulation as well, by making the shutter pins either completely block their sectors of uncover them only to the degree necessary for beam width modulation.