Patent US 4,092,540

A radiographic camera having a scintillator and an array of photodetectors positioned for viewing a common region of the scintillator, and wherein a mask system is interposed between the scintillator and the array of photodetectors for increasing the resolution of an image produced by the camera. The mask system has a pair of mask plates which are spaced apart and have similar formats of opaque materials thereon. The mask system provides a more rapid variaton in the intensity of light received at a photodetector as a function of locations of scintillations on the scintillator. A reference signal source providing a signal pattern in accordance with the intensity variation is utilized for decoding shadows cast by the mask to produce the image.