Abstract: In a digital fluorography system a television (TV) camera converts X-ray images to analog video signals that are converted to digital pixel words in an analog-to-digital converter (ADC). The sync signals for the TV camera and the sample clock signals for the ADC are derived from a novel resettable crystal controlled sync generator. A phase-locked loop provides an ac reference signal at one-half power line frequency which is equivalent to TV frame rate. The sync generator is reset to start a new frame and an ensuing sequence of crystal controlled horizontal sync pulses only in response to occurrence of ac reference signals so every frame is in registration. A digital video processor (DVP) subtracts a mask image from each image in a sequence of images that are acquired while an X-ray contrast medium is appearing in and disappearing from a blood vessel. The resulting difference images are stored in analog video signal format in an analog video disk recorder.

Abstract: An x-ray source projects successive high and low energy x-ray beam pulses through a body and the resultant x-ray images are converted to optical images. Two image pick-up devices such as TV cameras that have synchronously operated shutters receive the alternate images and convert them to corresponding analog video signals. In some embodiments, the analog signals are converted to a matrix of digital pixel signals that are variously processed and subtracted and converted to signals for driving a TV monitor display and analog storage devices. In other embodiments the signals are processed and subtracted in analog form for display. The high and low energy pulses can follow each other immediately so good registration between subtracted images is obtainable even though the anatomy is in motion. The energy levels of the x-ray pulses are chosen to maximize the difference in attenuation between the anatomical structure which is to be subtracted out and that which remains.

Abstract: Raster lines are obscured in a photograph of an image displayed on a video monitor. A photographic film is used as an integrating mechanism. The TV raster is vertically displaced during the camera shutter open time a total deflection of one horizontal line, thus blending the information between horizontal lines. Vertical raster deflection is accomplished by adding a series of delays to the normal vertical sync and then generating a processed composite sync to drive the external sync input to the monitor. The shutter is open for several video frames, each frame being deflected vertically by an integer amount greater than the previous frame until the total raster deflection equals one horizontal line.