Abstract: A multiple channel parallel transfer digital disk recorder is used to record digitized circular video images at the video frame rate. The digital pixel values for each image frame are written onto successive pages of a disk buffer memory (DBM) under video frame timing and are read from memory and written on disk under disk timing. When the last page image of the DBM is reached readout is switched back to the first page which is now filled with a frame of image data. Reading image data from disk and writing into successive pages of the DBM is done similarly. Only DBM locations containing pixels representative of actual image data within the circular boundaries of the image are addressed when reading from DBM and writing on disk and when reading from disk and writing onto DBM. Adjacent pixels in the image having predetermined bit lengths are written on disk with their bits in series.

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: A method of controlling a digital video processor in a digital fluorography system wherein the electronic components of the processor are variously configured to perform math functions and manipulations on digital image data obtained in connection with carrying out x-ray examination procedures and the images are displayed on a television monitor or recorded. A system controller sends a complete recipe for a procedure to the memory of a microprocessor based CPU that controls the video processor. The latter CPU interprets the instructions and effects configurations and reconfigurations in the data paths of the video processor during television vertical blanking intervals.