Abstract: A serial digital bit signal having signal bits occurring in a bit interval and at a signal bit speed, and each signal bit representing, alternatively, a first logic state and a second logic state, is transferred across a rotating interface by encoding each first logic state bit with a digital radio frequency (RF) carrier signal and coupling the encoded signal across the interface with an RF slipring.

Abstract: A CT apparatus produces a trigger position signal having a programmable angular spacing, for triggering the acquisition of projections, from an encoder index pulse having a different fixed angular spacing. An estimation circuit estimates the time of occurrence of a next pulse in the trigger position signal by evaluating the timing of the encoder index pulses. The estimation circuit may be a phase-locked-loop or a set of lookup tables keyed to gantry position and speed.

Abstract: Dual control of image level and window of a display is accomplished by rotation of a single trackball. Rotation of the trackball within a first band including the X axis controls one parameter, and rotation of the trackball in a second band including the Y axis controls a second parameter. No changes are made in the parameters in response to rotation of the trackball in a third deadband laying between the first band and second band. The operator of a tomography system can readily change display parameters by rotation of the trackball while viewing the display.

Abstract: A set of two processors operates on image pixel data using polynomial interpolation to generate pixel data for a spatially varied image. Image data is first stored in a buffer memory, and constants used in the polynomial interpolation are stored in a constants memory. One processor operates on the data from the buffer memory using constants from the constants memory, and the interpolated data is then stored in a display memory. The second processor controls the interpolation process by addressing the memories for the retrieval and storage of data.