Abstract: An apparatus for reconstructing an image signal of a foreground subject wherein a probe having a plurality of transducers for scanning a foreground subject by radiation, such as an ultrasonic beam, is connected to a phase detector through a receiver. An electrical signal corresponding to a wave reflected from the foreground subject is phase-detected by a phase detector. At least one resultant hologram signal is subjected to the A/D conversion to be stored in a buffer memory. A processing unit causes the hologram signal to be read out of the buffer memory, carries out the convolution integration of the hologram signal and the corresponding kernel function data by the synthetic aperture technique, thereby producing a reconstructed image signal. The processing unit further carries out the nonlinear compression of the amplitude of the hologram signal before the convolution integration and performs the nonlinear expansion of the amplitude of an image signal after the convolution integration.

Abstract: A cycle timer comprises an angle encoder for converting an mechanical angle information into an electrical angle information, a memory unit for storing timing information and a control program for setting an output if the angle information falls within an on region of predetermined timing information and for resetting the output if the angle information falls within an off region of the predetermined timing information, an arithmetic processing unit for reading out and outputting from the memory a timing condition of the information which has been outputted from the angle encoder, and a latch circuit adapted to be selectively set and reset one at a time in response to the output from the arithmetic processing unit.

Abstract: A digital scan converter employed in a sector scanning ultrasound diagnostic device has a digital memory for storing a received image signal in a cell whose address corresponds to the picture element and a system controller for reading out a signal from the memory by linear scanning. The digital scan converter is further provided with a signal generator and an adder for shifting the level of the image signal by a predetermined value when the signal is written in the memory, a level detector for detecting whether or not the signal read out from the memory is at level "0" and an interpolating section for converting the output signal from the memory into an interpolating signal by the output from the level detector.