A Scan Converter for use with an Ultrasonic Imaging System is disclosed, which permits the buffering of sweep address and video data with relatively fewer bits of information. In essence, the propogation path of the ultrasonic pulses is resolved into a pair of vectoral components while the propogation path media is defined by successive contiguous body segments which are to be respectively displayed as video picture elements. A series of first signals indicate the crossing of segment boundaries in the vectoral direction having the faster rate of boundary crossings. A second signal is produced having a unique valve which indicates a boundary crossing by the pulse in the other vectoral direction. Reflections of the ultrasonic pulse are sampled at a rate determined by the first signals; i.e., the rate at which segment boundaries are crossed in the first vectoral direction. The sample values are held for storage in memory. The memory includes a matrix of memory location associated with respective picture elements. The one coordinate of the memory address is successively incremented with the storage of the respective successive values. The second coordinate of the address is incremented by the unique value of the forementioned second signal; in other words, when a segment boundary is crossed in the slower vectoral direction.
Either a linear array ultrasound transducer or a phased array transducer is constrained to scan along a body in a single plane to derive data for enabling simultaneous display of static and real-time ultrasound images.
An improved scan converter for converting received echo signals representative of the amplitude of ultrasound energy returning from sampled points along a plurality of spaced apart paths distributed in an image space into signals to be displayed as display pixels in a raster scan display system. The scan converter includes a scan data memory for storing the received echo signals in quadrants of the scan data memory. Each quadrant is associated with even and odd numbered paths and sample row combinations. Sample rows are related to sample points along the spaced apart paths. The scan converter further includes a circuit for determining a gray scale value to be assigned to each selected display pixel based on a predetermined combination of four received echo signals adjacent the selected display pixel and chosen from the quadrants of the scan data memory. The improved scan converter is capable of operation in both linear and sector scan modes, and, when in the sector mode, over 90.degree. and 180.degree. sectors. Variable scaling between the image space and display space and correction of the hose error when the scanning system employs an oscillating wobbler scan head are provided. Various techniques for converting display pixel rectangular coordinates into polar coordinates in real time for raster scan display are employed.
In an ultrasonic sector scanner in which display control data is obtained from beam reflection vectors for controlling television display pixels, missed pixels in a display horizontal scan line between two vectors are filled by interpolating known pixel values in the two vectors. By property weighting the known pixel values an improved picture is presented in a display of a digital scanner system.
An improved still or frozen picture is provided in an ultrasonic sector scanner by generating and displaying two frames. The first frame is identical to the frame generated for dynamic real-time display. The second frame is generated from vectors lying intermediate vectors of the first frame with the same reflected signal data applied thereto. Accordingly, the pixel data is doubled in the still or frozen picture.
An ultrasonic apparatus including apparatus for detecting the position of an ultrasonic probe, a memory for storing the positions of the ultrasonic probe relative to a reference point in symbolized pattern of a human body, a memory for storing tomogram signals received by the probe relative to the stored positions timing pulse generator apparatus for reading out the stored signals, and apparatus for displaying the symbolized pattern, the position of the probe and the relative tomogram data simultaneously on the screen of a monitor. The position detecting apparatus includes auto-reset circuits for arbitrarily resetting the position of the probe in the memory to the reference point regardless of the actual position of the probe.
