Ultrasonic acoustic imaging apparatus

Abstract

Acoustical images are generated by frequency demodulating an electrical signal having frequency deviations corresponding to the scattering properties of a media supporting acoustic pulse propagation against which the signal is projected. The system includes a transmitter which generates a signal at a defined frequency, which signal is then transformed into an acoustic pressure signal and projected against the media by a transducer. The transducer also receives acoustic pressure signals reflected from the media. A receiver coupled to the transducer transforms the reflected acoustic pressure signals into electrical signals which are then frequency demodulated. The demodulated signal contains instantaneous frequency deviations responsive to the scattering properties of the media. The frequency demodulated signal may be processed by circuitry to generate a video signal, which is then algorithmically processed by a scan converter and displayed on a video screen. The frequency demodulation may be done by a conventional frequency demodulator, by a V-demodulator, or any other frequency demodulation process. The frequency demodulated signal may also be combined with an amplitude demodulated signal to produce linear or nonlinear combinations of frequency demodulated and amplitude demodulated images. Frequency demodulated and amplitude demodulated signals may be used to provide color images of the media.