TRANSMISSIVE IMAGING AND RELATED APPARATUS AND METHODS
Apparatus and methods are described that include ultrasound imaging devices, which may operate in a transmissive ultrasound imaging modality, and which may be used to detect properties of interest of a subject such as index of refraction, density and/or speed of sound. Devices suitable for performing high intensity focused ultrasound (HIFU), as well as HIFU and ultrasound imaging, are also described.
1 - 353 . (canceled)
354 . An apparatus, comprising:
a first ultrasound element configured as an ultrasound source;
transmit circuitry coupled to the ultrasound source and configured to provide to the ultrasound source a transmission signal to be emitted by the ultrasound source;
a second ultrasound element configured as an ultrasound sensor;
processing circuitry coupled to the ultrasound sensor and configured to process a signal emitted by the ultrasound source and received by the ultrasound sensor,
wherein the processing circuitry is configured to combine the signal received by the ultrasound sensor with a reference signal to produce a combined signal.
355 . The apparatus of claim 354 , wherein the reference signal is the transmission signal.
356 . The apparatus of claim 354 , wherein the reference signal is a chirp.
357 . The apparatus of claim 354 , wherein the processing circuitry is configured to generate the reference signal.
358 . The apparatus of claim 357 , wherein the processing circuitry is configured to generate the reference signal at least in part by using a local oscillator.
359 . The apparatus of claim 354 , wherein the processing circuitry is configured to combine the signal received by the ultrasound sensor with the reference signal by multiplying the received signal with the reference signal to obtain the combined signal.
360 . The apparatus of claim 354 , wherein the processing circuitry comprises a mixer having a first input configured to receive the signal received by the ultrasound sensor and a second input configured to receive the transmission signal from the transmit circuitry.
361 . The apparatus of claim 354 , wherein the processing circuitry comprises a low pass filter configured to be applied to the combined signal.
362 . The apparatus of claim 354 , wherein the processing circuitry is configured to perform a Fourier transform on the combined signal.
363 . The apparatus of claim 354 , wherein the processing circuitry is configured to combine the received signal with the reference signal before the received signal is processed by an analog-to-digital converter.
364 - 405 . (canceled)