Method and system for oblique backscattering ultrasound transmissive contrast imaging
An Oblique Backscatter Ultrasound imaging system includes a transceiver that has an US source and a plurality of US detectors configured in receive signals off axis from the US source. While the system is arranged in a reflective configuration, the device produces transmissive contrast signals to yield improved images. The transceiver can be mounted to a movable stage or robotic arm to enable it to scan the surface of a target. Alternatively, scanning can be performed by 1D or 2D phased-array transmission or detection.
1. An oblique backscatter acoustic imaging system comprising:
a transmitting transducer configured to produce focused acoustic waves propagating into and through a target;
two or more receiving transducers positioned on opposite sides of the transmitting transducer and configured to detect diffuse backscatter of the acoustic waves passing through the target; and
a signal processor configured to receive a signal from at least one of the receiving transducers representative of the detected backscatter of the acoustic waves that have passed through the target and produce a signal representative of at least one of a phase-gradient contrast signal or an absorption contrast signal from the received signal.
2. The oblique backscatter acoustic imaging system according to claim 1 wherein the transmitting transducer includes a one dimensional array of acoustic transmitting transducers.
3. The oblique backscatter acoustic imaging system according to claim 1 further comprising a scanning mechanism for moving the transmitting transducer and the two or more receiving transducers across an area of the target.
4. The oblique backscatter acoustic imaging system according to claim 1 wherein the transmitting transducer includes a two dimensional array of acoustic transmitting transducers.
5. The oblique backscatter acoustic imaging system according to claim 1 wherein the transmitting transducer is connected to an acoustic signal generator and the signal processor includes at least one detector configured to produce a demodulated signal representative of the backscatter acoustic waves received by at least one of the receiving transducers.
6. The oblique backscatter acoustic imaging system according to claim 5 wherein the signal processor includes at least two lock-in detectors, one connected to each receiving transducer and a signal processing component connected to the at least two lock-in detector and configured to receive demodulated signals from each receiving transducer and produce a signal representative of a difference between the received demodulated signals.
7. The oblique backscatter acoustic imaging system according to claim 5 wherein the signal processor includes at least two lock-in detectors, one connected to each receiving transducer and a signal processing component connected to the at least two lock-in detector and configured to receive demodulated signals from each receiving transducer and produce a signal representative of a sum of the received demodulated signals.
8. The oblique backscatter acoustic imaging system according to claim 1 wherein the transmitting transducer is connected to a pulsing acoustic signal generator and the signal processor includes at least one gated detection rectifier configured to produce an output signal representative of the backscatter acoustic waves received at least one of the receiving transducers.
9. The oblique backscatter acoustic imaging system according to claim 8 wherein the signal processor includes a time delayed gate and at least two gated detection rectifiers, one connected to each receiving transducer and a signal processing component connected to the at least two gated detection rectifiers and configured to receive output signals from each receiving transducer and produce a signal representative of a difference between the received output signals.
10. The oblique backscatter acoustic imaging system according to claim 8 wherein the signal processor includes a time delayed gate and at least two gated detection rectifiers, one connected to each receiving transducer and a signal processing component connected to the at least two gated detection rectifiers and configured to receive output signals from each receiving transducer and produce a signal representative of a sum of the received output signals.
11. An oblique backscatter acoustic imaging system comprising:
two or more transmitting transducers, each configured to produce acoustic waves propagating into and through a target;
a receiving transducer positioned between the transmitting transducers and adapted to detect diffuse backscatter of the acoustic waves passing through the target; and
a detector signal processor adapted to receive a signal from the receiving transducer representative of the detected backscatter of the acoustic waves that have passed through the target and produce a signal representative of at least one of a phase-gradient contrast signal or an absorption contrast signal from the received signal.
12. The oblique backscatter acoustic imaging system according to claim 11 wherein the receiving transducer includes a one dimensional array of acoustic receiving transducers.
13. The oblique backscatter acoustic imaging system according to claim 11 further comprising a scanning mechanism for moving the two or more transmitting transducers and the receiving transducer across an area of the target.
14. The oblique backscatter acoustic imaging system according to claim 11 wherein the receiving transducer includes a two dimensional array of acoustic receiving transducers.