During image acquisition in the scanner, they received no feedback on performance.
The PID controller's output signal is input to the Z-piezodriver for signal amplification to displace the Z-scanner so that the feedback error approaches zero.
At the scan rate of 4112 lines per second, the root mean square (RMS) error of the ILC can be reduced by a factor of 73 in comparison with the feedback controlled galvanometer scanner of the commercial system.
The experiment started with a short practice session outside the scanner, where participants were given feedback on their performance.
The performance of a feedback-controlled piezoelectric tube scanner is limited by its inherent nonlinear properties such as hysteresis and creep, its mechanical resonance modes and its displacement sensor bandwidth and associated noise properties.
Several tip and scanner artifacts as well as effects of vibrations, feedback, and image processing were also described [17].
Ultrasound provides a vehicle for education free of ionizing radiation or limitation by the expense of an MRI scanner for real-time imaging and instructor-based feedback.
Two phantom validation studies and one ex vivo experiment were performed to compare the newly developed self-referenced method with the conventional subtraction method and evaluate the ability of the feedback control system in the same MR scanner.
