Fig. 4.

Surface tracking performance of the imaging probe. (A) Step response; the probe immediately compensated the surface position error with the maximum speed of the motor without significant overshooting. (B) Dynamic response measured with an oscillating sample surface at 1 Hz; the probe successfully suppressed over 90% of the total surface motion. (C) Maximum surface position error with respect to the sample surface oscillating speed; within a typical brain physiological motion speed range, the probe can suppress the error to less than 0.1 mm.