Motion-robust blood perfusion sensing by LDF with focus control

For endoscopic Laser Doppler flowmetry (LDF), motion artifacts present a serious challenge for clinical applications. We propose a motion-robust LDF method that eliminates motion artifacts by controlling the lens positon with a feedback signal representing tissue motion. This method could be applied to an endoscopic device with micro-electro-mechanical-systems (MEMS) technology. To demonstrate the feasibility of the proposed method, a bench-top apparatus was constructed, and a blood flow phantom was used as the measurement target. Experimental tests shows that the controlled lens was moved to the target position under phantom movement, and the detected perfusion signal were stabilized by the focus control.