Distance-Robust, Video-Rate Fluorescence Lifetime Imaging and Ranging with a Switched Capacitor SPAD Sensor

Description

Macroscale fluorescence lifetime imaging (MFLI) enables robust visualization of tissue physiology, but video-rate performance is hindered by computationally expensive fitting or distance-sensitive alternatives. We present a SPAD-based system that performs in-pixel center of mass (CoM) computation of photon time-of-arrival, enabling video-rate lifetime imaging that is intrinsically robust to target-distance changes when the measurement window is placed in the decay tail. By shifting the window earlier to include the decay onset, the same hardware also provides target distance estimates with a single timing-setting change. We first evaluate distance robustness and ranging on near-infrared dye phantoms in a 12.5 cm sweep, where the measured lifetime varies by less than 6 ps/cm and the calibrated distance estimates show strong linearity with a maximum error below ±5 mm. To interpret residual non-idealities, we then compare against a reference TCSPC spectrometer and use a sliding-window CoM analysis to emulate distance-induced shifts, revealing effects of non-ideal decay and residual reflections.

Periode	3 jun. 2026
Evenementstitel	The International SPAD Sensor Workshop 2026
Evenementstype	Conference
Locatie	Seoul, Korea, Republic ofToon op kaart
Mate van erkenning	International