Hardware implementation algorithm and error analysis of high-speed fluorescence lifetime sensing systems using center-of-mass method.

A new, simple, high-speed, and hardware-only integration-based fluorescence-lifetime-sensing algorithm using a center-of-mass method (CMM) is proposed to implement lifetime calculations, and its signal-to-noise-ratio based on statistics theory is also deduced. Compared to the commonly used iterative least-squares method or the maximum-likelihood-estimation-based, general purpose fluorescence lifetime imaging microscopy (FLIM) analysis software, the proposed hardware lifetime calculation algorithm with CMM offers direct calculation of fluorescence lifetime based on the collected photon counts and timing information provided by in-pixel circuitry and therefore delivers faster analysis for real-time applications, such as clinical diagnosis. A real-time hardware implementation of this CMM FLIM algorithm suitable for a single-photon avalanche diode array in CMOS imaging technology is now proposed for implementation on field-programmable gate array. The performance of the proposed methods has been tested on Fluorescein, Coumarin 6, and 1,8-anilinonaphthalenesulfonate in water/methanol mixture.