Extend CFSS to broadened-echo scattering regimes

Extend the coarse-to-fine spline-sketching framework to stronger-scattering conditions in which broadened echo pulses may violate the performance regime defined by the fine-sketch placement criterion in Equation (\ref{eq:zs-regime}).

Background

The paper develops coarse-to-fine spline sketching (CFSS) for memory- and bandwidth-efficient SPAD-LiDAR ranging. Its fine-sketch placement criterion assumes a relationship between the instrument-response-function width, the measurement period, and the number of sketch coefficients; specifically, the method operates in the regime characterized by Equation (\ref{eq:zs-regime}).

The authors note that stronger-scattering media can broaden the echo pulse. Such broadening may cause the stated operating-regime condition to fail, potentially reducing the accuracy or validity of the existing CFSS reconstruction. Extending the framework to handle these broadened-echo conditions is explicitly left unresolved for future work.