  Single-Photon Avalanche Diodes (SPAD) are affordable photodetectors, capable
to collect extremely fast low-energy events, due to their single-photon
sensibility. This makes them very suitable for time-of-flight-based range
imaging systems, allowing to reduce costs and power requirements, without
sacrifizing much temporal resolution. In this work we describe a computational
model to simulate the behaviour of SPAD sensors, aiming to provide a realistic
camera model for time-resolved light transport simulation, with applications on
prototyping new reconstructions techniques based on SPAD time-of-flight data.
Our model accounts for the major effects of the sensor on the incoming signal.
We compare our model against real-world measurements, and apply it to a variety
of scenarios, including complex multiply-scattered light transport.
