  Time-resolved image sensors that capture light at pico-to-nanosecond
timescales were once limited to niche applications but are now rapidly becoming
mainstream in consumer devices. We propose low-cost and low-power imaging
modalities that capture scene information from minimal time-resolved image
sensors with as few as one pixel. The key idea is to flood illuminate large
scene patches (or the entire scene) with a pulsed light source and measure the
time-resolved reflected light by integrating over the entire illuminated area.
The one-dimensional measured temporal waveform, called \emph{transient},
encodes both distances and albedoes at all visible scene points and as such is
an aggregate proxy for the scene's 3D geometry. We explore the viability and
limitations of the transient waveforms by themselves for recovering scene
information, and also when combined with traditional RGB cameras. We show that
plane estimation can be performed from a single transient and that using only a
few more it is possible to recover a depth map of the whole scene. We also show
two proof-of-concept hardware prototypes that demonstrate the feasibility of
our approach for compact, mobile, and budget-limited applications.
