  Quantum channels in free-space, an essential prerequisite for fundamental
tests of quantum mechanics and quantum technologies in open space, have so far
been based on direct line-of-sight because the predominant approaches for
photon-encoding, including polarization and spatial modes, are not compatible
with randomly scattered photons. Here we demonstrate a novel approach to
transfer and recover quantum coherence from scattered, non-line-of-sight
photons analyzed in a multimode and imaging interferometer for time-bins,
combined with photon detection based on a 8x8 single-photon-detector-array. The
observed time-bin visibility for scattered photons remained at a high $95\%$
over a wide scattering angle range of -45 degree to +45 degree, while the
individual pixels in the detector array resolve or track an image in its field
of view of ca. 0.5 degrees. Using our method we demonstrate the viability of
two novel applications. Firstly, using scattered photons as an indirect channel
for quantum communication thereby enabling non-line-of-sight quantum
communication with background suppression, and secondly, using the combined
arrival time and quantum coherence to enhance the contrast of low-light imaging
and laser ranging under high background light. We believe our method will
instigate new lines for research and development on applying photon coherence
from scattered signals to quantum sensing, imaging, and communication in
free-space environments.
