  Photon counting 3D imaging allows to obtain 3D images with single-photon
sensitivity and sub-ns temporal resolution. However, it is challenging to scale
to high spatial resolution. In this work, we demonstrate a photon counting 3D
imaging technique with short-pulsed structured illumination and a single-pixel
photon counting detector. The proposed multi-resolution photon counting 3D
imaging technique acquires a high-resolution 3D image from a coarse image and
edges at successfully finer resolution sampled by Hadamard multiplexing along
the wavelet trees. The detected power is significantly increased thanks to the
Hadamard multiplexing. Both the required measurements and the reconstruction
time can be significantly reduced by performing wavelet-tree-based regions of
edges predication and Hadamard demultiplexing, which makes the proposed
technique suitable for scenes with high spatial resolution. The experimental
results indicate that a 3D image at resolution up to 512*512 pixels can be
acquired and retrieved with practical time as low as 17 seconds.
