Digital inline holography is an amazingly simple and effective approach for three-dimensional imaging, to which particle tracking velocimetry is of particular interest. Conventional digital holographic particle tracking velocimetry techniques
are computationally separated in particle and flow reconstruction, plus the expensive computations. Usually, the particle volumes are recovered firstly, from which fluid flows are computed. Without iterative reconstructions, This sequential spacetime
process lacks accuracy. This paper presents a joint optimization framework for digital holographic particle tracking velocimetry: particle volumes and fluid flows are reconstructed jointly in a higher space-time dimension, enabling faster
convergence and better reconstruction quality of both fluid flow and particle volumes within a few minutes on modern GPUs. Synthetic and experimental results are presented to show the efficiency of the proposed technique.