  Shock compression plate impact experiments conventionally rely on point-wise
velocimetry measurements based on laser-based interferometric techniques. This
study presents an experimental methodology to measure the free surface
full-field particle velocity in shock compression experiments using high-speed
imaging and three-dimensional (3D) digital image correlation (DIC). The
experimental setup has a temporal resolution of 100 ns with a spatial
resolution varying from 90 to 200 $\mu$m/pixel. Experiments were conducted
under three different plate impact configurations to measure spatially resolved
free surface velocity and validate the experimental technique. First, a normal
impact experiment was conducted on polycarbonate to measure the macroscopic
full-field normal free surface velocity. Second, an isentropic compression
experiment on Y-cut quartz-tungsten carbide assembly is performed to measure
the particle velocity for experiments involving ramp compression waves. To
explore the capability of the technique in multi-axial loading conditions, a
pressure shear plate impact experiment was conducted to measure both the normal
and transverse free surface velocities under combined normal and shear loading.
The velocities measured in the experiments using digital image correlation are
validated against previous data obtained from laser interferometry. Numerical
simulations were also performed using established material models to compare
and validate the experimental velocity profiles for these different impact
configurations. The novel ability of the employed experimental setup to measure
full-field free surface velocities with high spatial resolutions in shock
compression experiments is demonstrated for the first time in this work.
