The subtle vibrations on an object's surface contain information about the object's physical
properties and its interaction with the environment. Prior works imaged surface vibration to
recover the object's material properties via modal analysis, which discards the transient
vibrations propagating immediately after the object is disturbed. Conversely, prior works that
captured transient vibrations focused on recovering localized signals (eg, recording nearby
sound sources), neglecting the spatiotemporal relationship between vibrations at different …

For a well-aligned optical system, the relation between the image-plane shifts (dx, dy) and
the surface tilts (θx, θy) is described in Eq.(1) of the main paper. However, there might be
misalignment between the object plane axis and camera frame axis. And this misalignment
is hard to avoid when we are using anisotropic material with unknown anisotropy axis.(see
Fig. 2). Therefore, we compensate for this misalignment by adding an appropriate rotation
matrix to the measured shifts in Eq.(1)(θx, θy)=(hx, hy)⊙ R (αz)(dx, dy),(17) where