Optical detection of vibrations

A system for imaging of vibrations in a scene, the system comprising:

• at least one coherent light source configured to illuminate the scene comprising multiple scene elements;
• an optical unit in association with a pixelated detector comprising multiple pixels and a specified field of view that at least partly overlaps with the scene, wherein the optical unit is configured to focus light scattered from the multiple scene elements in the scene onto the pixelated detector such that light scattered from each scene element of the multiple scene elements is focused on a corresponding pixel of the multiple pixels on the pixelated detector, and wherein the detector is configured to provide, for each pixel of the multiple pixels, a pixel intensity signal of the pixel thereof, to thereby yield corresponding multiple pixel intensity signals, wherein the optical unit further comprises a spatially patterned mask configured to enhance a modulation of the pixel intensity signals and to increase a ratio between the modulation of the pixel intensity signals and a DC thereof;
• and
• a processing unit configured to analyze each pixel intensity signal of the multiple pixel intensity signals and to derive, for each pixel of the multiple pixels and based on the respective pixel intensity signal, a vibration spectrum of the scene element in the scene that corresponds to the pixel thereof, to thereby yield corresponding multiple vibration spectrums, wherein the processing unit is further configured to optimize the spatial pattern of the mask according to specified criteria.