Light field imaging device and method for depth acquisition and three-dimensional imaging

A method of imaging a scene, the method comprising:

• diffracting an optical wavefront originating from the scene with a diffraction grating having a grating period along a grating axis to generate a diffracted wavefront, the diffracted wavefront having, in a near-field diffraction region, an intensity profile that is spatially modulated according to the grating period and that shifts laterally along the grating axis upon varying an angle of incidence of the optical wavefront;
• detecting the diffracted wavefront with a pixel array comprising a plurality of light-sensitive pixels disposed under the diffraction grating in the near-field diffraction region, wherein said detecting comprises sampling different spatial parts of the intensity profile of the diffracted wavefront with first and second adjacent pixel groups of the plurality of light-sensitive pixels and generating therefrom respective first and second pixel responses that vary differently with the angle of incidence of the optical wavefront;
• computing a difference between the first and second pixel responses, wherein the computing comprises subtracting the first pixel responses from the second pixel responses to obtain angle-modulated pixel responses;
• and
• determining depth information about the scene from the angle-modulated pixel responses.