Digital Aperture Light Field Camera

Technology #13929

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FIGS. 1A and 1B are schematic diagrams of a light field camera with an actively addressable aperture defined by a spatial light modulator (SLM) with a pixel pitch Λ that illustrate how to avoid the deleterious effects of diffraction of incident light by the SLM.FIGS. 1A and 1B are schematic diagrams of a light field camera with an actively addressable aperture defined by a spatial light modulator (SLM) with a pixel pitch Λ that illustrate how to avoid the deleterious effects of diffraction of incident light by the SLM.FIG. 1C is a plot of interbeam angle θ1 between undiffracted and first-order diffracted beams versus angle of incidence θi for different ratios of wavelength λ to pixel pitch Λ.FIG. 1D is a plot of normalized displacement Δx/L of the first-order diffracted spot versus angle of incidence θi for different ratios of wavelength λ to pixel pitch Λ.FIG. 1E is a plot of normalized displacement Δx/L of the first-order diffracted spot versus the ratio of wavelength λ to pixel pitch Λ for different angle of incidence θi.FIGS. 2A-2D are schematic diagrams of light field cameras that includes stops configured to limit the angular field of view and/or the range of angles incident on the SLM.FIGS. 2A-2D are schematic diagrams of light field cameras that includes stops configured to limit the angular field of view and/or the range of angles incident on the SLM.FIGS. 2A-2D are schematic diagrams of light field cameras that includes stops configured to limit the angular field of view and/or the range of angles incident on the SLM.FIGS. 2A-2D are schematic diagrams of light field cameras that includes stops configured to limit the angular field of view and/or the range of angles incident on the SLM.
Categories
Inventors
Professor Douglas Hart
Department of Mechanical Engineering, MIT
External Link (meche.mit.edu)
Thomas Milnes
Department of Mechanical Engineering, MIT
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Actively addressable aperture light field camera

US Patent 8,497,934

The digital aperture light field camera uses an actively addressable aperture to capture a five-dimensional (5D) light field.

Applications

The invention is suitable for applications such as interactive displays, machine vision systems, autonomous navigation, 3D movies, visible light photography, medical applications and infrared imaging for military and industrial applications.

Problem Addressed

The full, five-dimensional (5D) light field can be obtained from the 4D parameterized light field. The major challenge is that current devices for constructing 4D light field from 2D images are either bulky or low resolution. This makes them unsuitable for a variety of consumer and industrial applications.

Technology

The invention is a camera that includes an actively addressable aperture, otherwise known as a digital aperture, that is positioned ahead of the rear surface of a camera lens. The actively addressable aperture is moved over the entire aperture plane and an image is taken at each position. This yields a 2D grid of 2D photos that can be assembled into a 4D parameterized light field. The many different-perspective images can be used to calculate the 3D depth of the object being imaged, resulting in a 3D model with 2D surface irradiance patterns, which is the full 5D, non-parameterized light field.

Advantages

  • The camera can be compact and have higher resolution than plenoptic cameras.
  • Simpler and faster than other 5D light cameras.
  • It can be adaptable for imaging at any wavelength.