Light field

About: Light field is a research topic. Over the lifetime, 5357 publications have been published within this topic receiving 87424 citations.

Visualizing Underwater Ocean Optics

Abstract: Simulating the in-water ocean light field is a daunting task. Ocean waters are one of the richest participating media, where light interacts not only with water molecules, but with suspended particles and organic matter as well. The concentration of each constituent greatly affects these interactions, resulting in very different hues. Inelastic scattering events such as fluorescence or Raman scattering imply energy transfers that are usually neglected in the simulations. Our contributions in this paper are a bio-optical model of ocean waters suitable for computer graphics simulations, along with an improved method to obtain an accurate solution of the in-water light field based on radiative transfer theory. The method provides a link between the inherent optical properties that define the medium and its apparent optical properties, which describe how it looks. The bio-optical model of the ocean uses published data from oceanography studies. For inelastic scattering we compute all frequency changes at higher and lower energy values, based on the spectral quantum efficiency function of the medium. The results shown prove the usability of the system as a predictive rendering algorithm. Areas of application for this research span from underwater imagery to remote sensing; the resolution method is general enough to be usable in any type of participating medium simulation.

System and method for preparing micro-pore array through femtosecond laser direct writing

Abstract: The invention discloses a system and a method for preparing a micro-pore array through femtosecond laser direct writing The system comprises a femtosecond vector light field generation system, a spatial filtering component, a computer and a three-dimensional mobile platform, wherein a 1/2 wave plate, a Glan-laser polarizer, a beam expander and the femtosecond vector light field generation system are arranged on an output straight light path of a femtosecond laser device in sequence; a 4f system is arranged on a light path behind a reflective pure phase spatial light modulator after a holographic phase plate is loaded; a spatial filter is arranged on a frequency spectrum surface; and positive and negative levels of diffraction light which pass through the spatial filter pass through a 1/4 wave plate respectively and are combined into a beam of laser through a Rochi grating A material is adjusted to a focal position through the spatial filtering component, an electronic diaphragm, a focusing lens and the three-dimensional mobile platform; and the spatial light modulator, the electronic diaphragm and the three-dimensional mobile platform are connected with a computer through data lines The device has the advantages of simple structure, convenience in operation and capabilities of preparing the micro-pore array with various patterns and improving the machining efficiency

Perception of illumination direction in images of 3-D convex objects: influence of surface materials and light fields.

Abstract: We investigated the perception of illumination direction in images of 3-D convex objects under variations of light field and surface material properties. In a first experiment, we used an illumination-matching procedure in order to measure observers' ability to estimate the direction of illumination in images of 3-D polyhedra rendered under different light fields and illumination directions. Match deviations were larger in frontal direction than in rear directions, mainly counterclockwise in azimuth component, and diverged, in elevation component, from the image plane. In a second experiment, we examined whether the direction estimate was affected by the surface material type (BRDF), the light field, and the illumination direction. Angular deviations varied with material surface type and were largest in the test elevation direction 0 degrees. Elevation component deviations also differed with surface type and were larger in hemispherical diffuse lighting than in collimated lighting. These results suggest that the direction estimation is better with images of evenly distributed intensity gradients than with those of drastically varying gradients, and that the visual system may not take intensity variations due to the surface material or the light field into account in estimating the direction of illumination.

Atomic spin squeezing in an optical cavity

Abstract: We consider squeezing of one component of the collective spin vector of an atomic ensemble inside an optical cavity. The atoms interact with a cavity mode, and the squeezing is obtained by probing the state of the light field that is transmitted through the cavity. Starting from the stochastic master equation, we derive the time evolution of the state of the atoms and the cavity field, and we compute expectation values and variances of the atomic spin components and the quadratures of the cavity mode. The performance of the setup is compared to spin squeezing of atoms by probing of a light field transmitted only once through the sample.