Light field

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

Iteratively reconstructing 4D light fields from focal stacks.

Abstract: Acquiring and representing the 4D space of rays in the world (the light field) is important for many computer vision and graphics applications. In this paper, we propose an iterative method to acquire the 4D light field from a focal stack. First, a discrete refocusing equation is derived from integral imaging principles. With this equation, a linear projection system is formulated to model the focal stack imaging process. Then we reconstruct the 4D light field from the focal stack through solving the inverse problem with a filtering-based iterative method. The experimental results show that our approach is effective and outperforms state-of-the-art methods in reconstruction accuracy, reduced sampling, and occluded boundaries.

Some aspects of the axially symmetric submarine daylight field

Abstract: A set of differential equations is derived to relate the light field and its derivative to the inherent optical properties of sea water (volume-scattering function and beam-attenuation coefficient) when the light field is axially symmetric From these equations, the volume-scattering function and the beam-attenuation coefficient can be calculated if the light field and its derivative with depth are known The equations are then used to provide an alternate proof for the asymptotic light field hypothesis The shape of the asymptotic light field is derived as a function of the inherent optical properties and the asymptotic decay constant It is finally shown that if the shape of the asymptotic light field and the asymptotic decay constant are known, the inherent optical properties can be calculated

Deflection of atoms by standing-wave radiation

Abstract: We have observed momentum transfer from a standing-wave light field to an atomic beam. The atomic beam is split symmetrically into two peaks whose separation increases with field strength. The short interaction time ensures that this deflection is due to induced forces; these are described using a semiclassical dressed-atom treatment, which gives good agreement with the data. In addition to the splitting, we have observed diffraction of the atomic beam due to the exchange of even numbers of photons with the field.

Accurate depth estimation in structured light fields

Abstract: Passive light field imaging generally uses depth cues that depend on the image structure to perform depth estimation, causing robustness and accuracy problems in complex scenes. In this study, the commonly used depth cues, defocus and correspondence, were analyzed by using phase encoding instead of the image structure. The defocus cue obtained by spatial variance is insensitive to the global spatial monotonicity of the phase-encoded field. In contrast, the correspondence cue is sensitive to the angular variance of the phase-encoded field, and the correspondence responses across the depth range have single-peak distributions. Based on this analysis, a novel active light field depth estimation method is proposed by directly using the correspondence cue in the structured light field to search for non-ambiguous depths, and thus no optimization is required. Furthermore, the angular variance can be weighted to reduce the depth estimation uncertainty according to the phase encoding information. The depth estimation of an experimental scene with rich colors demonstrated that the proposed method could distinguish different depth regions in each color segment more clearly, and was substantially improved in terms of phase consistency compared to the passive method, thus verifying its robustness and accuracy.

Virtual touch interface

Abstract: A user may issue commands to a computing device by moving a pointer within a light field. Sensors may capture light reflected from the moving pointer. A virtual touch engine may analyze the reflected light captured as light portions in a sequence of images by the sensors to issue a command to a computing device in response to the movements. Analyzing the sequence of images may include finding the light portions in the sequence of images, determining a size of the light portions, and determining a location of the light portions.