text: Light field imaging involves capturing both angular and spatial distribution of light; it enables new capabilities, such as post-capture digital refocusing, camera aperture adjustment, perspective shift, and depth estimation. Micro-lens array (MLA)-based light field cameras provide a cost-effective approach to light field imaging. There are two main limitations of MLA-based light field cameras: low spatial resolution and narrow baseline. While low spatial resolution limits the general purpose use and applicability of light field cameras, narrow baseline limits the depth estimation range and accuracy. In this paper, we present a hybrid stereo imaging system that includes a light field camera and a regular camera. The hybrid system addresses both spatial resolution and narrow baseline issues of the MLA-based light field cameras while preserving light field imaging capabilities.
  @cite_24: The Plenoptic camera, a digital realization of Lippmann's “Integral Photography” ideas, was introduced in 1992 by Adelson as an approach to solve computer vision problems. Recently, an improved version called Plenoptic 2.0 camera has been independently proposed by Ng, Fife, Lumsdaine, and others. The important part about it is the much higher spatial resolution. In this paper I will describe the two different focusing modes of this new camera, image rendering for it, as well as methods for capture extended modes at high resolution, including HDR, multispectral color, polarization, superresolution, and others. These are applicable only to Plenoptic 2.0 camera, which fact makes it unique. A live demo of the camera will be shown.
  @cite_29: Plenoptic cameras, constructed with internal microlens arrays, focus those microlenses at infinity in order to sample the 4D radiance directly at the microlenses. The consequent assumption is that each microlens image is completely defocused with respect to to the image created by the main camera lens and the outside object. As a result, only a single pixel in the final image can be rendered from it, resulting in disappointingly low resolution. In this paper, we present a new approach to lightfield capture and image rendering that interprets the microlens array as an imaging system focused on the focal plane of the main camera lens. This approach captures a lightfield with significantly higher spatial resolution than the traditional approach, allowing us to render high resolution images that meet the expectations of modern photographers. Although the new approach samples the lightfield with reduced angular density, analysis and experimental results demonstrate that there is sufficient parallax to completely support lightfield manipulation algorithms such as refocusing and novel views
  @cite_14: This paper contributes to the theory of photograph formation from light fields. The main result is a theorem that, in the Fourier domain, a photograph formed by a full lens aperture is a 2D slice in the 4D light field. Photographs focused at different depths correspond to slices at different trajectories in the 4D space. The paper demonstrates the utility of this theorem in two different ways. First, the theorem is used to analyze the performance of digital refocusing, where one computes photographs focused at different depths from a single light field. The analysis shows in closed form that the sharpness of refocused photographs increases linearly with directional resolution. Second, the theorem yields a Fourier-domain algorithm for digital refocusing, where we extract the appropriate 2D slice of the light field's Fourier transform, and perform an inverse 2D Fourier transform. This method is faster than previous approaches.
summary: Alternative to the standard MLA-based light field camera design @cite_14 , where the MLA is placed at the image plane of the main lens and the sensor is placed at the focal length of the lenslets, there is another design approach where the MLA is placed to relay image from the intermediate image plane of the main lens to the sensor @cite_29 . This design is known as focused plenoptic camera.'' As in the case of the standard light field camera approach, super-resolution restoration for focused plenoptic cameras is also possible @cite_24 .