Abstract: A system and method for expansion and reduction of images uses an absolute value associated with each pixel of an input image (e.g., a color and/or intensity value) to determine a respective energy value for each pixel. For example, a given color or range of colors (e.g., skin tones, or other high-priority colors) may be assigned higher energy values than other colors and/or color ranges, and may be protected during image reduction and/or expansion. These energy values may be used to determine a cost associated with various seams of the image, which may represent the priority of the seams in the image. One or more low-cost seams may be identified for removal or replication to produce a resized image. The methods may be used in conjunction with an automated skin tone detector or a user interface that allows selection of one or more high priority colors or color ranges.

Abstract: Sub pixel image alignment includes mapping first pixels from a first image and second pixels from a second image to a coordinate system and applying one or more sub-pixel shifts to the mapped first pixels. For each sub-pixel shift, an overall energy is calculated and is based on a plurality of gradients that represent changes in a channel value among the shifted first pixels and the mapped second pixels. The sub-pixel alignment further includes determining the sub-pixel shift that provides the lowest overall energy.

Abstract: An external mask-based radiance camera may be based on an external, non-refractive mask located in front of the main camera lens. The mask modulates, but does not refract, light. The camera multiplexes radiance in the frequency domain by optically mixing different spatial and angular frequency components of light. The mask may, for example, be a mesh of opaque linear elements, which collectively form a grid, an opaque medium with transparent openings, such as circles, or a pinhole mask. Other types of masks may be used. Light may be modulated by the mask and received at the main lens of a camera. The main lens may be focused on a plane between the mask and the main lens. The received light is refracted by the main lens onto a photosensor of the camera. The photosensor may capture the received light to generate a radiance image of the scene.

Abstract: Method and apparatus for radiance processing by demultiplexing in the frequency domain. A frequency domain demultiplexing module obtains a radiance image captured with a lens-based radiance camera. The image includes optically mixed spatial and angular frequency components of light from a scene. The module performs frequency domain demultiplexing on the radiance image to generate multiple parallax views of the scene. The method may extract multiple slices at different angular frequencies from a Fourier transform of the radiance image, apply a Fourier transform to each of the multiple slices to generate intermediate images, stack the intermediate images to form a 3- or 4-dimensional image, apply an inverse Fourier transform along angular dimension(s) of the 3- or 4-dimensional image, and unstack the transformed 3- or 4-dimensional image to obtain the multiple parallax views. During the method, phase correction may be performed to determine the centers of the intermediate images.