摘要:
In exemplary implementations of this invention, a light source illuminates a scene and a light sensor captures data about light that scatters from the scene. The light source emits multiple modulation frequencies, either in a temporal sequence or as a superposition of modulation frequencies. Reference signals that differ in phase are applied to respective subregions of each respective pixel. The number of subregions per pixel, and the number of reference signals per pixel, is preferably greater than four. One or more processors calculate a full cross-correlation function for each respective pixel, by fitting light intensity measurements to a curve, the light intensity measurements being taken, respectively, by respective subregions of the respective pixel. The light sensor comprises M subregions. A lenslet is placed over each subregion, so that each subregion images the entire scene. At least one temporal sequence of frames is taken, one frame per subregion.
摘要:
In exemplary implementations of this invention, a set of two scanning mirrors scans the one dimensional field of view of a streak camera across a scene. The mirrors are continuously moving while the camera takes streak images. Alternately, the mirrors may only between image captures. An illumination source or other captured event is synchronized with the camera so that for every streak image the scene looks different. The scanning assures that different parts of the scene are captured.
摘要:
In illustrative implementations of this invention, multi-path analysis of transient illumination is used to reconstruct scene geometry, even of objects that are occluded from the camera. An ultrafast camera system is used. It comprises a photo-sensor (e.g., accurate in the picosecond range), a pulsed illumination source (e.g. a femtosecond laser) and a processor. The camera emits a very brief light pulse that strikes a surface and bounces. Depending on the path taken, part of the light may return to the camera after one, two, three or more bounces. The photo-sensor captures the returning light bounces in a three-dimensional time image I(x,y,t) for each pixel. The camera takes different angular samples from the same viewpoint, recording a five-dimensional STIR (Space Time Impulse Response). A processor analyzes onset information in the STIR to estimate pairwise distances between patches in the scene, and then employs isometric embedding to estimate patch coordinates.
摘要:
In exemplary implementations of this invention, an automultiscopic display device includes (1) one or more spatially addressable, light attenuating layers, and (2) a controller which is configured to perform calculations to control the device. In these calculations, tensors provide sparse, memory-efficient representations of a light field. The calculations include using weighted nonnegative tensor factorization (NTF) to solve an optimization problem. The NTF calculations can be sufficiently efficient to achieve interactive refresh rates. Either a directional backlight or a uniform backlight may be used. For example, the device may have (1) a high resolution LCD in front, and (2) a low resolution directional backlight. Or, for example, the device may have a uniform backlight and three or more LCD panels. In these examples, all of the LCDs and the directional backlight (if applicable) may be time-multiplexed.
摘要:
A bidirectional screen alternately switches between a display mode showing conventional graphics and a capture mode in which the LCD backlight is disabled and the LCD displays a pinhole array or a tiled-broadband code. A large-format image sensor is placed behind the liquid crystal layer. Together, the image sensor and LCD function as a mask-based light field camera, capturing an array of images equivalent to that produced by an array of cameras spanning the display surface. The recovered multi-view orthographic imagery is used to passively estimate the depth of scene points from focus.
摘要:
In an exemplary implementation of this invention, light from a scattering scene passes through a spatial light attenuation pattern and strikes a sensor plane of a camera. Based on said camera's measurements of the received light, a processing unit calculates angular samples of the received light. Light that strikes the sensor plane at certain angles comprises both scattered and directly transmitted components; whereas light that strikes at other angles comprises solely scattered light. A processing unit calculates a polynomial model for the intensity of scattered-only light that falls at the latter angles, and further estimates the direct-only component of the light that falls at the former angles. Further, a processing unit may use the estimated direct component to calculate a reconstructed 3D shape, such as a 3D shape of a finger vein pattern, using an algebraic reconstruction technique.
摘要:
In exemplary implementations of this invention, a set of two scanning mirrors scans the one dimensional field of view of a streak camera across a scene. The mirrors are continuously moving while the camera takes streak images. Alternately, the mirrors may only between image captures. An illumination source or other captured event is synchronized with the camera so that for every streak image the scene looks different. The scanning assures that different parts of the scene are captured.
摘要:
In exemplary implementations of this invention, a 3D range camera “looks around a corner” to image a hidden object, using light that has bounced (reflected) off of a diffuse reflector. The camera can recover the 3D structure of the hidden object.
摘要:
In exemplary implementations of this invention, cataracts in the human eye are assessed and mapped by measuring the perceptual impact of forward scattering on the foveal region. The same method can be used to measure scattering/blocking media inside lenses of a camera. Close-range anisotropic displays create collimated beams of light to scan through sub-apertures, scattering light as it strikes a cataract. User feedback is accepted and analyzed, to generate maps for opacity, attenuation, contrast and sub-aperture point-spread functions (PSFs). Optionally, the PSF data is used to reconstruct the individual's cataract-affected view.
摘要:
A single camera acquires an input image of a scene as observed in an array of spheres, wherein pixels in the input image corresponding to each sphere form a sphere image. A set of virtual cameras are defined for each sphere on a line joining a center of the sphere and a center of projection of the camera, wherein each virtual camera has a different virtual viewpoint and an associated cone of rays, appearing as a circle of pixels on its virtual image plane. A projective texture mapping of each sphere image is applied to all of the virtual cameras on the virtual image plane to produce a virtual camera image comprising circle of pixels. Each virtual camera image for each sphere is then projected to a refocusing geometry using a refocus viewpoint to produce a wide-angle lightfield view, which are averaged to produce a refocused wide-angle image.