Enhancing imaging performance through the use of active illumination

摘要

A system includes a camera and a projector for capturing spatial detail having resolution exceeding that afforded by the imaging optics, and recovering topographic information lost to the projective nature of imaging. The projector projects a spatial pattern onto the scene to be captured. The spatial patterns may include any pattern or combination of patterns that result in complex sinusoidal modulation. Spatial detail such as texture on the objects in the scene modulate the amplitude of the spatial pattern, and produce Moiré fringes that shifts previously unresolved spatial frequencies into the camera's optical passband. The images may be demodulated, and the demodulated components may be combined with the un-modulated components. The resulting image has spatial detail previously inaccessible to the camera owing to the band-limited nature of the camera optics. A spatial pattern may also be projected and received by the camera to estimate topographic information about the scene.

主权项

1. A system comprising:
an illumination system operable to project a first illumination pattern having a first spatial periodicity and a second illumination pattern having a second spatial periodicity onto an object, and each of the first illumination pattern and the second illumination pattern comprise a superposition of sinusoids; an imaging system having a position spatially disposed from a projector, the imaging system operable to capture a plurality of images; the plurality of images including a first image of an object acquired under the first illumination pattern in a first orientation, wherein the image of the illuminated object is comprised of low frequency Moiré fringes encoding spatial frequencies inaccessible to imaging optics of the imaging system; the plurality of images including a second image of the object acquired under the second illumination pattern in a second orientation, wherein the observed pattern exhibits phase deformations that encode object topography; the first spatial periodicities oriented based on the position of the illumination system relative to the imaging system; the second spatial periodicities oriented based on the position of the illumination system relative to the imaging system and based on an orientation of the first spatial periodicities; and a processor, the processor operable to:
based on the low frequency Moiré fringes, construct an image of the object whose resolution exceeds the resolving power of the imaging system; andbased on the phase deformations, construct a depth map of the object.