Hemispherical confocal imaging

Abstract

We propose a new imaging method called hemispherical confocal imaging to visualize clearly a particular depth in a 3-D scene. The key optical component is a turtleback reflector which is a specially designed polyhedral mirror. To synthesize a hemispherical aperture, we combined the turtleback reflector with a coaxial camera and projector, to create on a hemisphere many virtual cameras and projectors with a uniform density. In such an optical device, high frequency illumination can be focused at a particular depth in the scene to visualize only that depth by employing descattering. The observed views are then factorized into masking, attenuation, reflected light, illuminance, and texture terms to enhance the visualization when obstacles are present. Experiments using a prototype system show that only a particular depth is effectively illuminated, and hazes caused by scattering and attenuation can be recovered even when obstacles are present. © 2011 Information Processing Society of Japan.