Abstract
We present here a technique for passively sensing the three-dimensional structure of a scene using a single compact
camera. The iris of a conventional camera is replaced by a mask with a prism array, forming multiple images, in which
the vision disparities between the sub-images are extracted to compute depth. The arrangement of the prisms array can
be regular or aperture coded. For a regular arrangement, each prism forms an independent sub-image that is viewed
from a portion of the aperture, like many mini-cameras encapsulated in one aperture. If the angle of each prism is
designed properly, the sub-images can be separated from each other on the plane of image detector, so that conventional
methods of depth determination in stereo vision can be applied. On the other hand, the macro-prism array also can be
arranged in aperture coded fashion. The coded aperture imaging method then can be employed here for depth sensing.
Unlike the previous arrangement, the macro-prisms are positioned according to certain coding array, such as random
array or non-redundant array, so that the images viewed from each prism are superimposed. In order to reconstruct the
final depth image, a related decoding step for imaging processing is done. The passive range technique we introduced
above should be considered as a multiple imaging problem. Since only a single compact camera is used, we avoid the
need for extrinsic camera calibration, greatly reduced the computational demanding of correspondence problem. The use
of refractive element, prism array, instead of pinhole array, can greatly increase the light transmission and the resolution
of images.
