One Eye Suffices: A Computational Model of Monocular Robot Depth Perception

A theory of monocular depth perception is presented. A moving cyclopean observer uses optical flow and shape information--which can also be derived monocularly--to recover the absolute depth of the object in view. The problem is studied for both cases of orthographic and perspective projection. and closed form solutions for the absolute depth functions are developed

Perception of Structure from Motion: Lower Bound Results

This paper investigates lower bounds in relation to the structure from motion problem, i.e., the minimal number of points from an ensemble of points that move in a rigid configuration and the minimal number of projections that are required to uniquely recover the structure. We prove that two orthographic projections of four noncoplanar points admit only four interpretations (up to a reflection) of structure. This forms the basis for an algorithm to recover structure from motion. We also show that it is possible to uniquely recover structure from three orthographic projections of three points in space, when a certain condition holds. Furthermore, when this condition does not hold. the number of structures compatible with the motion is at most two

Perception of Rigid Motion from Spatio-Temporal Derivatives of Optical Flow

The perception of rigid motion from the optical flow generated on the retina is considered. In general, the problem does not have a unique answer. In addition, the equation that constrains the motion parameters based on flow information is nonlinear. We show here that by using either the temporal or the spatial derivatives of the retinal flow, linear equations in the motion parameters can be derived, which can then be used to compute the motion parameters uniquely

Determining the Translation of a Rigidly Moving Surface, without Correspondence

A method is presented for the recovery of the three-dimensional translation of a rigidly moving textured object. The novelty of the method consists of the fact that four cameras are used in order to avoid the solution of the correspondence problem. The method seems to be immune to small noise percentages and to have good behavior when the noise increases