A method and apparatus to capture stereoscopic images is disclosed. A light source having a diffracting device to project a structured light unto a target object is provided. A plurality of imaging devices to capture images of the target object is provided.

The upper end of an elongate, rigid, mirror supporting arm is releasably secured at its upper end to an orientation ring, which is removably and rotatably mounted on the lower, cylindrically shaped end of the objective lens housing of an optical autofocus measurement system. The arm extends at its lower end beneath the housing and has secured thereon a mirror which is spaced beneath the housing, and lies in a plane that intersects and is inclined relative to the optical axis of the optical system contained in the housing. The mirror faces the surface of an object disposed in an object plane spaced laterally from the optical axis of the lens system, so that the system is focused along a supplemental optical axis which is inclined to, and intersects, the optical axis of the system in the housing. Images of the object in the offset object plane are therefore projected along the supplemental axis and then from the mirror to the optical system along its optical axis. This system enables a method of effecting autofocus measurements of an object placed in a first object plane that is intersected by the system optical axis when the mirror arm is removed from the lens housing, and, which also enables autofocusing of object surfaces in a second object plane when the mirror is attached by the arm to the lens housing.

A method for range scanning consists of projecting a sequence of radiation patterns onto a scene, capturing images of the scene, determining correspondences between image features and projection pattern features, and computing a range image of the scene by triangulation of the correspondences. Novel projection patterns allow tracking of pattern features between images, so that range images can be computed for moving scenes in real time. Global assumptions about surface continuity or reflectivity of the scene are not required for successful range scanning. Projection patterns may be based on two-stripe codes, parallel stripes of bright and dark intensity. In two-stripe coded patterns, pattern features are the boundaries between stripes, which take on values of either on-on, on-off, off-on, or off-off. A particular boundary's value over the entire pattern sequence defines its code, used to determine correspondences between the boundary image and its location in the projection pattern. The method is also useful for obtaining three-dimensional models of static objects. The object is slowly rotated while being imaged, and all resulting range images are aligned and merged to form the three-dimensional model. A system implementing the method can be mounted on a robot or vehicle for navigation in unknown environments.

A lens having at least one lens centration mark formed on a major surface of the lens is disclosed. The lens centration mark may be located at the intersection of a first axis and the major surface, where the major surface is symmetrical about the first axis such that the first axis is an axis of revolution of the surface. A method of making a lens having such lens centration mark, as well as a method for measuring the centration of a lens surface utilizing the lens centration mark, are also disclosed.

A lens having at least one lens centration mark formed on a major surface of the lens is disclosed. The lens centration mark may be located at the intersection of a first axis and the major surface, where the major surface is symmetrical about the first axis such that the first axis is an axis of revolution of the surface. A method of making a lens having such lens centration mark, as well as a method for measuring the centration of a lens surface utilizing the lens centration mark, are also disclosed.