A camera has a lens and aperture device for determining 3D information. A projector projects an optical pattern toward a surface. The camera has at least two off-axis apertures thereon, arranged to obtain an image of the projected pattern including defocused information. The camera is movable between different positions to image the surface from said different positions, and the projector is at a specified angle of at least 5° relative to said camera. A processor carries out a first operation using information received through the apertures to determine a pose of said camera, and to determine three dimensional information about the object based on a degree of deformation of said optical pattern on said surface indicative of a three dimensional surface. An embodiment projects a grid of laser dots and uses laser-dot defocusing for approximate Z and thus grid correspondence, which can greatly increase the working depth of the system.