1. A multi-pattern projection system to enhance dynamic reconstruction of a three-dimensional (x,y,z) depth map obtained from an imaged scene in which at least one target object may be present, said scene imaged by an acquisition system that optically acquires within a field of view (FOV) of said acquisition system at least a portion of said scene, said imaged scene processed by a processor system coupled to said acquisition system to yield said three-dimensional (x,y,z) depth map, the multi-pattern projection system, coupleable to said acquisition system, including: light source outputting optical energy; an electronically spatially reconfigurable pattern generator (SRPG) including: a first diffractive optical element (DOE), characterized by a near field, disposed optically downstream from said light source so as to receive at least some of said optical energy; a second DOE, characterized by a far field, disposed optically downstream from and within said near field of said first DOE, said first DOE and said second DOE being spaced-apart a distance Δz, said second DOE processing optical energy received from said first DOE and projecting a pattern P within said far field of said second DOE; and means for electronically controllably varying effective optical length traversed by optical energy from said light source traversing from said first DOE to said second DOE; wherein when said means for electronically controllably varying causes magnitude of said effective optical length to be a first distance said second DOE projects a first pattern P 1 and when said means for controllably varying causes magnitude of said effective optical length to be a second distance said second DOE projects a second different pattern P 2 ; and wherein disparity contributions resulting from presence of said first pattern P 1 and said second pattern P 2 in said scene enables a three-dimensional depth map of a target object in said scene to be more rapidly generated than if only one pattern were used.