The proposed project will investigate four differents systems/algorithms for passively ranging ships and other floating objects of interest using electro-optic sensors. This innovative research project includes three parts: I) evaluation of four approaches: dual-camera system, spectrum analysis auto-focus system, dual-sensor scanning system, and single-camera scanning system. 2) feasibility study of dual-camera system. 3) feasibility study of sincle-camera scanning system. The dual-sensors and single-camera approaches are invented by the principal investigators and the patent applications are pending. The proposed project will concentrate on the feasibility study for Naval applications including the compensation of uncertainties in the vertical reference, objects of unknown size, geometry, and maneuvering of both the ship platform and the viewed object. The feasibility study of full-view 3-d information and display will also be conducted in this project.