Design and Implementation of a High-Speed Solid-State Acousto-Optic Interference Pattern Projector for Three-Dimensional Imaging

A novel method of projecting interference patterns using acousto-optics has been developed and implemented in the context of the Accordion Fringe Interferometry (AFI) three-dimensional measurement technique developed at MIT Lincoln Laboratory. AFI is an active technique that relies on projecting interference fringes and triangulation to recover range information. AFI is suitable for a wide range of applications, and the solidstate acousto-optic interference fringe projector offers the combination of speed, robustness, and portability that can make AFI a very powerful tool for applications like machine vision, hand-held 3D scanning, high-throughput quality control systems, and motion study and modeling. This work presents the theory of acousto-optic devices and addresses design considerations for an acousto-optic AFI system. Moreover, a prototype is constructed and evaluated, and an algorithm is implemented to reconstruct the 3D surface of an object. The results indicate that an acousto-optic AFI system is practical and has high potential for applications that require high speed and portability from a 3D imaging system. Thesis Supervisor: Lyle G. Shirley Title: MIT Lincoln Laboratory Research Staff Thesis Supervisor: Dennis M. Freeman Title: Associate Professor in Electrical Engineering