| Phase evaluation exists mostly in, but not limited to, interferometric applications that utilize coherent multidimensional signals to modulate the physical quantity of interest into a nonlinear form, represented by repeating the phase modulo of 271 radians. In order to estimate the underlying physical quantity, the wrapped phase has to be unwrapped by an evaluation procedure which is usually called phase unwrapping. The procedure of phase unwrapping will obviously face the challenge of inconsistent phase, which could bring errors in phase evaluation. The main objectives of this research include addressing the problem of inconsistent phase in phase unwrapping and applications in modern optical techniques.In this research, a new phase unwrapping algorithm is developed. The creative idea of doing phase unwrapping between regions has an advantage over conventional pixel-to-pixel unwrapping methods because the unwrapping result is more consistent by using a voting mechanism based on all Zit-discontinuities hints. Furthermore, a systematic sequence of regional unwrapping is constructed in order to achieve a global consistent result. An implementation of the idea is illustrated in dct.il with step-by-step pseudo codes. The performance of the algorithm is demonstrated on real world applications.In order to solve a phase unwrapping problem which is caused by depth discontinuities in 3D shape measurement, a new absolute phase coding strategy is developed. The algorithm presented has two merits: effectively extends the coding range and preserves the measurement sensitivity. The performance of the proposed absolute coding strategy is proved by results of 3D shape measurement for objects with surface discontinuities.As a powerful tool for real world applications a universal software package, Optical Measurement and Evaluation Software (OMES), is designed for the purposes of automatic measurement and quantitative evaluation in 3D shape measurement and laser interferometry. Combined with different sensors or setups, OMES has been successfully applied in the industries, for example, GM Powertrain, Coming, and Ford Optical Lab., and used for various applications such as shape measurement, deformation/displacement measurement, strain/stress analysis, non-destructive testing, vibration/modal analysis, and biomechanics analysis. |
