Systematic error analysis and parameter design of a vision-based phase estimation method for ultra-precision positioning.

Ultra-precision position measurement is increasingly important in advanced manufacturing such as the semiconductor industry and fiber optics or photonics. A vision-based phase estimation method we proposed previously performs position measurement by imaging a 2D periodic pattern. In this paper, systematic errors of this method are analyzed and derived mathematically, which are classified into two types: spectrum leakage error caused by image truncation and window function modulation, and sub-pixel error resulting from discrete Fourier transform (DFT) intensity interpolation.

Forward fiber Fourier transform spectrometer modeling and design with PZT phase modulation real-time compensation.

Piezoelectric ceramic transducers (PZTs) are often applied in all-fiber Fourier transform spectrometers (FFTSs) to realize phase modulation. Combining a PZT and optical fiber features, a theoretical FFTS modeling is established. We systematically deduced the main causes of spectral errors and the factors of the instrumental resolution, then designed a new FFTS system and provided real-time compensation methods for spectral errors.