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http://cio.repositorioinstitucional.mx/jspui/handle/1002/810| SOME ASPECTS IN THE DESIGN OF LINEAR QUADRATURE FILTERS FOR PHASE SHIFTING | |
| CHRISTHIAN ADONAI GONZALEZ VALDEZ | |
| Manuel Servin Julio C. Estrada | |
| Acceso Abierto | |
| Atribución-NoComercial-SinDerivadas | |
| TIME SIGNALS, DIGITAL FILTER, INTERFEROMETRY, PSA, FINE-TUNING SPECTRAL SHAPING | |
| "Phase Shifting Interferometry (PSI) involves a group of experimental methods for retrieving a wave-front phase encoded in the interference fringes. The first step requires the registration of N-frames of fringes interferograms. The frames of fringes are formed by the addition of two wave-fronts, one called the reference, typically a wavefront coming from a flat surface, and a second wave-front reflected by an object under test. The reference wave-front is sequentially shifted in phase from frame to frame taking as reference the first phase distribution of this reference wave-front [1]. The phase-shift is based on synchronous detection, which has been used for a long time in electrical engineering for determining the phase difference between two electrical signals. The synchronous detection uses as reference an incoming sinusoidal signal, the sinusoidal signal is sampled and correlated with a cosinusoidal coming from the object under test [2, 3]. The automatic evaluation of interferometric measurements, actually called Phase Shifting Algorithms (PSA) are very popular, because of the rapid evaluation of digital interferometric data by a computer. The Phase Shifting Algorithms (PSA), are computer programs created with the objective of obtaining the modulated phase of a signal [4–12]. The PSA in fact are based on complex quadrature filters in the temporal domain. The convolution of this filter with the interferometric signal allows the estimation of the modulated phase φ(x, y). The use of the Fourier Transform applied to the quadrature filter function helps to find its spectral response or frequency transfer function. The information of the spectral response it is the most valuable information, this because helps to the interpretation and analysis of all of its properties. The frequency transfer function of any quadrature filter it is invariant to rotations and reference time shift[13]. A PSA is designed for phase estimation, the input arguments for its construction differ in the phase-shift values between captured interferograms, in the number of phase steps, and in their sensitivity to the noise [6, 14–20]. An accurate phase-shift is very common due to vibrations, miss-calibration in the experimental set-up, noise due to illumination, tall of these point leads to errors in the measured phase, a phenomenon known as detuning." | |
| 2012-04 | |
| Tesis de doctorado | |
| Inglés | |
| León, Guanajuato | |
| Público en general | |
| González Valdez, (2012). "Some Aspects in the Design of Linear Quadrature Filters for Phase Shifting". Tesis de Doctorado en Ciencias (Óptica). Centro de Investigaciones en Óptica, A.C. León, Guanajuato. 47 pp. | |
| ÓPTICA | |
| Versión publicada | |
| publishedVersion - Versión publicada | |
| Aparece en las colecciones: | DOCTORADO EN CIENCIAS (ÓPTICA) |
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