Error analysis in parallel two-step phase-shifting method

Abstract

This paper presents an analysis of error in parallel two-step phase-shifting method. From the analysis, it is clarified that the maximum bandwidth of the object that this technique can capture is a half bandwidth of recording devices. Also, the recording distance must be two times longer than the conventional method to have a good reconstruction image. The analysis was verified by simulations and experimental results.

Generation speed and reconstructed image quality enhancement of a long-depth object using double wavefront recording planes and a GPU

“…A pre-process is needed to deal with the object point data, or a new seeking method needs to be proposed. Phan et al proved recently that the maximum resolution of a reconstructed object is the resolution of the capture devices because of the cut-off frequency or bandwidth of the devices [12]. Although the scene of the object was sampled with very high resolution, the reconstructed object had a maximum resolution of only 1∕Δ.…”

Phase profile analysis of transparent objects through the use of a two windows interferometer based on a one beam splitter configuration

“…The polarization filters angles are: 1 = 0 • , 2 = 45 • , 3 = 90 • and 4 = 135 • , and each one of them represents phase shifts of 0, /2, and 3 /2 respectively. To minimize errors in amplitude generated by the placement of polarizers at different angles [7,8], every interferogram used was subjected to a rescaling and normalization process, using digital image processing techniques [9,10]. This procedure generates patterns of equal intensities.…”

Parallel two-step phase shifting interferometry using a double cyclic shear interferometer

“…These results are convenient to reduce the number of phase steps used to process the optical phase information. The principal advantage of this system, compared with others previously published [6,7,[12][13][14][15], is the elimination of the diffractive element and the polarizer array used at the output of the interferometer.…”

“…If these two beams go into a second CSI, we are capable of generating four beams, which can be properly made to interfere by displacing the mirror of this last CSI. As a result, we obtain the interference of pairs of beams, resulting in two interference patterns [12][13][14][15] that can be used to obtain the relative desired phase shift by using polarization phase shifting techniques. As shown in the following sections, the patterns generated by the Double Cyclic Shear Interferometer (DCSI) have relative phase shifts of π, and their separation can be freely adjusted.…”