Reduction of the ringing effect in off-axis digital holography reconstruction from two reconstruction distances based on Talbot effect

Microtopography and Thickness Measurement with Digital Holographic Microscopy Highlighting and Its Tomographic Capacity

“…We can note this behavior in both amplitude and phase distributions. Additionally, and in agreement with simulations performed in [22], we can observe not only a phase shift of 180° and reversal amplitude attained in the reconstruction at z ht1 . An unfavorable anomaly, but usual, phase, and amplitude variances are presented in boundaries (edges) due to single diffraction order that does not superpose with other diffraction orders [27].…”

“…When u is odd the self-imaging has 180° phase shift and contrast reversal [16]. The same result can be present in a thin phase attenuated sinusoidal grating as we presented in [22]. …”

“…As we have been mentioned, Figure 18(a) shows a profile where the ringing effect appear with a period of u = 53 μm. This profile is comparable to a variable transmittance function (VTF) grating simulated, according to Goodman [16] and confirmed in previous simulations [22] with the 180° phase shift and contrast reversal of the field distribution at the first TPO (z td1 ) property. Next a second reconstruction was performed at z = z + z td1 = 88.7 mm with the same size of the filter.…”

“…The method is based on the natural diffraction of light (Talbot effect). We previously showed that for variable grating, Talbot phenomenon is also present [22]. When you use a binary filter in order to attain the object-wave in off-axis digital holography, this allows an easy implementation of filtering mask in the filtering process.…”

“…When you use the BtwLPF of second order, the ringing effect and the blurring is similar to that observed in the Gaussian filtering. Then the ringing increased, according to the order of the filter as we commented in [22].…”