The reconstruction of the object surface with inherently discontinuous regions is usually a difficult problem by using
standard phase unwrapping technique i.e. the spatial unwrapping. To recover the range data of such a surface, Huntley
and Saldner recently proposed a temporal phase unwrapping procedure (TPUP) and Peng X. et al. based on their work
proposed an enhanced recursive scheme for the TPUP. However the phase jumps no necessarily they correspond to
multiples of 2pi exactly. Due to this, an enhanced scheme for temporal unwrapping in order to increase its efficiency is
introduced. Additionally, we present some results obtained by mean of temporal unwrapping and spatial unwrapping, in
order to compare them and to demonstrate the effectiveness of the temporal unwrapping.
In image processing, the wavelet transform is useful to enhance the local features of images, so that, the correlation of a target with a reference signal can be improved by wavelet filtering. The wavelet filtering operation and correlation can be photorefractively performed if a crystal is used as a dynamic holographic recording medium. In particular, the sillenite family of photorefractive crystals have a high photosensitivity and high carrier mobility which allow a fast response that makes them attractive for real-time image processing and optical phase conjugation. We analyze a real-time wavelet-matched optical correlator using phase conjugation in a four-wave mixing arrangement. The robustness of the correlator to the noise due the finite crystal depth is improved using a proper wavelet filter.
We present a computational model to analyze the electromagnetic contribution to Surface Enhanced Raman Scattering (SERS) based on Lorenz-Mie scattering for a single metal spherical particle covered by a shell of molecules, immerse, all the system, in a dielectric medium. In the model, all molecules are assumed to be an electrical dipole at fixed direction: the same of the linear polarization of the exciting plane electromagnetic field. The volume occupied for the molecules is twice the volume of the particle. A constant radial of molecular density is considered. The enhancement factor, EF is defined as the ratio of the total scattered power by the system particle-molecules to the total scattered power by the same distribution of molecules in the same dielectric medium. We study the EF for particles with radii between zero and 350 nm. Three wavelengths are used: 532, 633 and 382 nm. A comparative analysis between particles of copper, aurum and silver is presented. The 459 cm<sup>-1</sup> Stokes line of carbon tetrachloride is studied.
An algorithm based on image processing for detecting local defects in fabrics is presented. These defects may be considered as broken threads or double yarns, which can be viewed as straight lines in the fabric's background. Their detection is performed using the Radon transform on images previously preprocessed.
The chromatic confocal method to measure the refractive index and thickness of membranes is developed. The method is based on the longitudinal chromatic aberration produced by a diffractive element. The identification of the maximal spectral components coming from the membranes are used for measuring its thickness or its refractive index.
An analysis of the axial resolution of a chromatic dispersion confocal microscopy is presented. The system is based on the principle of focus multiplexing by wavelength encoding due to a phase Fresnel lens. The axial resolution is related with the measure of the FWHM value of every spectral response.
In this paper a dynamic method of analysis of the reflectance is presented starting form a polychromatic interferometric system that allows establishing the conte of materials to microscopic scale. The reflectance of the material is obtained starting from the distribution of intensities in the optical contact of an interferometric microscopic, where a device that can carry out displacement of the order of the nanometers in axial address was adapted, the interference pattern detection was carried out with a CCD in color. The determination of the local reflectivity realizes the presence of the materials that form the sample to microscopic, scale; given the nano technologies peak this method will allow to characterize with more resolution the composition of new materials.