Speckle denoising by variant nonlocal means methods.

This study aims to demonstrate the performances of nonlocal means (NLM) and their variant denoising methods, mainly focusing on NLM-shaped adaptive patches and several NLM-reprojection schemes for speckle noise reduction in amplitude and phase images of the digital coherent imaging systems. In the digital coherent imaging systems such as digital speckle pattern interferometry, digital holographic interferometry, etc., the image quality is severely degraded by additive uncorrelated speckle noise, due to the coherent nature of the light source, and therefore limits the development of several applications of these imaging systems in many fields.

Digital four-step phase-shifting technique from a single fringe pattern using Riesz transform.

A digital four-step phase-shifting method for obtaining the optical phase distribution from a single fringe pattern is proposed in this Letter. By computing the first-, second-, and third-order Riesz transform components for a given fringe pattern, three π/2 phase-shifted fringe patterns are generated from the obtained Riesz components and, finally, the wrapped phase map is extracted. The validity of the proposed method is demonstrated on both the simulated and experimentally obtained fringe patterns.

Speckle noise reduction in digital speckle pattern interferometric fringes by nonlocal means and its related adaptive kernel-based methods.

Digital speckle pattern interferometry (DSPI) is widely used in many scientific and industrial applications. Besides its several advantages, one of the basic problems encountered in DSPI is the undesired speckle noise existing in the fringe pattern. In this paper, we demonstrate the performance of nonlocal means (NLM) and its related adaptive kernel-based filtering methods for speckle noise reduction in DSPI fringes.

Local production of IgG and IgG subclasses in the aqueous humor of patients with Fuchs heterochromic cyclitis, herpetic uveitis and toxoplasmic chorioretinitis.

Changes in local immunity are important when considering the physiopathology of uveitis. The aim of this study was to measure IgG and IgG subclass concentrations in the serum and the AH of patients with three different types of uveitis and to determine for each of them the presence of a local production of IgG in the intra-ocular compartment. This investigation was extended to IgG subclasses.

Amsler's sign associated significantly with Fuch's heterochromic cyclitis (FHC).

To investigate the frequency and diagnostic significance of Amsler's sign in patients with Fuch's heterochromic cyclitis (FHC), we performed a diagnostic AC puncture of the eyes of 31 patients with this disease and looked for the same sign in 104 patients with intermediate uveitis and 373 patients with various other types of uveitis who underwent the same procedure. AS was significantly more frequent in the FHC patients than in either of the other two groups of patients, and occurred infrequently in all other types of chronic uveitis. We therefore consider its occurrence to have important differential diagnostic value.