High topographical accuracy by optical shot noise reduction in digital holographic microscopy.

In this work, we present a new method to reduce the shot noise in phase imaging of digital holograms. A spatial averaging process of phase images reconstructed at different reconstruction distances is performed, with the reconstruction distance range being specified by the numerical focus depth of the optical system. An improved phase image is attained with a 50% shot noise reduction. We use the integral of the angular spectrum as a reconstruction method to obtain a single-object complex amplitude that is needed to perform our proposal. We also show the corresponding simulations and experimental results. The topography of a homemade TiO2 stepwise of 100 nm high was measured and compared with the atomic force microscope results.

Dynamic 3-D shape measurement method based on quadrature transform.

In this work, it is presented a combination of temporal phase unwrapping technique and Fourier-based quadrature transform to obtain the dynamic phase map from a vibrating object. The proposed combination results on a very simple algorithm which allows an accurate and versatile 3D reconstruction of the object under analysis.

Experiencia en el manejo de lesiones quirurgicas de vía biliar / Experience in the management of surgical lesions biliary

Introducción: Las lesiones quirúrgicas de las vías biliares (LQVB) se definen como la detención del flujo biliar por ligadura, clipado o estenosis cicatricial, sección parcial o completa de la vía biliar principal o de los conductos biliares aberrantes. Objetivo: Describir la experiencia en el manejo de la lesión quirúrgica de la vía biliar en el Servicio de Cirugía del Hospital Nacional de Itauguá. Pacientes y método: Estudio retrospectivo, descriptivo, observacional de corte transverso,fueron incluidos los pacientes con lesión quirúrgica de la vía biliar atendidos en el Servicio de Cirugía General del Hospital Nacional de Itauguá entre marzo del 2010 hasta noviembre del 2015. Resultados: De los 29 casos de lesión de vía biliar, 25 casos fueron del sexo femenino y 4 del sexo masculino. El promedio de edad fue de 43 años, con una mínima de 17 y una máxima de 74 años. 21 de las lesiones fueron remitidos de otros centros hospitalarios. 14 casos durante cirugías programadas, 21 vía convencional y 8 vía laparoscópica. El diagnóstico intraoperatorio fue en 10 casos. En 14 casos las lesiones fueron complejas (mayor a 50% de la luz o asociada a lesión vascular) donde la reparación en estos pacientes fue la derivación Hepático yeyuno anastomosis en Y de Roux tipo Hepp-Couinaud. La mortalidad fue en 1 caso (3,4%)...

Introduction: Surgical lesions of the bile ducts (LQVB) are defined as the arrest of bile flow by ligation, clipping or scar stenosis, partial or complete bile duct or bile ducts abhorrent section. Objective: To describe the experience in the management of the surgical lesion of the bile in the surgery service of the National Hospital of Itauguá. Patients and methods: study retrospective, descriptive, observational transverse cut, they were included patients with surgical bile duct injury treated in General Surgery from the National Hospital of Itauguá service between March 2010 until November 2015. Results: Of the 29 cases of injury biliary tract, 25 cases were female and 4 male. The average age was 43 years, with a minimum of 17 and maximum of 74 years. 21 lesions were referred from other hospitals. 14 cases during elective surgery, 21 conventional route and 8 laparoscopically. The intraoperative diagnosis was in 10 cases. In 14 cases the lesions were complex (greater than 50% of the light or associated with vascular injury) where repair in these patients was the jejunum Hepático bypass anastomosis Roux-Y Hepp-Couinaud type. Mortality was 1 case (3.4%)...

Uncertainty analysis of displacements measured by in-plane electronic speckle-pattern interferometry with spherical wave fronts.

Displacement measurements by optical interferometry depend on the induced phase difference and on the interferometer's sensitivity vector; the latter depends in turn on the illuminating sources and on the geometry of the optical arrangement. We have performed an uncertainty analysis of the in-plane displacements measured by electronic speckle-pattern interferometry with spherical incident wave fronts. We induced the displacements by applying a uniaxial tensile load on a nominally flat elastic sample. We approached the displacement uncertainty by propagating the uncertainties that we considered reasonable to assign to the measured phase difference and to the characteristic parameters of the interferometer's sensitivity vector. Special attention was paid to evaluating contributions to the displacement uncertainty. Moreover, we observed that the uncertainty decreases if the angles of incidence and the source-target distances are increased.

Quadratic cost functional for wave-front reconstruction.

A quadratic cost functional for reconstruction of a high-resolution wave front from a coarse wave front is presented. The functional uses as data the position and the direction of the coarse wave front that had previously been computed with a ray-tracing method. This functional uses an optical relationship between the ray information and the wave front's shape to reconstruct a high-density wave front. The performance of the proposed functional is illustrated by reconstruction of complicated wave fronts for which this functional has an accuracy that is superior to that of conventional interpolation methods.

Three-dimensional deformation measurement from the combination of in-plane and out-of-plane electronic speckle pattern interferometers.

An optical setup that can be switched to produce in-plane and out-of-plane sensitivity interferometers was designed for three-dimensional deformation measuring by electronic speckle pattern interferometry. Divergent illumination is considered in the evaluation of sensitivity vectors to measure both in-plane and out-of-plane displacement components. The combination of these interferometers presents the advantage of greater sensitivity in directions u, v, and w than a typical interferometer with three illumination beams provides. The system and its basic operation are described, and results with an elastic target that is exposed to a mechanical load are reported.

Development in situ for gratings recorded in photoresist.

A technique for developing recording gratings in situ in Photoresist Shipley S-1822 is described. The developing process is accomplished by use of a spray without removing the sample from the optical setup. The results for the diffraction efficiency show that there is not a large difference between gratings achieved with the traditional wet development process and those obtained with the in situ developing technique. The potential of this in situ developing technique is shown with a moiré interferometric experimental setup used for displacement showing.