Maria Susana Avila-Garcia

Modified All-Fiber Fabry–Perot Interferometer and Its Refractive Index, Load, and Temperature Analyses

An all-fiber Fabry-Perot (FP) interferometer is proposed and validated by the arc splicing technique. By using conventional fiber and special hollow-core photonic crystal fiber, several FP cavities were formed at the conventional fiber tip using arc discharges. As a result of the interaction between these cavities, modified FP principle operation was obtained; and temperature, refractive index, and load analyses validated this operation modification. In addition, this all-fiber interferometer presents good resolution and sensitivity in each parameter examined. The structure offers compactness, robustness, high repeatability, and stability measurement.

Fast Parabola Detection Using Estimation of Distribution Algorithms

This paper presents a new method based on Estimation of Distribution Algorithms (EDAs) to detect parabolic shapes in synthetic and medical images. The method computes a virtual parabola using three random boundary pixels to calculate the constant values of the generic parabola equation. The resulting parabola is evaluated by matching it with the parabolic shape in the input image by using the Hadamard product as fitness function. This proposed method is evaluated in terms of computational time and compared with two implementations of the generalized Hough transform and RANSAC method for parabola detection. Experimental results show that the proposed method outperforms the comparative methods in terms of execution time about 93.61% on synthetic images and 89% on retinal fundus and human plantar arch images. In addition, experimental results have also shown that the proposed method can be highly suitable for different medical applications.

Ytterbium Fiber Laser Based on a Three Beam Optical Path Mach–Zehnder Interferometer

In this letter, a switchable ytterbium doped double cladding photonic crystal fiber (Yb-doped-DCPCF) laser based on a three optical path Mach-Zehnder interferometer (MZI) is presented. Here, the MZI with three-beam path was achieved by fusion splicing a segment of an Yb-doped-DCPCF between two pieces of single mode fibers. Moreover, in the proposed laser arrangement, the Yb-doped-DCPCF segment is acting simultaneously as the MZI and also as the gain medium. This laser can be switched to emit a single or double line by controlling the polarization state and it operates within the range from 1028 to 1033 nm. In addition, the laser emission has a linewidth of 0.07 nm and a single-mode suppression ratio of 40 dB. Finally, it is shown that the fiber laser arrangement is compact and robust and that requires a relativity simple fabrication procedure.

Implementation of a laser beam analyzer using the image acquisition card IMAQ (NI)

In this work we address our attention to the implementation of a beam analyzer. The software was designed under LabView, platform and using the Image Acquisition Card IMAQ of National Instruments. The objective is to develop a graphic interface which has to include image processing tools such as characteristic enhancement such as bright, contrast and morphologic operations and quantification of dimensions. An application of this graphic interface is like laser beam analyzer of medium cost, versatile, precise and easily reconfigurable under this programing environment.

A Novel Multiscale Gaussian-Matched Filter Using Neural Networks for the Segmentation of X-Ray Coronary Angiograms

The accurate and efficient segmentation of coronary arteries in X-ray angiograms represents an essential task for computer-aided diagnosis. This paper presents a new multiscale Gaussian-matched filter (MGMF) based on artificial neural networks. The proposed method consists of two different stages. In the first stage, MGMF is used for detecting vessel-like structures while reducing image noise. The results of MGMF are compared with those obtained using six GMF-based detection methods in terms of the area (Az) under the receiver operating characteristic (ROC) curve. In the second stage, ten thresholding methods of the state of the art are compared in order to classify the magnitude of the multiscale Gaussian response into vessel and nonvessel pixels, respectively. The accuracy measure is used to analyze the segmentation methods, by comparing the results with a set of 100 X-ray coronary angiograms, which were outlined by a specialist to form the ground truth. Finally, the proposed method is compared with seven state-of-the-art vessel segmentation methods. The vessel detection results using the proposed MGMF method achieved an Az = 0.9357 with a training set of 50 angiograms and Az = 0.9362 with the test set of 50 images. In addition, the segmentation results using the intraclass variance thresholding method provided a segmentation accuracy of 0.9568 with the test set of coronary angiograms.