Multiscale Image Segmentation Using Active Contours

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We present an application of the conformal mapping (CM) method to determine the magnetic field and force in an electromechanical actuator. First, we show how to find, using a special type of CM known as the Schwarz-Christoffel mapping, the magnetic field in such a configuration. Then, we integrate the field in order to determine the force acting on the actuator moving part. The results are verified by a finite-element method.

This paper proposes a rate-distortion optimal a posteriori quantization scheme for Matching Pursuit coefficients. The a posteriori quantization applies to a Matching Pursuit expansion that has been generated off-line, and cannot benefit of any feedback loop to the encoder in order to compensate for the quantization noise. The redundancy of the Matching Pursuit dictionary provides an indicator of the relative importance of coefficients and atom indices, and subsequently on the quantization error. It is used

This paper presents an improved tracking based method for retinal vessel segmentation that uses blood vessel morphology to adapt the tracking parameters. The method includes branching detection and avoidance methods. A bi-level threshold method, based on local vessel information, is used for segmentation. Tracking is based on Kalman filtering. The results are compared with existing ground truth. It is concluded that ground truth segmentation is not easily comparable.

A method and a microscopy imaging apparatus for generating an optically sectioned image of a specimen are provided. The method comprises the steps of:illuminating the specimen with a modulating, spatially periodic illumination pattern; imaging said specimen on a conjugate image plane; acquiring a plurality of signals at respective positions on said image plane, each signal corresponding to the incident light intensity at that position and having an oscillatory component caused by the modulation of the illum

Text embedded in images and videos represents a rich source of information for content-based indexing and retrieval applications. In this paper, we present a new method for localizing and recognizing text in complex images and videos. Text localization is performed in a two step approach that combines the speed of a focusing step with the strength of a machine learning based text verification step. The experiments conducted show that the support vector machine is more appropriate for the verification task t

In this study we describe an ambulatory system for estimation of spatio-temporal parameters during long periods of walking. This original method based on wavelet analysis is proposed to compute the values of temporal gait parameters from the angular velocity of lower limbs. Based on a mechanical model, the medio-lateral rotation of the lower limbs during stance and swing, the stride length and velocity are estimated by integration of the angular velocity. Measurement's accuracy was assessed using as a crite

Shadows are often integral parts of natural scenes and their identification is an important task in image analysis. In this paper, we propose an algorithm for recognition of shadows cast by objects on the scene's background. The proposed approach is based on the use of color information by means of photometric invariant color transformations. The method is divided into two levels: first, object and shadow edges are extracted from the RGB components and only object edges from the invariant features; then, ed

We propose a novel multiresolution-multigrid based signal reconstruction method from arbitrarily spaced samples. The signal is reconstructed on a uniform grid using B-splines basis functions. The computation of spline weights is formulated as a variational problem. Specifically, we minimize a cost that is a weighted sum of two terms: (i) the sum of squared errors at the specified points; (ii) a quadratic functional that penalizes the lack of smoothness. The problem is equivalent to solving a very large syst

This paper proposes a technique that segments into speaker turns based on their location, essentially implementing a discrete source tracking system. In many multi-party conversations, such as meetings or teleconferences, the location of participants is restricted to a small number of regions, such as seats around a table. In such cases, segmentation according to these discrete regions would be a reliable means of determining speaker turns. We propose a system that uses microphone pair time delays as featur

We present a method for the exact computation of the moments of a region bounded by a curve represented by a scaling function or wavelet basis. Using Green's Theorem, we show that the computation of the area moments is equivalent to applying a suitable multidimensional filter on the coefficients of the curve and thereafter computing a scalar product. The multidimensional filter coefficients are precomputed exactly as the solution of a two-scale relation. To demonstrate the performance improvement of the new

The aim of the proposed paper is to extend the well known complex torque coefficient method for synchronous machine rotor oscillations, to auxiliary devices (voltage regulators, power system stabilizers (PSS), ...) in electrical networks. To illustrate the effectiveness of the proposed extension, the study is performed on a model power system. Results obtained by this method are compared with those given, in the one hand, by an eigenvalue analysis, and in the other hand by numerical simultations.

We propose a new algorithm to find the corpus callosum automatically from midsagittal brain MR (magnetic resonance) images using the statistical characteristics and shape information of the corpus callosum. We first extract regions satisfying the statistical characteristics (gray level distributions) of the corpus callosum that have relatively high intensity values. Then we try to find a region matching the shape information of the corpus callosum. In order to match the shape information, we propose a new d

Multiscale Image Segmentation Using Active Contours

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Analyzing an electromechanical actuator by Schwarz-Christoffel mapping

A Posteriori Quantization of Progressive Matching Pursuit Streams

Vessel Segmentation and Branching Detection using an Adaptive Profile Kalman Filter in Retinal Blood Vessel Structure Analysis

Optically sectioned image generating method for microscopy imaging apparatus involves combining measured characteristics of signals from respective positions of conjugate image plane to generate optically sectioned image of specimen

Text Detection and Recognition in Images and Videos

Spatio-temporal parameters of gait measured by an ambulatory system using miniature gyroscopes

Cast Shadow Recognition in Color Images

Multigrid Image Reconstruction from Arbitrarily Spaced Samples

Location Based Speaker Segmentation

An Exact Method for Computing the Area Moments of Wavelet and Spline Curves

Extension of the Complex Torque Coefficient Method for Synchronous Generators to Auxiliary Devices in Electrical Networks.

Automated Segmentation of the Corpus Callosum in Midsagittal Brain Magnetic Resonance Images