Search results for " processing"

Multispectral integral imaging acquisition and processing using a monochrome camera and a liquid crystal tunable filter

2012

This paper presents an acquisition system and a procedure to capture 3D scenes in different spectral bands. The acquisition system is formed by a monochrome camera, and a Liquid Crystal Tunable Filter (LCTF) that allows to acquire images at different spectral bands in the [480, 680]nm wavelength interval. The Synthetic Aperture Integral Imaging acquisition technique is used to obtain the elemental images for each wavelength. These elemental images are used to computationally obtain the reconstruction planes of the 3D scene at different depth planes. The 3D profile of the acquired scene is also obtained using a minimization of the variance of the contribution of the elemental images at each …

The comparison of reliabilities in dental imaging methods.

2003

Objectives: Common practice in the statistical comparison of imaging instruments with limited reproducibility consists in the separate estimation of the instrument's reliabilities. However, as soon as one of the imaging methods is subject to item-specific bias (which has to be expected in many dentomaxillofacial imaging procedures), this approach will end in severe errors in reliability computation and in corresponding erroneous clinical conclusions. This paper seeks to point out these effects and to illustrate a more appropriate model for the comparison of instrumental reliabilities. Methods: A standard reliability model was adjusted for item-specific bias and illustrated by the comparison…

Coronary artery anomalies: incidence, pathophysiology, clinical relevance and role of diagnostic imaging

2006

Conventional coronary angiography is the gold standard for the diagnosis of coronary artery anomalies. Coronary anomalies are relatively rare findings in patients undergoing conventional coronary angiography for suspected obstructive coronary artery disease. Recently, the increasing performance of diagnostic techniques, such as electron beam tomography (EBT), magnetic resonance (MR) and, more recently, multislice computed tomography (MSCT), has enabled their application to cardiac imaging. MSCT, in particular, has a prominent role in coronary imaging due to its spatial and temporal resolution and three-dimensional capabilities. We report the incidence and pathophysiology of coronary artery …

Generative Adversarial Networks in Cardiology

2021

A B S T R A C T Generative Adversarial Networks (GANs) are state-of-the-art neural network models used to synthesize images and other data. GANs brought a considerable improvement to the quality of synthetic data, quickly becoming the standard for data generation tasks. In this work, we summarize the applications of GANs in the field of cardiology, including generation of realistic cardiac images, electrocardiography signals, and synthetic electronic health records. The utility of GAN-generated data is discussed with respect to research, clinical care, and academia. Moreover, we present illustrative examples of our GAN-generated cardiac magnetic resonance and echocardiography images, showin…

Three-dimensional visualization of the human embryo: a potential revolution in prenatal diagnosis

1996

Hidden Markov random field model and Broyden–Fletcher–Goldfarb–Shanno algorithm for brain image segmentation

2018

International audience; Many routine medical examinations produce images of patients suffering from various pathologies. With the huge number of medical images, the manual analysis and interpretation became a tedious task. Thus, automatic image segmentation became essential for diagnosis assistance. Segmentation consists in dividing the image into homogeneous and significant regions. We focus on hidden Markov random fields referred to as HMRF to model the problem of segmentation. This modelisation leads to a classical function minimisation problem. Broyden-Fletcher-Goldfarb-Shanno algorithm referred to as BFGS is one of the most powerful methods to solve unconstrained optimisation problem. …

On the terminology of voice research

1993

Summary This article reviews problems associated with establishment of a scientifically accurate, internationally recognized, multilingual terminology to describe voice. Two strategies for developing terminology are discussed: consensus and dictation. Ontological decisions are considered an integral part of developing terminology. We conclude that terminological problems should be solved by a terminological committee—as yet to be established—as they average from problems in interpreting the literature and the results of voice research. A comprehensive bibliography and audio tape of the multilingual terminology describing voice would help facilitate adaptation and understanding of the terms …

Multi-level contrast filtering in image difference metrics

2013

In this paper, we present a new metric to estimate the perceived difference in contrast between an original image and a reproduction. This metric, named weighted-level framework Δ E E (WLF-DEE), implements a multilevel filtering based on the difference of Gaussians model proposed by Tadmor and Tolhurst (2000) and the new Euclidean color difference formula in log-compressed OSA-UCS space proposed by Oleari et al. (2009). Extensive tests and analysis are presented on four different categories belonging to the well-known Tampere Image Database and on two databases developed at our institution, providing different distortions directly related to color and contrast. Comparisons in performance wi…

Purification of Large Cytosolic Proteases for In Vitro Assays: 20S and 26S Proteasomes

2012

Proteasomes are the main cytosolic proteases responsible for generating peptides for antigen processing and presentation in the MHC (major histocompatibility complex) class-I pathway. Purified 20S and 26S proteasomes have been widely used to study both specificity and efficiency of antigen processing. Here, we describe the purification of active human 20S and 26S proteasomes from human erythrocytes by DEAE-ion exchange chromatography, ammonium sulfate precipitation, glycerol density gradient centrifugation, and Superose-6 size exclusion chromatography and their characterization using fluorogenic substrates and specific inhibitors.

Conformation constraints for efficient viscoelastic fluid simulation

2017

The simulation of high viscoelasticity poses important computational challenges. One is the difficulty to robustly measure strain and its derivatives in a medium without permanent structure. Another is the high stiffness of the governing differential equations. Solutions that tackle these challenges exist, but they are computationally slow. We propose a constraint-based model of viscoelasticity that enables efficient simulation of highly viscous and viscoelastic phenomena. Our model reformulates, in a constraint-based fashion, a constitutive model of viscoelasticity for polymeric fluids, which defines simple governing equations for a conformation tensor. The model can represent a diverse pa…