Search results for " Pattern recognition"
showing 10 items of 1050 documents
Unsupervised low-key image segmentation using curve evolution approach
2013
Low-key images widely exist in imaging-based systems such as space telescopes, medical imaging equipment, machine vision systems. Unsupervised low-key image segmentation is an important process for image analysis or digital measurement in these applications. In this paper, a novel active contour model with the probability density function (PDF) of gamma distribution for image segmentation is proposed. The flexible gamma distribution is used to describe both of the heterogeneous foreground and dark background in a low-key image. Besides, an unsupervised curve initialization method is also designed in this paper, which helps to accelerate the convergence speed of curve evolution. The effectiv…
Remote sensing image segmentation by active queries
2012
Active learning deals with developing methods that select examples that may express data characteristics in a compact way. For remote sensing image segmentation, the selected samples are the most informative pixels in the image so that classifiers trained with reduced active datasets become faster and more robust. Strategies for intelligent sampling have been proposed with model-based heuristics aiming at the search of the most informative pixels to optimize model's performance. Unlike standard methods that concentrate on model optimization, here we propose a method inspired in the cluster assumption that holds in most of the remote sensing data. Starting from a complete hierarchical descri…
An architecture for autonomous agents exploiting conceptual representations
1998
An architecture for autonomous agents is proposed that integrates the functional and the behavioral approaches to robotics. The integration is based on the introduction of a conceptual level, linking together a subconceptual, behavioral, level, and a linguistic level, encompassing symbolic representation and data processing. The proposed architecture is described with reference to an experimental setup, in which the robot task is that of building a significant description of its working environment. © 1998 Elsevier Science B.V. All rights reserved.
A context-aware approach for long-term behavioural change detection and abnormality prediction in ambient assisted living
2015
This research aims to describe pattern recognition models for detecting behavioural and health-related changes in a patient who is monitored continuously in an assisted living environment. The early anticipation of anomalies can improve the rate of disease prevention. Here we present different learning techniques for predicting abnormalities and behavioural trends in various user contexts. In this paper we described a Hidden Markov Model based approach for detecting abnormalities in daily activities, a process of identifying irregularity in routine behaviours from statistical histories and an exponential smoothing technique to predict future changes in various vital signs. The outcomes of t…
Data-based modeling of vehicle crash using adaptive neural-fuzzy inference system
2014
Vehicle crashes are considered to be events that are extremely complex to be analyzed from the mathematical point of view. In order to establish a mathematical model of a vehicle crash, one needs to consider various areas of research. For this reason, to simplify the analysis and improve the modeling process, in this paper, a novel adaptive neurofuzzy inference system (ANFIS-based) approach to reconstruct kinematics of colliding vehicles is presented. A typical five-layered ANFIS structure is trained to reproduce kinematics (acceleration, velocity, and displacement) of a vehicle involved in an oblique barrier collision. Subsequently, the same ANFIS structure is applied to simulate different…
Assessing the Relationship Between Attitudinal and Perceptual Component of Body Image Disturbance Using Virtual Reality
2018
Body image disturbance (BID) affects quality of life even in the absence of clinically diagnosable eating pathology, and numerous studies have shown its crucial role in the emergence and maintenance of eating disorders. This study aimed at exploring attitudinal and perceptual components of BID using a novel virtual reality (VR)-based paradigm. A community sample of women (N = 27) recreated in VR their perceived body in both an allocentric (third-person view) and egocentric (first-person view) perspective. Specifically, women were able to choose between a wide range of three-dimensional bodies spanning body mass index 12.5-42.5 kg/m2. Attitudinal indexes of BID (body dissatisfaction, body un…
Evidence for a spatial bias in the perception of sequences of brief tones
2013
Listeners are unable to report the physical order of particular sequences of brief tones. This phenomenon of temporal dislocation depends on tone durations and frequencies. The current study empirically shows that it also depends on the spatial location of the tones. Dichotically testing a three-tone sequence showed that the central tone tends to be reported as the first or the last element when it is perceived as part of a left-to-right motion. Since the central-tone dislocation does not occur for right-to-left sequences of the same tones, this indicates that there is a spatial bias in the perception of sequences. © 2013 Acoustical Society of America.
Recollection and familiarity in hippocampal amnesia
2008
Currently, there is a general agreement that two distinct cognitive operations, recollection and familiarity, contribute to performance on recognition memory tests. However, there is a controversy about whether recollection and familiarity reflect different memory processes, mediated by distinct neural substrates (dual-process models), or whether they are the expression of memory traces of different strength in the context of a unitary declarative memory system (unitary-strength models). Critical in this debate is the status of recognition memory in hippocampal amnesia and, in particular, whether the various structures in the medial temporal lobe (MTL) contribute differentially to the recol…
Effect of luminance on photopic visual acuity in the presence of laser speckle
1988
Visual acuity in coherent and incoherent light has been determined by using square-wave gratings of 100% contrast. Luminance was varied from 3 to 400 cd/m2. Coherent illumination resulted in a 40% loss of visual acuity. This is probably due to the masking effect of coherent spatial noise (speckle). However, the most interesting finding is the change in shape of the photopic visual-acuity-luminance function. With coherent illumination, the function is vertically displaced and of a different gradient. An increase in luminance produces a decrease in visual acuity. This indicates that the masking effect of the speckle is dependent on luminance. Two observers were used, and similar results were …
Testing the egocentric mirror-rotation hypothesis.
2011
AbstractAlthough observers know about the law of reflection, their intuitive understanding of spatial locations in mirrors is often erroneous. Hecht et al. (2005) proposed a two-stage mirror-rotation hypothesis to explain these misconceptions. The hypothesis involves an egocentric bias to the effect that observers behave as if the mirror surface were rotated by about 2° to be more orthogonal than is the case. We test four variants of the hypothesis, which differ depending on whether the virtual world, the mirror, or both are taken to be rotated. We devised an experimental setup that allowed us to distinguish between these variants. Our results confirm that the virtual world — and only the v…