Search results for " recognition"
showing 10 items of 3220 documents
Blocking by word frequency and neighborhood density in visual word recognition: A task-specific response criteria account
2004
International audience; Effects of blocking words by frequency class (high vs. low) and neighborhood density (high vs. low) were examined in two experiments using progressive demasking and lexical decision tasks. The aim was to examine the predictions of a task-specific response criteria account of list-blocking effects. Distinct patterns of blocking effects were obtained in the two tasks. In the progressive demasking task, a pure-list disadvantage was obtained to low frequency-high density words, whereas high frequency-low density produced a trend toward a pure-list advantage. In lexical decision, high-frequency words showed a pure-list advantage that was strongest in high-density words, w…
Phase information of time-frequency transforms as a key feature for classification of atrial fibrillation episodes
2015
[EN] Patients suffering from atrial fibrillation can be classified into different subtypes, according to the temporal pattern of the arrhythmia and its recurrence. Nowadays, clinicians cannot differentiate a priori between the different subtypes, and patient classification is done afterwards, when its clinical course is available. In this paper we present a comparison of classification performances when differentiating paroxysmal and persistent atrial fibrillation episodes by means of support vector machines. We analyze short surface electrocardiogram recordings by extracting modulus and phase features from several time-frequency transforms: short-time Fourier transform, Wigner-Ville, Choi-…
Does Bold Emphasis Facilitate the Process of Visual-Word Recognition?
2014
AbstractThe study of the effects of typographical factors on lexical access has been rather neglected in the literature on visual-word recognition. Indeed, current computational models of visual-word recognition employ an unrefined letter feature level in their coding schemes. In a letter recognition experiment, Pelli, Burns, Farell, and Moore-Page (2006), letters in Bookman boldface produced more efficiency (i.e., a higher ratio of thresholds of an ideal observer versus a human observer) than the letters in Bookman regular under visual noise. Here we examined whether the effect of bold emphasis can be generalized to a common visual-word recognition task (lexical decision: “is the item a wo…
Simulating Images Seen by Patients with Inhomogeneous Sensitivity Losses
2012
PURPOSE We aim to simulate how colored images are perceived by subjects with local achromatic and chromatic contrast sensitivity losses in the visual field (VF). METHODS The spatiochromatic corresponding pair algorithm, introduced in a previous article (J Opt Soc Am (A) 2004;21:176-186), has been implemented with a linear model of the visual system. Spatial information is processed separately by the chromatic and achromatic mechanisms by means of a multiscale model, with sensors selective to frequency, orientation, and spatial position, whose mechanism-dependent relative weights change with the spatial location of the image. These weights have been obtained from perimetric data from a patie…
Neural specialization to human faces at the age of 7 months.
2021
AbstractSensitivity to human faces has been suggested to be an early emerging capacity that promotes social interaction. However, the developmental processes that lead to cortical specialization to faces has remained unclear. The current study investigated both cortical sensitivity and categorical specificity through event-related potentials (ERPs) previously implicated in face processing in 7-month-old infants (N290) and adults (N170). Using a category-specific repetition/adaptation paradigm, cortical specificity to human faces, or control stimuli (cat faces), was operationalized as changes in ERP amplitude between conditions where a face probe was alternated with categorically similar or …
Quantifying stenosis in renal arteriograms: a fuzzy syntactic analysis.
1999
AbstractThe introduction of fuzzy logic improves a system for the automatic quantification of renal artery lesions seen in digital subtraction angiograms. A two-step approach has been followed. An earlier system based on non-fuzzy syntactic analysis provided a clear symbolic description of the stenotic lesions. Although this system worked correctly, it did not take into account the variability and uncertainty inherent to image processing and to knowledge on the reference diameter. This system has been improved by the introduction of fuzzy logic in the representation of the reference diameter. It provides a description of the stenosis in terms of fuzzy quantities. To illustrate the benefits …
A robust aerial image registration method using Gaussian mixture models
2014
Aerial image registration is one of the bases in many aerospace applications, such as aerial reconnaissance and aerial mapping. In this paper, we propose a novel aerial image registration algorithm which is based on Gaussian mixture models. First of all, considering the characters of the aerial images, the work uses a shape feature detector which computes the boundaries of regions with nearly the same gray-value to extract invariant feature. Then, a Gaussian mixture models (GMM) based image registration model is built and solved to estimate the transformation matrix between two aerial images. Furthermore, the proposed method is applied on real aerial images, and the results demonstrate the …
Compensatory strategies in processing facial emotions: evidence from prosopagnosia.
2006
We report data on the processing of facial emotion in a prosopagnosic patient (H.J.A.). H.J.A. was relatively accurate at discriminating happy from angry upright faces, but he performed at chance when the faces were inverted. Furthermore, with upright faces there was no configural interference effect on emotion judgements, when face parts expressing different emotions were aligned to express a new emergent emotion. We propose that H.J.A.'s emotion judgements relied on local rather than on configural information, and this local information was disrupted by inversion. A compensatory strategy, based on processing local face parts, can be sufficient to process at least some facial emotions.
Do transposed-letter effects occur across lexeme boundaries?
2006
A masked priming lexical decision experiment was conducted to examine whether or not assignment of letter position in a word can be influenced by lexeme boundaries. The experiment was run in Basque, which is a strongly agglutinating language with a high proportion of inflected and compound words. Nonword primes were created by transposing two nonadjacent letters that crossed or did not cross morphological boundaries. Specifically, we compared morphologically complex prime-target pairs (e.g., arbigide-ARGIBIDE) with orthographic controls (e.g., arkipide-ARGIBIDE; note that ARGIBIDE is a compound of ARGI + BIDE) and noncompound pairs (e.g., ortakila--ORKATILA) with orthographic controls (e.g.…
E-Hitz: A word frequency list and a program for deriving psycholinguistic statistics in an agglutinative language (Basque)
2007
We describe a Windows program that enables users to obtain a broad range of statistics concerning the properties of word and nonword stimuli in an agglutinative language (Basque), including measures of word frequency (at the whole-word and lemma levels), bigram and biphone frequency, orthographic similarity, orthographic and phonological structure, and syllable-based measures. It is designed for use by researchers in psycholinguistics, particularly those concerned with recognition of isolated words and morphology. In addition to providing standard orthographic and phonological neighborhood measures, the program can be used to obtain information about other forms of orthographic similarity, …