Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63.749
Filtrar
1.
Nat Commun ; 12(1): 5234, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34475391

RESUMO

In spite of the reduced visual acuity, parafoveal information plays an important role in natural reading. However, competing models on reading disagree on whether words are previewed parafoveally at the lexical level. We find neural evidence for lexical parafoveal processing by combining a rapid invisible frequency tagging (RIFT) approach with magnetoencephalography (MEG) and eye-tracking. In a silent reading task, target words are tagged (flickered) subliminally at 60 Hz. The tagging responses measured when fixating on the pre-target word reflect parafoveal processing of the target word. We observe stronger tagging responses during pre-target fixations when followed by low compared with high lexical frequency targets. Moreover, this lexical parafoveal processing is associated with individual reading speed. Our findings suggest that reading unfolds in the fovea and parafovea simultaneously to support fluent reading.


Assuntos
Macula Lutea/fisiologia , Leitura , Movimentos Oculares/fisiologia , Feminino , Fixação Ocular/fisiologia , Fóvea Central/fisiologia , Humanos , Masculino , Modelos Neurológicos , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
2.
Dev Psychol ; 57(7): 1025-1041, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34435820

RESUMO

We extend decades of research on infants' visual processing by examining their eye gaze during viewing of natural scenes. We examined the eye movements of a racially diverse group of 4- to 12-month-old infants (N = 54; 27 boys; 24 infants were White and not Hispanic, 30 infants were African American, Asian American, mixed race and/or Hispanic) as they viewed images selected from the MIT Saliency Benchmark Project. In general, across this age range infants' fixation distributions became more consistent and more adult-like, suggesting that infants' fixations in natural scenes become increasingly more systematic. Evaluation of infants' fixation patterns with saliency maps generated by different models of physical salience revealed that although over this age range there was an increase in the correlations between infants' fixations and saliency, the amount of variance accounted for by salience actually decreased. At the youngest age, the amount of variance accounted for by salience was very similar to the consistency between infants' fixations, suggesting that the systematicity in these youngest infants' fixations was explained by their attention to physically salient regions. By 12 months, in contrast, the consistency between infants was greater than the variance accounted for by salience, suggesting that the systematicity in older infants' fixations reflected more than their attention to physically salient regions. Together these results show that infants' fixations when viewing natural scenes becomes more systematic and predictable, and that predictability is due to their attention to features other than physical salience. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Fixação Ocular , Percepção Visual , Adulto , Idoso , Terapia Comportamental , Cognição , Movimentos Oculares , Humanos , Lactente , Masculino
3.
Acta Psychol (Amst) ; 219: 103375, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34333278

RESUMO

Subsequent search misses (SSM) refer to the decrease in accuracy of second target detection in dual-target visual search. One of the theoretical explanations of SSM errors is similarity bias - the tendency to search for similar targets and to miss the dissimilar ones. The current study focuses on both perceptual and categorical similarity and their individual roles in SSM. Five experiments investigated the role of perceptual and categorical similarity in subsequent search misses, wherein perceptual and categorical similarities were manipulated separately, and task relevance was controlled. The role of both perceptual and categorical similarity was revealed, however, the categorical similarity had greater impact on second target detection. The findings of this research suggest the revision of the traditional perceptual set hypothesis that mainly focuses on perceptual target similarity in multiple target visual search.


Assuntos
Atenção , Reconhecimento Visual de Modelos , Viés , Humanos , Percepção Visual
4.
Sensors (Basel) ; 21(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34372413

RESUMO

Gaze movement and visual stimuli have been utilized to analyze human visual attention intuitively. Gaze behavior studies mainly show statistical analyses of eye movements and human visual attention. During these analyses, eye movement data and the saliency map are presented to the analysts as separate views or merged views. However, the analysts become frustrated when they need to memorize all of the separate views or when the eye movements obscure the saliency map in the merged views. Therefore, it is not easy to analyze how visual stimuli affect gaze movements since existing techniques focus excessively on the eye movement data. In this paper, we propose a novel visualization technique for analyzing gaze behavior using saliency features as visual clues to express the visual attention of an observer. The visual clues that represent visual attention are analyzed to reveal which saliency features are prominent for the visual stimulus analysis. We visualize the gaze data with the saliency features to interpret the visual attention. We analyze the gaze behavior with the proposed visualization to evaluate that our approach to embedding saliency features within the visualization supports us to understand the visual attention of an observer.


Assuntos
Movimentos Oculares , Fixação Ocular , Humanos , Movimento , Percepção Visual
5.
J Bodyw Mov Ther ; 27: 676-681, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34391306

RESUMO

INTRODUCTION: Stroke patients often exhibit an altered perception of verticality, but there are no studies evaluating verticality perception in the first 72 h after stroke and its relationship with trunk control. Therefore, this study aimed to analyze visual and haptic verticality in the acute phase of stroke. METHODS: This was a cross-sectional study conducted with two groups: (a) 13 individuals with stroke and (b) 12 healthy participants. We assessed verticality via the subjective visual vertical (SVV) and the subjective haptic vertical (SHV); and we measured trunk control with the Trunk Impairment Scale (TIS). We performed t-tests to compare the SVV and SHV between groups. Pearson correlation was performed between verticality tests with National Institutes of Health Stroke Scale (NIHSS) and the TIS. RESULTS: Participants with recent stroke presented higher true and absolute SVV deviation values than did the control group. There was significant negative correlation between absolute (r = -0.57; p = 0.02) and true SVV (r = -0.54; p = 0.01) with TIS scores There was also significant positive correlation between absolute (r = 0.63; p = 0.009) and true SVV (r = 0.61; p = 0.003) with NIHSS. A significant negative correlation between NIHSS and TIS scores also was found (r = -0.80; p = 0.005). CONCLUSION: Individuals with acute stroke presented larger variability in their perceptions of visual verticality than did healthy controls, and verticality perceptions were positively correlated with trunk impairment.


Assuntos
Acidente Vascular Cerebral , Percepção Visual , Estudos Transversais , Voluntários Saudáveis , Humanos , Percepção Espacial , Estados Unidos
6.
BMC Ecol Evol ; 21(1): 151, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34344323

RESUMO

BACKGROUND: Crypsis by background-matching is a critical form of anti-predator defence for animals exposed to visual predators, but achieving effective camouflage in patchy and variable natural environments is not straightforward. To cope with heterogeneous backgrounds, animals could either specialise on particular microhabitat patches, appearing cryptic in some areas but mismatching others, or adopt a compromise strategy, providing partial matching across different patch types. Existing studies have tested the effectiveness of compromise strategies in only a limited set of circumstances, primarily with small targets varying in pattern, and usually in screen-based tasks. Here, we measured the detection risk associated with different background-matching strategies for relatively large targets, with human observers searching for them in natural scenes, and focusing on colour. Model prey were designed to either 'specialise' on the colour of common microhabitat patches, or 'generalise' by matching the average colour of the whole visual scenes. RESULTS: In both the field and an equivalent online computer-based search task, targets adopting the generalist strategy were more successful in evading detection than those matching microhabitat patches. This advantage occurred because, across all possible locations in these experiments, targets were typically viewed against a patchwork of different microhabitat areas; the putatively generalist targets were thus more similar on average to their various immediate surroundings than were the specialists. CONCLUSIONS: Demonstrating close agreement between the results of field and online search experiments provides useful validation of online citizen science methods commonly used to test principles of camouflage, at least for human observers. In finding a survival benefit to matching the average colour of the visual scenes in our chosen environment, our results highlight the importance of relative scales in determining optimal camouflage strategies, and suggest how compromise coloration can succeed in nature.


Assuntos
Pigmentação , Comportamento Predatório , Animais , Meio Ambiente , Humanos , Especialização , Percepção Visual
7.
Accid Anal Prev ; 159: 106273, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34218196

RESUMO

Perceptual markings on roads are verified with short-term effectiveness for accident prevention. However, the long-term performance of them is seldomly investigated, which unintentionally impedes its more widely recognition and application as a low-cost and readily achievable countermeasure. Also, the previous perceptual markings were only tested for speed reduction effect, little is known concerning their influence on headway adjustment. Given this, in this study, we investigated the short-, medium-, and long-term performance of the reverse linear perspective markings (RLPMs) on driving behaviors and safety benefits in car-following. The RLPMs were a form of markings pattern that can produce reverse linear perspective visual information on the lane and lead to distance underestimation. The RLPMs were permanently installed on a straight and a curve segment of a freeway in China, and the naturalistic vehicle flow data one day, four months, one year, two years, and three years after the installation of the RLPMs were collected. The statistical analyses of general and sectional relative differences of speed, distance headway and time headway suggest that 1) the speed reduced and distance and time headways increased in short-, medium-, and long-term as compared with the baseline on both the straight and curve segments; 2) the long-term performance of RLPMs significantly weakened as compared with the short-term performance, yet sustained to 0.50 m/s in speed reduction, 3.77 m in distance headway increase, and 0.097 s in time headway increase on average within the observations in one year and above on the straight segment; similar sustained performance of 0.47 m/s in speed reduction, 2.60 m in distance headway increase, and 0.072 s in time headway increase were observed on the curve segment; 3) the RLPMs were tested to have positive and relatively endured effectiveness on mitigating crash risk in car-following measured by two surrogate safety indicators based on time-to-crash (TTC) and deceleration rate to avoid a crash (DRAC). The findings of this study suggest the RLPMs could be an especially applaudable form of perceptual markings as they are relatively effective in the long-term and are multifunctional in intervening speed, distance, headway, and crash risk. This study also emphasizes the challenge of more field tests and observations on the long-term performance of the perceptual markings, and the thorough considerations of the visual perception mechanism behind the markings to achieve an alternative solution to the long-term issue.


Assuntos
Condução de Veículo , Automóveis , Prevenção de Acidentes , Acidentes de Trânsito/prevenção & controle , Humanos , Percepção Visual
8.
Appl Ergon ; 97: 103522, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34261002

RESUMO

Recent research has developed two eye-controlled highlighting techniques, namely, block highlight display (BHD) and single highlight display (SHD), that enhance information presentation based on a user's current gaze position. The present research aimed to investigate how these techniques facilitate mental processing of users' visual search in high information-density visual environments. In Experiment 1, 60 participants performed 3-, 6-, 9-, and 12-icon visual search tasks. The search times significantly increased as the number of icons increased with the SHD but not with the BHD. In Experiment 2, 40 participants performed a 49-icon visual search task. The search time was faster, and the fixation spatial density was lower with the BHD than with the SHD. These results suggested that the BHD supported parallel processing in the highlighted area and serial processing in the broader display area; thus, the BHD improved search performance compared to the SHD, which primarily supported serial processing.


Assuntos
Percepção Visual , Humanos , Tempo de Reação
9.
Appl Ergon ; 97: 103524, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34284281

RESUMO

Everyday we consume massive amounts of visual information on mobile devices like smartphones. However, are there consequences for viewing information on these devices? In 2 experiments, participants viewed several target objects on two differently sized virtual smartphone displays, and then made a judgment of the size of each target item. Results from both experiments confirm that smartphone display size does impact user perceptions of size, such that larger displays cause users to significantly underestimate the size of objects. This effect held when target items were presented alone, or concurrently with a non-target referent. This is the first study to confirm such an effect and suggests that the size of a smartphone display can negatively influence the accuracy of users' visual perception. Thus, beyond aesthetics or cost, it must be realized that the choice of device might have additional perceptual consequences for consumers.


Assuntos
Smartphone , Percepção Visual , Computadores de Mão , Humanos , Julgamento
11.
Neuroscience ; 472: 1-10, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34311017

RESUMO

Lifelong auditory and visual sensory deprivation have been demonstrated to alter both perceptual acuity and the neural processing of remaining senses. Recently, it was demonstrated that individuals with anosmia, i.e. complete olfactory sensory deprivation, displayed enhanced multisensory integration performance. Whether this ability is due to a reorganization of olfactory processing regions to focus on cross-modal multisensory information or whether it is due to enhanced processing within multisensory integration regions is not known. To dissociate these two outcomes, we investigated the neural processing of dynamic audio-visual stimuli in individuals with congenital anosmia and matched controls (both groups, n = 33) using functional magnetic resonance imaging. Specifically, we assessed whether the previously demonstrated multisensory enhancement is related to cross-modal processing of multisensory stimuli in olfactory associated regions, the piriform and olfactory orbitofrontal cortices, or enhanced multisensory processing in established multisensory integration regions, the superior temporal and intraparietal sulci. No significant group differences were found in the a priori hypothesized regions using region of interest analyses. However, exploratory whole-brain analysis suggested higher activation related to multisensory integration within the posterior superior temporal sulcus, in close proximity to the multisensory region of interest, in individuals with congenital anosmia. No group differences were demonstrated in olfactory associated regions. Although results were outside our hypothesized regions, combined, they tentatively suggest that enhanced processing of audio-visual stimuli in individuals with congenital anosmia may be mediated by multisensory, and not primary sensory, cerebral regions.


Assuntos
Privação Sensorial , Percepção Visual , Estimulação Acústica , Percepção Auditiva , Mapeamento Encefálico , Humanos , Imageamento por Ressonância Magnética , Estimulação Luminosa , Olfato
12.
Exp Brain Res ; 239(8): 2635-2648, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34216231

RESUMO

Visual transients can interrupt overt orienting by abolishing the execution of a planned eye movement due about 90 ms later, a phenomenon known as saccadic inhibition (SI). It is not known if the same inhibitory process might influence covert orienting in the absence of saccades, and consequently alter visual perception. In Experiment 1 (n = 14), we measured orientation discrimination during a covert orienting task in which an uninformative exogenous visual cue preceded the onset of an oriented probe by 140-290 ms. In half of the trials, the onset of the probe was accompanied by a brief irrelevant flash, a visual transient that would normally induce SI. We report a time-dependent inhibition of covert orienting in which the irrelevant flash impaired orientation discrimination accuracy when the probe followed the cue by 190 and 240 ms. The interference was more pronounced when the cue was incongruent with the probe location, suggesting an impact on the reorienting component of the attentional shift. In Experiment 2 (n = 12), we tested whether the inhibitory effect of the flash could occur within an earlier time range, or only within the later, reorienting range. We presented probes at congruent cue locations in a time window between 50 and 200 ms. Similar to Experiment 1, discrimination performance was altered at 200 ms after the cue. We suggest that covert attention may be susceptible to similar inhibitory mechanisms that generate SI, especially in later stages of attentional shifting (> 200 ms after a cue), typically associated with reorienting.


Assuntos
Atenção , Movimentos Sacádicos , Sinais (Psicologia) , Movimentos Oculares , Humanos , Tempo de Reação , Percepção Visual
13.
Sensors (Basel) ; 21(14)2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34300382

RESUMO

Both physiological and neurological mechanisms are reflected in pupillary rhythms via neural pathways between the brain and pupil nerves. This study aims to interpret the phenomenon of motion sickness such as fatigue, anxiety, nausea and disorientation using these mechanisms and to develop an advanced non-contact measurement method from an infrared webcam. Twenty-four volunteers (12 females) experienced virtual reality content through both two-dimensional and head-mounted device interpretations. An irregular pattern of the pupillary rhythms, demonstrated by an increasing mean and standard deviation of pupil diameter and decreasing pupillary rhythm coherence ratio, was revealed after the participants experienced motion sickness. The motion sickness was induced while watching the head-mounted device as compared to the two-dimensional virtual reality, with the motion sickness strongly related to the visual information processing load. In addition, the proposed method was verified using a new experimental dataset for 23 participants (11 females), with a classification performance of 89.6% (n = 48) and 80.4% (n = 46) for training and test sets using a support vector machine with a radial basis function kernel, respectively. The proposed method was proven to be capable of quantitatively measuring and monitoring motion sickness in real-time in a simple, economical and contactless manner using an infrared camera.


Assuntos
Enjoo devido ao Movimento , Realidade Virtual , Fadiga , Feminino , Humanos , Pupila , Percepção Visual
14.
Sensors (Basel) ; 21(14)2021 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-34300474

RESUMO

In this paper, we propose a novel approach that enables simultaneous localization, mapping (SLAM) and objects recognition using visual sensors data in open environments that is capable to work on sparse data point clouds. In the proposed algorithm the ORB-SLAM uses the current and previous monocular visual sensors video frame to determine observer position and to determine a cloud of points that represent objects in the environment, while the deep neural network uses the current frame to detect and recognize objects (OR). In the next step, the sparse point cloud returned from the SLAM algorithm is compared with the area recognized by the OR network. Because each point from the 3D map has its counterpart in the current frame, therefore the filtration of points matching the area recognized by the OR algorithm is performed. The clustering algorithm determines areas in which points are densely distributed in order to detect spatial positions of objects detected by OR. Then by using principal component analysis (PCA)-based heuristic we estimate bounding boxes of detected objects. The image processing pipeline that uses sparse point clouds generated by SLAM in order to determine positions of objects recognized by deep neural network and mentioned PCA heuristic are main novelties of our solution. In contrary to state-of-the-art approaches, our algorithm does not require any additional calculations like generation of dense point clouds for objects positioning, which highly simplifies the task. We have evaluated our research on large benchmark dataset using various state-of-the-art OR architectures (YOLO, MobileNet, RetinaNet) and clustering algorithms (DBSCAN and OPTICS) obtaining promising results. Both our source codes and evaluation data sets are available for download, so our results can be easily reproduced.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador , Reconhecimento Psicológico , Percepção Visual
15.
Proc Biol Sci ; 288(1955): 20211142, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34284623

RESUMO

Symmetries are present at many scales in natural scenes. Humans and other animals are highly sensitive to visual symmetry, and symmetry contributes to numerous domains of visual perception. The four fundamental symmetries-reflection, rotation, translation and glide reflection-can be combined into exactly 17 distinct regular textures. These wallpaper groups represent the complete set of symmetries in two-dimensional images. The current study seeks to provide a more comprehensive description of responses to symmetry in the human visual system, by collecting both brain imaging (steady-state visual evoked potentials measured using high-density EEG) and behavioural (symmetry detection thresholds) data using the entire set of wallpaper groups. This allows us to probe the hierarchy of complexity among wallpaper groups, in which simpler groups are subgroups of more complex ones. We find that both behaviour and brain activity preserve the hierarchy almost perfectly: subgroups consistently produce lower-amplitude symmetry-specific responses in visual cortex and require longer presentation durations to be reliably detected. These findings expand our understanding of symmetry perception by showing that the human brain encodes symmetries with a high level of precision and detail. This opens new avenues for research on how fine-grained representations of regular textures contribute to natural vision.


Assuntos
Potenciais Evocados Visuais , Córtex Visual , Animais , Encéfalo , Humanos , Reconhecimento Visual de Modelos , Percepção Visual
16.
Sci Rep ; 11(1): 14448, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34262075

RESUMO

Faces hold a substantial value for effective social interactions and sharing. Covering faces with masks, due to COVID-19 regulations, may lead to difficulties in using social signals, in particular, in individuals with neurodevelopmental conditions. Daily-life social participation of individuals who were born preterm is of immense importance for their quality of life. Here we examined face tuning in individuals (aged 12.79 ± 1.89 years) who were born preterm and exhibited signs of periventricular leukomalacia (PVL), a dominant form of brain injury in preterm birth survivors. For assessing the face sensitivity in this population, we implemented a recently developed experimental tool, a set of Face-n-Food images bordering on the style of Giuseppe Arcimboldo. The key benefit of these images is that single components do not trigger face processing. Although a coarse face schema is thought to be hardwired in the brain, former preterms exhibit substantial shortages in the face tuning not only compared with typically developing controls but also with individuals with autistic spectrum disorders. The lack of correlations between the face sensitivity and other cognitive abilities indicates that these deficits are domain-specific. This underscores impact of preterm birth sequelae for social functioning at large. Comparison of the findings with data in individuals with other neurodevelopmental and neuropsychiatric conditions provides novel insights into the origins of deficient face processing.


Assuntos
Encéfalo/fisiologia , Reconhecimento Facial , Reconhecimento Visual de Modelos , Nascimento Prematuro , Cognição Social , Adolescente , Transtorno do Espectro Autista , COVID-19 , Criança , Cognição , Neurociência Cognitiva , Expressão Facial , Feminino , Humanos , Leucomalácia Periventricular , Gravidez , Qualidade de Vida , Reconhecimento Psicológico/fisiologia , Fatores Sexuais , Comportamento Social , Percepção Visual/fisiologia
17.
Nat Commun ; 12(1): 4081, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34215754

RESUMO

A central regularity of visual perception is the co-occurrence of objects in the natural environment. Here we use machine learning and fMRI to test the hypothesis that object co-occurrence statistics are encoded in the human visual system and elicited by the perception of individual objects. We identified low-dimensional representations that capture the latent statistical structure of object co-occurrence in real-world scenes, and we mapped these statistical representations onto voxel-wise fMRI responses during object viewing. We found that cortical responses to single objects were predicted by the statistical ensembles in which they typically occur, and that this link between objects and their visual contexts was made most strongly in parahippocampal cortex, overlapping with the anterior portion of scene-selective parahippocampal place area. In contrast, a language-based statistical model of the co-occurrence of object names in written text predicted responses in neighboring regions of object-selective visual cortex. Together, these findings show that the sensory coding of objects in the human brain reflects the latent statistics of object context in visual and linguistic experience.


Assuntos
Encéfalo/fisiologia , Idioma , Percepção Visual/fisiologia , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Reconhecimento Visual de Modelos , Percepção , Córtex Visual/fisiologia
18.
Artigo em Inglês | MEDLINE | ID: mdl-34198645

RESUMO

This study aimed to compare the prevalence rate of atypical sensory processing in late preterm (LP) and term children at two years of age and to further investigate the co-occurrence of atypical sensory processing and behavioral problems (internalizing/externalizing) in both groups of children. A total of 104 children (52 LP and 52 sex- and birth order-matched term children) were included. The primary caregivers were asked to complete the Infant/Toddler Sensory Profile-Chinese version and the Child Behavior Checklist 1.5-5Y-Chinese version (CBCL-C/1.5-5). We found that the LP group had a similar prevalence rate of atypical sensory processing to the term group. However, neonatal intensive care unit experience (r = -0.356, p = 0.013, with visual processing) and days of ventilation and supplementary oxygen (r = -0.392, p = 0.004, with low registration) after birth were significantly correlated with the atypical sensory processing of LP children. Both LP and term children with behavioral problems seemed to have a higher prevalence rate of atypical sensory processing than their peers without behavioral problems. However, when Bonferroni correction was used to control for the statistical errors of multiple comparisons, only in the LP group did the co-occurrence of atypical sensory processing (auditory and oral sensory processing and sensation avoiding) and behavioral problems reach significance. In conclusion, the influence of late preterm birth on sensory processing may become subtle at age two, with the exception of those LP children experiencing complicated medical management after birth. A high level of co-occurrence of atypical sensory processing and behavioral problems suggests that the administration of a sensory processing assessment may be helpful to clarify the cause of problematic behavior and to recommend an appropriate intervention for LP children with behavioral problems.


Assuntos
Nascimento Prematuro , Comportamento Problema , Cognição , Feminino , Humanos , Lactente , Recém-Nascido , Gravidez , Sensação , Percepção Visual
19.
Comput Intell Neurosci ; 2021: 9922697, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34211548

RESUMO

Recognition of human activities is an essential field in computer vision. The most human activity consists of the interaction between humans and objects. Many successful works have been done on human-object interaction (HOI) recognition and achieved acceptable results in recent years. Still, they are fully supervised and need to train labeled data for all HOIs. Due to the enormous space of human-object interactions, listing and providing the training data for all possible categories is costly and impractical. We propose an approach for scaling human-object interaction recognition in video data through the zero-shot learning technique to solve this problem. Our method recognizes a verb and an object from the video and makes an HOI class. Recognition of the verbs and objects instead of HOIs allows identifying a new combination of verbs and objects. So, a new HOI class can be identified, which is not seen by the recognizer system. We introduce a neural network architecture that can understand and represent the video data. The proposed system learns verbs and objects from available training data at the training phase and can identify the verb-object pairs in a video at test time. So, the system can identify the HOI class with different combinations of objects and verbs. Also, we propose to use lateral information for combining the verbs and the objects to make valid verb-object pairs. It helps to prevent the detection of rare and probably wrong HOIs. The lateral information comes from word embedding techniques. Furthermore, we propose a new feature aggregation method for aggregating extracted high-level features from video frames before feeding them to the classifier. We illustrate that this feature aggregation method is more effective for actions that include multiple subactions. We evaluated our system by recently introduced Charades challengeable dataset, which has lots of HOI categories in videos. We show that our proposed system can detect unseen HOI classes in addition to the acceptable recognition of seen types. Therefore, the number of classes identifiable by the system is greater than the number of classes used for training.


Assuntos
Redes Neurais de Computação , Reconhecimento Automatizado de Padrão , Atividades Humanas , Humanos , Aprendizagem , Percepção Visual
20.
Neuropsychologia ; 159: 107949, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34228997

RESUMO

The ability to process speech evolves over the course of the lifespan. Understanding speech at low acoustic intensity and in the presence of background noise becomes harder, and the ability for older adults to benefit from audiovisual speech also appears to decline. These difficulties can have important consequences on quality of life. Yet, a consensus on the cause of these difficulties is still lacking. The objective of this study was to examine the processing of speech in young and older adults under different modalities (i.e. auditory [A], visual [V], audiovisual [AV]) and in the presence of different visual prediction cues (i.e., no predictive cue (control), temporal predictive cue, phonetic predictive cue, and combined temporal and phonetic predictive cues). We focused on recognition accuracy and four auditory evoked potential (AEP) components: P1-N1-P2 and N2. Thirty-four right-handed French-speaking adults were recruited, including 17 younger adults (28 ± 2 years; 20-42 years) and 17 older adults (67 ± 3.77 years; 60-73 years). Participants completed a forced-choice speech identification task. The main findings of the study are: (1) The faciliatory effect of visual information was reduced, but present, in older compared to younger adults, (2) visual predictive cues facilitated speech recognition in younger and older adults alike, (3) age differences in AEPs were localized to later components (P2 and N2), suggesting that aging predominantly affects higher-order cortical processes related to speech processing rather than lower-level auditory processes. (4) Specifically, AV facilitation on P2 amplitude was lower in older adults, there was a reduced effect of the temporal predictive cue on N2 amplitude for older compared to younger adults, and P2 and N2 latencies were longer for older adults. Finally (5) behavioural performance was associated with P2 amplitude in older adults. Our results indicate that aging affects speech processing at multiple levels, including audiovisual integration (P2) and auditory attentional processes (N2). These findings have important implications for understanding barriers to communication in older ages, as well as for the development of compensation strategies for those with speech processing difficulties.


Assuntos
Sinais (Psicologia) , Percepção da Fala , Estimulação Acústica , Idoso , Percepção Auditiva , Humanos , Pessoa de Meia-Idade , Qualidade de Vida , Fala , Percepção Visual
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...