Chromatic Cues for Face Detection in Natural Scenes

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 294-294
Author(s):  
A Oliva ◽  
S Akamatsu ◽  
P G Schyns
Keyword(s):  
Face Detection ◽  
Reaction Times ◽  
Detection Task ◽  
Natural Scenes ◽  
Colour Space ◽  
Affect Detection ◽  
Detection Of Objects ◽  
Chromatic Cues ◽  
Colour Histograms ◽  
Euclidian Distances

One of the challenging problems of human and machine vision is the detection of objects against complex backgrounds. Our research addresses the question of how faces can be very quickly detected in naturalistic scenes on the basis of luminance and chromatic cues. Although luminance information varies with pose and illumination differences, chromatic information is by and large invariant under these transformations. Hence, chromatic information might be a very powerful cue for segmentation and detection. We compared faces of different pigmentation against background scenes of different colours. Specifically, colour histograms were computed in a perceptually uniform colour space (L*u*v*). We computed the Euclidian distances between the averages of the colour histograms of faces and scenes in L*u*v*. This metric was used to calibrate the contrast between face and scene colour in the experimental design. In a face detection task, subjects saw faces against scene backgrounds at a different distance in colour space. Each combination face - scene was presented for 120 ms (to prevent saccadic explorations), and the subject's task was to indicate whether or not a face was present. Controls involved face - scene pairs on an isoluminant background. Results revealed that luminance information did not affect detection on the basis of chromatic cues. Importantly, the metric of detectability in L*u*v* space between scene and faces predicted reaction times to detection.

scholarly journals A causal relationship between face-patch activity and face-detection behavior

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Srivatsun Sadagopan ◽  
Wilbert Zarco ◽  
Winrich A Freiwald
Keyword(s):  
Object Detection ◽  
Causal Relationship ◽  
Face Detection ◽  
Real World ◽  
Face Processing ◽  
Detection Task ◽  
Natural Scenes ◽  
Critical Importance ◽  
Primate Brain

The primate brain contains distinct areas densely populated by face-selective neurons. One of these, face-patch ML, contains neurons selective for contrast relationships between face parts. Such contrast-relationships can serve as powerful heuristics for face detection. However, it is unknown whether neurons with such selectivity actually support face-detection behavior. Here, we devised a naturalistic face-detection task and combined it with fMRI-guided pharmacological inactivation of ML to test whether ML is of critical importance for real-world face detection. We found that inactivation of ML impairs face detection. The effect was anatomically specific, as inactivation of areas outside ML did not affect face detection, and it was categorically specific, as inactivation of ML impaired face detection while sparing body and object detection. These results establish that ML function is crucial for detection of faces in natural scenes, performing a critical first step on which other face processing operations can build.

Rapid Serial Auditory Presentation

2015 ◽  
Vol 62 (5) ◽  
pp. 346-351 ◽  
Author(s):  
Ana Franco ◽  
Julia Eberlen ◽  
Arnaud Destrebecqz ◽  
Axel Cleeremans ◽  
Julie Bertels
Keyword(s):  
Statistical Learning ◽  
Reaction Times ◽  
Visual Presentation ◽  
Detection Task ◽  
Speech Segmentation ◽  
Auditory Presentation ◽  
Indirect Measure ◽  
Speech Stream ◽  
Adult Participants ◽  
Presentation Procedure

Abstract. The Rapid Serial Visual Presentation procedure is a method widely used in visual perception research. In this paper we propose an adaptation of this method which can be used with auditory material and enables assessment of statistical learning in speech segmentation. Adult participants were exposed to an artificial speech stream composed of statistically defined trisyllabic nonsense words. They were subsequently instructed to perform a detection task in a Rapid Serial Auditory Presentation (RSAP) stream in which they had to detect a syllable in a short speech stream. Results showed that reaction times varied as a function of the statistical predictability of the syllable: second and third syllables of each word were responded to faster than first syllables. This result suggests that the RSAP procedure provides a reliable and sensitive indirect measure of auditory statistical learning.

Face Detection in Natural Scenes

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 67-67 ◽  
Author(s):  
H Hill ◽  
R Watt
Keyword(s):  
Face Detection ◽  
Face Processing ◽  
Feature Detection ◽  
Processing System ◽  
Decision Task ◽  
Natural Scenes ◽  
Natural Scene ◽  
Energy Models ◽  
The Face ◽  
And Performance

The first task of any face processing system is detection of the face. We studied how the human visual system achieves face detection using a 2AFC task in which subjects were required to detect a face in the image of a natural scene. Luminance noise was added to the stimuli and performance was measured as a function of orientation and orientation bandwidth of the noise. Sensitivity levels and the effects of orientation bandwidth were similar for horizontally and vertically oriented noise. Performance was reduced for the smallest orientation bandwidth (5.6°) noise but sensitivity did not decrease further with increasing bandwidth until a point between 45° and 90°. The results suggest that important information may be oriented close to the vertical and horizontal. To test whether the results were specific to the task of face detection the same noise was added to the images in a man-made natural decision task. Equivalent levels of noise were found to be more disruptive and the effect of orientation bandwidth was different. The results are discussed in terms of models of face processing making use of oriented filters (eg Watt and Dakin, 1993 Perception22 Supplement, 12) and local energy models of feature detection (Morrone and Burr, 1988 Proceedings of the Royal Society of London B235 221 – 245).

The Time Course of Perceptual Grouping in Natural Scenes

2012 ◽  
Vol 23 (12) ◽  
pp. 1482-1489 ◽  
Author(s):  
Ilia Korjoukov ◽  
Danique Jeurissen ◽  
Niels A. Kloosterman ◽  
Josine E. Verhoeven ◽  
H. Steven Scholte ◽  
...  
Keyword(s):  
Visual Perception ◽  
Perceptual Grouping ◽  
Time Course ◽  
Reaction Times ◽  
Object Classification ◽  
Natural Scenes ◽  
Single Object ◽  
Object A ◽  
Object Parsing ◽  
Different Parts

Visual perception starts with localized filters that subdivide the image into fragments that undergo separate analyses. The visual system has to reconstruct objects by grouping image fragments that belong to the same object. A widely held view is that perceptual grouping occurs in parallel across the visual scene and without attention. To test this idea, we measured the speed of grouping in pictures of animals and vehicles. In a classification task, these pictures were categorized efficiently. In an image-parsing task, participants reported whether two cues fell on the same or different objects, and we measured reaction times. Despite the participants’ fast object classification, perceptual grouping required more time if the distance between cues was larger, and we observed an additional delay when the cues fell on different parts of a single object. Parsing was also slower for inverted than for upright objects. These results imply that perception starts with rapid object classification and that rapid classification is followed by a serial perceptual grouping phase, which is more efficient for objects in a familiar orientation than for objects in an unfamiliar orientation.

Spatial recoding of sound: Pitch-varying auditory cues modulate up/down visual spatial attention

2012 ◽  
Vol 25 (0) ◽  
pp. 150-151 ◽  
Author(s):  
Irune Fernández-Prieto ◽  
Fátima Vera-Constán ◽  
Joel García-Morera ◽  
Jordi Navarra
Keyword(s):  
Spatial Attention ◽  
Visual Target ◽  
Reaction Times ◽  
Detection Task ◽  
Spatial Processing ◽  
Intraparietal Sulcus ◽  
Auditory Cues ◽  
Visual Spatial Attention ◽  
Visual Spatial ◽  
Pitch Direction

Previous studies suggest the existence of facilitatory effects between, for example, responding upwards/downwards while hearing a high/low-pitched tone, respectively (e.g., Occeli et al., 2009; Rusconi et al., 2006). Neuroimaging research has started to reveal the activation of parietal areas (e.g., the intraparietal sulcus, IPS) during the performance of various pitch-based musical tasks (see Foster and Zatorre, 2010a, 2010b). Since several areas in the parietal cortex (e.g., the IPS; see Chica et al., 2011) are strongly involved in orienting visual attention towards external events, we investigated the possible effects of perceiving pitch-varying stimuli (i.e., ‘ascending’ or ‘descending’ flutter sounds) on the spatial processing of visual stimuli. In a variation of the Posner cueing paradigm (Posner, 1980), participants performed a speeded detection task of a visual target that could appear at one of four different spatial positions (two above and two below the fixation point). Irrelevant ascending (200–700 Hz) or descending (700–200 Hz) flutter sounds were randomly presented 550 ms before the onset of the visual target. According to our results, faster reaction times were observed when the visual target appeared in a position (up/down) that was compatible with the ‘pitch direction’ (ascending or descending) of the previously-presented auditory ‘cuing’ stimulus. Our findings suggest that pitch-varying sounds are recoded spatially, thus modulating visual spatial attention.

scholarly journals Mask Detection and Tracing System

2021 ◽  
pp. 406-412
Author(s):  
Sanket Shete ◽  
Kiran Tingre ◽  
Ajay Panchal ◽  
Vaibhav Tapse ◽  
Prof. Bhagyashri Vyas
Keyword(s):  
Neural Networks ◽  
Face Detection ◽  
Large Scale ◽  
Face Mask ◽  
Detection Algorithm ◽  
Detection Task ◽  
Loss Of Face ◽  
Satisfactory Performance ◽  
Training Samples ◽  
The Face

Covid19 has given a new identity for wearing a mask. It is meaningful when these masked faces are detected accurately and efficiently. As a unique face detection task, face mask detection is much more difficult because of extreme occlusions which leads to the loss of face details. Besides, there is almost no existing large-scale accurately labelled masked face dataset, which increase the difficulty of face mask detection. The system encourages to use CNN-based deep learning algorithms which has done vast progress towards researches in face detection In this paper, we propose novel CNN-based method which is formed of three convolutional neural networks to detect face mask. Besides, because of the shortage of face masked training samples, we propose a new dataset called” face mask dataset” to finetune our CNN models. We evaluate our proposed face mask detection algorithm on the face mask testing set, and it achieves satisfactory performance

scholarly journals A decisional space account of saccadic reaction times towards personally familiar faces

2018 ◽  
Author(s):  
Meike Ramon ◽  
Nayla Sokhn ◽  
Roberto Caldara
Keyword(s):  
Visual Processing ◽  
Reaction Times ◽  
Task Demands ◽  
Natural Scenes ◽  
Familiar Face ◽  
Processing Times ◽  
Electrophysiological Studies ◽  
Neurological Patients ◽  
Saccadic Reaction Times ◽  
Time Required

AbstractManual and saccadic reaction times (SRTs) have been used to determine the minimum time required for different types of visual categorizations. Such studies have demonstrated that faces can be detected within natural scenes within as little as 100ms (Crouzet, Kirchner & Thorpe, 2010), while increasingly complex decisions require longer processing times (Besson, Barragan-Jason, Thorpe, Fabre-Thorpe, Puma et al., 2017). Following the notion that facial representations stored in memory facilitate perceptual processing (Ramon & Gobbini, 2018), a recent study reported 180ms as the fastest speed at which “familiar face detection” based on expressed choice saccades (Visconti di Ollegio Castello & Gobbini, 2015). At first glance, these findings seem incompatible with the earliest neural markers of familiarity reported in electrophysiological studies (Barragan-Jason, Cauchoix & Barbeau, 2015; Caharel, Ramon & Rossion, 2014; Huang, Wu, Hu, Wang, Ding & Qu et al., 2017), which should temporally precede any overtly observed behavioral (oculomotor or manual) categorization. Here, we reason that this apparent discrepancy could be accounted for in terms of decisional space constraints, which modulate both manual RTs observed for different levels of visual processing (Besson et al., 2017), as well as saccadic RTs (SRTs) in both healthy observers and neurological patients (Ramon, in press; Ramon, Sokhn, Lao & Caldara, in press). In the present study, over 70 observers completed three different SRT experiments in which decisional space was manipulated through task demands and stimulus probability. Subjects performed a gender categorization task, or one of two familiar face “recognition” tasks, which differed with respect to the number of personally familiar identities presented (3 vs. 7). We observe an inverse relationship between visual categorization proficiency and decisional space. Observers were most accurate for categorization of gender, which could be achieved in as little as 140ms. Categorization of highly predictable targets was more error-prone and required an additional ~100ms processing time. Our findings add to increasing evidence that pre-activation of identity-information can modulate early visual processing in a top-down manner. They also emphasize the importance of considering procedural aspects as well as terminology when aiming to characterize cognitive processes.

scholarly journals The relationship between alertness and spatial attention under simulated shiftwork

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
D. Chandrakumar ◽  
J. Dorrian ◽  
S. Banks ◽  
H. A. D. Keage ◽  
S. Coussens ◽  
...  
Keyword(s):  
Spatial Attention ◽  
Health And Safety ◽  
Reaction Times ◽  
Vigilance Task ◽  
Detection Task ◽  
Future Research ◽  
Tentative Evidence ◽  
Stanford Sleepiness Scale ◽  
Psychomotor Vigilance ◽  
The Relationship

Abstract Higher and lower levels of alertness typically lead to a leftward and rightward bias in attention, respectively. This relationship between alertness and spatial attention potentially has major implications for health and safety. The current study examined alertness and spatial attention under simulated shiftworking conditions. Nineteen healthy right-handed participants (M = 24.6 ± 5.3 years, 11 males) completed a seven-day laboratory based simulated shiftwork study. Measures of alertness (Stanford Sleepiness Scale and Psychomotor Vigilance Task) and spatial attention (Landmark Task and Detection Task) were assessed across the protocol. Detection Task performance revealed slower reaction times and higher omissions of peripheral (compared to central) stimuli, with lowered alertness; suggesting narrowed visuospatial attention and a slight left-sided neglect. There were no associations between alertness and spatial bias on the Landmark Task. Our findings provide tentative evidence for a slight neglect of the left side and a narrowing of attention with lowered alertness. The possibility that one’s ability to sufficiently react to information in the periphery and the left-side may be compromised under conditions of lowered alertness highlights the need for future research to better understand the relationship between spatial attention and alertness under shiftworking conditions.

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