scholarly journals An awareness-dependent saliency map in the human visual system

2021 ◽  
Author(s):  
LIJUAN WANG ◽  
LING HUANG ◽  
MENGSHA LI ◽  
XIAOTONG WANG ◽  
SHIYU WANG ◽  
...  
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Effective Connectivity ◽  
Saliency Map ◽  
Exogenous Attention ◽  
Connectivity Analysis ◽  
Bottom Up ◽  
Winner Take All ◽  
Take All

The bottom-up contribution to the allocation of exogenous attention is a saliency map. However, how the saliency map is distributed when multiple salient stimuli are presented simultaneously and how this distribution interacts with awareness remain unclear. These questions were addressed here using visible and invisible stimuli that consisting of two salient foregrounds: the high one served as the target and the low one served as the distractor, which did or did not interfere the target' saliency, indicating a gradient or winner-take-all manner, respectively. By combining psychophysics, fMRI, and effective connectivity analysis, we found that the saliency map was distributed as a gradient or winner-take-all manner with and without awareness, respectively. Crucially, we further revealed that the gradient manner was derived by feedback from pIPS, whereas the winner-take-all manner was constructed in V1. Together, our findings indicate an awareness-dependent saliency map and reconcile previous, seemingly contradictory findings on the saliency map.

scholarly journals Gravitational models explain shifts on human visual attention

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dario Zanca ◽  
Marco Gori ◽  
Stefano Melacci ◽  
Alessandra Rufa
Keyword(s):  
Visual Attention ◽  
Temporal Dynamics ◽  
Sensory Information ◽  
Saliency Map ◽  
Feature Maps ◽  
Single Feature ◽  
Single Location ◽  
Two Phases ◽  
Winner Take All ◽  
Take All

Abstract Visual attention refers to the human brain’s ability to select relevant sensory information for preferential processing, improving performance in visual and cognitive tasks. It proceeds in two phases. One in which visual feature maps are acquired and processed in parallel. Another where the information from these maps is merged in order to select a single location to be attended for further and more complex computations and reasoning. Its computational description is challenging, especially if the temporal dynamics of the process are taken into account. Numerous methods to estimate saliency have been proposed in the last 3 decades. They achieve almost perfect performance in estimating saliency at the pixel level, but the way they generate shifts in visual attention fully depends on winner-take-all (WTA) circuitry. WTA is implemented by the biological hardware in order to select a location with maximum saliency, towards which to direct overt attention. In this paper we propose a gravitational model to describe the attentional shifts. Every single feature acts as an attractor and the shifts are the result of the joint effects of the attractors. In the current framework, the assumption of a single, centralized saliency map is no longer necessary, though still plausible. Quantitative results on two large image datasets show that this model predicts shifts more accurately than winner-take-all.

Ant-Inspired Visual Saliency Detection in Image

2011 ◽  
pp. 263-272
Author(s):  
Jing Tian ◽  
Weiyu Yu
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Saliency Detection ◽  
Visual Saliency ◽  
Saliency Map ◽  
Experimental Results ◽  
Superior Performance ◽  
Local Phase ◽  
Visual Saliency Detection ◽  
Pheromone Information

Visual saliency detection aims to produce saliency map of images via simulating the behavior of the human visual system (HVS). An ant-inspired approach is proposed in this chapter. The proposed approach is inspired by the ant’s behavior to find the most saliency regions in image, by depositing the pheromone information (through ant’s movements) on the image to measure its saliency. Furthermore, the ant’s movements are steered by the local phase coherence of the image. Experimental results are presented to demonstrate the superior performance of the proposed approach.

scholarly journals BCCT: A GUI Toolkit for Brain Structural Covariance Connectivity Analysis on MATLAB

2021 ◽  
Vol 15 ◽  
Author(s):  
Qiang Xu ◽  
Qirui Zhang ◽  
Gaoping Liu ◽  
Xi-jian Dai ◽  
Xinyu Xie ◽  
...  
Keyword(s):  
Graphical User Interface ◽  
Causal Analysis ◽  
Group Comparison ◽  
Connectivity Analysis ◽  
Structural Covariance ◽  
Time Period ◽  
User Friendly ◽  
Winner Take All ◽  
The Brain ◽  
Take All

Brain structural covariance network (SCN) can delineate the brain synchronized alterations in a long-range time period. It has been used in the research of cognition or neuropsychiatric disorders. Recently, causal analysis of structural covariance network (CaSCN), winner-take-all and cortex–subcortex covariance network (WTA-CSSCN), and modulation analysis of structural covariance network (MOD-SCN) have expended the technology breadth of SCN. However, the lack of user-friendly software limited the further application of SCN for the research. In this work, we developed the graphical user interface (GUI) toolkit of brain structural covariance connectivity based on MATLAB platform. The software contained the analysis of SCN, CaSCN, MOD-SCN, and WTA-CSSCN. Also, the group comparison and result-showing modules were included in the software. Furthermore, a simple showing of demo dataset was presented in the work. We hope that the toolkit could help the researchers, especially clinical researchers, to do the brain covariance connectivity analysis in further work more easily.

Saliency Detection through Nonlinear Metric Fusion

2014 ◽  
Vol 926-930 ◽  
pp. 3692-3695
Author(s):  
Zhi Yang
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Saliency Detection ◽  
Saliency Map ◽  
Difficult Problem ◽  
Fusion Strategy ◽  
Cross Diffusion ◽  
Saliency Maps ◽  
Feature Information ◽  
Nature Scene

In order to detect the saliency part in the picture of nature scene, usually, bottom-up saliency models use several feature information such as color and orientation, each feature is taken to compute the saliency map respectively, then these saliency maps are linearly combined to a final saliency map. However, how to fuse these features are still a difficult problem, linearly combined is not appropriate to the human visual system, so in this paper we propose a nonlinear metric fusion strategy with different features namely cross diffusion, it fuse the metric from diverse features which can be used to detect the saliency more appropriate.

scholarly journals Functional dynamics of de-afferented early visual cortex in glaucoma

2020 ◽  
Author(s):  
Gokulraj T. Prabhakaran ◽  
Khaldoon O. Al-Nosairy ◽  
Claus Tempelmann ◽  
Markus Wagner ◽  
Hagen Thieme ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Human Visual System ◽  
General Feature ◽  
System Stability ◽  
Visual Field Defects ◽  
List Type ◽  
Bottom Up ◽  
Functional Dynamics ◽  
Early Visual Cortex

AbstractfMRI studies in macular degeneration (MD) and retinitis pigmentosa (RP) demonstrated that responses in the lesion projection zones (LPZ) of V1 are task related, indicating significant limits of bottom-up visual system plasticity in MD and RP. In advanced glaucoma (GL), a prevalent eye disease and leading cause of blindness, the scope of visual system plasticity is currently unknown. We performed 3T fMRI in patients with extensive visual field defects due to GL (n=5), RP (n=2) and healthy controls (n=7; with simulated defects). Participants viewed contrast patterns drifting in 8 directions alternating with uniform gray and performed 3 tasks: (1) passive viewing (PV), (2) one-back task (OBT) and (3) fixation-dot task (FDT). During PV, they passively viewed the stimulus with central fixation, during OBT they reported the succession of the same two motion directions, and during FDT a change in the fixation color. In GL, LPZ responses of the early visual cortex (V1, V2 and V3) shifted from negative during PV to positive for OBT [p (corrected): V1(0.006); V2(0.04); V3(0.008)], while they were negative in the controls’ simulated LPZ for all stimulation conditions. For RP a similar pattern as for GL was observed. Consequently, activity in the de-afferented visual cortex in glaucoma is, similar to MD and RP, task-related. In conclusion, the lack of bottom-up plasticity appears to be a general feature of the human visual system. These insights are of importance for the development of treatment and rehabilitation schemes in glaucoma.HighlightsFunctional dynamics of early visual cortex LPZ depend on task demands in glaucomaBrain activity in deprived visual cortex suggests absence of large-scale remappingLimited scope of bottom-up plasticity is a general feature of human visual systemVisual system stability and plasticity is of relevance for therapeutic advances

Evaluation of the Human Visual System in Cosmetics Foundation Colour Selection

2020 ◽  
Vol 2020 (1) ◽  
pp. 60-64
Author(s):  
Altynay Kadyrova ◽  
Majid Ansari-Asl ◽  
Eva Maria Valero Benito
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Skin Tone ◽  
Skin Colour ◽  
Psychophysical Experiment ◽  
Spectral Measurements ◽  
Practical Applications ◽  
Subjective Evaluations ◽  
Colour Measurements ◽  
Colour Quantification

Colour is one of the most important appearance attributes in a variety of fields including both science and industry. The focus of this work is on cosmetics field and specifically on the performance of the human visual system on the selection of foundation makeup colour that best matches with the human skin colour. In many cases, colour evaluations tend to be subjective and vary from person to person thereby producing challenging problems to quantify colour for objective evaluations and measurements. Although many researches have been done on colour quantification in last few decades, to the best of our knowledge, this is the first study to evaluate objectively a consumer's visual system in skin colour matching through a psychophysical experiment under different illuminations exploiting spectral measurements. In this paper, the experiment setup is discussed and the results from the experiment are presented. The correlation between observers' skin colour evaluations by using PANTONE Skin Tone Guide samples and spectroradiometer is assessed. Moreover, inter and intra observer variability are considered and commented. The results reveal differences between nine ethnic groups, between two genders, and between the measurements under two illuminants (i.e.D65 and F (fluorescent)). The results further show that skin colour assessment was done better under D65 than under F illuminant. The human visual system was three times worse than instrument in colour matching in terms of colour difference between skin and PANTONE Skin Tone Guide samples. The observers tend to choose lighter, less reddish, and consequently paler colours as the best match to their skin colour. These results have practical applications. They can be used to design, for example, an application for foundation colour selection based on correlation between colour measurements and human visual system based subjective evaluations.

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