Search results for "Visual Perception"

Retinal image quality and visual stimuli processing by simulation of partial eye cataract

2016

Visual stimuli were demonstrated on a 4.3’’ mobile phone screen inside a “Virtual Reality” adapter that allowed separation of the left and right eye visual fields. Contrast of the retina image thus can be controlled by the image on the phone screen and parallel to that at appropriate geometry by the AC voltage applied to scattering PDLC cell inside the adapter. Such optical pathway separation allows to demonstrate to both eyes spatially variant images, that after visual binocular fusion acquire their characteristic indications. As visual stimuli we used grey and different color (two opponent components to vision – red-green in L*a*b* color space) spatially periodical stimuli for left and ri…

Image Content Enhancement Through Salient Regions Segmentation for People With Color Vision Deficiencies

2019

Color vision deficiencies affect visual perception of colors and, more generally, color images. Several sciences such as genetics, biology, medicine, and computer vision are involved in studying and analyzing vision deficiencies. As we know from visual saliency findings, human visual system tends to fix some specific points and regions of the image in the first seconds of observation summing up the most important and meaningful parts of the scene. In this article, we provide some studies about human visual system behavior differences between normal and color vision-deficient visual systems. We eye-tracked the human fixations in first 3 seconds of observation of color images to build real f…

How Our Gaze Reacts to Another Person’s Tears? Experimental Insights Into Eye Tracking Technology

2020

Crying is an ubiquitous human behavior through which an emotion is expressed on the face together with visible tears and constitutes a slippery riddle for researchers. To provide an answer to the question “How our gaze reacts to another person’s tears?,” we made use of eye tracking technology to study a series of visual stimuli. By presenting an illustrative example through an experimental setting specifically designed to study the “tearing effect,” the present work aims to offer methodological insight on how to use eye-tracking technology to study non-verbal cues. A sample of 30 healthy young women with normal visual acuity performed a within-subjects task in which they evaluated images of…

Evaluation of visual-motor reaction time and quality of response in rugby sevens players after the application of a neurocognitive training programme

2019

This work proposes a neurocognitive training (NCT) programme that seeks to optimise the mechanisms of visual perception, the processing of information and decision making. Also, to evaluate the eff...

Correlations between Reading Disabilities and Learning Disabilities

2015

The article is devoted to reveal correlations between reading disabilities and learning disabilities. These problems need to be explained and teachers need to have reasonable solutions. Number of school-children with learning disabilities is increasing and teacher is not able to find the best and most precise ways of diagnostics and treatment/intervention. Causes of learning disabilities are different: brain damage or distorted functioning of it; auditory or visual perception and operating problems; language acquisition or processing problems etc. Symptoms are mostly noticed in the main areas – reading, writing and mathematics. Reading disabilities are one of the most obvious and serious pr…

Visual Perception and Graphic Analysis. The Pattern of Inlays in the Cathedral of Palermo

2017

The Cathedral of Palermo is one of the monuments belonging to the Arab-Norman Itinerary, declared a UNESCO World Heritage site in 2015. This text uses geometric analysis to describe some of the inlaid circular designs from the eastern façade, the corner towers and the apses. The cataloguing of the two-tone geometric motifs also reveals aspects that can be linked back to the laws of visual perception. Hence, the text investigates these aspects based on a new reading. In fact, decomposing these elements based on the experience of their perception also facilitates the recognition of elementary figures. The attempt made in this brief text intends to induce a new perceptive awareness resulting f…

Suppression of extinction with TMS in humans: from healthy controls to patients.

2006

We review a series of studies exemplifying some applications of single-pulse and paired-transcranial magnetic stimulation (TMS) in the study of spatial attention and of its deficits. We will focus primarily on sensory extinction, the failure to consciously perceive a contralesional sensory stimulus only during bilateral stimulation of homologous surfaces. TMS studies in healthy controls show that it is possible either to interfere or modulate the excitability of the parietal cortex during sensory (i.e. tactile and visual) attentional tasks, thus reproducing a condition of virtual extinction. TMS studies in patients with unilateral (mainly right) brain damage show that the modulation of the …

Visual mismatch negativity (vMMN): a prediction error signal in the visual modality

2015

Frontiers in Human Neuroscience, 8

Saliency Map for Visual Perception

2015

Human and other primates move their eyes to select visual information from the scene, psycho-visual experiments (Constantinidis, 2005) suggest that attention is directed to visually salient locations in the image. This allows human beings to bring the fovea onto the relevant parts of the image, to interpret complex scenes in real time. In visual perception, an important result was the discovery of a limited set of visual properties (called pre attentive), detected in the first 200-300 milliseconds of observation of a scene, by the low-level visual system. In last decades many progresses have been made into research of visual perception by analyzing both bottom up (stimulus driven) and top d…

2015

Previewing distracters enhances the efficiency of visual search. Watson and Humphreys (1997) proposed that the preview benefit rests on visual marking, a mechanism which actively encodes distracter locations at preview and inhibits them afterwards at search. As Watson and Humphreys did, we used a letter-color search task to study constraints of visual marking in conjunction search and near-efficient single-feature search with single-colored and homogeneous distracter letters. Search performance was measured for fixed target and distracter features (block design) and for randomly changed features across trials (random design). In single-feature search there was a full preview benefit for bot…