Search results for " Vision"
showing 10 items of 2709 documents
Calculate Pulse from Touch Error Free PPG Signal with 2ndOrder Butterworth Filter
2021
With the ongoing heart problems of the population worldwide, the medical requirements of the people are expected to increase. Electrocardiogram (ECG) is one of the proven to capture the heart response signal to assess the electrical and muscular functions of the heart. The ECG setup is expensive and needs proper training, and of course, it is not instant. For fast, accurate heart parameter monitoring, scientists pay attention to the photoplethysmogram signal (PPG), based on the light intensity of a particular wavelength. Android smartphone with a good quality camera has come to ordinary people's reach and has become one of the most necessary and rugged devices for today and future generatio…
A Method Based on Multi-source Feature Detection for Counting People in Crowded Areas
2019
We propose a crowd counting method for multisource feature fusion. Image features are extracted from multiple sources, and the population is estimated by image feature extraction and texture feature analysis, along with for crowd image edge detection. We count people in high-density still images. For instance, in the city’s squares, sports fields, subway stations, etc. Our approach uses a still image taken by a camera on a drone to appraise the count in the population density image, using a kind of sources of information: HOG, LBP, CANNY. We furnish separate estimates of counts and other statistical measurements through several types of sources. Support vector machine SVM, classification an…
Shared feature representations of LiDAR and optical images: Trading sparsity for semantic discrimination
2015
This paper studies the level of complementary information conveyed by extremely high resolution LiDAR and optical images. We pursue this goal following an indirect approach via unsupervised spatial-spectral feature extraction. We used a recently presented unsupervised convolutional neural network trained to enforce both population and lifetime spar-sity in the feature representation. We derived independent and joint feature representations, and analyzed the sparsity scores and the discriminative power. Interestingly, the obtained results revealed that the RGB+LiDAR representation is no longer sparse, and the derived basis functions merge color and elevation yielding a set of more expressive…
3D inter-subject medical image registration by scatter search
2005
Image registration is a very active research area in computer vision, namely it is used to find a transformation between two images taken under different conditions. Point matching is an image registration approach based on searching for the right pairing of points between the two images. From this matching, the registration transformation we are searching, can be inferred by means of numerical methods. In this paper, we propose a scatter search (SS) algorithm to solve the matching problem. SS is a hybrid metaheuristic with a good trade-off between search space diversification and intensification. On the one hand, diversity is basically introduced from a population-based approach where syst…
Visual defects in subjects with Down’s syndrome
1995
Because the incidence of other visual defects is much higher in cases of Down’s syndrome than in individuals with other forms of retardation (Gardiner, 1967; Aitchison et al., 1990), we tested the color vision of a population of Down’s syndrome patients, using Ishihara plates and the Davico anomaloscope. The Down’s syndrome group had a significantly higher proportion of color deficiencies than either normal controls or a matched mentally retarded population. Refractive errors were corrected with static retinoscopy, and spatial contrast sensitivity was measured with the Vistech test.
Digital Device Usage Time and Ocular Symptoms during COVID-19 Pandemic
2021
Bakalaura darbs ir uzrakstīts angļu valodā uz 25 lappusēm. Tas satur 10 attēlus, 6 tabulas un 22 atsauces uz literatūras avotiem. Šī pētījuma galvenais mērķis bija novērtēt kā digitālo ierīču lietošanas izmaiņas ikdienā pirms Covid-19 pandēmijas un pandēmijas laikā Itālijā ietekmē acu nogurumu. Digitālo ierīču ietekme uz acīm tika novērtēta, apkopojot pētījuma dalībnieku atbildes uz anketas jautājumiem. Digitālo ierīču izmantošana mūsdienās ir plaši izplatīta, tās ir jāizmanto, bet ievērojot nepieciešamos piesardzības pasākumus, lai neradītu traucējumus redzes un psihiskajā sistēmās.
Developmental dyslexia: Visual abnormalities during ocular rotation
2005
[u]Purpose[/u]: Most of the studies dealing with visual perception disabilities in children suffering from developmental dyslexia have been done in orthophoric position. The objective of the present study is to explore the visual perception during eye movements. [u]Methods[/u]: Sixty male patients (11.8 ± 1.8 years) were examined by neuropsychologists to evaluate reading difficulties. Visual perception during ocular rotation was assessed with a Clement Clarke synoptophore with G3–G4 slides, in primary gaze, then laterally at 20, 30 and 40° in dim light. [u]Results[/u]: Three main abnormalities were found. • Isolated perception abnormalities with intermittent shading of the image, central, p…
Professional vision in the classroom: Teachers’ knowledge-based reasoning explaining their visual focus of attention to students
2023
This study investigated Grade 2 teachers' (N = 50) professional vision through eye-tracking methodology and retrospective think-aloud interviews. The study examined the extent to which teachers' knowledge-based reasoning explains their visual focus of attention to whole class and individual students. We found that teachers' descriptions of students' social relations and emotions associated positively with teachers' visual focus of attention to the whole class. Teachers' descriptions of teacher-related information/elaboration and pedagogy linked negatively with teachers' visual focus of attention to individual students. The findings suggest that teachers' visual focus of attention to student…
Robust Selective Stereo SLAM without Loop Closure and Bundle Adjustment
2013
This paper presents a novel stereo SLAM framework, where a robust loop chain matching scheme for tracking keypoints is combined with an effective frame selection strategy. The proposed approach, referred to as selective SLAM (SSLAM), relies on the observation that the error in the pose estimation propagates from the uncertainty of the three-dimensional points. This is higher for distant points, corresponding to matches with low temporal flow disparity in the images. Comparative results based on the reference KITTI evaluation framework show that SSLAM is effective and can be implemented efficiently, as it does not require any loop closure or bundle adjustment.
Raw data and code for the Fouilloux et al. (2023) paper: Visual environment of rearing sites affects larval response to perceived risk
2023
Data and code for the Fouilloux et al. (2023) study: Visual environment of rearing sites affects larval response to perceived risk. The study examined the effect of nursery turbidity on the (visual) perception of risk for tadpoles that develop in epehemeral pools of water (phytotelmata). Attached to the data is a Data Description PDF file, which includes the definition of the two data sheets (LAS_VISION_OCT2022 and FG_TURB_JAN2023) and the methods required to collect these data. The R code that goes along with these data is also provided. The full work is cited and contextualized in the Journal of Experimental Biology.