Search results for " Vision"
showing 10 items of 2709 documents
Binocular vision alterations after refractive and cataract surgery: a review.
2018
To review binocular and accommodative disorders documented after corneal or intraocular refractive surgery, in normal healthy prepresbyopic patients. A bibliographic revision was performed; it included works published before 1st July 2017 where accommodation and/or binocularity was assessed following any type of refractive surgical procedure. The search in Pubmed yielded 1273 papers, 95 of which fulfilled the inclusion criteria. Few publications reporting binocular vision and/or accommodative changes after refractive surgery in normal subjects were found. The reduction in fusional vergence is the most frequently reported alteration. Anisometropia is an important risk factor for postoperativ…
Early warning thresholds for partially saturated slopes in volcanic ashes
2013
Rainfall-induced landslides in steep soil slopes of volcanic origin are a major threat to human lives and infrastructure. In the context of constructing early warning systems in regions where extensive data on landslide occurrences and associated rainfall are inexistent, physically-based tools offer the possibility to establish thresholds for measurable field quantities. In this paper, a combined finite element infinite slope model is presented to study the transient hydraulic response of volcanic ash slopes to a series of rainfall events and to estimate seasonal safety factors. Furthermore, analytical considerations of partially saturated infinite slopes are made to define capillary stress…
On Augmented Reality for the Learning of 3D-Geometric Contents: A Preliminary Exploratory Study with 6-Grade Primary Students
2019
Nowadays, Augmented Reality (AR) is one of the emerging technologies with a greater impact in the Education field. Research has proved that AR-based activities improve the teaching and learning processes. Also, the use of this type of technology in classroom facilitates the understanding of contents from different areas as Arts, Mathematics or Science. In this work we propose an AR-based instruction in order to explore the benefits in a 6th-grade Primary course related to 3D-geometry shapes. This first experiment, designed from an exploratory approach, will shed light on new study variables to perform new implementations whose conclusions become more consistent. The results obtained allow u…
Fostering sustained teacher learning: a longitudinal assessment of the influence of vision building and goal interdependence on information sharing
2020
To support school improvement, understanding the mechanisms that enhance teachers’ engagement in professional learning activities within schools over time is paramount. The purpose of this three-wave longitudinal study is to examine the role of workplace conditions (school leaders’ vision building and teams’ shared goals), in supporting teachers’ engagement in information sharing over time. To test the directionality of the relationships between the concepts, we analyzed survey data from 655 vocational education and training teachers in the Netherlands using a cross-lagged panel model. Results suggest that teachers’ engagement in information sharing remains stable over time, and the results…
Contributions à la Vision par Ordinateur pour les Systèmes en Lumière Structurée et les Systèmes Catadioptriques
2008
Mes travaux de recherche concernent essentiellement la vision par ordinateur, ou vision artificielle. Basiquement, je me suis efforcé d'imaginer des dispositifs, d'étudier des algorithmes, d'intégrer des méthodes et techniques connues dans des méthodologies nouvelles, de développer çà et là des aspects théoriques originaux. Je me suis beaucoup intéressé à des systèmes de vision alternatifs comme les systèmes en lumière structurée ou catadioptriques. Ces systèmes permettent d'étudier les techniques usuelles de vision par ordinateur sous un éclairage différent, ils nous obligent à ajuster le problème aux caractéristiques qui leur sont propres ; ils permettent, en quelq…
Zero-shot Semantic Segmentation using Relation Network
2021
Zero-shot learning (ZSL) is widely studied in recent years to solve the problem of lacking annotations. Currently, most studies on ZSL are for image classification and object detection. But, zero-shot semantic segmentation, pixel level classification, is still at its early stage. Therefore, this work proposes to extend a zero-shot image classification model, Relation Network (RN), to semantic segmentation tasks. We modified the structure of RN based on other state-of-the-arts semantic segmentation models (i.e. U-Net and DeepLab) and utilizes word embeddings from Caltech-UCSD Birds 200-2011 attributes and natural language processing models (i.e. word2vec and fastText). Because meta-learning …
Time Unification on Local Binary Patterns Three Orthogonal Planes for Facial Expression Recognition
2019
International audience; Machine learning has known a tremendous growth within the last years, and lately, thanks to that, some computer vision algorithms started to access what is difficult or even impossible to perceive by the human eye. While deep learning based computer vision algorithms have made themselves more and more present in the recent years, more classical feature extraction methods, such as the ones based on Local Binary Patterns (LBP), still present a non negligible interest, especially when dealing with small datasets. Furthermore, this operator has proven to be quite useful for facial emotions and human gestures recognition in general. Micro-Expression (ME) classification is…
WATCHING PEOPLE: ALGORITHMS TO STUDY HUMAN MOTION AND ACTIVITIES
2020
Nowadays human motion analysis is one of the most active research topics in Computer Vision and it is receiving an increasing attention from both the industrial and scientific communities. The growing interest in human motion analysis is motivated by the increasing number of promising applications, ranging from surveillance, human–computer interaction, virtual reality to healthcare, sports, computer games and video conferencing, just to name a few. The aim of this thesis is to give an overview of the various tasks involved in visual motion analysis of the human body and to present the issues and possible solutions related to it. In this thesis, visual motion analysis is categorized into thr…
Restoration and Enhancement of Historical Stereo Photos
2021
Restoration of digital visual media acquired from repositories of historical photographic and cinematographic material is of key importance for the preservation, study and transmission of the legacy of past cultures to the coming generations. In this paper, a fully automatic approach to the digital restoration of historical stereo photographs is proposed, referred to as Stacked Median Restoration plus (SMR+). The approach exploits the content redundancy in stereo pairs for detecting and fixing scratches, dust, dirt spots and many other defects in the original images, as well as improving contrast and illumination. This is done by estimating the optical flow between the images, and using it …
Space-Frequency Quantization for Image Compression With Directionlets
2007
The standard separable 2-D wavelet transform (WT) has recently achieved a great success in image processing because it provides a sparse representation of smooth images. However, it fails to efficiently capture 1-D discontinuities, like edges or contours. These features, being elongated and characterized by geometrical regularity along different directions, intersect and generate many large magnitude wavelet coefficients. Since contours are very important elements in the visual perception of images, to provide a good visual quality of compressed images, it is fundamental to preserve good reconstruction of these directional features. In our previous work, we proposed a construction of critic…