5. Perception of a 3-D world

2017 ◽  
pp. 59-83
Author(s):  
Brian Rogers
Keyword(s):  
Visual System ◽  
Optic Flow ◽  
Motion Parallax ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Depth Cues ◽  
Depth Constancy ◽  
Different Sources

The ability to perceive the 3-D world has often been regarded as a task that poses particular problems for the visual system. However, ‘Perception of a 3-D world’ argues that we are particularly fortunate because there are multiple sources of information to tell us about the different aspects of the 3-D structure of objects. It discusses three of these sources of information—perspective, occlusion, and shading—and then explains motion parallax, optic flow, binocular stereopsis, eye vergence and depth constancy, vertical disparities and differential perspective, and primary and secondary depth cues. The effectiveness of these different sources of 3-D information is considered along with how they are all brought together.

scholarly journals A neural mechanism for detecting object motion during self-motion

2021 ◽  
Author(s):  
HyungGoo Kim ◽  
Dora Angelaki ◽  
Gregory DeAngelis
Keyword(s):  
Visual System ◽  
Moving Objects ◽  
Binocular Disparity ◽  
Motion Parallax ◽  
Neural Mechanism ◽  
Object Motion ◽  
Depth Cues ◽  
Behavioral Studies ◽  
Observer Motion ◽  
Self Motion

Detecting objects that move in a scene is a fundamental computation performed by the visual system. This computation is greatly complicated by observer motion, which causes most objects to move across the retinal image. How the visual system detects scene-relative object motion during self-motion is poorly understood. Human behavioral studies suggest that the visual system may identify local conflicts between motion parallax and binocular disparity cues to depth, and may use these signals to detect moving objects. We describe a novel mechanism for performing this computation based on neurons in macaque area MT with incongruent depth tuning for binocular disparity and motion parallax cues. Neurons with incongruent tuning respond selectively to scene-relative object motion and their responses are predictive of perceptual decisions when animals are trained to detect a moving object during selfmotion. This finding establishes a novel functional role for neurons with incongruent tuning for multiple depth cues.

MST Responses to Pursuit Across Optic Flow With Motion Parallax

2000 ◽  
Vol 84 (2) ◽  
pp. 818-826 ◽  
Author(s):  
Urmen D. Upadhyay ◽  
William K. Page ◽  
Charles J. Duffy
Keyword(s):  
Flow Field ◽  
Optic Flow ◽  
Visual Motion ◽  
Motion Parallax ◽  
Depth Plane ◽  
Relative Depth ◽  
Depth Cues ◽  
Medial Superior Temporal ◽  
Heading Direction ◽  
Mst Neurons

Self-movement creates the patterned visual motion of optic flow with a focus of expansion (FOE) that indicates heading direction. During pursuit eye movements, depth cues create a retinal flow field that contains multiple FOEs, potentially complicating heading perception. Paradoxically, human heading perception during pursuit is improved by depth cues. We have studied medial superior temporal (MST) neurons to see whether their heading selectivity is also improved under these conditions. The responses of 134 MST neurons were recorded during the presentation of optic flow stimuli containing one or three speed-defined depth planes. During pursuit, multiple depth-plane stimuli evoked larger responses (71% of neurons) and stronger heading selectivity (70% of neurons). Responses to the three speed-defined depth-planes presented separately showed that most neurons (54%) preferred one of the planes. Responses to multiple depth-plane stimuli were larger than the averaged responses to the three component planes, suggesting enhancing interactions between depth-planes. Thus speed preferences create selective responses to one of many depth-planes in the retinal flow field. The presence of multiple depth-planes enhances those responses. These properties might improve heading perception during pursuit and contribute to relative depth perception.

scholarly journals 4-5-year-old children adapt to the reliability of conflicting sources of information to learn novel words

2020 ◽  
Author(s):  
Marion Beretti ◽  
Naomi Havron ◽  
Anne CHRISTOPHE
Keyword(s):  
Language Acquisition ◽  
The Other ◽  
Induction Phase ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Novel Object ◽  
Linguistic Representations ◽  
New Knowledge ◽  
Reasonable Choice ◽  
Different Sources

A central challenge in language acquisition is the integration of multiple sources of information, potentially in conflict, to acquire new knowledge and adjust current linguistic representations. One way to accomplish this is to assign more weight to more reliable sources of information in context. We test the hypothesis that children adjust the weight of different sources of information during learning, considering two specific sources of information: their knowledge of the meaning of familiar words (semantics) and their familiarity with syntax. We varied the reliability of these sources of information through an induction phase (reliable-syntax or reliable-semantics). At test, French 4-5-year-old children and adults listened to sentences where information provided by these two cues conflicted, and were asked to choose between two videos that illustrate the sentence. One video presented the reasonable choice if the sentence is assumed to be syntactically correct, but familiar words refer to novel things (e.g., une mange - "an eats" describes a novel object). The other video was the reasonable choice if the sentence is assumed to be syntactically incorrect and familiar words’ meaning is preserved (e.g., "an eats" describes a girl eating, and should have actually been "she eats"). As predicted, the proportion of syntactic choices (e.g., interpreting mange - "eats", as a novel noun) was found to be higher in the reliable-syntax condition than in the reliable-semantics condition, showing that children and adults can adapt their expectations to the reliability of sources of information.

Use of Global Optical Flow Rate and Discontinuity Rate Depends on Their Validity as Determinants of Egospeed

1998 ◽  
Vol 42 (22) ◽  
pp. 1540-1544 ◽  
Author(s):  
Terry G. Ballard ◽  
Tony Roach ◽  
Brian P. Dyre
Keyword(s):  
Visual System ◽  
Optical Flow ◽  
Flow Rate ◽  
Frame Rate ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Relative Validity ◽  
Self Motion ◽  
Source Of Information ◽  
Information Frame

Previous research found both discontinuity rate and global optical flow rate contribute to the perception of egospeed but differed in estimates of which source of information dominated. This research examined two methodological differences that may explain the conflicting results: frame rate, and the relative validity of discontinuity rate and flow rate as determinants of egospeed. Observers estimated egospeed perceived during simulations of self-motion. Discontinuity rate and flow rate were manipulated independently by varying velocity and altitude. Frame rates were consistent with Dyre (1997) and the validity of discontinuity rate and flow rate as determinants of egospeed was varied. We found the relative use of discontinuity rate and flow rate was related to the validity of these sources of information. Frame rate was not an important factor. These results suggest the visual system is sensitive to multiple sources of information for perceiving egospeed and adapts to the most optimal source.

Determinants Considered by Consumers for Brand Selection - with Reference to Laptops in Albania

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Margret Plloçi ◽  
Macit Koc
Keyword(s):  
Primary Data ◽  
Battery Life ◽  
Decision Making Process ◽  
Light Weight ◽  
Sources Of Information ◽  
Technical Features ◽  
The Relationship ◽  
The City ◽  
Different Sources ◽  
Core Features

Abstract Purpose of the article There is relatively a big number of brands in the market of laptops nowadays in Albania. It appears that the number of brands offered in this market could easily be compared to the number of brands in Europe and even broader. The purpose of this study is to help Albanian vendors understand the criteria that consumers take into consideration when they make the decision to purchase a laptop. Methodology/methods The research is based on the collection and the analyses of the primary data collected through interviews to people like managers or employees who work in the sector of trading laptops or in businesses like education where laptops are broadly used recently; then a survey is done through a questionnaire delivered to customers who already own and use a laptop and customers who are potential buyers of laptops. Scientific aim The aim of the research is to identify if there are any relationships between the demographics of the consumers and the criteria of buying a laptop; on the other hand, to find out how is the relationship between the demographics and the features of different brands. Findings The study found out that Albanian consumers have good knowledge of laptops and their brands, and they use different sources of information for making their decisions in buying a laptop; it is found that there are relationships between some demographics like age or gender and the appraisal for some attributes of the laptops like price, design and high graphics card; it is also found that some technical features and other attributes of using laptops are some of the determinants that influence the laptops’ purchases. Conclusions It is realized that one of the most important demographics of the consumers is their age. Some core features like RAM, ROM, battery life, processor quality, light weight or attributes that are connected to the purposes of using the laptop computers like practicality and mobility in using them, work and studying processes, quick access to the internet are determinant factors which influence the decision making process of purchasing a laptop. I would recommend that future researches be focused also on the relationship between the customers’ income and their preferred brand or ranking brands according to the customers’ preferences. Such studies should also extend outside the city of Tirana.

Supporting the Development of Clinical Reasoning of Preprofessional Novices in Dysphagia Management

2019 ◽  
Vol 40 (03) ◽  
pp. 151-161 ◽  
Author(s):  
Sebastian Doeltgen ◽  
Stacie Attrill ◽  
Joanne Murray
Keyword(s):  
Clinical Reasoning ◽  
Clinical Decision Making ◽  
Management Practice ◽  
Clinical Decision ◽  
Assessment Process ◽  
Evidence Based ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Implicit Processing ◽  
Reasoning Skills

AbstractProficient clinical reasoning is a critical skill in high-quality, evidence-based management of swallowing impairment (dysphagia). Clinical reasoning in this area of practice is a cognitively complex process, as it requires synthesis of multiple sources of information that are generated during a thorough, evidence-based assessment process and which are moderated by the patient's individual situations, including their social and demographic circumstances, comorbidities, or other health concerns. A growing body of health and medical literature demonstrates that clinical reasoning skills develop with increasing exposure to clinical cases and that the approaches to clinical reasoning differ between novices and experts. It appears that it is not the amount of knowledge held, but the way it is used, that distinguishes a novice from an experienced clinician. In this article, we review the roles of explicit and implicit processing as well as illness scripts in clinical decision making across the continuum of medical expertise and discuss how they relate to the clinical management of swallowing impairment. We also reflect on how this literature may inform educational curricula that support SLP students in developing preclinical reasoning skills that facilitate their transition to early clinical practice. Specifically, we discuss the role of case-based curricula to assist students to develop a meta-cognitive awareness of the different approaches to clinical reasoning, their own capabilities and preferences, and how and when to apply these in dysphagia management practice.

Feature-based multi-criteria recommendation system using a weighted approach with ranking correlation

2021 ◽  
Vol 25 (4) ◽  
pp. 1013-1029
Author(s):  
Zeeshan Zeeshan ◽  
Qurat ul Ain ◽  
Uzair Aslam Bhatti ◽  
Waqar Hussain Memon ◽  
Sajid Ali ◽  
...  
Keyword(s):  
Recommendation System ◽  
Sources Of Information ◽  
Multiple Features ◽  
Recommendation Algorithms ◽  
Label Correlations ◽  
Feature Based ◽  
Multicriteria Model ◽  
Implicit And Explicit ◽  
Hybrid Recommendation ◽  
Different Sources

With the increase of online businesses, recommendation algorithms are being researched a lot to facilitate the process of using the existing information. Such multi-criteria recommendation (MCRS) helps a lot the end-users to attain the required results of interest having different selective criteria – such as combinations of implicit and explicit interest indicators in the form of ranking or rankings on different matched dimensions. Current approaches typically use label correlation, by assuming that the label correlations are shared by all objects. In real-world tasks, however, different sources of information have different features. Recommendation systems are more effective if being used for making a recommendation using multiple criteria of decisions by using the correlation between the features and items content (content-based approach) or finding a similar user rating to get targeted results (Collaborative filtering). To combine these two filterings in the multicriteria model, we proposed a features-based fb-knn multi-criteria hybrid recommendation algorithm approach for getting the recommendation of the items by using multicriteria features of items and integrating those with the correlated items found in similar datasets. Ranks were assigned to each decision and then weights were computed for each decision by using the standard deviation of items to get the nearest result. For evaluation, we tested the proposed algorithm on different datasets having multiple features of information. The results demonstrate that proposed fb-knn is efficient in different types of datasets.

scholarly journals Mobility Trends before and after the Pandemic Outbreak: Analyzing the Metropolitan Area of Barcelona through the Lens of Equality and Sustainability

2021 ◽  
Vol 13 (14) ◽  
pp. 7908
Author(s):  
Lucía Mejía-Dorantes ◽  
Lídia Montero ◽  
Jaume Barceló
Keyword(s):  
Metropolitan Area ◽  
Spatial Arrangement ◽  
Individual Characteristics ◽  
Sources Of Information ◽  
Mobility Patterns ◽  
Multiple Sources ◽  
Temporal Dimension ◽  
Population Groups ◽  
Highly Educated ◽  
Before And After

The spatial arrangement of a metropolis is of utmost importance to carry out daily activities, which are constrained by space and time. Accessibility is not only shaped by the spatial and temporal dimension, but it is also defined by individual characteristics, such as gender, impairments, or socioeconomic characteristics of the citizens living or commuting in this area. This study analyzes mobility trends and patterns in the metropolitan area of Barcelona before and after the COVID-19 pandemic outbreak, with special emphasis on gender and equality. The study draws on multiple sources of information; however, two main datasets are analyzed: two traditional travel surveys from the transport metropolitan area of Barcelona and two coming from smartphone data. The results show that gender plays a relevant role when analyzing mobility patterns, as already highlighted in other studies, but, after the pandemic outbreak, some population groups were more likely to change their mobility patterns, for example, highly educated population groups and those with higher income. This study also highlights that e-activities may shape new mobility patterns and living conditions for some population segments, but some activities cannot be replaced by IT technologies. For all these reasons, city and transport planning should foster sustainable development policies, which will provide the maximum benefit for society.

scholarly journals Retro-Reflective-Marker-Aided Target Pose Estimation in a Safety-Critical Environment

2020 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Laura Gonçalves Ribeiro ◽  
Olli J. Suominen ◽  
Ahmed Durmush ◽  
Sari Peltonen ◽  
Emilio Ruiz Morales ◽  
...  
Keyword(s):  
Pose Estimation ◽  
Stereo Matching ◽  
Motion Parallax ◽  
Extreme Temperature ◽  
Single Camera ◽  
Safety Critical ◽  
Depth Cues ◽  
Significant Challenge ◽  
Visual Technologies ◽  
Marker Detection

Visual technologies have an indispensable role in safety-critical applications, where tasks must often be performed through teleoperation. Due to the lack of stereoscopic and motion parallax depth cues in conventional images, alignment tasks pose a significant challenge to remote operation. In this context, machine vision can provide mission-critical information to augment the operator’s perception. In this paper, we propose a retro-reflector marker-based teleoperation aid to be used in hostile remote handling environments. The system computes the remote manipulator’s position with respect to the target using a set of one or two low-resolution cameras attached to its wrist. We develop an end-to-end pipeline of calibration, marker detection, and pose estimation, and extensively study the performance of the overall system. The results demonstrate that we have successfully engineered a retro-reflective marker from materials that can withstand the extreme temperature and radiation levels of the environment. Furthermore, we demonstrate that the proposed maker-based approach provides robust and reliable estimates and significantly outperforms a previous stereo-matching-based approach, even with a single camera.

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