Search results for "Stereopsis"

Pràctica 4. Agudetza visual estereoscòpica

2018

El document forma part dels materials docents programats mitjançant l'ajut del Servei de Política Lingüística de la Universitat de València. Pràctica 4 de l'assignatura de psicofísica de la visió on l'objectiu és trobar l’agudetza visual estereoscòpica emprant el mètode d’estímuls constants

Efficient and accurate monitoring of the depth information in a Wireless Multimedia Sensor Network based surveillance

2017

International audience; Abstract—Wireless Multimedia Sensor Network (WMSN) is a promising technology capturing rich multimedia data like audio and video, which can be useful to monitor an environment under surveillance. However, many scenarios in real time monitoring requires 3D depth information. In this research work, we propose to use the disparity map that is computed from two or multiple images, in order to monitor the depth information in an object or event under surveillance using WMSN. Our system is based on distributed wireless sensors allowing us to notably reduce the computational time needed for 3D depth reconstruction, thus permitting the success of real time solutions. Each pa…

Luminance threshold for stereopsis.

1981

Visual performance comparison between contact lens-based pinhole and simultaneous vision contact lenses.

2011

Background The aim was to evaluate the visual performance provided with a contact lens-based pinhole design against a simultaneous vision multifocal contact lens. Methods In a cross-over study at the University of Valencia, 22 presbyopic patients were evaluated using an artificial pupil fitted on the non-dominant eye and the simultaneous vision PureVision Multifocal contact lenses. After one month of contact lens wear, binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance contrast sensitivity, binocular near contrast sensitivity, and stereoacuity were measured, under photopic conditions (85 cd/m2). In addition, binocular distance vis…

Application of Genetic Algorithms to 3-D Shape Reconstruction in an Active Stereo Vision System

2001

In this paper, a new method for reconstructing 3-D shapes is proposed. It is based on an active stereo vision system composed of a camera and a light system which projects a set of structured laser rays on the scence to be analyzed. The depth information is provided by matching the laser rays and the corresponding spots appearing in the image. The matching task is performed by using Genetic Algorithms (GAs). The process converges towards the optimum solution which proves that GAs can effectively be used for this problem. An efficient 3-D reconstruction method is introduced. The experimental results demonstrate that the proposed approach is stable and provides high accuracy 3-D object recons…

Time response of the vision binocularity by use of dynamic suppression of retinal images

1999

We present a novel technique for determination the stereopsis dynamic response, using as stimulus a random dot stereopair. Stereopsis can be evoked or depressed by continuous or flash illumination of the stimulus with simultaneous control of a special light scattering obstacle build in the visual path of one eye. The obstacle--a thin plate of electrooptical PLZT ceramics-- exposes (by applying of the voltage to semitransparent gold electrodes deposited on both surfaces of the plate) light scattering so blurring the retinal image, similar as for an eye with a cataract, depressing stereopsis. The random dot stereopair contains contours of images with a different stereodisparity. The PLZT plat…

Choosing local matching score method for stereo matching based-on polarization imaging

2010

Polarization imaging is a powerful tool to observe hidden information from an observed object. It has significant advantages, such as computational efficiency (it only needs gray scale images) and can be easily applied by adding a polarizer in front of a camera. Many researchers used polarization in various areas of computer vision, such as object recognition, segmentation and so on. However, there is very little research in stereo vision based on polarization. Stereo vision is a well known technique for obtaining depth information from pairs of stereo digital images. One of the main focuses of research in this area is to get accurate stereo correspondences. In our work, we will study and d…

Color difference threshold of chromostereopsis induced by flat display emission

2015

The study of chromostereopsis has gained attention in the backdrop of the use of computer displays in daily life. In this context, we analyze the illusory depth sense using planar color images presented on a computer screen. We determine the color difference threshold required to induce an illusory sense of depth psychometrically using a constant stimuli paradigm. Isoluminant stimuli are presented on a computer screen, which stimuli are aligned along the blue–red line in the computer display CIE xyY color space. Stereo disparity is generated by increasing the color difference between the central and surrounding areas of the stimuli with both areas consisting of random dots on a black backgr…

Comparison of stereo vision techniques for cloud-top height retrieval

2007

This paper presents an ongoing study for the estimation of the cloud-top height by using only geometrical methods. In agreement with some recent studies showing that it is possible to achieve reliable height estimations not only with the classical methods based on radiative transfer, this article includes a comparison of performances of a selected set of vision algorithms devoted to extract dense disparity maps or motion fields from Infra Red stereo image pairs. This collection includes both area-based techniques and an optical flow-based method and the comparison is accomplished by using a set of cloudy scenes selected from the Along-Track Scanning Radiometer (ATSR2) database. The first gr…

3-D shape reconstruction in an active stereo vision system using genetic algorithms

2003

Abstract The recovery of 3-D shape information (depth) using stereo vision analysis is one of the major areas in computer vision and has given rise to a great deal of literature in the recent past. The widely known stereo vision methods are the passive stereo vision approaches that use two cameras. Obtaining 3-D information involves the identification of the corresponding 2-D points between left and right images. Most existing methods tackle this matching task from singular points, i.e. finding points in both image planes with more or less the same neighborhood characteristics. One key problem we have to solve is that we are on the first instance unable to know a priori whether a point in t…