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Perception of Objects in the World
Published in Robert W. Proctor, Van Zandt Trisha, Human Factors in Simple and Complex Systems, 2018
Robert W. Proctor, Van Zandt Trisha
Stereoscopic pictures take advantage of binocular disparity to create an impression of depth. A camera takes two pictures at a separation that corresponds to the distance between the eyes. A stereoscope presents these disparate images to each respective eye. The red and green or polarized lenses used for 3D movies accomplish the same purpose. The lenses allow each eye to see a different image. A similar effect occurs while viewing random-dot stereograms (Julesz, 1971), pairs of pictures in which the right stereogram is created by shifting a pattern of dots slightly from the locations in the left stereogram (see Figure 6.19). This perception of objects in depth takes place in the absence of visible contours. “Magic Eye®” posters, called autostereograms, produce the perception of 3D images in the same way but in a single picture (see Figure 6.20). This happens when you fixate at a point in front of or behind the picture plane, which then allows each eye to see a different image (Ninio, J. (2007). The science and craft of autostereograms. Spatial Vision, 21, 185�200). We don’t yet understand how the visual system determines what dots or part of an image go together to compute these depth relations in random-dot stereograms.
Adopting the instructional science paradigm to encompass training in virtual environments
Published in Florian Jentsch, Michael Curtis, Eduardo Salas, Simulation in Aviation Training, 2017
D. Dorsey, G. Campbell, S. Russell
The capabilities of VEs for training include architecture applications, engineering design, data representation and visualisation, teleoperation, checking emergency or standard operating procedures, planetary surface exploration, video game development, large-scale simulation networks and even interactive art (Ellis 1994, Wilson 1999). In military settings, VE technology has been used to train naval officers in ship manoeuvring and soldiers in battlefield strategy (Rose et al. 2000). In medical settings, virtual reality (VR) simulators of minimally invasive procedures have been used to interact with 'virtual' organs. In fact, physicians wishing to treat patients suffering from plaque build-up in the carotid artery must now undergo FDA-approved VR training on the use of specially constructed wire stents to improve blood flow (Scerbo 2005). VE applications such as 'virtual workbench' and 'responsive workbench' feature the projection of stereoscopic images onto a horizontal display surface to produce 3-D fields. Multiple users (even geographically distributed teammates) can stand around the workbench and interact with the VE using hand-held wands. Creem-Regehr et al. (2004) used a semi-immersive locomotion interface called 'the Treadport' to study perceptions of geographical slant (i.e. the slope of a hill). Students wearing a mechanical harness walked along a treadmill surrounded on three sides by projected landscape images.
Application of Taguchi Method on 3D Display Quality
Published in Peter Vink, Advances in Social and Organizational Factors, 2012
Ming-Hui Lin, Chin-Sen Chen, Yung-Sheng Chang, Sheue-Ling Hwang, Pei-Chia Wang, Hsiao-Ting Huang, Chao-hua Wen
Disparity is the main causes for viewers to experience depth while watching stereoscopic images. Research has shown that depth has correlation with visual experience and could affect viewers’ perceived image quality. Seuntiëns et al. (2007) used 3D video and found that increasing depth too much would decrease naturalness and viewing experience due to the artifacts that are created. Depth may also have a negative contribution to the image quality due to crosstalk, which leads to blurring and ghosting (Kaptein et al., 2008). Nevertheless, depth also has positive effect on visual experience. An increase in depth may lead to an enhanced sense of presence, provided depth is perceived as natural (IJsselsteijn et al., 1998).
Impact of parallax and interpupillary distance on size judgment performances of virtual objects in stereoscopic displays
Published in Ergonomics, 2019
Bereket Haile Woldegiorgis, Chiuhsiang Joe Lin, Wei-Zhe Liang
Display systems that mimic a human visual system (Kim 2005) should be ergonomically designed to meet the requirements of the users. To understand how stereoscopic cameras and display systems function, Woods, Docherty, and Koch (1993) suggested six parameters that need to be determined, as follows: distance between the cameras, convergence distance, fields of view of the cameras, distance of the observer from the display, display size and distance between the viewer's eyes. Different combinations of these parameters result in variable depth and size information, with different forms of distortion. In projection-based VR systems, the depth can be set by adjusting the distance between the images captured by the right and left eyes, termed parallax.
3D pavement macrotexture parameters from close range photogrammetry
Published in International Journal of Pavement Engineering, 2021
Marcelo Medeiros Jr., Lucas Babadopulos, Renan Maia, Veronica Castelo Branco
Photogrammetry or Stereoscopic vision is a technique used for recovering the 3D structure of a body from two or more photographs of the same object taken from different viewpoints (Liu et al.2020). The concept of stereoscopic vision to describe pavement surface texture is not new. In the 1970s, Schonfeld (1974) used this principle to describe pavement surface in terms of parameters such as, height, width, angularity, depth distribution, among others. His approach required the capture of several photographs of the pavement from various angles using an analog camera. These photographs were then viewed through a pair of stereographs and interpreted to determine the texture parameters based on a predefined table. Ordinary digital cameras can be used for tridimensional reconstruction of pavement's surface, using the so-called close-range photogrammetry (Kogbara et al.2018; Chen et al.2019). This process depends on the calibration of camera parameters and image overlapping processes which, will define relative positions between subsequent image snapshots. This approach is also capable of applying scale factors and correcting lens distortions (Nikolov and Madsen 2016). Although apparently complex, the process in question can be simplified by using a software package, which incorporates self-calibration algorithms, since a considerable number of subsequent images are taken. An in-depth description of the self-calibrating algorithms and further references on the subject can be found elsewhere (Luhmann et al. 2016; Ma and Liu 2018; Ramírez-Hernández et al.2020). These packages automatise the steps of self-calibration, feature matching, triangulation process, depth extraction, and 3D mesh generation. This way, topographical maps of the surfaces can be easily generated and analysed.
Adequacy of Immersive Virtual Reality for the Perception of Daylit Spaces: Comparison of Real and Virtual Environments
Published in LEUKOS, 2019
Kynthia Chamilothori, Jan Wienold, Marilyne Andersen
To create the perception of depth with two-dimensional images, we can generate a stereoscopic scene by projecting a different picture to each eye (Fig. 3, right) simultaneously. If the viewpoints of these images have a disparity in the horizontal axis in a measure equal to the interpupillary distance (d) of the subject’s eyes (Fig. 3, left), the resulting image is perceived as three-dimensional.