Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

A framework for applying the principles of depth perception to information visualization

Cataloged from PDF version of article.During the visualization of 3D content, using the depth cues selectively to support the design goals and enabling a user to perceive the spatial relationships between the objects are important concerns. In this novel solution, we automate this process by proposing a framework that determines important depth cues for the input scene and the rendering methods to provide these cues. While determining the importance of the cues, we consider the user's tasks and the scene's spatial layout. The importance of each depth cue is calculated using a fuzzy logic-based decision system. Then, suitable rendering methods that provide the important cues are selected by performing a cost-profit analysis on the rendering costs of the methods and their contribution to depth perception. Possible cue conflicts are considered and handled in the system. We also provide formal experimental studies designed for several visualization tasks. A statistical analysis of the experiments verifies the success of our framework

Motion Parallax in Stereo 3D: Model and Applications

Binocular disparity is the main depth cue that makes stereoscopic images appear 3D. However, in many scenarios, the range of depth that can be reproduced by this cue is greatly limited and typically fixed due to constraints imposed by displays. For example, due to the low angular resolution of current automultiscopic screens, they can only reproduce a shallow depth range. In this work, we study the motion parallax cue, which is a relatively strong depth cue, and can be freely reproduced even on a 2D screen without any limits. We exploit the fact that in many practical scenarios, motion parallax provides sufficiently strong depth information that the presence of binocular depth cues can be reduced through aggressive disparity compression. To assess the strength of the effect we conduct psycho-visual experiments that measure the influence of motion parallax on depth perception and relate it to the depth resulting from binocular disparity. Based on the measurements, we propose a joint disparity-parallax computational model that predicts apparent depth resulting from both cues. We demonstrate how this model can be applied in the context of stereo and multiscopic image processing, and propose new disparity manipulation techniques, which first quantify depth obtained from motion parallax, and then adjust binocular disparity information accordingly. This allows us to manipulate the disparity signal according to the strength of motion parallax to improve the overall depth reproduction. This technique is validated in additional experiments

Use of Depth Perception for the Improved Understanding of Hydrographic Data

This thesis has reviewed how increased depth perception can be used to increase the understanding of hydrographic data First visual cues and various visual displays and techniques were investigated. From this investigation 3D stereoscopic techniques prove to be superior in improving the depth perception and understanding of spatially related data and a further investigation on current 3D stereoscopic visualisation techniques was carried out. After reviewing how hydrographic data is currently visualised it was decided that the chromo stereoscopic visualisation technique is preferred to be used for further research on selected hydrographic data models. A novel chromo stereoscopic application was developed and the results from the evaluation on selected hydrographic data models clearly show an improved depth perception and understanding of the data models

Spatial Displays and Spatial Instruments

The conference proceedings topics are divided into two main areas: (1) issues of spatial and picture perception raised by graphical electronic displays of spatial information; and (2) design questions raised by the practical experience of designers actually defining new spatial instruments for use in new aircraft and spacecraft. Each topic is considered from both a theoretical and an applied direction. Emphasis is placed on discussion of phenomena and determination of design principles

2d To 3d Video Conversion

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2011Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2011Son yıllarda 3 boyut teknolojisinin gelişmesiyle birlikte tüketici elektroniği piyasasında 3 boyutlu video içeriği ihtiyaç haline gelmiştir. 3 boyutlu gösterim teknolojisi tüketicilerin sahip olup, evlerinde kullanabilecekleri kaliteye erişmiştir. Fakat 3 boyutlu video içeriği 3 boyutlu gösterim cihazlarına oranla geride kalmış bulunmaktadır. Bunun sebebi, 3 boyutlu içerik oluşumu için gerekli olan stereoskopik kameraların çekim maliyetinin yüksek ve kameraların teknik kurulumunun zor olmasıdır. Aynı zamanda 2 boyuttan 3 boyuta çevrim problemi için 2 boyutlu içerik, manüel olarak 3 boyutlu grafiğe çevrilmektedir. Fakat bu iki yol, pahalı, zaman alıcı ve emek gerektiren yöntemlerdir. Bu metotlar yerine bilinen yöntemlerle çekilmiş 2 boyutlu videoları kamera parametre bilgileri olmadan 3 boyut efekti verebilen otomatik 2D/3D dönüştürücü algoritmaları bulunmaktadır. Bu tez çalışmasında, kamera parametleri bilinmeyen 2 boyutlu bir videoya 2D/3D dönüştürme algoritması uygulanarak 3 boyutlu görüntü efektinin oluşturulması hedeflenmiştir. Algoritmayı kurgulamak için, insan derinlik algısı ve 2 boyutlu içerik bilgisi ile 3 boyutlu içerik bilgisi arasındaki ilişki (derinlik haritası) araştırılmıştır. 2 boyuttan 3 boyuta dönüşüm algoritmasında iki farklı method kullanılarak 3 boyut efekti elde edilmeye çalışılmıştır. İlk yöntemde, derinlik haritası, hareket kestirimi yöntemi sonucu elde edilen hareket vektörleri ile oluşturulmuştur. Ve ikinci yöntemde derinlik haritası kenar bilgisi kullanılarak oluşturulmuştur. Derinlik bilgisi sayesinde, iki metot da aynı kaydırma algoritmasını kullanarak yapay stereoskopik çift (sol ve sağ resim) oluştururlar. Stereoskopik video sonuçları görebilmek ve aynı zamanda en ucuz yöntem olduğu için, sonuçlar anaglif formata çevrilmiştir. İzleyebilmek için anaglif gözlüklere ihtiyaç duyulmaktadır. Oluşan stereoskopik videoların kalitesi sübjektif olarak değerlendirilmiş ve kullanılan iki farklı yöntem de birbirleri ile kıyaslanmıştır. Dahası hesaplama zamanları hesaplanmış ve birbirleri ile karşılaştırılmıştır.In recent years, with the development of 3D technology 3D video content has become a need for the consumer electronics market. 3D display technology has reached the quality that consumers can buy and use it in their homes. However, compared with 3D display devices, the development of 3D video content has remained behind. The reason of that is stereoscopic cameras, which are required for shooting 3D content of the video, are very expensive and the technical setup of these cameras is difficult. At the same time, for the problem of 2D to 3D conversion, 2D content information is manually converted to 3D graphics. However, these shooting and manually converting methods are expensive, time consuming and labor-intensive methods. Instead of these methods, there are automatic 2D to 3D conversion algorithms, which generate 3D effect from conventional videos without knowing specific camera parameters. In this thesis, 3D effect generation is aimed by applying 2D to 3D conversion algorithm applied to a conventional 2D video with unknown camera parameters. For implementing this algorithm human depth perception and the relation between 2D and 3D content information (depth map) were investigated. For the 2D to 3D conversion algorithm, two different methods are used to obtain the 3D effect. In the first method, the depth map was generated by using motion vectors that are obtained using motion estimation. In the second method, the depth map was generated by using edge information. With respect to depth information, both methods use the same shift method to create artificial stereo image pairs (left and right images). Results were converted to the anaglyph format for viewing stereoscopic videos. The other reason to use the anaglyph format is that it is the cheapest way to view the stereoscopy. Created stereoscopic videos are evaluated subjectively. Two different methods are used and compared to each other. Computational run time results are also calculated and compared to each other.Yüksek LisansM.Sc

Bringing the real world into the fMRI scanner: Repetition effects for pictures versus real objects

Our understanding of the neural underpinnings of perception is largely built upon studies employing 2-dimensional (2D) planar images. Here we used slow event-related functional imaging in humans to examine whether neural populations show a characteristic repetition-related change in haemodynamic response for real-world 3-dimensional (3D) objects, an effect commonly observed using 2D images. As expected, trials involving 2D pictures of objects produced robust repetition effects within classic object-selective cortical regions along the ventral and dorsal visual processing streams. Surprisingly, however, repetition effects were weak, if not absent on trials involving the 3D objects. These results suggest that the neural mechanisms involved in processing real objects may therefore be distinct from those that arise when we encounter a 2D representation of the same items. These preliminary results suggest the need for further research with ecologically valid stimuli in other imaging designs to broaden our understanding of the neural mechanisms underlying human vision

A fuzzy logic based approach for enchanging depth perception in computer graphics

Ankara : The Department of Computer engineering and the Institute of Engineering and Science of Bilkent University, 2010.Thesis (Master's) -- Bilkent University, 2010.Includes bibliographical references leaves 78-83.Rapid progress in 3D rendering and display technologies brings the problem of better visualization of 3D content. Providing correct depth information and enabling the user to perceive the spatial relationship between the objects is one of the main concerns during the visualization of 3D content. In this thesis, we introduce a solution that can either be used for automatically enhancing the depth perception of a given scene, or as a component that suggests suitable rendering methods to application developers. In this novel solution, we propose a framework that decides on the suitable depth cues for a given 3D scene and the rendering methods which provide these cues. First, the system calculates the importance of each depth cue using a fuzzy logic based algorithm which considers the user's tasks in the application and the spatial layout of the scene. Then, a knapsack model is constructed to keep the balance between the rendering costs of the graphical methods that provide these cues and their contribution to depth perception. This cost-pro t analysis step selects the proper rendering methods for the given scene. In this work, we also present several objective and subjective experiments which show that our automated depth perception enhancement system is statistically (p < 0.05 ) better than the other method selection techniques that are tested.Çipiloğlu, ZeynepM.S