![]() ![]() Further investigations are needed to evaluate the importance of motion parallax for people with impaired vision. While motion parallax is an important source of depth information in a scene presented on a screen, in the physical world, pictorial cues may often be sufficient for estimating the depth of objects, reducing the importance of motion parallax. Lateral motion parallax only increased the accuracy of depth estimation when the acuity reduction was severe and the pictorial cues in the scene were manipulated to be misleading. The accuracy of depth estimation for static viewing in the physical space was higher than that in the virtual space, and the effect of observer motion was weaker. Chapter 4 examines the effect of motion parallax for observers who walked in a physical space. The results show that when estimating object depth in a virtual scene on a computer screen, for participants with both intact acuity and artificially reduced acuity, the accuracy in the static viewing condition was low, lateral motion parallax yielded higher accuracy than expansive motion parallax, and the continuous motion was more beneficial than discrete object image displacement. Chapters 2 and 3 focus on the effect of visual signals from motion parallax. In all three experiments, the participants looked at two objects in a virtual or physical scene and estimated the depth separation between the objects either by moving a slider on the screen or by verbal report. Chapter 1 provides an overview of the three experiments described in the thesis. The present paper will focus on the relative effectiveness of motion parallax as compared to stereoscopic depth perception. ![]() To control the level of acuity loss, the participants included in this thesis were normally sighted, and the acuity reduction was simulated with digital filters or blur goggles. ![]() This thesis investigates three questions regarding the effect of motion parallax on depth perception for people with intact and artificially reduced acuity: whether motion parallax increases depth perception accuracy compared to static viewing with pictorial depth cues present whether expansive and lateral motion parallax differs from each other in assisting depth perception and whether continuous motion provides more benefit to accurate depth perception than object image displacement. When an observer walks forward to approach an object, the image of the object expands in the field of view, inducing expansive motion parallax when the motion direction of the observer contains a lateral component, the object image shifts laterally to the left or right, which is termed lateral motion parallax. Motion parallax: As an observer moves laterally, nearer objects move more quickly than distant ones. When an observer moves through an environment, the retinal images of surrounding objects shift in the field of view, creating motion parallax, which can be used to infer the depths of the objects. (In the past this has required a special piece of equipment called a "multiplane camera" - see the extras on Disney's Bambi DVD for details - but the effect has become much easier to manage in the digital age.) Excessively cheap animation (see Filmation, Hanna-Barbera) uses the single Wraparound Background, and this intensifies the fakeness.Depth perception is essential for safe and effective mobility. To get around this problem in animation, some use multiple background cel layers, moving at different speeds. A common bragging point on the boxes of many games is the number of simultaneously composited scrolling parallax layers the game displays at once. This same idea was used to create pseudo-3D backgrounds for computer games during the 16-bit era, when computers and consoles didn't have the horsepower for proper, textured 3D. Live action shows with windows on the set (and sufficient budgets) will often build the landscape outside as several layers of flat cutouts, thus giving some motion parallax to the background. It can call into question, very quickly, the flatness of a painted backdrop, either on set or in animation. Thus, any truck or pedestal movement will reveal depth information not available to the single eye of the camera. The monocular motion parallax happens when you move your head and objects that are farther away appear to move at a different speed than those. Some neurological research suggests that motion parallax gives more depth-perception information than our binocular vision does, note which makes sense given that neither retinal disparity nor convergence is useful out past about 50 feet / 17 meters or so thus a one-eyed person can still determine distance quite well, if he moves his head a bit. Monocular motion parallax This one’s a mindblower. This is due to the distortion of length due to perspective. When an observer is in motion, from side to side or vertically, distant objects will seem to move much slower than nearby objects. ![]()
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