1. Chapter 4. Spatial Display Three Dimensions and depth Engineering Psychology and Human Performance Seo-Jung Ko, industrial Engineering , Hanyang University. 2. Contents 1. Three dimensions and depth2. Depth Judgments Object-Centered Cues Observer-Centered Cues Effect of Distance on Cue Effectiveness.3. Perceptual Hypotheses and Ambiguity faulty assumptions solutions4. three-dimensional displays of three-dimensional space Focused Attention and Artificial Frameworks Resolving Ambiguities. Stereoscopic DisplaysSeo-Jung Ko, industrial Engineering , Hanyang University. 3. contents 1. Three dimensions and depth2. Depth Judgments Object-Centered Cues Observer-Centered Cues Effect of Distance on Cue Effectiveness. 3. Perceptual Hypotheses and Ambiguity faulty assumptions solutions4. three-dimensional displays of three-dimensional space Focused Attention and Artificial Frameworks Resolving Ambiguities. Stereoscopic Displays Seo-Jung Ko, industrial Engineering , Hanyang University. 4. Three dimensions and depth definition there are situations in which a third dimension on a display is represented as depth, or as the perceived distance from the observer along an axis perpendicular(=vertical) to the plane of the display. These displays are intended to represent three dimensions of Euclidean spacetwo general purposes ① a display is constructed to guide the pilot in a flight path, or to plan the 3D trajectory ofa robot arm manipulating hazardous material. ② The display may use the third (depth) dimension to represent another (non-distance)quantity.To understand the advantages and costs of 3-D displays ① the causes of certain systematic distortions왜곡 in our ability to use depth in the natural world ② some of the fundamental characteristics of perceiving depth.Seo-Jung Ko, industrial Engineering , Hanyang University. 5. contents 1. Three dimensions and depth 2. Depth Judgments Object-Centered Cues : Characteristics of the object or world we are perceiving depth. Observer-Centered Cues : Characteristics of the human visual system. Effect of Distance on Cue Effectiveness. 3. Perceptual Hypotheses and Ambiguity faulty assumptions solutions4. three-dimensional displays of three-dimensional space Focused Attention and Artificial Frameworks Resolving Ambiguities. Stereoscopic Displays Seo-Jung Ko, industrial Engineering , Hanyang University. 6. Depth Judgments Object-Centered Cues 1. Linear perspective2. Interposition3. Height in the plane4. Light and shadow5. Relative (familiar) size6. Textural gradients7. Proximity-luminance covariance8. Aerial perspective9. Motion parallax Seo-Jung Ko, industrial Engineering , Hanyang University. 7. Depth Judgments Observer-Centered Cues1. Binocular disparity The images received by the two eyes, located at slightly different points in space, are disparate. The degree of disparity provides a basis for the judgment of distance. known as streoscopic displays . 2. Convergence “cross-eyed사시” required to focus on objects as they are brought close to the observer, is necessary to bring the image onto the detail-sensitive retina망막 of both eyes. Proprioceptive고유감각 message from the eye muscles to the perceptual centers of the brain inform the latter of the degree of convergence, and therefore of and object’s distance. 3. AccommodationIn this case the muscles adjust the shape of the lens수정체 to bring the image into focus on th e retina망막.Seo-Jung Ko, industrial Engineering , Hanyang University. 8. Depth Judgments Effect of Distance on Cue EffectivenessNot all the cues are equally effective at different distance.Of course, the range depicted in the figure is based on natural viewing situations and does not necessarily apply when depth is synthesized in displays.For examples, stereoscopic displays can be used to represent differences in the distance of objects that are miles away.Seo-Jung Ko, industrial Engineering , Hanyang University. 9. contents 1. Three dimensions and depth2. Depth Judgments Object-Centered Cues Observer-Centered Cues Effect of Distance on Cue Effectiveness. 3. Perceptual Hypotheses and Ambiguity faulty assumptions solutions4. three-dimensional displays of three-dimensional space Focused Attention and Artificial Frameworks Resolving Ambiguities. Stereoscopic Displays Seo-Jung Ko, industrial Engineering , Hanyang University. 10. Perceptual Hypotheses and Ambiguity Perceptual hypotheses and assumptions • We often speak of depth and distance perception as governed by perceptual hypotheses about the way things are, based on our assumptions.• These hypotheses and assumptions reflecting top-down processing are relatively automatic and unconscious.Examples of faulty assumptions1. a study by Eberts and MacMillan(1985) of the causes of rear-end collision. The frequency with which small cars are rear-ended is greater than that for large cars. They reasoned that drivers’ judgments about how far a car is in front, and there-fore how soon they must apply the brakes, are based on the cue of relative size.큰 차 : 상대적으로 가까이 있는 것 같아 보임. 브레이크를 일찍 밟는다.작은 차 : 상대적으로 멀리 있는 것 같아 보임. 브레이크를 늦게 밟는다.2. Figure 4.16 3. Figure 4.17Seo-Jung Ko, industrial Engineering , Hanyang University. 11. Perceptual Hypotheses and Ambiguity Examples of faulty assumptionssolution Figure 4.16 의 경우, 계기판을 주시Figure 4.17 의 경우, separated 그래프에도 눈금을표시하여 원근감에 따른 길이 기준을 설정권장 고도그렇더라도, 3차원에서 정확한 거리 판단 시체감 고도=조정 고도 깊이는 사용하지 않는 게 효과적. 체감 수평면 실제 수평면Seo-Jung Ko, industrial Engineering , Hanyang University. 12. contents 1. Three dimensions and depth2. Depth Judgments Object-Centered Cues Observer-Centered Cues Effect of Distance on Cue Effectiveness. 3. Perceptual Hypotheses and Ambiguity faulty assumptions solutions4. three-dimensional displays of three-dimensional space Focused Attention and Artificial Frameworks Resolving Ambiguities. Stereoscopic Displays Seo-Jung Ko, industrial Engineering , Hanyang University. 13. three-dimensional displays of three-dimensional space Effective of 3-D displays• a three-dimensional display representation is more compatible with the operator’s mental model of the three-dimensional world than a two-dimensional counterpart.• 3-D human form graphic was more effective than 2-D views when complex, asym metric postures were assessed –postures that would require integration of infor mation from all three spatial공간의 dimensions.Seo-Jung Ko, industrial Engineering , Hanyang University. 14. three-dimensional displays of three-dimensional space Effective of 3-D displays• a three-dimensional display representation is more compatible with the operator’s mental model of the three-dimensional world than a two-dimensional counterpart.• 3-D human form graphic was more effective than 2-D views when complex, asym metric postures were assessed –postures that would require integration of infor mation from all three spatial공간의 dimensions. Two limitations relative to their two-dimensional counterparts① three-dimensional displays are not effective displays for focused attention tasks. Focused Attention and Artificial Frameworks ② three-dimensional display generate false hypotheses. Resolving AmbiguitiesSeo-Jung Ko, industrial Engineering , Hanyang University. 15. three-dimensional displays of three-dimensional space Focused Attention and Artificial Frameworks • Three-dimensional representations in a two-dimensional display plane are inherently ambiguous in specifying absolute distances and depth.ex) figure 4.17의object display 보다separate display가 얼마나 수행하기 나은가.figure 4.19.a) 의 항공기 예측 상징은 비행경로 밑으로 얼마나 멀리 있는가.• A potential solution to this limitation may be offeredby incorporating artificial frameworks into the display. Seo-Jung Ko, industrial Engineering , Hanyang University. 16. three-dimensional displays of three-dimensional space Resolving Ambiguities. false hypotheses to be formed about depth and distancebecause the necessary cues for depth perception are not incorporated into the display. textural gradienterror of display interpretation logical solution would be to incorporate additional redundant depth cues, such as the cues of interp osition (hidden lines) and textural gradient shown in figure 4.20.cThe study of cue dominance • the addition of cues, particularly in computer-driven dynamic displays, can be expensive and should be avoided if they are unnecessary. The study of cue dominance :: interposition, motion parallax, and binocular disparitySeo-Jung Ko, industrial Engineering , Hanyang University. 17. three-dimensional displays of three-dimensional space Stereoscopic Displays a relatively accurate sense of three-dimensionality can be createdthrough stereopsis입체시, presenting slightly different images to the two eyes.Advantage of Stereoscopic Display1. adding stereo to a perspective display for judgments of azimuth방위각 and elevation of computer-generated objects. 2. time : adding binocular disparity information reduced response times. But..편광안경 등 전문적 장치 필요. 열악한 관찰조건. 낮은 강도, 해상도2차적 원근 디스플레이에 비해 이점이 거의 없음끝In Chapter 5, we will focus on interactive displays that are also spatial, andthe nature of the navigational tasks that often use such displays.(map)Seo-Jung Ko, industrial Engineering , Hanyang University.