Eyestrain Reduction in Stereoscopy

Stereoscopic processes are increasingly used in virtual reality and entertainment. This technology is interesting because it allows for a quick immersion of the user, especially in terms of depth perception and relief clues. However, these processes tend to cause stress on the visual system if used over a prolonged period of time, leading some to question the cause of side effects that these systems generate in their users, such as eye fatigue. This book explores the mechanisms of depth perception with and without stereoscopy and discusses the indices which are involved in the depth perception. The author describes the techniques used to capture and retransmit stereoscopic images. The causes of eyestrain related to these images are then presented along with their consequences in the long and short term. The study of the causes of eyestrain forms the basis for an improvement in these processes in the hopes of developing mechanisms for easier virtual viewing.

Stereoscopic processes are increasingly used in virtual reality and entertainment. This technology is interesting because it allows for a quick immersion of the user, especially in terms of depth perception and relief clues. However, these processes tend to cause stress on the visual system if used over a prolonged period of time, leading some to question the cause of side effects that these systems generate in their users, such as eye fatigue.This book explores the mechanisms of depth perception with and without stereoscopy and discusses the indices which are involved in the depth perception. The author describes the techniques used to capture and retransmit stereoscopic images. The causes of eyestrain related to these images are then presented along with their consequences in the long and short term. The study of the causes of eyestrain forms the basis for an improvement in these processes in the hopes of developing mechanisms for easier virtual viewing.

Acknowledgments ixIntroduction xiChapter 1. Principles of Depth and Shape Perception 11.1. Function of the eye 11.2. Depth perception without stereoscopy 21.2.1. Monocular cues 21.2.2. Proprioceptive cues 71.3. Depth perception through stereoscopic vision 91.4. Perception of inclinations and curves 101.4.1. Perception of inclination and obliqueness 101.4.2. Perception of curves 141.5. Artificial stereoscopic vision 22Chapter 2. Technological Elements 252.1. Taking a picture 252.2. Reproduction 262.2.1. Colorimetric differentiation 272.2.2. Differentiation by polarization 282.2.3. Active glasses 302.2.4. Auto-stereoscopic screens 312.2.5. Virtual reality headsets 332.3. Motion parallax restitution 342.3.1. Pseudoscopic movement 342.3.2. Correcting pseudoscopic movements 352.3.3. Monoscopic motion parallax 40Chapter 3. Causes of Visual Fatigue in Stereoscopic Vision 413.1. Conflict between accommodation and convergence 413.2. Too much depth 443.3. High spatial frequencies 463.3.1. Limits of fusion 493.3.2. Comfort and high frequencies. 503.4. High temporal frequency 523.5. Conflicts with monoscopic cues 523.6. Vertical disparities 533.7. Improper device settings 553.7.1. Quality of image and display 553.7.2. Differences between left and right images 563.7.3. Speed of correction of pseudoscopic movements 57Chapter 4. Short- and Long-term Consequences 594.1. Short-term effects 594.1.1. Decreasing ease of accommodation 594.1.2. Decrease in stereoscopic acuity 594.1.3. Effects on the punctum proximum 614.1.4. More subjective effects 614.2. Long-term consequences 624.2.1. Long-term effects on children 62Chapter 5. Measuring Visual Fatigue 635.1. Visual acuity 635.1.1. Different possible measurements 645.1.2. Optotypes 645.2. Proximum accommodation function 655.3. Ease of accommodation 665.4. Stereoscopic acuity 675.4.1. Tests of distance vision 675.4.2. Tests of near vision 685.5. Disassociated heterophorias 715.6. Fusional reserves 725.7. Subjective tests 74Chapter 6. Reducing Spatial Frequencies 756.1. Principle 756.2. Technical solution 756.2.1. Wavelets 766.2.2. BOX FILTER 926.2.3. Using a rolling average and other "blurs" 986.2.4. Comparison of algorithms 1036.2.5. Chosen solution 1146.3. Experiment 1166.3.1. The task 1166.4. Measurements of fatigue taken 1186.4.1. Objective measurements 1186.4.2. Procedure 1196.4.3. The subjects 1206.5. Result 1206.5.1. Proximum accommodation function 1206.5.2. Ease of accommodation 1216.5.3. Stereoscopic acuity 1226.5.4. Effectiveness in execution of the task 1226.5.5. Subjective measurements 1236.5.6. Conclusions 1246.5.7. Discussion 124Chapter 7. Reducing the Distance Between the Virtual Cameras 1317.1. Principle 1317.1.1. Usefulness of stereoscopy in depth perception 1327.1.2. The objects 1337.1.3. Hypothesis 1427.2. Experiment 1427.2.1. Tasks 1427.2.2. Experimental conditions 1437.2.3. Subjects 1447.2.4. Measurements 1447.3. Results 1457.3.1. Results for fatigue 1457.3.2. Perception results 1477.4. Discussion 1527.4.1. Influence on visual fatigue 1527.4.2. Influence on visual perception 153Conclusion 155Bibliography 157Index 167