Moja lekcja

psychological cues of computer graphics

perspective shortening, occlusion of objects, light and shadow, texture gradients, atmospheric perspective

5 mile stones in VR

1949- first CG on a computer at MIT, 1956-sensorama, 1962-sketchpad the first interactive CG system, 1965-VR challenges(sutherland), 1968-the ultimate display of Sutherland

visible light + good and bad conditions

380(violet)-780(red), around 625 in bad conditions(scotopic), around 780 in good conditions(photopic)

) Why is stereoscopic vision alone not sufficient to fulfill all visual representation requirements of Virtual Reality?

Stereoscopic vision ⇒ illusion of depth in an image by presenting two offset images separately to the left and right eye • But: motion parallax is missing ⇒ no realistic feedback during motions of the users’ head

What additional feature has to be included to provide a “holographic” perception? and what kinda hardware is required for this?

User centered projection ⇒ Perspective has to be adapted to the users position and orientation? 2. Tracking system

Discuss the pros and cons of electro-magnetic and opto-electronic tracking systems, respectively (electro)

electro-magnetic: • + position and orientation • + no occlusion • - sensitive to ferromagnetic materials in the environment • - accuracy decreases with growing distance between sender and receiver • - rather large sensors (1–2 cm) • - cabling

Discuss the pros and cons of electro-magnetic and opto-electronic tracking systems, respectively (opto)

opto-electronic: • +accuracy • + passive markers available: no cabling, nearly non-intrusive + latency (-occlusion -no orientation (combine 3 non-collinear markers) -calibration process (rather comfortable in today’s systems)

Convergence

When watching an object close to us, our eyes point slightly inward. This difference in the direction of the eyes is called convergence

Stereopsis

As our eyes see the world from slightly different locations, the images sensed by the eyes are slightly different. This difference is called Binocular Paralax. binocular parallax is the most important depth cue for medium viewing distances.

Accommodation

Accommodation is the tension of the muscle that changes the focal length of the lens of eye. Thus it brings into focus objects at different distances

Motion paralax

If we close one of our eyes, we can perceive depth by moving our head. This happens because human visual system can extract depth information in two similar images sensed after each other, in the same way it can combine two images from different eyes.