• Important to understand human abilities and limits • Determine appropriate range for input and output (frame rate, resolution, etc) • Understand that different senses have different ranges and abilities • Determine appropriate sensory channel to use to transfer information • Avoid sickness and injury
Human Perceptual Systems
• • • • • • Visual Vestibular Auditory Olfactory Haptic Gustatory
• Visual information is often considered the primary feature of virtual environments, we gather large amounts of information with vision in everyday life • The visual channel generally can process much larger bandwidth than other senses • This channel is also sensitive to very small anomalies, especially when motion is involved
Tips on Visual Perception
• Wider FOV is usually better • Use caution with large amounts of disparity • Use caution with motion, especially when it is fast, or wide FOV is used, or looming is involved • Consider that some simple depth cues may be much easier or cheaper to implement and result in only a slight decline in performance
• Audio in VEs is often absent or implemented poorly (only as an afterthought). But the entertainment industry recognizes that sound is vital to creating ambience and emotion. • Sound can also be used to transmit useful and important information • Senses such as visual must be directed at the stimulus to receive information – the auditory channel is continually receiving information. • When sound is done poorly, the brain notices!
• Senses movements/accelerations of the head/body. • Primary organs used are: – Three vestibular canals (rotations) – Otolith organs: Utricle and saccule (gravity and linear accelerations) – These organs are connected Your ear is not just a microphone! Image from www.kyent.com/ hearing_loss_types.htm
• We generally use information from this sense without conscious thought. We are usually aware of it only when something is wrong. • Vestibular information works together with visual and kinesthetic information to maintain posture. These senses are also tightly coupled. • This sense is a major factor in motion sickness and cybersickness – people without a working vestibular system do not experience these phenomenon.
• Compared to other senses, olfaction is poorly understood • lack of effective displays and difficulty in producing broad range of stimuli (no “RGB” for smell) make research difficult • available research is highly specific; other research is secretive (funded by perfume companies)
• olfactory events (odor sources) may be near or far, but directional sensitivity is generally poor • sensitivity is relatively high - we can detect odors in sparse concentrations (low threshold) • range of sensitivity is large - we can perceive in very small or very large quantities • temporal sensitivity is poor and response times are slow – may need between 20-60 seconds between stimuli to resolve different smells ("cleansing of the palate") – no real control over stimulus decay rate (without significant air circulation or respiration control)
• Basic elements of taste
– Sweet – Sour – Bitter – Salty – Smell – Umami – savory/meaty, Asian origin, found in glutamate
Taste receptor distribution
(1901 by Deiter Hanig)
– High variability between people – Different thresholds for each basic element – humans perceive bitterness in small quantities but need much more salt or sugar to experience a response – Learning/experience – Interactions between taste sensations – Affected by other senses - Strong influence of smell on taste – Need more than flavor, ex: texture, sensations like “fizz” – Primaries seem incomplete: “heat,” astringency, metallic…
• Greek term, relates to physical contact or touch, includes tactile/cutaneous...