Visually Coupled Systems Hardware and the Human Interface By Dean Kocian and H. Lee Task Summarized by Geb Thomas

Topics n HMD optical systems n Helmet/Head tracking systems n System Integration n Applications

Visually Coupled Systems (VCS) n Integrates the natural visual and motor skills of an operator into the system he is controlling –head- or helmet-mounted visual display –head tracking and/or eye tracking system –visual information dependent on above signals physical source synthetic source

Simple Magnifier

Compound Microscope

See-Through HMD Type II has see-through, Type 1 has none.

Miniature Image Source n Emissive versus non-emissive n Monochrome (narrow bandwidth) versus color n Magnification n Luminance –diffuse versus Lambertian emitter n Resolution

Emissive Displays n Lasers -- low power, requires very reliable scanning system, requires high scan rates to avoid flicker problems n Field-emission displays (FEDs) -- Mission of individual electron emitter guns, combine to light a single pixel. Prototype 512x512 displays operate at 5kV

Miniature CRTs n Best choice for many see-through HMDs. n Disadvantages: long dimensions, high- voltage power supply, weight, hand assembly required n Advantages -- light conversion efficiency, resolution (>1M resolution elements/20 mm.), geometry correction in scan electronics.

Non-emissive Displays n Low voltage n Low current n Thermally sensitive n Subtractive color for LCDs.

Tracking Systems n Head/Helmet-mounted tracker (HMT) n Position and orientation tracker (P&OT) n Head orientation and position (HOP) n Resolution must be known and repeatable. n Multiple frames of reference (Eye, Earth, Space, Aircraft)

System Characteristics n System head coverage and motion box n Static accuracy n Resolution and repeatability n Update rate, throughput rate, and display refresh rate –for visual 240 Hz is OK, –for spatial hearing, may be required n # transducers, interference

System Integration n Ocularity –Monocular –Biocular –Binocular n Color n Type I or II n Field of View –Mono, total, binocular n Field of regard n Resolution n Luminance n Combiner ratio –transmittance, reflectance n Vignetting n Exit pupil size n Eye relief distance

More Integration Issues n Interpupillary distance mm n Distortion (barrel or pin-cushion) n Update rate n Refresh rate n Eye relief vrs FOV n Resolution vrs FOV n Focus/accommodation