Once again, the trend toward portability appears. An important step for VR was taken in 1968 with the introduction of Ivan Sutherland's Sword of Damocles, which leveraged the power of modern displays and computers (Figure 1.30(b)) [320,321]. He constructed what is widely considered to be the first VR headset. As the user turns his head, the images presented on the screen are adjusted to compensate so that the virtual objects appear to be fixed in space. This yielded the first glimpse of an important concept in this book: The perception of stationarity. To make an object appear to be stationary while you move your sense organ, the device producing the stimulus must change its output to compensate for the motion. This requires sensors and tracking systems to become part of the VR system. Commercial VR headsets started appearing in the 1980s with Jaron Lanier's company VPL, thereby popularizing the image of goggles and gloves; Figure 1.30(c). In the 1990s, VR-based video games appeared in arcades (Figure 1.30(d)) and in home units (Figure 1.30(e). The experiences were not compelling or comfortable enough to attract mass interest. However, the current generation of VR headset leverages the widespread availability of high resolution screens and sensors, due to the smartphone industry, to offer lightweight, low-cost, high-field-of-view headsets, such as the Oculus Rift (Figure 1.30(f)). This has greatly improved the quality of VR experiences while significantly lowering the barrier of entry for developers and hobbyists. This also caused a recent flood of interest in VR technology and applications.
Steven M LaValle 2019-03-14