3D – A team of researchers at the Kanagawa Institute of Technology (Kanagawa, Japan) headed by Masahiro Suzuki are addressing an interesting issue in 3D technology: development of a display system that is capable of presenting 3D imagery at a long distance. In the context of this work, a “long distance” means up to hundreds of yards. This is a considerably greater distance than images typically formed by current 3D display systems.
The reason that a display system having this long range capability is needed, is the advent of outdoor applications for which 3D imagery is a part of the desired solution. Perhaps one of the more interesting of these outdoor applications might be in an automobile navigation system. In such a system, navigation imagery is displayed in the space in front of the windshield and overlays the user’s view of the real world. The researchers suggest that the most intuitive and intelligible way of presenting such navigation imagery is to display the 3D images carefully aligned to the positions in real space as the features/objects used by the navigational system. One example in the vehicle navigation application that can be used to illustrate the need for the use of 3D imagery at a long distance is providing an arrow for directional guidance at an upcoming intersection that is tens to even hundreds of yards ahead.
It is certainly true that a conventional 3D display system, one based on the use of optical disparity as a depth cue, can produce 3D images that can be positioned at a range of distances. However, such conventional 3D displays are limited in their ability to provide refined distance information to a user when the virtual objects are at a large distance. This is a consequence of the characteristics of human vision. As an example, based on disparity alone, a user might just be able to detect a 20 yard difference in object distance when the object is about 200 yards away.
Since a simple disparity based approach alone does not meet the requirements for an in-vehicle navigation system, the researchers are developing a new 3D display methodology. The most recent results of the team were posted in a June 17th online article that is available for purchase here. The article will be published in Displays, Volume 35, Issue 4, October 2014, Pages 213-219.
The principle behind the new display technology derives from previous studies on human visual perception that have shown that changing object size strongly affects the perception of object distance. In the proposed system, the size of 3D virtual objects are smoothly changed as an additional cue to depth perception. In the navigation system application, the size of the change in virtual objects is determined based on the forward motion of the vehicle. This size adjustment is applied only to those 3D objects that are presented beyond a given distance from the vehicle. Going back to the previous example, as the user approaches an intersection, the virtual 3D directional arrow would be made to smoothly increase in size.
The article goes on to describe the results of experiments performed to evaluate the feasibility of the proposed approach to 3D at a distance. The evaluations consisted of subjective tests using a moving mini-van in which observers were presented a test pattern that overlaid the view of the real world seen through the windshield. The optical system utilized by the researchers is illustrated in the figure below.
The results obtained from these subjective tests demonstrated the ability to produce useful 3D images when the 3D objects were at a distance from tens to hundreds of yards. In future work, the researchers plan to further investigate the relation between range, vehicle velocity and object growth rate that can be usefully applied to the proposed display. -Arthur Berman
Kanagawa Institute of Technology, Masahiro Suzuki, +81-46-291-3315, [email protected]
