3D Displays, by Ernst Lueder -
Introduction from the book:
The design and manufacture of displays are now mature enough to introduce three-dimensional (3D) displays into the marketplace. This happened first with displays for mobile devices in the form of near-to- the-eye displays, but home TV will follow suit. This book covers five approaches to realize 3D perception, namely, stereoscopic and autostereoscopic displays, integral imaging, holography, and volumetric displays.
The intention guiding the book is to promote a well-founded understanding of the electro-optic effects of 3D systems and of the addressing circuits. Equations are as a rule not simply stated but are derived, or, if not fully done so, at least hints for the derivation are given. An example of this concept is the explanation of the basics of holography by phasors, which will be outlined, but which are also known from electrical engineering or from the Jones vector. This renders complex facts associated with holograms easier to understand.
Emphasis is placed on stereoscopic and autostereoscopic displays as they are closest to being commercialized. The basic components of stereoscopic displays are patterned retarders and to a lesser degree wire grid polarizers. Autostereoscopic displays rely on beam splitters, lenticular lenses, parallax barriers, light guides and various types of 3D films. All of these elements are explained in detail.
The glasses required for stereoscopic displays distinguish between the left and the right eye views either by shutters or by circular polarization. Linearly polarized glasses have the disadvantage of being sensitive to tilting of the head.
Special attention is given to 3D systems working in a spatial or temporal multiplex, as well as in a combination of the two, and to novel fast addressing schemes. In order to suppress crosstalk and blur, a
240 Hz frame rate is preferred. The increased speed of addressing is handled by parallel processing and by
the recently published interleaved addressing, which also parallels the images. Special care is taken to outline how the autostereoscopic approach is able to provide side views, the perspectives, of the object. This paves the way for an understanding of integral images (IIs) with a pickup stage for information similar to the lenticular lenses of the autostereoscopic displays. Very naturally this leads to the ingenious design of an II projector working with real and virtual images where the viewer can walk around the
displayed object, thus enjoying a first solution for a true 3D display.
The chapter on holography leads the reader on to digital computer-generated holography, which is not yet a real-time process.
Volumetric displays consist of a stack of LCDs, each of which is devoted to a particular depth, where also the limitations of the fusion of the images become noticeable.
Notably, Chapter 4 is devoted to familiarizing designers of flat panel displays with the work done by computer scientists on the assessment and improvement of 3D image quality. Algorithms are introduced for evaluating the properties of 3D displays based on objective and subjective criteria and on tracking the motion of selected special features. Special attention is drawn to establishing disparity maps and preparing a 3D image ready for transmission with a bandwidth-saving “depth image - based rendering” (DIBR). Head tracking for 3D reception by a group of single viewers is not included.