By Andrew J. Woods, Centre for Marine Science and Technology, Curtin University

Abstract

Crosstalk, also known as ghosting or leakage, is a primary factor in determining the image quality of stereoscopic three dimensional (3D) displays. In a stereoscopic display, a separate perspective view is presented to each of the observer’s two eyes in order to experience a 3D image with depth sensation. When crosstalk is present in a stereoscopic display, each eye will see a combination of the image intended for that eye, and some of the image intended for the other eye—making the image look doubled or ghosted. High levels of crosstalk can make stereoscopic images hard to fuse and lack fidelity, so it is important to achieve low levels of crosstalk in the development of high-quality stereoscopic displays. Descriptive and mathematical definitions of these terms are formalized and summarized. The mechanisms by which crosstalk occurs in different stereoscopic display technologies are also reviewed, including micropol 3D liquid crystal displays (LCDs), autostereoscopic (lenticular and parallax barrier), polarized projection, anaglyph, and time-sequential 3D on LCDs, plasma display panels and cathode ray tubes. Crosstalk reduction and crosstalk cancellation are also discussed along with methods of measuring and simulating crosstalk.

Introduction

Stereoscopic three dimensional (3D) displays present a 3D image to an observer by sending a slightly different perspective view to each of an observer’s two eyes. The visual system of most observers is able to process the two perspective images so as to interpret an image containing a perception of depth by invoking binocular stereopsis so they can see it in 3D.

There are a wide range of technologies available to present stereoscopic 3D images to an audience, and the discussion in this paper will be limited to so-called “plano-stereoscopic” displays1—i.e., displays that present both left and right perspective images on the same planar surface and then use a coding/decoding scheme (e.g., glasses) to present the correct image to each eye. Examples of such plano-stereoscopic displays include liquid crystal display (LCD) or plasma display panel (PDP) 3D TVs viewed using active shutter 3D glasses, 3D LCD monitors or 3D cinema systems viewed using passive polarized 3D glasses, or autostereoscopic displays utilizing either a parallax barrier or lenticular lens sheet to allow the 3D image to be viewed without 3D glasses. The aim of all of these displays is to send separate left- and right-eye views to each eye, but due to various inaccuracies, which will be described in detail later in the paper, the image intended only for one eye may be leaked to the other eye. This leakage of one image channel to the other in a stereoscopic display system is known as crosstalk or sometimes ghosting or leakage. Crosstalk is a primary factor affecting the image quality of stereoscopic 3D displays and is the focus of this review paper.

This paper starts by providing a summary of descriptive and mathematical definitions of crosstalk and related terms as they are now in common usage, along with a short summary of the perceptual effects of crosstalk. The bulk of the paper describes the various methods by which crosstalk can occur in various stereoscopic display technologies. This is followed by a description of the methods of measuring crosstalk, a discussion of ways in which crosstalk can be reduced, and last, some coverage of the role of simulation of crosstalk analysis. [more…]

Source: Journal of Electronic Imaging