Crosstalk (also known as "ghosting", "leakage", or "extinction"), a vitally important concept in stereoscopic 3D
displays, has not been clearly defined or measured in the stereoscopic literature (Woods). In this paper, a
mathematical definition is proposed which uses a "physical" approach. This derivation leads to a clear definition of leftview
or right-view crosstalk and shows that 1), when the display's black level is not zero, it must be subtracted out and
2), when the source intensities are equal, crosstalk can be measured using observed intensities totally within the
respective view. Next, a simple method of measuring crosstalk is presented, one that relies on only viewing a test chart
on the display. No electronic or optical instruments are needed. Results of the use of the chart are presented, as well as
optical measurements, which did not agree well with chart results. The main reason for the discrepancy is the difficulty
of measuring very low light levels. With wide distribution, this tool can lead to the collection of useful performance
information about 3D displays and, therefore, to the production of the best stereoscopic displays.
Single lens stereoscopy is the method where a stereo pair is derived by sampling light from two sides of an aperture within a single optical path. I first review the formation of the two images and the characteristics of these images. Of special interest are the differences between single-lens stereoscopy and dual-lens stereoscopy. Then I consider various practical considerations of using this method to make real-world products.
We review the literature on, and techniques for, the generation of left/right stereo pairs from a single lens--from 1677 to present. We attempt to answer the question: `Just how can you get two images from a single lens, anyway?'
In some applications, such as industrial inspection, it is often convenient or necessary to generate a stereo pair of images with a single photographic, X-ray, or video camera. The left and right views are created by moving the objects or the camera. This paper discusses this method of stereo image acquisition, illustrates some pitfalls, and shows how to overcome them. Examples images are presented that have come from applying the methods to the radiographic inspection of armament and tires.
`Volume imaging' is the process of visualizing image data that exists on a grid in three- dimensions: at every point in the volume, a gray-level or color value is known. These image volumes usually result from building a `stack' from a sequence of cross-sectional views, such as those from CT, MRI, and confocal imaging. Stereoscopic viewing is a very effective way of viewing and analyzing these volumes. The stereo pair is constructed using ray projections. My objectives for this paper are three-fold: (1) To present a new way to view stereo images on a PC computer. (2) To demonstrate the ease-of-use and high image quality of the system using sample images from confocal microscopy. (3) To present preliminary results for projection image processing on a PC from CT and MRI image stacks.
A stereoscopic system was developed that integrates hardware and software components for image acquisition, digitization, processing, display, and measurements. The model-induced trajectories of nearly neutrally buoyant fluorescent particles, illuminated with a 15-W pulsed copper vapor laser, are tracked in a towing tank by stereoscopic time-lapse photography using two 35-mm cameras positioned at a 90-degree angle from the top and the side. A C program, HI, drives two data I/O boards hosted in a PC to set up the run parameters, control the operations of the laser and camera shutters, and acquire the stereo images. The photographic records are digitized and processed to derive the centroids of reference marks and particle images. The centroids are then fed into a Windows-based program, Track/3D, to perform image correlation, correction for image distortion, stereo conversion, stereoscopic display, and measurements. The display module incorporates a graphics library that drives a stereoscopic display adapter attached to a monitor; the stereogram must be viewed with polarizing glasses. Functions are available for image translation, rotation, zooming, and on- screen measurements. The velocity and acceleration components of the 3-D flow field induced by the model are derived from the trajectories, serving as a basis for whole-field stereoscopic quantitative flow visualization.
The depth of an object in stereo is determined by the horizontal separation (i.e., disparity) of the object between the left and right images. For digitized images the disparity is in increments of pixels. Since all points in a given depth plane have the same disparity, the `cut- plane' procedure can theoretically eliminate a given depth plane by simply subtracting the stereo image pairs from each other after horizontally shifting them a specific number of pixels. Mathematical analysis and simulations with abstract objects have determined that both the length and disparity of objects with widths greater than one pixel may be modified by the `cut- plane' procedure; even when the object is not in the depth plane being eliminated. To what extent an object is modified depends on the original disparity and width of the object. The application of this procedure to chest x rays is presented with a demonstration of how certain pitfalls of the `cut-plane' procedure can be surmounted.