Live-action stereoscopic feature films are, for the most part, produced using a costly post-production process to convert planar cinematography into stereo-pair images and are only occasionally shot stereoscopically using bulky dual-cameras that are adaptations of the Ramsdell rig. The stereoscopic lens design described here might very well encourage more live-action image capture because it uses standard digital cinema cameras and workflow to save time and money.
A primary requirement when elements are to be combined stereoscopically, is that homologous points in each eye view
of each element have identical parallax separation at any point of interaction. If this is not done, the image parts on one
element will appear to be at a different distance from the corresponding or associated parts on the other element. This
results in a visual discontinuity that appears very unnatural. For example, if a live actor were to appear to "shake hands"
with a cartoon character, a very natural appearing juncture may appear to be the case when seen in 2-D, but their hands
may appear to miss when seen in 3-D.
Previous efforts to compensate, or correct these errors have involved painstaking time-consuming trial-and-error tests.
In the area of pure animation, efforts to make cartoon characters appear more realistic were developed. A "motion
tracking" technique was developed. This involves an actor wearing a special suit with indicator marks at various points
on their body. The actor walks through the scene, then the animator tracks the points using motion capture software.
Because live action and CG elements can interact or change at several different points and levels within a scene,
additional requirements must also be addressed. "Occlusions" occur when one object passes in front of another. A
particular tracking point may appear in one eye-view, and not the other. When Z-axis differentials are to be considered
in the live action as well as the CG elements, and both are to interact with each other, both eye-views must be tracked,
especially at points of occlusion.
A new approach would be to generate a three dimensional grid, within which the action is to take place. This grid can
be projected, onto the stage where the live action part is to take place. When differential occlusions occur, the grid may
be seen and CG elements plotted in reference to it. Because of the capability of precisely locating points in a digital
image, a pixel-accurate virtual model of both the actual and the virtual scene may be matched with extreme accuracy.
The metrology of the grid may also be easily changed at any time, not only as to the pitch of the lines, but also the
introduction of intentional distortions, such as when a forced perspective is desired.
This approach would also include using a special parallax indicator, which may be used as a physical generator, such as
a bar-generator light and actually carried in the scene. Parallax indicators can provide instantaneous "readouts" of the
parallax at any point on the animator's monitor. Customized software would equate as the cursor is moved around the
screen, the exact parallax at that indicated pixel would appear on the screen, immediately adjacent to that point.
Preferences would allow the choice of either keying the point to the left-eye image, the right-eye image, or a point midway
Stereoscopic DVDs can now be created in many different formats including alternate image, for use with alternate image viewing devices such as alternate field and alternate frame type LCD glasses. DVD welcomes al forms of stereoscopic content and provides a dynamic method for presentation as well as distribution. Because of its universal compatibility, there are specific standards and specifications that must be adhered to in preparing your content for DVD. Alternate field presentations are especially vulnerable to these compression schemes but encoders can be manipulated to maintain content integrity. The navigational capabilities of the DVD specification leave a tremendous amount of creative liberties. This freedom led to the development of the zDVDtm. The zDVDtm Is a DVD disc that allows the viewer to seamlessly switch between watching the program in standard 2D or stereoscopic 3D.
The display of stereoscopic images implies an attempt to create as realistic an exhibition as can be attained with the particular image display system as possible. Therefore, consideration must be given to the method by which the human visual mechanism perceives and renders such images, so both in the real world and as a result of viewing such displays. Although there are several similarities between the way images are perceived by the human visions system in real life and the way they are perceived when viewing stereoscopic displays, there are also several very important differences. The substance of this paper is directed toward the minimization or, where possible, the elimination of these differences. Both stereoscopic and autostereoscopic display systems are covered, and specified separately where necessary. From the standpoint of the relationship of human vision to the design of a particular display, in many (but not all) instances the requirements necessary to simulate normal human vision are similar in both stereoscopic and autostereoscopic type displays. The descriptions as referenced to, are compared with the corresponding function(s) of the human visual mechanism, emphasizing the strong correlation of the eye-brain model, and the ways by which our perception is affected by the parameters of the particular display.