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# Device for Creating 3D Video Effect by Parallax

IP.com Disclosure Number: IPCOM000089412D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 5 page(s) / 113K

IBM

## Related People

Bantz, DF: AUTHOR [+2]

## Abstract

A device is described for creating a three-dimensional (3D) video effect by parallax by automatically processing digital data. Relative motion between overlayed images caused by parallax is used to distinguish foreground from background.

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Device for Creating 3D Video Effect by Parallax

A device is described for creating a three-dimensional (3D) video effect by parallax by automatically processing digital data. Relative motion between overlayed images caused by parallax is used to distinguish foreground from background.

The device performs automatically the function performed manually by the multiplane camera in animation. Fig. 1A shows a diagram of a camera and a number of transparent sheets for an animated scene. The scene consists of a man running with a background of trees and in the far background a scene of mountains. The man located on the top sheet remains in the center of the scene but the two backgrounds are moved small amounts to give a three dimensional effect. The effect being created is a camera travelling parallel to the man and at his speed. An effect similar to a camera panning the scene may be created.

Fig. 1B shows the geometry of producing the parallax effect. A camera moves from location C1 to C2. Object I, which was at the right edge of the scene, moves a distance a in the scene when the camera moves from C1 to C2. The fraction of the maximum motion across the scene is a/t, which is proportional to the distance from object I to the camera (the distance 1). The calculation is achieved as follows: m over t = s over l, by similar triangles m = a S = k, a constant depending on Alpha & m a/t = K 1 over l, fraction of motion across visible scene.

To place the invention in perspective, Fig. 2A shows a block diagram of a multiplane memory refreshing a raster CRT. The viewable image is the superimposition of the images stored in the three planes.

The first modification to the system of Fig. 2A required to facilitate a simulated multiplane camera is shown in Fig. 2B, where each plane of the refresh buffer contains a color image at a certain distance from the observer.

The desired viewable image is not the superimposition of the images held in the memory planes. The image is formed by observing that if the data in a memory plane corresponding to a certain distance from the observer is not transparent (transparent data is zero intensity for all the primary colors), then this data is displayed rather than the data for a corresponding point in a "more distant" plane. The combiner circuit (Fig. 2B) is a priority encoder, shown in more detail in Fig.
3. The priority encoder sets the multiplexer to select the data from register 1 (the "closest") if that data is not zero, otherwise from register 3. Register 3 may also be selected if all are zero. Thus, data from the "closer" memory planes (register 1 in this example) take precede...