Stereoscopic Motion-Picture Filming

motion-picture filming in which an object is photographed simultaneously from two or several viewing points in such a way that the images obtained on the film or films form a stereopair.

The basic system of stereoscopic motion-picture filming using a single-lens camera and two mirrors positioned at an angle to each other is shown in Figure 1 ,a. The object is viewed as if from two different points; the distance between these points is the photographic, or stereoscopic, base length. In the camera, the left and right images of a stereopair are produced on the film. Stereoscopic motion-picture filming using two lenses can be done in two ways. In the first method, two separate, synchronously operated, single-lens cameras are used, each with its own film. In the second method, a single, twin-lens, stereoscopic motion-picture camera photographs both images on a single film. In the twin-lens camera, a system of movable mirrors is used to adjust the magnitude of the stereoscopic base length (Figure l,b). Increasing the base length increases the resolution of fine relief details. When projected, however, such an image is perceived by the viewer as a model that can be distinguished from the real object because the dimensions are reduced.

Figure 1. Diagram of stereoscopic motion-picture filming: (a) with a single-lens camera, (b) with a twin-lens camera; (Ob) object being filmed, (C) motion-picture camera, (M,) left mirror, (M₁) right mirror, (C,) and (C₁) left and right apparent points of filming, respectively, (L) left image of a stereopair, (R) right image of a stereopair.

Figure 2. Diagram of panoramic filming: (A) and (B) points on the object being filmed, (L) large-diameter lens, (D) diaphragm, (K) lens-raster film, (A’) and (B’) images of the points A and B, respectively, on the lens raster of the film, (1’), (0’), and (2’) images of the point A on the photosensitive layer of the film, formed by rays that passed near the points 1, 0, and 2, respectively, on the lens

Stereoscopic multi-image filming is usually done with a motion-picture camera with multiple (up to ten) lenses. In panoramic filming, a continuous change of linear parallaxes is recorded for each point on the image. As a result, a multitude of images of the object, photographed from different points, is formed on the motion-picture film, and the images merge into one other (Figure 2). Such an image is called in Russian ksografiia. Additional spatial information about an object can be obtained by producing a hologram of the object.