5.2 Enhancement of Depth, Viewing Angle, and Resolution of 3D Integral Images

In integral imaging the perception of depth is limited by out-of-focus images originating from a narrow depth of field area, by a narrow viewing angle given by the f-number of the lenses, defined as the focal length divided by the diameter of the aperture, and by limited resolution. The resolution of a small area of an elemental image is supposed to represent the better part of the entire object, which requires a large and not-easy-to-realize pixel density. Remedies for an improvement in all of these challenges will be presented in the following sections. There are solutions with only one or with several integral imaging devices.

5.2.1 Enhancement of Depth

The two integral imaging displays in Figure 5.4 carry 3D information of the same object but are focused on two different depths called central depth planes [5–7]. The beam splitter, here working as a beam combiner, superimposes the two elemental images which the viewer perceives as overlaid images, each focused in a different depth. The eyes can focus on one central depth plane but also glimpse the remainder of the image. When they then focus on the other central depth plane they have the sensation of an enhanced depth. Figure 5.5a and 5.5b shows the letter A in front of the letter B. While using only one display plate focused on the depth of letter A, the viewer sees the image in Figure 5.5a, where B is out of focus and hence broken up. With two display plates, one focused on A and the other on B, the viewer sees Figure 5.5b where both letters are clearly in focus.