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(a)
(b)
Fig. 5
An electronically captured unidirectional 3D holoscopic image a) Full. b)
Magnification.
Other optical techniques proposed for the pseudoscopic to orthoscopic conver-
sion by using a convergence lens as a substitute to the image transfer screen in
figure 2 [17]. However, due to the non-constant lateral magnification of the con-
verging lens, the reconstructed image appears clearly distorted.
Among digital methods proposed for pseudoscopic to orthoscopic conversion,
Okano
et. al.
[18-19] demonstrated a system which captures the micro-images us-
ing a microlens array in front of a high resolution video camera and electronically
inverts the each micro-image at the plane of capture. Although the image is ac-
ceptable the presentation reduces the parallax angle for close points in the scene.
Another digital technique for pseudoscopic to orthoscopic conversion has been
proposed by Martinez-Corral
et. al.
[20]. However, to avoid typical aliasing prob-
lems in the pixels mapping, it is necessary to assume that the number of pixels per
lenslet is a multiple of the number of lenslets. This makes the number of pixels per
micro-image very large (order of 100s) and renders the procedure impractical for
many 3D display applications.
3 Computer Generation of 3D Holoscopic Images
In recent years several research groups have proposed techniques for generating
3D holoscopic graphics [27-35]. However, most of the work concentrated on re-
producing the various physical setups using computer generation software pack-
ages. To produce computer generated 3D holoscopic image content a software
model capable of generating rendered orthoscopic 3D holoscopic images is
needed. The general properties of projective transformations were used in a vari-
ety of methods which evolved from micro-images containing spherical aberra-
tions, defocus and field curvature to micro-images generated using an approach
which alleviated many problems associated with the previous attempts. The
