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10.1117/2.1200702.0547
3D display with floated integral
imaging
Byoungho Lee, Joohwan Kim, and Sung-Wook Min
Floating display and integral imaging technologies can be combined to
produce 3D images for unaided viewing at close range.
With flat-panel display technologies approaching saturation,
prospects for 3D techniques are currently attracting much industry
attention. We suggest a new system for generating images
that appear three-dimensional to viewers without the need for
special glasses.
Our system combines two 3D display techniques: integral
imaging and floating display. 1–3 An integral imaging system
consists of a two-dimensional (2D) lens array and display system.
An elemental image on a 2D panel gives a different perspective
to each elemental lens, as shown in Figure 1. The lens
array integrates the elemental images to form a 3D image with
full parallax and an almost continuous view.
However, due to the lens law, integral imaging provides good
quality 3D only around an image plane that delivers a focused
image. If the separation between the lens array and display plane
is equal to the focal length of the lens array, the image plane can
be located at infinity. In this case, a 3D image may be formed at
any location, but with poor resolution. Hence, with the display at
a distance, a method is needed to bring the 3D integrated image
closer without sacrificing quality.
A floating display would be one solution. This 3D technique,
frequently used in exhibitions and magic shows, employs a convex
lens (also known as a floating lens) or concave mirror to form
a realistic image close to the observer. This technology typically
uses 2D images for dynamic image-floating systems. Our proposed
system uses a convex lens to move a 3D image constructed
by integral imaging into the vicinity of the observer, as depicted
in Figure 2.
Important parameters for such a system include the viewing
window, viewing angle, and expressible depth range. Angle and
expressible depth range are related to image parameters while
the window is a unique display characteristic in this system. It
is a 2D area through which 3D images, undistorted or unbro-
Figure 1. The concept of integral imaging.
ken, can be observed. This is explained by the fact that parallel
rays refracted by a convex lens converge at its focal plane.
Moreover, the point of convergence is farther from the principal
axis because the rays are steeper before refraction. We can
thus conclude that the position of the viewing window is at the
focal plane, and its border will be made up of by the convergent
points of the rays forming the viewing angle of the integral
imaging system. We have discussed and analyzed this system in
detail elsewhere. 2
We have implemented an integral floating display using a
floating lens with a focal length of 175mm. The integral imaging
system had a viewing angle of 32 ◦ and the lens array was
comprised of 13 × 13 lenses with focal lengths of 22mm. We calculated
the size of the viewing window to be 101mm × 101mm,
while the viewing angle was 14 ◦ with an expressible depth range
of 19mm. Figure 3 shows the experimental results.
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10.1117/2.1200702.0547 Page 2/2
SPIE Newsroom
Byoungho Lee received his PhD in electrical engineering and
computer science from the University of California at Berkeley
in 1993 . Since 1994 he has been with Seoul National University,
where he is currently a full professor. He has authored or
coauthored more than 180 papers in international journals and
presented more than 290 international conference papers. He is
a fellow of SPIE and OSA, and has served as a member for the
Engineering, Science and Technology Policy (ESTeP) Committee
of SPIE.
References
1. S. -W. Min, M. Hahn, J. Kim, and B. Lee, “Three-dimensional electro-floating
display system using an integral imaging method,” Optics Express 13(12), pp. 4358–
4369, 2005.
2. B. Lee, J. Kim, and S. -W. Min, “Integral floating 3d display system: principle
and analysis,” Three-Dimensional TV, Video, and Display V, Optics East, Boston, MA,
USA, Proc. SPIE 6392-18, 2006.
3. J. -H. Park, S. -W. Min, S. Jung, and B. Lee, “Analysis of viewing parameters
for two display methods based on integral photography,” Applied Optics 40(29),
pp. 5217–5232, 2001.
Figure 2. (a) The concept of the integral floating display and (b) its
implementation.
Figure 3. The experimental results. The left view was taken at an angle
of 7 ◦ to the left and the right view at an angle of 7 ◦ to the right (viewing
angle of 14 ◦ ). In the left and right views we placed white lines at
the predicted borders of the viewing window, with the flipped images
positioned such that they can be concealed if we block the area outside
the window. The objects are constructed to be positioned inside the expressible
depth-range to ensure that perspective and shape are of good
quality.
Author Information
Byoungho Lee, Joohwan Kim and Sung-Wook Min
School of Electrical Engineering
Seoul National University
Seoul, Korea
http://oeqelab.snu.ac.kr
c○ 2007 SPIE—The International Society for Optical Engineering