System Introduction of Morphovision
1) Introduction
Recent progress in digital and
device technology has brought forth new 3D display techniques
[1]. These techniques share the ability to heighten viewer interest
by presenting 3D images that can be appreciated in natural circumstances
with the naked eye. In reflection of this demand for 3D images,
we devised a method for generating 3D images utilizing persistence
of vision, and achieved a new representation by distorting the
3D images in real time. We call this new method "Morphovision".
Morphovision is a unique display system that interactively transforms
and animates a 3D solid object before our eyes. In this system,
a model house is rotated at high speed, and is illuminated with
special lighting from a projector. This enables the model to be
distorted into various shapes.
2) Development of Morphovision
2.1 System configuration
The main technique of Morphovision
is to scan 3D objects rotating in a darkened environment with
slit lighting. This enables the 3D objects to be displayed in
distorted form. The system configuration is illustrated in Fig.2.
Morphovision consists of a projector that produces the slit lighting
image, a rotating polygon mirror for sequential scanning, and
a three-dimensional object that is illuminated with the slit lighting.
Figure 2 : System configuration
A high contrast, high resolution DLP projector is used for the projector to emit the slit lighting images. The 12-face polygon mirror produces a scanning angle of about 60 degrees. The slit lighting illuminates the entire object, but does not hinder the viewer.
2.2 Distortion principle
When a stationary object is lit
with a high-speed scanned slit lighting in a dark environment,
the object appears to be lit with normal lighting. When the object
is rotated at high-speed, the angle of lighted area changes according
to the rotation, while the slit lighting scans over the object.
When the rotation speed of the object is synchronized with the
scan speed of the slit lighting, the object appears as a stationary
distorted shape. This is caused by persistence of vision. The
type of distortion can be changed accordingly, by changing the
shape of the slit lighting image. When the slit lighting is given
a wavy shape, the object is distorted into a wavy shape, as seen
in Fig. 1 (b).
2.3 Creating the distorted house
We used Morphovision to create
the "Distorted House" exhibit Fig.1 (a)(b)(c).
The distortion effect is enhanced by using a house and ladder,
which we are accustomed to see as shapes formed from straight
lines and right angles. The display frequency is 20 Hz, the rotation
speed of the polygonal mirror is 100 rpm and the rotation speed
of the illuminated object is a little over 600 rpm. The system
provides 16 slit lighting patterns and two rotation directions,
which the viewer can select from a touch panel labeled with icons
(Fig.1 (d)). When the user touches the operation panel, the model
house begins to rotate, and the shape of the solid model becomes
distorted. The touch panel has a selection of icons showing different
patterns. The distortion can be viewed simultaneously by any number
of people, from any angle, without the use of special glasses.
3) Conclusion
The main objective of this work
was to develop a new 3D image generation system, and to apply
that system for creating new ways of representing 3D images. By
using Morphovision to construct the ÒDistorted HouseÓ exhibit,
we demonstrated the generation of a natural 3D image by means
of slit lighting illumination of 3D objects that are rotating
at high speed. Morphovision employs persistence of vision, which
is a characteristic also utilized in TV systems. Therefore, it
holds potential as a new 3D image display technique for TV systems.
Reference
[1]:"Perspecta Display",
Actuality Systems, Inc., 2002
http://www.actuality-systems.com/site/content/pdf/Actuality_Whitepaper_AeroSense_2002.pdf
Written by Takashi Fukaya