Spinning-disc 3D Television
Hideaki NII∗

Kouta Minamizawa†
The University of Tokyo

Naoki Kawakami‡

Susumu Tachi§

Figure 1: Image of Spinning-disc 3D Television(Left), Looking from another angle(Right)

1 Executive Summary
In this work, we have incorporated a novel LED-projection technology into the simple structure of a spinning-disc television. Inorder to display a 3D image, we have replaced the conventionallyused light bulbs with an LED array. With the aid of this technology,
users can view different images from different viewing angles.

2 Project Overview
The transmission of three-dimensional (3D) images can be used tocreate the visual experience of people and objects at remote locations sharing the same spatiotemporal space. In other words, 3D
image transmission technology can eliminate the boundary between
spatial and temporal domains. Our ultimate goal is to develop an
image display technology that can eliminate the distance between
two spaces so that users perceive the 3D presence of an object.
Toward this goal, we have previously developed TWISTER[Tanakaet al. 2002] and Seelinder[Endo et al. 2005] to realize an autostereoscopic display without the need for wearing any special equipment.
The present work extends the abovementioned prototypes toward
reconstructing a more natural 3D ”presence” of objects. The firstspinning-disc television system was publicly demonstrated by J. L.
Baird in 1926[Tiltman 1933]. This system realized the spatial transmission of two-dimensional visual information. Baird was also
the first to invent a stereoscopic display that employed the same
method. The attractiveness of this method lies in the fact that theresulting reconstructed images are sufficiently realistic for the user
to perceive the presence of an object. In this work, we have incorporated a novel LED-projection technology into the classical structureof the spinning-disc television. In this system, the light rays aroundFigure 2: Diagrammatic illustration

an object are first acquired. Each of these light rays is then projected in order to reconstruct the motion parallax and the binocularstereopsis. The system can use this process to acquire, reconstruct,
or even deform volumetric visual information at a remote location.
The visual experience provided by this system can overcome spatial and temporal distances, thereby enabling the convergence of theentire on the same visual plane.

3 Vision∗ E-mail:Hideaki Nii@ipc.i.u-tokyo.ac.jp† E-mail:kouta minamizawa@ipc.i.u-tokyo.ac.jp‡ E-mail:kawakami@star.t.u-tokyo.ac.jp§ E-mail:tachi@star.t.u-tokyo.ac.jp

A spinning-disc 3D television can improve 2D image display. Thissystem displays not only a flat image but also one that is in spatial
motion without the user having to wear any special glasses. People
can view the correct 3D video image from their individual viewing
positions.
This system will be used for installation art work. In the future, thissystem might serve as the foundation for the development of 3D
display systems.

The screen resolution is 45 × 45 pixels (see Figure 1). The frame
rate is up to 20 frames per second (fps), and the screen size is 25mm × 25 mm.
The Siggraph version will have a larger disc and higher resolution.
In this system, the LED array will have a 64-pixel resolution andthe observer can view 64 images. The photo sensor array will also
have a 64-pixel resolution, similar to the LEDs.
Therefore, 64 different images can be captured and displayed. Theframe rate of this system will be up to 30 fps.

5 Context
Figure 3: Implementation of the system

4Technical Innovation

The system displays multiple images based on the viewer’s line ofsight. It can display both horizontal and vertical parallax. Currently,
the system can display twenty monocolor images simultaneously.
Plans are currently underway to develop this system further so thatit displays eight by eight full-color images. The system can capture
the images by the camera part. In addition, it can display movingimages. Figure 2 show a diagrammatic illustration of the system.
This system comprises three components:• spinning disc with holes• LED array for displaying multiple images• photo diode array for capturing multiple images
The spinning disc, also known as the Nipkow disc, controls the raysof light, which pass through its hole. The rotating disk has holesarranged in a spiral formation around its circumference. The lightthat passes through the holes as the disk rotates produces a rasterscanning pattern with a rectangular area. As a result, the disc canconvert the time-line light intensity from a scene for image capture
or convert an image from the time-line light intensity for image
display.
The LED array can display multiple images simultaneously. The
conventional Nipkow disc employs only a single bulb, and it candisplay only a single image. In this new system, however, each
LED element displays different images and an observer can view
different LED elements through the hole in the disc.
The photodiode array captures different images by the same method
as that employed by the LED array. Conventionally, the photodiodearray employs only a single light detector, which is placed behindthe disc. In our system, however, each viewing direction has a separate light detector array.
With the aid of these components, the system can display multiple
parallax images.

4.1

System Configuration

We have developed a prototype display system (see Figure 3). This
prototype system has a 380-mm-diameter Nipkow disc with 45
holes. It has twenty LEDs placed behind the disc, and the observer
can view twenty different images from his/her viewing position.

Thus far, many systems that can suitably realize stereoscopic andmultiple parallax displays have been proposed. Among stereoscopic systems are several varieties of head-mounted displays(HMDs)[Sutherland 1968] and immersive multi-display units suchas CAVE[Cruz-Neira et al. 1993]. These systems require the observer to wear special glasses for stereopsis. However, observers
would find it more convenient to view a display without wearing
special glasses. In order to circumvent this problem, parallax barriers and lenticular lenses have been used in a number of systems.
We developed TWISTER[Tanaka et al. 2002], an immersive autostereoscopic display. This system works as a cylindrical display
by rotating 36 display units around the observer while preserving
the time-varying patterns. Each of these display units contains
two LED arrays, one vertical 1D array for each eye, and a thinbarrier. The units rotate at a speed of about 100 revolutions per
minute (rpm), and the controller synchronizes the display update
to create an effective frame rate of 60 fps. With this system, theobserver can view a stereoscopic image in 360˚ without wearing
special glasses. We also developed Seelinder[Endo et al. 2005], acylindrical rotating display with a parallax barrier. With this system, the observer can view 3D images from 360˚ without wearing special glasses. Next, we examine the possibility of realizing
a flat-panel-type multiple-parallax image display. Many types offlat stereoscopic display systems that do not require the observer towear glasses are available[HAMAGISHI et al. 1996]. These systems display multiple images along multiple directions. Therefore,
an observer can view stereoscopic images. However, in this system, there is a trade-off between the number of directions and theresolution. If the system displays a horizontal and vertical parallax
image simultaneously, the resolution decreases significantly. Thespinning-disc television was invented by J. L. Baird almost 80 years
ago in 1925. Baird conducted a public experiment of the system in1926. The spinning disc is also known as the Nipkow disc. We
found that the spinning disc can be employed in a system to display
multiple parallax images. We therefore extended its application to3D television.

6 User Experience
We will install a disc that is approximately 2.5 feet in diameter
along with an LED array. All the components will be covered withtransparent safety shields. The observer will be able to view computer graphics and camera images. Each image would move and alter the scene automatically, and each observer would require about
one or two minutes to complete this procedure.

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