1. Porthole: A spatial interface to provide scrolling, zooming-in, and zooming-out

2. Introduction How do you see a Large Image within a Limited Screen?
A successful answer
A main screen to display part of the image
A sub window to display the entire image

3. Scrolling, Zooming-in, and Zooming-out
Introduction
Our answer came from a Porthole.
In our system,
More direct, intuitive,
easier access.
Scrolling, Zooming-in, and Zooming-out
A spatial interface to
based on Porthole Metaphor

4. Porthole Metaphor Visual Effects while Walking around. Front-Position
It describes
Front-Position
Far-Position
Near-Position
Terms
View
Scene
Viewpoint
View: an area within which we see.
Scene: an image that is seen through the view.
Viewpoint: a point from which we see.

5. The scene flows to the reverse.
Porthole Metaphor
Front-Position
Far-Position
Near-Position
The scene flows to the reverse.

6. Front-Position Far-Position Near-Position
Porthole Metaphor
Front-Position
Far-Position
Near-Position
The view is contracted and the scene is narrowed.

7. The view is expanded and the scene is widened.
Porthole Metaphor
Front-Position
Far-Position
Near-Position
The view is expanded and the scene is widened.

8. Scrolling Zooming-in Zooming-out As if the scene flowed.
Porthole Metaphor
Scrolling
Zooming-in
Zooming-out
As if the scene flowed.
As if the scene was narrowed.
As if the scene was widened.

9. Porthole Metaphor
Front-Position
Far-Position
Near-Position
Zooming-out
Scrolling
Zooming-in
The Basic Idea of
A spatial interface to Scrolling, Zooming-in, and Zooming-out based on Porthole metaphor

10. How to Realize
Scrolling
virtual space
real space

11. Zooming-out Zooming-in H/h = ACCd * (xr / xhome – 1.0) +1.0
How to Realize
Zooming-out
Zooming-in
virtual space
H/h = ACCd * (xr / xhome – 1.0) +1.0
real space

12. A map viewer A map viewer system A screen Web cameras projects images
as if you have seen
through a porthole.
Screen size
Height 27.5cm
Width 35.6cm
Web cameras
track the user’s viewpoint.

13. Framework of the system
A map viewer
Framework of the system

14. Examples of Viewing Initial Settings A map viewer 150cm Home plane
Screen
ACCv = 7.3 (200cm/27.5cm)
ACCh = 5.6 (200cm/35.6cm)
ACCd = 2.0
The vicinity of BOSTON

15. A map viewer
Examples of Viewing
Viewing of Scrolling
18cm

16. Examples of Viewing Viewing of Zooming-in & Zooming-out A map viewer
100cm
220cm

17. Front-Position, Far-Position, and Near-Position.
Conclusions
Contributions
Porthole Metaphor was introduced as three visual effects;
Front-Position, Far-Position, and Near-Position.
The similarity between these three visual effects and those of Scrolling, Zooming-in, and Zooming-out was focused on.
A spatial interface to Scrolling, Zooming-in, and Zooming-out was proposed based on Porthole Metaphor.