microsoft research’s ‘dualview’ uses a single LCD screen to simultaneously present two different images or video
the above example, the reflection of the computer screen in the mirror
appears to show a completely different image than the one onscreen,
because of the different perspective
click here to download the file used to create this illusion and experience the effect yourself on most laptops; follow the instructions below
developed by a team at microsoft research, ‘dualview’ is a method of using a single LCD screen to simultaneously present
two different sets of content when viewed at various angles. the technology requires no additional hardware,
instead exploiting quirks of the technical limitations of twisted nematic (TN) LCD screens (the most widely used).
a technique called ‘spatial multiplexing’, the software is based on the
fact that TN screens vary in their colour fidelity
when viewed at various angles, as a result of the arrangement of the liquid crystals in the screen.
the project permits two users to each have an independent view of their role in a multiplayer video game;
permit two viewers to simultaneously watch two different films; or achieve a ‘magic mirror’ effect where
the screen’s reflection seemingly shows completely different content than the physical object’s.
with screen surface technologies, the software could be used for digital card tables, letting each player
see his own virtual cards in front of him, while those of others at the table are hidden.
illustration of the orientation of the liquid crystals in TN displays,
responsible for the variations in colour and contrast that are exploited
right: graph of the various intersection points for showing or hiding specific ranges of colour based on viewing angle (X-axis)
1. click the image to
download at its actual size;
that your monitor is set to its native resolution;
3. maximize your
viewing window in a default imaging program and select ‘actual size’ for the view;
4. flip the laptop screen up and down, or view it in a mirror, to see the effect!