Privacy Enhanced Computer Display
The privacy-enhanced computer display uses a ferroelectric shutter glasses and a special device driver to produce a computer display which can be read only by the desired recipient, and not by an onlooker. The display alternately displays the desired information in one field, then the inverse image of the desired information in the next field, at up to 120 Hz refresh. The ferroelectric shutter glasses allow only the desired information to be viewed, while the inverse image causes unauthorized viewers to perceive only a flickering gray image, caused by the persistence of vision in the human visual system (as illustrated here). It is also possible to use the system to "underlay" a private message on a public display system.
Background & Objective: The Privacy Enhanced Computer Display is appropriate for situations where a computer display is to be located in a publicly accessible area, but the display itself may show information that should be kept private. Places such as banks (bank balances) hospitals (patient health information), pharmacies (drug information), airline ticketing and airport gate agent stations (passenger and security information) are all candidates for a privacy-enhanced computer display.
Technical Discussion: The system consists of two display sources (the public display image Pij and the secret display image Sij) a special device driver, a fast-refreshing CRT, and a set of synchronized ferroelectric shutter glasses. If there is no desired public display, the RGB value (255, 255, 255) can be used. The special device driver alternately displays images of (Pij - Sij ) and ( Sij ). The human eye's persistence of vision blurs the two images into (Pij - Sij + Sij ) / 2, which reduces to Pij / 2, which is the public image, without any secret image being visible. To someone wearing the synchronized glasses, only the Sij image is seen.
Modification Date: August 2, 2001