Embedding and decoding hidden data channels on computer displays

Abstract

In a given setup, a LCD screen is mounted horizontally so that objects, e.g. game tokens, can be placed on the surface of the display. A PC displays information on the screen, e.g. a floor plan of a board game. The object placed on the screen is equipped with one or more optical sensors that ¿look¿ at the display area under the object. The information captured by the sensor is transmitted back to the PC that displays the information (after optional pre-processing the object). In order to determine de position of the objects in the screen, the screen is partitioned into a large number of separate areas. A separate hidden data channel has to be implemented in each of these areas. The data transmitted through these data channels can be used to transmit position identifying the given area. The task of this work is to research and design a system for implementing such a multitude of hidden data channels on a video display with the following constraints: - The displayed hidden data channel shall be invisible or at least unobtrusive to the human eye in the chosen setup. - The capacity of the channel should be as large as possible. - The system should be able to function if the sensor is placed between two, or three of the hidden data channel areas. - The system needs to be robust against typical error signals like ¿strobing back light of the display¿. - The system should be able to adapt to special conditions found on different types of display families.