An interactive display system includes an electronic camera which
intermittently records a participant's image and digitally inputs the
video image into a computer, creating a digitized "virtual user image".
The camera is positioned behind a large viewing screen which faces the
user and records the user's image through an opening provided within the
screen. The computer further receives a text string having a fall rate
value. For each digital image received by the camera, a software program
determines the destination of each line of text according to its fall
rate, and then uses pixel color comparison techniques to determine if a
"virtual obstacle" is located at the particular destination. If not, the
text is displayed at the destination so that the text appears to "fall"
on the screen. If a virtual obstacle is present, a new higher destination
is determined until the virtual obstacle is no longer detected. This
arrangement causes the falling text displayed on the screen to be
selectively "caught" by the user and otherwise manipulated in the virtual
environment.