In this project, a virtual reality area-monitoring system was developed using a pan & tilt unit and a head mounted display.
The pan & tilt unit is a combination of two stepping motors which cause
its platform to rotate either
horizontally (pan) or vertically (tilt). The resolution of the motors
is ~19.4 positions/degree and they can rotate at velocities in the range
of 2 to 150 degrees/sec. The maximum range of motion for panning is
-160 to 160 degrees, and for tilting -47 to 31 degrees. The unit
is controlled by the computer through a serial interface.
The head mounted display
used in this project is the Virtual I/O I-Glasses. This HMD employs
two LCD displays (one for each eye), each having pixel resolutions of 640x320.
NTSC video is used for input into the display.
This unit also contains a 3DOF rotational head tracker which sends angular
data to the computer through a serial connection.
One method developed for allowing the user to look around the environment
consisted of continually tracking the user's head direction and speed and
moving the ptu to match them.
In the second method developed the pan & tilt unit continually scans the area around it. This area encompasses a field of view approximately 300 degrees horizontally by 100 degrees vertically.
The pictures captured at each location are combined
to create a panoramic picture of the environment. Each picture has a field
of view of ~28 degrees.
By this method when the user looks around while having the HMD on, the
data displayed is extracted from this panoramic picture.
This display is based on the user's head position,
which is measured by the head tracker, and a given visual field of view.
The given visual field of view is usually set to match that of the camera's,
but it can be changed during operation. This leads to the user being able to
cause the display to zoom in or out.
Ongoing research is investigating the process of updating the panoramic view with live video data as it is captured.