This work proposes a complete sensor-independent visual system that
provides robust target motion detection. First, the way sensors obtain
images, in terms of resolution distribution and pixel neighbourhood, is
studied. This allows a spatial analysis of motion to be carried out.
Then, a novel background maintenance approach for robust target motion
detection is implemented. Two different situations are considered: a
fixed camera observing a constant background where objects are moving;
and a still camera observing objects in movement within a dynamic
background. This distinction lies on developing a surveillance mechanism
without the constraint of observing a scene free of foreground elements
for several seconds when a reliable initial background model is
obtained, as that situation cannot be guaranteed when a robotic system
works in an unknown environment. Other problems are also addressed to
successfully deal with changes in illumination, and the distinction
between foreground and background elements.