A. Image Preprocessing
This research using image preprocessing to reduce the
noise because the environment is complicated and the
noise is unpredictable, moreover, the differences of range,
strength and continuity between the object and the
background are stronger than the noise. So we use the
median filter to keep the degree of differences and smooth
the noise as much as possible. The noise of median filter
will still be retained in complex scene, so the next step is
to use the smoothing filter. The smoothing filter will
smooth the noise and filter out the sharpness, so the
smoothing filter must be used after the median filter.