The purpose of the image preprocessing is not only to
filter the noise but to decrease the tiny differences
between the pixels. In the instance of the image
preprocessing, the differences pixels between the shaky
groves and the reflection of the glass windows will be
smoothed. We can always find the differences pixels
between the shaky groves and the reflection of the glass
windows will be decreased by appropriate adjusting the
divisor of the smoothing filter, and it is easier to classify
the differences into the static background. The median
filter method is defined as follows (1) and the smoothing
filter function is defined as follows (2):