The Wound healing trend analysis is performed on a time
sequence of images belonging to a given patient to monitor the
wound healing status. The current trend is obtained by comparing
the wound feature vectors between the current wound record
and the one that is just one standard time interval earlier (typically
one or two weeks). Alternatively, a longer term healing
trend is obtained by comparing the feature vectors between the
current wound and the base record which is the earliest record
for this patient.