I. Introduction
In recent years, there have been increasing interests in the area of traffic surveillance system (TSS), especially in Vietnam and other developing countries. The main goal of a TSS is to gain an understanding of traffic situations through an extraction of information (counts, speed, vehicle type, and density) from sensors' signals. So far, many studies have been carried out using cutting-edge TSSs. However, the detectors in use are costly, bulky and are difficult to maintain, while still providing limited information [1]. Perhaps for those reasons, video-based TSSs are becoming more popular. They are capable of providing more information about traffic conditions and can adapt to a wide range of view condition. They are characterized as low cost, less disruptive and more maintainable than others.