Surveillance cameras are applied in security field. Its pixels and resolution are higher than computer video heads, and lower than professional digital cameras or DV. Surveillance cameras are mostly just a single video capture device and rarely have data storage capabilities. Surveillance cameras are mainly divided into bullet type, dome type, high speed dome type, and there is also a distinction between analog camera and IP network camera. They are widely used in schools, companies, banks, transportation, safe cities and other security areas.