1. A face detection and tracking method of a robotic device, comprising: obtaining a video frame from a camera of the,robotic device; performing a face detection process on the video frame to detect one or more faces in the video frame; after the face detection process, identifying the detected one or more faces in the video frame; performing a vision-based tracking process to track the identified one or nore faces using a combination of a feature points tracker and a correlation tracker; and after the vision-based tracking process, performing a detection and tracking fusion process and providing desired target prediction of the identified one or more faces.