Object tracking and positioning on video images

This study presents an application of digital video camera for object tracking and positioning. The main purpose of the study is to automatically trace and position a motionless object on the video images that are recorded on a moving vehicle. Because of the change of the focal length of camera and the movement of the vehicle, the appearance of a motionless object on the video images firstly will gradually change its shape and completely lose its trace after a period of time. The variation of the shape apparently will bring about the complexity for developing the automated algorithm to trace and position object on the video image. In this study, we develop a shape-based tracking technique to implement the tracking task. The technique uses the shape matrix algorithm (SMA) that has scale and rotation invariant characteristics to calculate the similarity of variant shapes between adjacent video frames. After the object is traced in every video frame, the photogrammetric collinearity condition equations are used to transform the object from the image coordinates to the ground coordinates. An experiment is performed to trace a motionless ship in the open sea. The result shows that the proposed method can successfully trace and position the ship even the ship had become entirely out of shape on the video images.