Abstract: Systems and methods for obtaining camera parameters from images are provided. First, a sequence of original images associated with a target object under circular motion is obtained. Then, a background image and a foreground image corresponding to the target object within each original image are segmented. Next, shadow detection is performed for the target object within each original image. A first threshold and a second threshold are respectively determined according to the corresponding background and foreground images. Each original image, the corresponding background image, the first and second threshold are used for obtaining silhouette data and feature information associated with the target object within each original image. At least one camera parameter is obtained based on the entire feature information and the geometry of circular motion.