1. A medical information system comprising: (a) a depth camera for generating a 3D depth map and a low-resolution 2D image; (b) an image camera for generating a high-resolution 2D image; and (c) a processor in communication with the depth camera and the image camera, the processor being configured to: (i) identify a human body part within the 3D depth map; (ii) identify an approximate object silhouette of the human body part within the low-resolution 2D image using information about the human body part from the 3D depth map; (iii) identify the approximate object silhouette in the high-resolution 2D image using information about the approximate object silhouette from the low-resolution 2D image; (iv) generate a refined object silhouette within the high-resolution 2D image using a region segmentation process; (v) track the human body part using the refined object silhouette; (vi) extract a gesture based on tracking the human body part; and (vii) generate an input command based on the extracted gesture; and (d) an electronic device configured to receive the input command and display medical information based upon the input command.