A method includes generating a depth map from at least one image, detecting objects in the depth map, and identifying anomalies in the objects from the depth map. Another method includes identifying at least one anomaly in an object in a depth map, and using the anomaly to identify future occurrences of the object. A system includes a three dimensional (3D) imaging system to generate a depth map from at least one image, an object detector to detect objects within the depth map, and an anomaly detector to detect anomalies in the detected objects, wherein the anomalies are logical gaps and/or logical protrusions in the depth map.