A system includes a memory and a processing unit coupled to the memory. The processing unit is configured to receive first image data from a first image sensor exterior to a body, the first image data including data of an object; receive second image data from a second image sensor interior to the body, the second image data including data of the object; track the object moving across a body wall of the body based on the first and second image data to generate a tracking result to indicate a status of movement of the object across the body wall.