A robot-assisted surgical system comprises a plurality of robotic system components independently positionable relative to a patient in a room, at least one of the robotic system components being a robotic manipulator configured for robotic positioning of a surgical instrument in a body cavity. Other robotic system components may include a second robotic manipulator and/or a patient bed. A camera is positioned to generate an image of a portion of the room, including the robotic manipulator, or an instrument carried by the robotic manipulator as it is moved within the body. Image processing is used to detect the robotic system components on the image captured by the camera, or the tracked portion of the instrument. Once the robotic components or tracked portion of the instruments are detected in the image, the relative positions of the bases within the room may be determined.
