A method of controlling an unmanned aerial vehicle (UAV) includes receiving an image from one or more vision sensors of the UAV. The image is captured while the UAV is in flight and includes a marker within an environment. The marker has a visual pattern. The method further includes identifying the visual pattern to determine a plurality of instructions encoded in the visual pattern, and controlling, in response to the plurality of instructions, the UAV to perform an action including at least one of adjusting position of a payload, swapping a payload, or capturing an image of a selected subject.