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Path Planning for Autonomous Cinematic Drones

A student research project I mentored, comparing A*, Dijkstra's and Greedy Best-First Search for drones that film smoothly while avoiding obstacles.

Gazebo and RViz simulation of a quadcopter in an art gallery environment
Fig. Quadcopter simulated in Gazebo in an art-gallery environment, with RViz visualization.
~70%
less search time, A* vs. Dijkstra
76%
fewer nodes searched
~30%
less travel time vs. GBFS

The project

Drones are central to modern cinematography, but flying them by hand risks collisions and shaky footage. My student, Brayden T., studied how a drone could autonomously find the smoothest path between shot locations while keeping the camera steady. I mentored the project from start to finish: I taught ROS, guided the experiments and edited the paper.

Methods

Results

In the panels below, the black dot is the drone, the red dot is the goal, the green line is the planned path and the yellow cells are the nodes each planner searched.

Small obstacle map

GBFS on small obstacle map
A. Greedy Best-First
Dijkstra on small obstacle map
B. Dijkstra's
A-star on small obstacle map
C. A*
AlgorithmNodes searchedSearch (s)Travel (s)Total (s)
Dijkstra's142213.4645.0658.52
GBFS490.0245.4045.42
A*3474.1145.0449.15

Large concave obstacle map

GBFS on large concave obstacle map
D. Greedy Best-First
Dijkstra on large concave obstacle map
E. Dijkstra's
A-star on large concave obstacle map
F. A*
AlgorithmNodes searchedSearch (s)Travel (s)Total (s)
Dijkstra's17729.0572.5981.64
GBFS1991.94102.84104.78
A*3972.7870.5173.30

GBFS searched the fewest nodes but took long detours around the concave obstacle. Dijkstra's found optimal paths but searched far more of the map. A* balanced both: it found the optimal route quickly, which left the drone more time to film and produced smooth camera motion with few zig-zags.

Roadmap planning on known territory

Roadmap path planning on OpenStreetMap
Fig. Roadmap planning on OpenStreetMap. The white line is the optimal route along roads between start (blue) and goal (green).

Next steps

A* slows down on very large or cluttered maps. The paper points to D* and to faster, sub-optimal planners such as RRTs and potential fields. It also points to computer vision, so the drone could choose its own shot locations.