A system and method for calibration of cameras on Unmanned Aerial Vehicles (UAVs) is provided. The system receives a set of anchor images of a human subject from a set of anchor cameras and a group of images of the human subject from multiple viewpoints in three-dimensional (3D) space from a group of cameras on a group of UAVs. The system determines a first set of two-dimensional (2D) positions of human joints from the set of anchor images and a second set of 2D positions of the human joints from the group of images. The system computes, as 3D key-points, 3D positions of the human joints based on triangulation using the first set of 2D positions and determines a 2D re-projection error between the 3D key-points and the second set of 2D positions. Thereafter, by minimizing the 2D re-projection error, the system calibrates each camera of the group of cameras.