Estimating spin rate and axis of a ball using deep learning

A method comprising:

• at a first time, training a deep learning network on a series of training images of spinning balls, each spinning ball having at least one feature point in a time series that forms a three-dimensional (3D) circle in 3D space and a corresponding two-dimensional (2D) ellipse image in a 2D plane;
• at a second time after the first time, capturing, with at least one camera, a series of images of a ball;
• predicting, with the trained deep learning network, spin measurements associated with the ball based on the series of images;
• determining, with at least one processor, a spin rate of the ball based on the spin measurements;
• determining, with the at least one processor, coefficients of a 2D ellipse model based on the spin measurements and the spin rate;
• and
• determining, with the at least one processor, a spin axis of the ball in 3D space based on the 2D ellipse model and the spin rate.