The other day, I saw a tennis instructor picking up tennis balls with a tennis ball hopper (example: www.amazon.com/gp/product/B0000BW9YP ). That seems to be a relatively efficient way of picking up tennis balls, considering most people just use their hands and bend down to pick them up. A tennis ball hopper allows people to pick up balls without bending over, and with greater efficiency.
I was thinking an even quicker way of picking up tennis balls would be to create a machine to pick up tennis balls. Perhaps the machine could recognize the size and color of the ball, and automatically pick up the balls into a basket, almost like a magnet that attracts metals to it. Such a tennis ball pickup machine seemed like a quick and easy way to pick up lots of tennis balls scattered all over the tennis courts. It would probably also need to carve out a boundary for itself so that it doesn't pick up balls from other courts.
