Counting Crowds

Interesting application, note the technique of training in various contexts of measurement.   We don't do that enough with other problems.

A bird’s-eye view of a huge crowd of people. AI Could Help Count How Many People are in Large Crowds

New Scientist  by  Chris Stokel-Walker

German Aerospace Center researchers have developed an artificial intelligence (AI) system that can accurately count the number of people in large crowds. The researchers hand-counted nearly 250,000 people in 33 images of a large crowd taken from planes, drones, and helicopters, then used this data to train an algorithm called MRCNet. The algorithm divides each image into small squares and analyzes how many people are in each. The algorithm’s results were at least 15% more accurate than those of other AI-powered crowd estimation systems. The system is much faster than hand counting, taking 0.03 milliseconds to compute the number of people in each square. .... "