What is the minimum Pixels Per Foot (PPF) for counting people and vehicles?

Camio counts people and vehicles  using virtual turnstiles or scene segmentation. In either case, reliable counts require minimum Pixels Per Foot (PPF) on the target object being counted.

Virtual Turnstiles

People Counting

10 PPF is the minimum for detecting and counting people in the scene. Camio tracks people on their paths across the floor-plane grid, so intermittent dips below 10 PPF are OK as long as PPF values remain above 10 PPF generally.

For example, this illustrates operation at the limits of detection with only 6 PPF, where some people on the right side of the scene aren't reliably detected:
camio-min-ppf-people-counting.png

 

Vehicle Counting

15 PPF is the minimum for detecting and counting vehicles in the scene. Camio tracks vehicles on their paths across the floor-plane grid, so intermittent dips below 15 PPF are OK as long as PPF values remain above 15 PPF generally.

Scene Segmentation

Unlike virtual turnstiles, scene segmentation doesn't have the benefit of tracking objects as they move across the floor-plane grid. That means they're less resilient to drops in PPF. Camio really needs the minimum 10 PPF for people and 15 PPF for vehicles.

It's much less expensive to count with scene segmentation, since the compute power is applied only to periodic snapshots rather than to the continuous tracking of each object.

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