A stereoscopic 3D sensor is an overhead device with two lenses that views a scene the way human eyes do, comparing the two images to calculate depth. In people counting, it builds a height map of the entrance so it can detect and count individuals as they cross a line.
The sensor is mounted above a doorway, looking straight down. Because it measures the height of objects, it can separate people from shadows, trolleys, bags and door movements, and it can tell adults from small children if configured to. Processing usually happens inside the device, and only counts, not video, are sent on to cloud reporting.
Retailers, shopping centres and venues choose 3D sensors for main entrances where accuracy matters, such as stores with wide doors or heavy two-way traffic. Many models can also track movement within the sensor's field of view, which allows the same device to support dwell time, queue and zone reporting.
Installation matters as much as the hardware. Each model has a recommended mounting height and a maximum doorway width, and exceeding either lowers accuracy. Direct sunlight, glass and reflective floors can affect some sensors, so site conditions should be checked. Configuring the counting line correctly and verifying against a manual count after setup is good practice.
The technology matters because count accuracy underpins every metric built on it, from conversion rate to staffing models. Compared with simple infrared beams, depth sensing copes better with groups, prams and people walking in opposite directions. V-Count, supplied by RetailCare, offers sensors in this category.