Integration
This page contains tips to create a data capture system for a certain space using Carto.
Covering a space with Orbbec Femto Megas
The goal of a multi-camera system is to be able to capture visual data on the entire are where we envision people to interact with an installation. To make sure the system can provide reliable 3D data at all time, we need to optimise space coverage by positioning cameras in a careful manner.
According to the technical specifications of the Femto Mega devices, two modes of depth data capture are available: the Wide Field of View (WFoV) mode and the Narrow Field of View (NFoV) mode. Using the wide field of view widens the captured area near the device while the narrow filed of view can allow the device to get data from further distances. The technical specifications are displayed in the following table. Note that the distance recommended in the table is a conservative estimate: We have been able to get depth data from more than 8m of a device using the NFoV mode. Outdoors performances are very limited; it is preferable to use a lidar.
The disposition of the devices in the space will be determined by the size of the captation area and by the height of the ceilings. The higher the ceilings are, the easier it is to cover a large captation area with having to care about occlusions of the camera’s field of view. (This assumes we are able to mount cameras to the ceiling of a room).
The standard use case of a multi-camera system is to obtain visual information in a 3D zone of a height of at least 2 meters. This makes it possible to detect the bodies of every individual in the space. Low ceilings requires more cameras to offer a complete coverage of the area and to avoid occlusion.
Note that the number of cameras required and the required precision of the calibration depends on what kind of informations we want to get. The first objective will always be to get a spatial understanding of movement: Notably to be able to project the 3D location of a participant on an adjacent surface.