Depth camera

Below we describe our conclusions from testing using depth cameras in some of our projects.

Possibilities

• Depth cameras are a convenient solution for the preparation of interactive systems (including the interactive floor), because one device includes all the basic components required to prepare an interactive installation - a camera and an infrared illuminator.
• Depth cameras usually work using infrared light, which fulfils the requirements presented on the subpage Camera selection > Requirements explanation > General guidelines.
• Depth cameras differ from classic 2D cameras as they have information about the distance of elements from the camera. In the case of an interactive floor, this enables you to specify the distance range of objects to be observed and interacting with the application, e.g. only elements that are just above the floor (feet, legs) may be detected and elements higher up (e.g. hands and head) are skipped.

Limitations

Why are depth cameras not always the optimal solution for preparing an interactive floor?

• In the case of depth cameras, there is a problem with precise observation of objects being on the floor level, such as the hands of children who play on their laps. These elements in the image from the camera merge with the ground and are difficult to isolate by the motion detector.
• Depth cameras are not suitable for interaction with infrared (IR) accessories like IR pens or IR toy guns.
• The side mounting of such a camera requires additional treatments during image processing, because different distances of objects from the camera must be taken into account.
• An attempt to narrow the scope of interaction to areas just above the floor is not always effective because the elements located higher (hands, head and torso) that we want to omit may cover the legs and, consequently, instead of improving the interaction experience, it may turn out that in certain situations (at certain angles), some movements of the user will not generate the interaction effect.
• The viewing angle of the depth cameras is smaller than the projection angle, so an additional mounting point for the camera or a reduction in the size of the projection area is required.

Recommendations

• The depth camera is sufficient for the basic motion interaction effect on the interactive floor. We recommend testing with the Orbbec® Astra™ or Intel® RealSense™ D435 camera.
• If you need full effect of motion interaction, use USB camera board and external IR illuminator or get your CCTV camera ready to work.
• If you plan to prepare an interactive floor with all the ways of interacting that Motioncube offers (motion, IR pens, vehicles, and more) use Motioncube IR-Kit.