A device-mounted infrared (IR) camera and a hybrid visible/IR light projector may be used to project visible animation sequences along with invisible (to the naked eye) tracking signals, (e.g. a near IR fiducial marker). A software (or firmware) platform (either on the handheld device or to which the device communicates) may track multiple, independent projected images in relation to one another using the tracking signals when projected in the near-IR spectrum. The resulting system allows a broad range of new interaction scenarios for multiple handheld projectors being used in any environment with adequate lighting conditions without requiring the environment to be instrumented in any way.