1. A depth imaging system, comprising: a depth camera input to receive a depth map representing an observed scene imaged by a depth camera, the depth map including a plurality of pixels and a depth value for each of the plurality of pixels; a tag identification module to identify a 3D tag imaged by the depth camera and represented in the depth map, the 3D tag comprising one or more depth features, each of the one or more depth features comprising one or more characteristics recognizable by the depth camera; and a tag decoding module to translate the one or more depth features into machine-readable data.