Fig. 1: Contactless sensors for ambient intelligence.
From: Illuminating the dark spaces of healthcare with ambient intelligence
Brightly coloured pixels denote objects that are closer to the depth sensor. Black pixels denote sensor noise caused by reflective, metallic objects. The radio sensor shows a micro-Doppler signature of a moving object, for which the x axis denotes time (5 s) and the y axis denotes the Doppler frequency. The radio sensor image is reproduced from ref. 89. The acoustic sensor displays an audio waveform of a person speaking, for which the x axis denotes time (5 s) and the y axis denotes the signal amplitude.
