Your TV can see through walls

Digital TV signals can be exploited to detect and measure human movement through walls by analyzing how reflections of the signal interfere with the direct path. When a person moves, they create predictable disturbances in the signal's phase that appear as striped patterns in spectrograms, allowing researchers to estimate walking speed with reasonable accuracy. This same principle applies to other wideband radio signals like WiFi and LTE, raising implications for privacy and surveillance.