Principles of 3D imaging using the time-of-flight-based range measurement technique [1]. The solid sinusoidal curve is the amplitude-modulated IR light that is emitted onto the scene by a source, and the dashed curve is the reflected signal that is detected by an imaging device. Note that the reflected signal is attenuated and phase-shifted by an angle ϕ relative to the emitted signal, and includes a background signal that is assumed to be constant. The distance or the depth map is determined using the phase shift and the modulation wavelength.