As the sound propagates in the medium (air, water...) at a finite known speed, a sound source is perceived by the microphones at different time instants and at different sound intensities that depend on both the sound source location and the microphone location. One popular method to obtain an acoustic image from the measurement of the microphone is to use beamforming: By delaying each microphone signal relatively and adding them, the signal coming from a specific direction ( θ 0 , ϕ 0 ) {\displaystyle \left(\theta _{0},\phi _{0}\right)} is amplified while signals coming from other directions are canceled. The power of this resulting signal is then calculated and reported on a power map at a pixel corresponding to the direction ( θ 0 , ϕ 0 ) {\displaystyle \left(\theta _{0},\phi _{0}\right)} .