Factors Affecting ENF Capture in Audio

The electric network frequency (ENF) signal is an environmental signature that can be captured in audiovisual recordings made in locations where there is electrical activity. This signal is influenced by the power grid in which the recording is made, and recent work has shown that it can be useful toward a number of forensics and security applications. An under-studied area of ENF research is the factors that can affect the capture of ENF traces in media recordings. Not all recordings made in the areas of electrical activity will carry prominent ENF traces, and the strengths by which the ENF traces are captured can vary from one recording to another. A thorough understanding of the factors that can affect the capture of ENF traces in recordings is essential to understanding the applicability of ENF-based approaches and can help inform related studies in the future. This paper carried out a study on such factors, with a focus on audio signals. The impact of the characteristics of an audio recorder and the environment and manner of recording on the intrinsically captured ENF are shown and analyzed.