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- Electrical_network_frequency_analysis abstract "Electrical network frequency (ENF) analysis is a forensic science technique for validating audio recordings by comparing frequency changes in background mains hum in the recording with long-term high-precision historical records of mains frequency changes from a database. In effect the mains hum signal is treated as if it were a time-dependent digital watermark that can help identify when the recording was created, and help detect any edits in the recording. Historical records of main frequency changes are kept on record, e.g., by police in the German federal state of Bavaria since 2010.The technology has been hailed as "the most significant development in audio forensics since Watergate." However, according to a paper by Huijbregtse and Geradts, the ENF technique, although powerful, has significant limitations caused by ambiguity based on fixed frequency offsets during recording, and self-similarity within the mains frequency database, particularly for recordings shorter than 10 minutes.More recently, researchers demonstrated that the indoor lights such as fluorescent lights and incandescent bulbs vary their light intensity in accordance with the voltage supplied, which in turn depends on the voltage supply frequency. As a result, the light intensity can carry the frequency fluctuation information to the visual sensor recordings in the similar way as the electromagnetic waves from the power transmission lines carry the ENF information to audio sensing mechanisms. Based on this result, researchers demonstrated that visual track from still video taken in an indoor lighting environments also contain ENF traces that can be extracted by estimating the frequency at which ENF will appear in a video as low sampling frequency of video (25–30 Hz) cause significant aliasing. It was also demonstrated in the same research that the ENF signatures from visual stream and the ENF signature from audio stream in a given video should match. As a result, the matching between the two signals can be used to determine if the audio and visual track was recorded together or superimposed later.".
- Electrical_network_frequency_analysis wikiPageID "27579471".
- Electrical_network_frequency_analysis wikiPageRevisionID "528174019".
- Electrical_network_frequency_analysis hasPhotoCollection Electrical_network_frequency_analysis.
- Electrical_network_frequency_analysis subject Category:Electric_power.
- Electrical_network_frequency_analysis subject Category:Forensic_techniques.
- Electrical_network_frequency_analysis subject Category:Sound_recording.
- Electrical_network_frequency_analysis type Ability105616246.
- Electrical_network_frequency_analysis type Abstraction100002137.
- Electrical_network_frequency_analysis type Cognition100023271.
- Electrical_network_frequency_analysis type ForensicTechniques.
- Electrical_network_frequency_analysis type Know-how105616786.
- Electrical_network_frequency_analysis type Method105660268.
- Electrical_network_frequency_analysis type PsychologicalFeature100023100.
- Electrical_network_frequency_analysis type Technique105665146.
- Electrical_network_frequency_analysis comment "Electrical network frequency (ENF) analysis is a forensic science technique for validating audio recordings by comparing frequency changes in background mains hum in the recording with long-term high-precision historical records of mains frequency changes from a database. In effect the mains hum signal is treated as if it were a time-dependent digital watermark that can help identify when the recording was created, and help detect any edits in the recording.".
- Electrical_network_frequency_analysis label "Electrical network frequency analysis".
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- Electrical_network_frequency_analysis sameAs Q5357730.
- Electrical_network_frequency_analysis sameAs Q5357730.
- Electrical_network_frequency_analysis sameAs Electrical_network_frequency_analysis.
- Electrical_network_frequency_analysis wasDerivedFrom Electrical_network_frequency_analysis?oldid=528174019.
- Electrical_network_frequency_analysis isPrimaryTopicOf Electrical_network_frequency_analysis.