title: A Novel Fiber Optic Based Surveillance System for Prevention of Pipeline Integrity Threats.
abstract: This paper presents a novel surveillance system aimed at the detection and classification of threats in the vicinity of a long gas pipeline. The sensing system is based on phase-sensitive optical time domain reflectometry (ϕ-OTDR) technology for signal acquisition and pattern recognition strategies for threat identification. The proposal incorporates contextual information at the feature level and applies a system combination strategy for pattern classification. The contextual information at the feature level is based on the tandem approach (using feature representations produced by discriminatively-trained multi-layer perceptrons) by employing feature vectors that spread different temporal contexts. The system combination strategy is based on a posterior combination of likelihoods computed from different pattern classification processes. The system operates in two different modes: (1) machine + activity identification, which recognizes the activity being carried out by a certain machine, and (2) threat detection, aimed at detecting threats no matter what the real activity being conducted is. In comparison with a previous system based on the same rigorous experimental setup, the results show that the system combination from the contextual feature information improves the results for each individual class in both operational modes, as well as the overall classification accuracy, with statistically-significant improvements.
authors.affiliation: FOCUS S.L., 28804 Madrid, Spain. javier.tejedor@focustech.eu.
authors.forename: Javier
authors.initials: J
authors.lastname: Tejedor
authors.affiliation: Department of Electronics, University of Alcalá, 28801 Alcalá de Henares, Spain. macias@depeca.uah.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Macias-Guarasa
authors.affiliation: FOCUS S.L., 28804 Madrid, Spain. hugo.martins@focustech.eu.
authors.forename: Hugo F
authors.initials: HF
authors.lastname: Martins
authors.affiliation: FOCUS S.L., 28804 Madrid, Spain. daniel.piote@focustech.eu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Piote
authors.affiliation: Department of Electronics, University of Alcalá, 28801 Alcalá de Henares, Spain. juan.pastor@depeca.uah.es.
authors.forename: Juan
authors.initials: J
authors.lastname: Pastor-Graells
authors.affiliation: Department of Electronics, University of Alcalá, 28801 Alcalá de Henares, Spain. sonia.martin@depeca.uah.es.
authors.forename: Sonia
authors.initials: S
authors.lastname: Martin-Lopez
authors.affiliation: Instituto de Óptica, CSIC, 28006 Madrid, Spain. p.corredera@csic.es.
authors.forename: Pedro
authors.initials: P
authors.lastname: Corredera
authors.affiliation: Department of Electronics, University of Alcalá, 28801 Alcalá de Henares, Spain. miguelg@depeca.uah.es.
authors.forename: Miguel
authors.initials: M
authors.lastname: Gonzalez-Herraez
keywords: distributed acoustic sensing; feature-level contextual information; fiber optic systems; pipeline integrity threat monitoring; system combination; ϕ-OTDR