title: Two-dimensional wavelet transform feature extraction for porous silicon chemical sensors.
abstract: Designing reliable, fast responding, highly sensitive, and low-power consuming chemo-sensory systems has long been a major goal in chemo-sensing. This goal, however, presents a difficult challenge because having a set of chemo-sensory detectors exhibiting all these aforementioned ideal conditions are still largely un-realizable to-date. This paper presents a unique perspective on capturing more in-depth insights into the physicochemical interactions of two distinct, selectively chemically modified porous silicon (pSi) film-based optical gas sensors by implementing an innovative, based on signal processing methodology, namely the two-dimensional discrete wavelet transform. Specifically, the method consists of using the two-dimensional discrete wavelet transform as a feature extraction method to capture the non-stationary behavior from the bi-dimensional pSi rugate sensor response. Utilizing a comprehensive set of measurements collected from each of the aforementioned optically based chemical sensors, we evaluate the significance of our approach on a complex, six-dimensional chemical analyte discrimination/quantification task problem. Due to the bi-dimensional aspects naturally governing the optical sensor response to chemical analytes, our findings provide evidence that the proposed feature extractor strategy may be a valuable tool to deepen our understanding of the performance of optically based chemical sensors as well as an important step toward attaining their implementation in more realistic chemo-sensing applications.
authors.affiliation: BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA.
authors.forename: José S
authors.initials: JS
authors.lastname: Murguía
authors.forename: Alexander
authors.initials: A
authors.lastname: Vergara
authors.forename: Cecilia
authors.initials: C
authors.lastname: Vargas-Olmos
authors.forename: Travis J
authors.initials: TJ
authors.lastname: Wong
authors.forename: Jordi
authors.initials: J
authors.lastname: Fonollosa
authors.forename: Ramón
authors.initials: R
authors.lastname: Huerta
mesh_terms: D000465:Algorithms; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D005740:Gases / Q000032:analysis*; D010084:Oxidation-Reduction; D016062:Porosity; D025341:Principal Component Analysis; D012825:Silicon / Q000737:chemistry*; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D005740:Gases; D012825:Silicon