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Digitally balanced detection for optical tomography.
Rev Sci Instrum. 2007 Oct; 78(10):103101.RS

Abstract

Analog balanced Photodetection has found extensive usage for sensing of a weak absorption signal buried in laser intensity noise. This paper proposes schemes for compact, affordable, and flexible digital implementation of the already established analog balanced detection, as part of a multichannel digital tomography system. Variants of digitally balanced detection (DBD) schemes, suitable for weak signals on a largely varying background or weakly varying envelopes of high frequency carrier waves, are introduced analytically and elaborated in terms of algorithmic and hardware flow. The DBD algorithms are implemented on a low-cost general purpose reconfigurable hardware (field-programmable gate array), utilizing less than half of its resources. The performance of the DBD schemes compare favorably with their analog counterpart: A common mode rejection ratio of 50 dB was observed over a bandwidth of 300 kHz, limited mainly by the host digital hardware. The close relationship between the DBD outputs and those of known analog balancing circuits is discussed in principle and shown experimentally in the example case of propane gas detection.

Authors+Show Affiliations

Hafiz R
Sensors, Imaging and Signal Processing Group, School of Electrical Engineering and Electronics, The University of Manchester, P.O. Box 88, Manchester M601QD, United Kingdom.
Ozanyan KB
No affiliation info available

MeSH

AlgorithmsEquipment DesignEquipment Failure AnalysisImage EnhancementImage Interpretation, Computer-AssistedImaging, Three-DimensionalReproducibility of ResultsSensitivity and SpecificitySignal Processing, Computer-AssistedTomography, Optical

Pub Type(s)

Evaluation Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17979400

Citation

Hafiz, Rehan, and Krikor B. Ozanyan. "Digitally Balanced Detection for Optical Tomography." The Review of Scientific Instruments, vol. 78, no. 10, 2007, p. 103101.
Hafiz R, Ozanyan KB. Digitally balanced detection for optical tomography. Rev Sci Instrum. 2007;78(10):103101.
Hafiz, R., & Ozanyan, K. B. (2007). Digitally balanced detection for optical tomography. The Review of Scientific Instruments, 78(10), 103101.
Hafiz R, Ozanyan KB. Digitally Balanced Detection for Optical Tomography. Rev Sci Instrum. 2007;78(10):103101. PubMed PMID: 17979400.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Digitally balanced detection for optical tomography. AU - Hafiz,Rehan, AU - Ozanyan,Krikor B, PY - 2007/11/6/pubmed PY - 2008/1/9/medline PY - 2007/11/6/entrez SP - 103101 EP - 103101 JF - The Review of scientific instruments JO - Rev Sci Instrum VL - 78 IS - 10 N2 - Analog balanced Photodetection has found extensive usage for sensing of a weak absorption signal buried in laser intensity noise. This paper proposes schemes for compact, affordable, and flexible digital implementation of the already established analog balanced detection, as part of a multichannel digital tomography system. Variants of digitally balanced detection (DBD) schemes, suitable for weak signals on a largely varying background or weakly varying envelopes of high frequency carrier waves, are introduced analytically and elaborated in terms of algorithmic and hardware flow. The DBD algorithms are implemented on a low-cost general purpose reconfigurable hardware (field-programmable gate array), utilizing less than half of its resources. The performance of the DBD schemes compare favorably with their analog counterpart: A common mode rejection ratio of 50 dB was observed over a bandwidth of 300 kHz, limited mainly by the host digital hardware. The close relationship between the DBD outputs and those of known analog balancing circuits is discussed in principle and shown experimentally in the example case of propane gas detection. SN - 0034-6748 UR - https://www.unboundmedicine.com/medline/citation/17979400/Digitally_balanced_detection_for_optical_tomography_ DB - PRIME DP - Unbound Medicine ER -