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Proceedings Paper

Dynamic optical tomographic imager with optimized digital lock-in filtering
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Paper Abstract

We describe a new dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data-acquisition and filtering techniques. At the heart of this continuous wave instrument is a digital signal processor (DSP) that collects, collates, processes, and filters the digitized data set. A digital lock-in filter that has been designed for this particular application maximizes measurement fidelity. The synchronously-timed processes are controlled by a complex programmable logic device (CPLD) that is also used in conjunction with the DSP to orchestrate data flow. Real-time data rates as high as 140Hz can be achieved. The operation of the system is implemented through a graphical user interface designed with LabVIEW software, Performance analysis shows very low system noise (~600fW RMS noise equivalent power), excellent signal precision (<0.04% - 0.2%) and long-term system stability (<1% over 40 min). A large dynamic range (~195dB) accommodates a wide scope of measurement geometries and tissue types. First experiments on tissue phantoms show that dynamic behavior is accurately captured and spatial location can be correctly tracked using this system.

Paper Details

Date Published: 12 July 2007
PDF: 11 pages
Proc. SPIE 6629, Diffuse Optical Imaging of Tissue, 662903 (12 July 2007); doi: 10.1117/12.728578
Show Author Affiliations
Joseph M. Lasker, Columbia Univ. (United States)
James M. Masciotti, Columbia Univ. (United States)
Yang Li, Columbia Univ. (United States)
Chris Fong, Columbia Univ. (United States)
Andreas H. Hielscher, Columbia Univ. (United States)

Published in SPIE Proceedings Vol. 6629:
Diffuse Optical Imaging of Tissue
Brian W. Pogue; Rinaldo Cubeddu, Editor(s)

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