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Proceedings Paper

Particle detection from spatially modulated fluorescence signals
Author(s): Siegfried W. Kettlitz; Carola Moosmann; Sebastian Valouch; Uli Lemmer
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Paper Abstract

Flow cytometry relies on the detection of cells selectively stained with fluorescence markers. Optically they can be detected as fluorescence particles. The use of microuidics offers a wide range of benefits over traditional flow cytometer designs but when replacing expensive components with inexpensive counterparts the sensitivity of the instrument suffers. To increase the sensitivity of the detection system, spatial modulation has been proposed. Spatial modulation is implemented via _ne pitched shadow masks close to the microuidic channel which generate a signal pattern when a fluorescent particle passes by. Using a _ne pitch and long total length for the pattern a high spatial resolution and long total exposure time are combined. Particle detection from local maxima is not directly possible with spatially modulated signals due to the jagged pulse shape. We compare the performance of different approaches for particle detection from local maxima. Matched filtering and the derivative of the correlation signal provide either a good peak-signal-to-noise ratio (PSNR) or a high spatial resolution. But both approaches suffer from low dynamic range due to side maxima. We derive the solution for a minimum- mean-square-error (MMSE) filter which transforms the modulated pulse shape into a target pulse shape with a single strong maximum. We investigate the performance of the MMSE filter and find that it provides tunable suppression of noise and side maxima along with a high spatial resolution. The use of the MMSE filter therefore is an ideal choice for particle detection from spatially modulated signals.

Paper Details

Date Published: 8 May 2014
PDF: 10 pages
Proc. SPIE 9129, Biophotonics: Photonic Solutions for Better Health Care IV, 91291B (8 May 2014); doi: 10.1117/12.2052169
Show Author Affiliations
Siegfried W. Kettlitz, Karlsruher Institut für Technologie (Germany)
Carola Moosmann, Karlsruher Institut für Technologie (Germany)
Sebastian Valouch, Karlsruher Institut für Technologie (Germany)
Uli Lemmer, Karlsruher Institut für Technologie (Germany)

Published in SPIE Proceedings Vol. 9129:
Biophotonics: Photonic Solutions for Better Health Care IV
Jürgen Popp; Valery V. Tuchin; Dennis L. Matthews; Francesco Saverio Pavone; Paul Garside, Editor(s)

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