title: Denoising Stimulated Raman Spectroscopic Images by Total Variation Minimization.
abstract: High-speed coherent Raman scattering imaging is opening a new avenue to unveiling the cellular machinery by visualizing the spatio-temporal dynamics of target molecules or intracellular organelles. By extracting signals from the laser at MHz modulation frequency, current stimulated Raman scattering (SRS) microscopy has reached shot noise limited detection sensitivity. The laser-based local oscillator in SRS microscopy not only generates high levels of signal, but also delivers a large shot noise which degrades image quality and spectral fidelity. Here, we demonstrate a denoising algorithm that removes the noise in both spatial and spectral domains by total variation minimization. The signal-to-noise ratio of SRS spectroscopic images was improved by up to 57 times for diluted dimethyl sulfoxide solutions and by 15 times for biological tissues. Weak Raman peaks of target molecules originally buried in the noise were unraveled. Coupling the denoising algorithm with multivariate curve resolution allowed discrimination of fat stores from protein-rich organelles inC. elegans. Together, our method significantly improved detection sensitivity without frame averaging, which can be useful forin vivospectroscopic imaging.
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Chien-Sheng
authors.initials: CS
authors.lastname: Liao
authors.affiliation: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Joon Hee
authors.initials: JH
authors.lastname: Choi
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Delong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA; Department of Statistics, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Stanley H
authors.initials: SH
authors.lastname: Chan
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA; School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA; Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA; Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA; Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Ji-Xin
authors.initials: JX
authors.lastname: Cheng
keywords: Imaging processing; Label-free microscopy; Non-linear microscopy; Raman spectroscopy