Single snapshot multiple frequency modulated imaging of subsurface optical properties of turbid media with structured light

M Xu,Weihao Lin,Zili Cao,Bixin Zeng,Xinlin Chen,Longfei Zheng

doi:10.1063/1.4971428

M Xu, Weihao Lin + Show 4 more

Open Access

https://doi.org/10.1063/1.4971428

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Journal: AIP Advances	Publication Date: Dec 1, 2016
Citations: 16	License type: cc-by

Affiliation: Fairfield University, Wenzhou Medical University

Abstract

We report a novel demodulation method that enables single snapshot wide field imaging of optical properties of turbid media in the Spatial Frequency Domain (SFD). This Single Snapshot Multiple frequency Demodulation (SSMD) method makes use of the orthogonality of harmonic functions to extract the modulation transfer function (MTF) at multiple modulation frequencies simultaneously from a single structured-illuminated image at once. The orientation, frequency, and amplitude of each modulation can be set arbitrarily subject to the limitation of the implementation device. We first validate and compare SSMD to the existing demodulation methods by numerical simulations. The performance of SSMD is then demonstrated with experiments on both tissue mimicking phantoms and in vivo for recovering optical properties by comparing to the standard three-phase demodulation approach. The results show that SSMD increases significantly the data acquisition speed and reduces motion artefacts. SSMD exhibits excellent noise suppression in imaging as well at the rate proportional to the square root of the number of pixels contained in its kernel. SSMD is ideal in the implementation of a real-time spatial frequency domain imaging platform and will open up SFDI for vast applications in imaging and monitoring dynamic turbid medium and processes.

Highlights

Spatial Frequency Domain Imaging (SFDI) is one emerging non-contact and quantitative wide field modality for rapid mapping of the optical properties of turbid media such as biological tissue.[1,2,3] It has attracted significant attention recently as SFDI has been proved effective in probing the microarchitecture of the sub-surface of the turbid medium over a wide field[4] and has promising clinical applications in hemodynamics monitoring,[5,6] brain,[7] burns,[8] pathology evaluations,[9] and surgery guidance.[10]
In order to validate Snapshot Multiple frequency Demodulation (SSMD), numerical simulations are performed to compare the results obtained with the standard three-phase, the Hilbert demodulation, the snapshot optical properties method (SSOP), and the SSMD methods
We described and validated the Single Snapshot Multiple frequency Demodulation method applied to the Spatial Frequency Domain Imaging

Summary

Introduction

Spatial Frequency Domain Imaging (SFDI) is one emerging non-contact and quantitative wide field modality for rapid mapping of the optical properties of turbid media such as biological tissue.[1,2,3] It has attracted significant attention recently as SFDI has been proved effective in probing the microarchitecture of the sub-surface of the turbid medium over a wide field[4] and has promising clinical applications in hemodynamics monitoring,[5,6] brain,[7] burns,[8] pathology evaluations,[9] and surgery guidance.[10]. The standard three phase demodulation method requires three images at different phase delay (0, 2π/3, and 4π/3) to compute MTF at one spatial frequency (one AC component). A minimum of 4 images (one DC and one AC) or 6 images (two AC components of different frequency) will be needed to recover the optical property map, which in turn hinders SFDI in real time applications such as when monitoring fast temporal dynamics

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Conclusion