Construction and verification of portable hyper-spectral imaging system
Date Issued
2012
Date
2012
Author(s)
Pi, Hsiang-Chen
Abstract
The gist of this research is to construct a portable hyper-spectral imaging (HSI) system. This system utilizes imaging fiber bundle as a detection probe to gathering spatially-resolved diffuse reflectance (DRS) and fluorescence signals. And we use DRS fitting tools to extract tissue optical parameters: scattering/absorption coefficients, hemoglobin concentration, and tissue thickness.
The system has two types of fiber probe: oblique and perpendicular probes. These probes can be applied to obtain optical signals from superficial and deeper tissue layers. The system integrates motorized electronic shutters and broadband/UV light sources to switch DRS and fluorescence measurements. And the system uses self-made chromium (Cr) attenuation filter to eliminate the specular reflection from the surface of imaging fiber bundles. In the signal analysis, we designed two analysis modes: 1.choosing circular region of interests (ROI) from source fiber to outside detection fibers along the center of imaging fiber bundles; 2.selecting concentric ROI from source fiber to outside.
We used verified scaling Monte Carlo (MC) forward simulation spectrum to calibrate practical DRS spectrum data. At this study, we measured and compared two different sizes of scattering phantoms (polystyrene). The averages of calibration error achieved to 6.02% or below at SDS = 400、600、800 μ"m" . It shows that the portable system possesses proper performance in DRS measurements. And this study shows the DRS results of normal human oral mucous tissues, including experimental spectra and extracted optical parameters by calibration and inverse fitting tools. Based on standard calibration protocols and fitting tools, we expect to use this portable system to execute DRS measurements of double layer phantom and live tissues, to extract precise optical parameters from measured data by inverse simulation spectrum, and to quantify the contents of hemoglobin and blood oxygen saturation.
For the fluorescence measurements, our research team will search for enough information of fluorescence excitation-emission matrix (EEM) to choose proper light source and filters for uses. The final aim is to establish a stable and portable optical system for clinical diagnosis.
Subjects
diffuse reflectance spectrum
fluorescence spectrum
hyper-spectral imaging system
imaging fiber bundle
Type
thesis
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