Light-Guide Snapshot Imaging Spectrometer for Biomedical Applications
Master of Science
Fiber-based snapshot imaging spectrometer has found increasing potential of applications in the field of biomedical imaging these years. However, currently the technique’s spatial and spectral sampling still need improvement for most requirements in biomedical applications. In this thesis, I propose a strategy design and proof-of-principle prototype system of fiber-based snapshot imaging spectrometer to provide a solution for increasing the spatial and spectral sampling. Through a custom fabricated fiber bundle, the object image is collected with an 81 x 96 spatial sampling, then divided into 3 x 96 spatial groups with gaps in between for dispersion, and finally captured by a CCD camera. To extract the (x, y, λ) datacube from the raw image, a spectral calibration algorithm is implemented to locate each wavelength and obtain point spectrum. Then a phase-shifting spatial calibration procedure is performed to remap the fibers and reconstruct single channel images. The prototype system is designed for visible range from 400 nm to 700 nm and is able to record 71 spectral samples within the range. Preliminary results of oxygen-saturation in occluded finger are presented to show the system spectral and spatial resolving ability. The fibers are packed in an efficient way and the system could be scalable to larger formats with higher spatial sampling. The gaps between fiber groups are designed to be tunable to enable high spectral sampling which has advantage in medical devices such as optical coherence tomography (OCT) in the future.
snapshot imaging spectrometry; hyperspectral imaging; fiber bundle