Prof. Koichi Shimizu
Xidian University, China and Waseda University, Japan
Title: Optical 3D imaging of internal organs by transillumination of near-infrared light with scattering suppression
Abstract:
Noninvasive optical imaging of internal organ structures remains a critical challenge in biomedical research. Near-infrared (NIR) light within the 700–1200 nm wavelength range offers a promising approach for noninvasive imaging of internal structures in biological tissues through transillumination. However, the inherent strong light scattering in body tissues often leads to significant image blurring, which hinders the acquisition of clear structural information. To address this challenge, we have developed advanced methodologies to suppress scattering effects and reconstruct three-dimensional (3D) images from blurred two-dimensional (2D) transillumination images. Our approach integrates theoretical modeling, algorithmic deblurring, and deep learning techniques. By deriving a point spread function (PSF) based on the diffusion approximation of light propagation in turbid media, we quantitatively characterize image blur as a function of absorber depth. This PSF enables the generation of synthetic training data for neural networks by creating pairs of clear and blurred images. Our novel neural network methodology enables three key capabilities: (1) deblurring of transillumination images, (2) depth estimation of absorbing structures, and (3) reconstruction of clear 3D images from single blurred 2D inputs. Simulations and experimental validations confirm the efficacy of our scattering suppression methods and 3D reconstruction techniques. This study highlights the potential of NIR transillumination imaging as a powerful, noninvasive tool for biomedical imaging, offering significant advancements in both structural and functional diagnostics.
Keywords: noninvasive imaging, transillumination imaging, macroscopic imaging, animal bodies, image deblurring, three-dimensional imaging, deep learning, scattering suppression.
Biography:
Koichi Shimizu received M.S. and Ph.D. degrees, from University of Washington (UW), Seattle, USA in 1976 and 1979, respectively. He was a Research Associate in University of Washington in 1974-79. He was an Assistant Professor, an Associate Professor, and a Professor in Hokkaido University, Sapporo, Japan in 1979-2016. He was a Professor in Waseda University in 2016-2021. He is currently a Professor of Xidian University, China, an Invited Research Professor of Waseda University, Japan, and a Professor Emeritus of Hokkaido University, Japan. He has been engaged in the studies of biomedical engineering including those of wave propagation in biological media, optical imaging and measurement, biotelemetry, and biological effects of electromagnetic field. He served as an associate editor of IEEE Trans. ITB in 1999–2007. He has been a Fellow of the Electromagnetics Academy, and an editorial board member of Scientific Reports, Nature.