The City University of New York

City College of New York

Research Foundation of Cuny

The Research Foundation

Wei Cai

Robert R Alfano

Swapan Kumar Gayen

Melvin Lax

Feng Liu

Bidyut B Das

Binlin Wu

Jin Pin Ying

R R Alfano

A time reversal optical tomography (TROT) method for near-infrared (NM) diffuse optical imaging of targets embedded in a highly scattering turbid medium is presented. TROT combines the basic symmetry of time reversal invariance and subspace-based signal processing for retrieval of target location. The efficacy of TROT is tested using simulated data and data obtained from NIR imaging experiments on absorptive, scattering and fluorescent targets embedded in Intralipid-20% suspension in water, as turbid medium, as well as, a realistic cancerous model breast assembled using ex vivo human breast tissues with two embedded tumors. The results demonstrate the potential of TROT for detecting and locating small targets in a turbid medium, such as, breast tumors in early stages of growth.

Time reversal optical tomography for locating targets in a highly scattering turbid medium

A reconstruction technique for reducing computation burden in the 3D image processes, wherein the reconstruction procedure comprises an inverse and a forward model. The inverse model uses a hybrid dual Fourier algorithm that combines a 2D Fourier inversion with a 1D matrix inversion to thereby provide high-speed inverse computations. The inverse algorithm uses a hybrid transfer to provide fast Fourier inversion for data of multiple sources and multiple detectors. The forward model is based on an analytical cumulant solution of a radiative transfer equation. The accurate analytical form of the solution to the radiative transfer equation provides an efficient formalism for fast computation of the forward model.

Hybrid-dual-fourier tomographic algorithm for a fast three-dimensionial optical image reconstruction in turbid media

A method of improving a signal-to-noise (S/N) ratio for a light signal transmitted by wireless optical communication through adverse environmental conditions, the light signal including a snake component and a ballistic component for carrying coded information, and a diffusive component that adds to background noise, the method comprising the steps of: encoding information to be transmitted by the light signal, wherein the light signal is one of a serial train of code pulses or a modulated light beam; selecting an appropriate wavelength for the encoded light signal; transmitting the encoded light signal though the adverse environmental conditions; receiving the encoded light signal; sorting the received encoded light signal to preferentially select the information carrying components and reduce the diffusive component; and detecting the sorted encoded light signal with a photo-detector.

Methods of improving line of sight wireless optical communication through adverse environmental conditions

A method for imaging objects in a highly scattering turbid medium, such as breast, brain, prostate in human body and clouds, smoke in atmosphere environment, using backscattered light. The method involves using a group of sources and detectors setting on same side of medium to generate a plurality of time-resolved intensity data of backscattered light from the medium. The inverse computation using a reconstruction algorithm, taking the measured data as input, produces a three-dimensional image map of the internal structure of a turbid medium. The invention teaches (1) developing an accurate analytical solution of the Boltzmann photon transport equation in a uniform infinite medium, and its extension to the case of a semi-infinite medium, which serves as a background Green's function for the forward model; (2) building a forward physical model of relationship between measurement of backscattered light and inhomogeneity structure of the medium; (3) designing an inverse algorithm for backscattering tomography; (4) designing experimental setups for breast tumor detection using backscattering tomography; (5) using fsec, psec, and nsec laser pulse with different wavelengths in the near infrared spectral region; and (6) using pico-second time gating system as detectors to collect time-slicing data.

Time-resolved optical backscattering tomographic image reconstruction in scattering turbid media

A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium: wherein W is a matrix relating output at source and detector positions r.sub.s and r.sub.d, at time t, to position r, .LAMBDA. is a regularization matrix, chosen for convenience to be diagonal, but selected in a way related to the ratio of the noise, &lt;nn&gt;to fluctuations in the absorption (or diffusion) X.sub.j that we are trying to determine:

Time-resolved diffusion tomographic 2D and 3D imaging in highly

A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium: ##EQU1## wherein W is a matrix relating output at source and detector positions r.sub.s and r.sub.d, at time t, to position r, .LAMBDA. is a regularization matrix, chosen for convenience to be diagonal, but selected in a way related to the ratio of the noise, &lt;nn&gt; to fluctuations in the absorption (or diffusion) X.sub.j that we are trying to determine:

A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium:

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Bronx, NY, United States of America

Wei Cai