Patent ID: 6064917
Filing Date: 2000-05-16
Classification: G01N

Abstract:
Method of detecting the location of inhomogeneities in three dimensions in a turbid medium by analyzing a scattered wave returned by said medium comprising the steps of:(a) projecting into said turbid medium electromagnetic radiation having a time varying pattern of photon density capable of being scattered and absorbed while migrating in said turbid medium;(b) retrieving in a detection plane a detected electromagnetic signal, which has passed through said medium in accordance with step (a), indicative of said inhomogeneities;(c) computer processing said detected signal by(c-1) calculating a homogeneous signal component of said detected signal;(c-2) subtracting said homogeneous signal component from said detected signal for producing a scattered component of said detected signal;(c-3) Fourier transforming said scattered component to produce a transform of the detected scattered component;(c-4) selecting a location of a reconstruction plane in which to reconstruct the scattered wave;(c-5) dividing the transform of the detected scattered component produced in accordance with step (c-3) by a propagation transfer function(c-6) stability filtering the result of the performance of step (c-5);(c-7) inverse Fourier transforming a signal produced in accordance with step (c-6) to produce a transformed signal;(c-8) inserting said transformed signal resulting from performance of step (c-7) into a reconstructed signal volume plane;(c-9) repeating steps (c-2) through (c-8) until a given plurality of reconstruction planes are reconstructed;(c-10) localizing an inhomogeneity in depth by finding a peak of a reconstructed scattered wave's amplitude in a reconstruction plane behind the detection plane; and(c-11) localizing an inhomogeneity laterally by finding a peak of the reconstructed scattered wave amplitude in said detection plane.