Measurement of object position inside high scattering medium by use of optical tomography method with neural processing

摘要

Optical imaging of objects inside high scattering medium by use of light instead of X-rays is called optical tomography. There are several types of optical tomography methods. One of them is direct transillumination with laser light in order to collect shadow images as a starting point for tomography procedure leading to three-dimensional object imaging. In this paper we present a modification of a direct transillumination optical tomography method with neural processing to measure a position of the object placed inside water solution of Intralipid, i.e. inside liquid, which simulates optical properties of a living tissue. As a light source a laser diode emitting red light beam (λ≈670 nm) is used. Detection system of transillumination images is based on scanning of the optical field by photodiode. Scattered field measurements for opposite directions of object illumination, are processed by the neural net. In this approach all the time-consuming computations are conducted while training the artificial neural network. Results of object position measurement obtained in works leading to the paper show that neural processing is helpful in better accuracy of the object positioning, than direct image processing.