Vv. Shuvalov et al., Spatial resolution, measuring time, and fast visualization of hidden deep phantoms in diffusion optical tomography of extended scattering objects, LASER PHYS, 11(5), 2001, pp. 636-649
We present the results of testing a prototype of an optical tomograph (a co
ntinuous-wave diode laser with a wavelength of 775 nm and a power of 15-20
mW) and fast algorithms for the I reconstruction of the internal structure
of extended (with linear sizes up to 150 mm) strongly scattering objects. M
odel experiments (with absorption coefficients of 0.005-0.015 and scatterin
g coefficients of 1.4 mm(-1)) have demonstrated that the distributions of t
he probability that detected photons pass through such objects (projections
) can he described in terms of the coefficient of relative trajectory lengt
hening, whose value is independent of the arrangement of a light source and
a detector. This experimental finding, confirmed by Monte Carlo numerical
simulations, allows a simple scaling of projections in the case when the di
stance between the light source and the detector changes, thus providing an
opportunity to implement fast real-time approximate statistical nonlinear
algorithms for the solution of inverse and direct problems of optical tomog
raphy. Experimental testing of the prototype and the developed algorithms h
as shown that, for a model object with a diameter of 140 mm within the stud
ied range of optical parameters, the coefficient of relative trajectory len
gthening ranges from 1.2 to 1.9, and the reconstruction of an image of a st
rongly absorbing inclusion with a diameter of 1-2 mm requires no more than
0.5-1 min.