Angular domain image detectability with changing turbid medium scattering coefficients

Enhanced angular domain imaging in turbid media using Gaussian line illumination

“…In previous work 15 we first showed this was best created using a Cylindrical Spherical Cylindrical (CSC) beam expander/shrinker of Figure 8. This starts with a horizontal 15.7x Galilean cylindrical beam expander created by a vertical cylindrical f=-12 mm lens aligned to a f=200 mm spherical convex lens, which creates a collimated beam in the horizontal axis, but a focusing beam in the vertical axis.…”

“…The Angular Domain experimental setup shown in Figure 6 (see previous papers 15 for details) consists of an argon ion laser operating at 514 nm with a 2 mm 1/e 2 beam diameter, and a beam expander to create a thin line of light to illuminate the sample, the test container holding a scattering solution with embedded phantom test structures, a computer-controlled z-axis table for moving the test container, the SMCA aligned to the line of light, and a CMOS digital imager to capture the filtered light. The experiments were conducted in the Class 1000 clean room at Simon Fraser University to prevent contamination of the collimators.…”

“…A liquid scattering solution is held in an open glass container 15 which allows the phantom test objects to be placed at various depths (1 cm, 2 cm, 3 cm, 4 cm) within the scattering solution and at the front of the container (5 cm thickness). To create an easily controllable scattering medium, a solution was created by mixing specific amounts of 2% partially skimmed milk with de-ionized (DI) water to achieve a desired scattering level.…”

“…A computer controlled 11 precision z-axis stage (50 nm repeatability) moved the test container in 10 pixel steps which for the CMOS imager employed 15 was 520 microns (selected to match the collimator hole vertical size 15 ). Similar to other scanning techniques, the sample was moved rather than the SMCA and the laser beam so that alignment of the array to the beam could be maintained.…”