Abstract

The usual approach for estimating bulk optical properties using an integrating sphere measurement setup is by acquiring spectra from three measurement modes namely collimated transmittance (T_c), total transmittance (T_d), and total diffuse reflectance (R_d), followed by the inversion of these measurements using the adding–doubling method. At high scattering levels, accurate acquisition of T_c becomes problematic due to the presence of significant amounts of forward-scattered light in this measurement which is supposed to contain only unscattered light. In this paper, we propose and investigate the effectiveness of using alternative sets of integrating sphere measurements that avoid the use of T_c and could potentially increase the upper limit of concentrations of suspensions at which bulk optical property measurements can be obtained in the visible–near-infrared (Vis-NIR) region of the spectrum. We examine the possibility of replacing T_c with one or more reflectance measurements at different sample thicknesses. We also examine the possibility of replacing both the collimated (T_c) and total transmittance (T_d) measurements with reflectance measurements taken from different sample thicknesses. The analysis presented here indicates that replacing T_c with a reflectance measurement can reduce the errors in the bulk scattering properties when scattering levels are high. When only multiple reflectance measurements are used, good estimates of the bulk optical properties can be obtained when the absorption levels are low. In addition, we examine whether there is any advantage in using three measurements instead of two to obtain the reduced bulk scattering coefficient and the bulk absorption coefficient. This investigation is made in the context of chemical and biological suspensions which have a much larger range of optical properties compared to those encountered with tissue.

© 2016 The Author(s)

Optical properties of normal and carcinomatous bronchial tissue

Jianan Qu, Calum MacAulay, Stephen Lam, and Branko Palcic
Appl. Opt. 33(31) 7397-7405 (1994)

Optical properties of apple skin and flesh in the wavelength range from 350 to 2200 nm

Wouter Saeys, Maria A. Velazco-Roa, Suresh N. Thennadil, Herman Ramon, and Bart M. Nicolaï
Appl. Opt. 47(7) 908-919 (2008)

Double-integrating-sphere system for measuring the optical properties of tissue

John W. Pickering, Scott A. Prahl, Niek van Wieringen, Johan F. Beek, Henricus J. C. M. Sterenborg, and Martin J. C. van Gemert
Appl. Opt. 32(4) 399-410 (1993)

Inverse hybrid technique for determining the optical properties of turbid media from integrating-sphere measurements

I. V. Yaroslavsky, A. N. Yaroslavsky, T. Goldbach, and H.-J. Schwarzmaier
Appl. Opt. 35(34) 6797-6809 (1996)

Accuracy of retrieving optical properties from liquid tissue phantoms using a single integrating sphere

Vinoin Devpaul Vincely and Karthik Vishwanath
Appl. Opt. 61(2) 375-385 (2022)