Evaluation of the temporally extrapolated absorbance method for dual-wavelength imaging through tissuelike scattering media

Application of time-of-flight near infrared spectroscopy for detecting sugar and acid contents in apples

A newly constructed optical measurement system was introduced to nondestructively measure the composition of the inside of an apple by time-of-flight near-infrared spectroscopy (TOF-NIRS). As sugar content increased, optical parameters concerned with time-resolved profile of transmitted pulsed light (the attenuance of peak maxima, At, the time delay of peak maxima, Deltat, and the variation of full width at half-maximum, Deltaw) decreased gradually. When the acid content increased, At and Deltaw increased; however, a significant tendency could not be found for Deltat. At, Deltat, and Deltaw were employed as the explanatory variables for multiple linear regression, principle component regression, and partial least-squares analysis. It was possible to predict both sugar and acid contents in an apple with high precision by TOF-NIRS. Especially, the superiority of TOF-NIRS lied in more precise determination of acid content.

Time-domain optical imaging: discrimination between scattering and absorption

A technique for discriminating between scattering and absorbing inclusions located in the center of a scattering slab is presented. The technique is based on an empirical model that provides a simple mathematical expression to describe the change in the time-resolved transmission resulting from the presence of an inclusion. Experimental results from various configurations show that the technique allows for proper recognition of the type of an inclusion whether it is scattering or absorbing. This technique is a significant step toward tissue differentiation.