3波長の近赤外半導体レーザーを用いた果実糖度の非破壊計測手法の開発

抄録

A new measurement technique based on three near-infrared laser diodes is proposed for non-destructive evaluation of sugar content in fruits. A parameter γ, which is independent of the optical path length is considered, such that γ=ln (R_i/R_k)/ln (R_i/R_k), where the values of reflectance R_{i, j, k} represent the ratio of values of diffuseli ght power reaching to two receiving fibers corresponding to different wavelengths λi, j, k.Based on a simulation with a modeled-apple, it was found that there are optimum combinations among three wavelengths for which the correlation between the parameter γ and the sugar content of fruit becomes sufficiently high. The sugar content of apples was also measured experimentally with an accuracy of 0.63 Brix, by employing three laser diodes with wavelengths of 911, 936 and 1055 nm. The measurements clearly show the usefulness of the proposed technique.