Study On Optical-Nondestructive Detection Of Watercore And Breakdown Apples

In this thesis, some primary work was done for the study of detecting the watercore-apple by using the self-made difference-meter, and predicting the internal disorder degreed of watercore and breakdown by using visible-near-infrared spectroscopy. The result displayed that density-methods can classify sound apple and serious watercore apple (class4) only. A classifier based on the discriminant analysis both OD810nm and OD760nm was used to segregate 200 samples to each grade. It is corrected classified 68.5% at the place of stem-up, and 69% at the place of calyx-up. Apple mould core affected the optical density. Excluded the mould core apple, total misclassification decreased to 28.19%. The continuous spectrum correctly classified the five grades watercore was 83%. The stem-up and calyx-up have the similar result, but the result of the stem-level place is worse than them. SMLR and PLS calculation models applied to independent prediction sets gave R=0.932, 0.925. Spectral OD value increase was observed in the rage 700~900nm during the watercore apple storage, but it became to decline after 11 th weeks. Using the continuous spectrum predicted the internal browning disorder rate, SMLR and PLS models at stem-up place (R2=0.898, 0.765; RMSEP=9.35, 11.9) were better than another place(R2=0.893, 0.745; RMSEP=9.65, 13.9). However, the A OD(715-750) and OD(715-810) non-linear regression models had the similar predicted result at both places (RMSEP=9.74, 9.75; RMSEP=10.0, 10.07). SMLR model was the best at all of calculation models. Two non-linear models took second place. If 715nm, 750nm, 810nm three waves were selected as the character wave, 97.32% of the breakdown apple and 91.38% of sound apple were correctly classified by discriminant analysis.