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在运往欧盟等选择性国际市场前,需要有效的措施来去除柑橘中的溃疡果。本研究的目的是使用高光谱图像来确定溃疡病变的检测尺寸限。先前开发了基于近红外-可见光波的多光谱算法来将溃疡柑橘果实从其他果实中(正常的、腻斑病、虫害、黑病变、痂和风疤)分割出来,然而,这项工作没有考虑到损伤的尺寸。本研究选用带有一个基于阈值的简单分类器的、使最大总体分类精度达到95.7%双波段比值(834 nm和729 nm反射波长的比率)的方法来估计病变大小。检测到的最小的溃疡病变尺寸的当量直径是1.66 mm。观察了阈值的变化和侵蚀环的数量对最小可检测损伤评估的影响(多次运用形态学腐蚀图像),发现最小阈值获得了更好的溃疡分类精度,但总体分类精度较低。同时,阈值越高,趋势相反。1.275阈值在溃疡分类精度、总体分类精度和最小损伤尺寸检测三个方面获得了最优权重。增加侵蚀环的数量减少了小溃疡病变的检出率,因此可以得出结论,一个侵蚀环给能够获得最好的大小估计结果。试验过程中应用的侵蚀内核尺寸为3 mm×3 mm。
Before shipping to a selective international market such as the EU, effective measures are needed to remove the ulcer fruit from the citrus. The purpose of this study was to use hyper-spectral images to determine the detection limit of ulcer lesions. Previously, a multispectral algorithm based on near infrared-visible light waves was developed to segment ulcerated citrus fruit from other fruits (normal, greyhound, insect pests, black lesions, scabs and wind scars), however, this work did not take into account Damage size. In this study, the lesion size was estimated using a simple threshold-based classifier that maximizes the overall classification accuracy to a 95.7% dual-band ratio (the ratio of the 834 nm to the 729 nm reflected wavelengths). The equivalent diameter of the smallest lesion size detected was 1.66 mm. The effect of threshold change and the number of erosion rings on the minimum detectable damage assessment was observed. Morphological erosion images were used multiple times. It was found that the minimum thresholds obtained better classification accuracy of ulcer, but the overall classification accuracy was lower. At the same time, the higher the threshold, the opposite trend. 1.275 The threshold obtains the optimal weight in the three aspects of ulcer classification accuracy, overall classification accuracy and minimum damage size detection. Increasing the number of erosion rings reduces the detection rate of small ulcer lesions, so it can be concluded that an erosion ring gives the best estimate of size. The size of the erosion kernel used during the experiment was 3 mm × 3 mm.