基于高光谱成像的苹果虫伤缺陷与果梗/花萼识别方法  

Recognition method of insect damage and stem/calyx on apple based on hyperspectral imaging

作　　者：田有文[1] 程怡[1] 王小奇[2] 刘思伽[1] 

机构地区：[1]沈阳农业大学信息与电气工程学院,沈阳110866 [2]沈阳农业大学植物保护学院,沈阳110866

出　　处：《农业工程学报》2015年第4期325-331,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：农业部公益性行业(农业)科研专项资助项目(201103024);辽宁省教育厅科学技术研究资助项目(L2011114)

摘　　要：为了快速、准确、无损检测在果梗/花萼的干扰下苹果虫伤缺陷,该文利用高光谱成像技术,首先选取正常果和虫伤果各80个,提取并分析了苹果表面感兴趣区域(虫伤区域、果梗区域、花萼区域、正常区域)的光谱曲线,结合824 nm波长特征图像的阈值分割和主成分分析,对获得的第一主成分图像提取160×120像素大小的感兴趣区域。然后提取感兴趣区域的能量、熵、惯性矩和相关性4个纹理特征,融合646、824 nm波段的相对光谱反射率的光谱特征,采用支持向量机对苹果虫伤区域和正常区域、果梗/花萼区域进行识别。试验结果表明:选取160×120像素大小的感兴趣区域图像、采用径向基核函数对正常果、果梗/花萼果与虫伤果的识别效果最好,总体识别率为97.8%。该研究为苹果质量等级在线评判提供理论依据。Insect damage is one of the main defects of the apple, which could make it lose edibility and greatly reduce the quality of the apple and commercial value. So whether apples exist insect damage is one of the important indicators of the grade apple quality. In this study, we aim to nondestructively detect insect damage on apples under the interference of stem / calyx with hyperspectral imaging technique. 160 ‘Red Fuji＇ apples,including 80 intact and 80 insect infected, picked from an apple planting demonstration garden in the Shenbei New Area in Shenyang city. A hyperspectral imaging collection system with the wavelength range of 400-1 000 nm and spectral resolution ratio of 2.8 mm was established in order to acquire the hyperspectral images of these apple samples. These acquisition apples hyperspectral images were carried out black and white plate correction in order to eliminate the noise generated hyperspectral imaging instrument in the acquisition process. The extraction and analysis of spectral reflectance of apple surface interested region, which were insect damage region, stem/calyx region and normal region, exhibted great differences in spectral reflectance at the 824 nm wavelength. So, the images of the 824 nm wavelength were named the feature images. Then, the feature images were processed by threshold segmentation, dilation, and erosion operation. A binarization image was obtained in the end. The binarization image was used to mask for apple hyperspectral image in order to remove noise of background on hyperspectral image. So a mask apple hyperspectral image was obtained. These processed hyperspectral images were carried by principal component analysis. The optimum PC1 image was chosen and processed by the maximum entropy threshold segmentation to get the insect damage region, stem/calyx region. According to interested region segmentation results, an interested region image was obtained from the PC1 image of each sample, with 80×60 pixels, 160×120 pix and 240×180 pix, respectively. Later, there w

关 键 词：无损检测 图像处理 主成分分析 苹果虫伤 果梗/花萼 高光谱成像 支持向量机 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]