谢忠红, 徐焕良, 黄秋桂, 王培. 基于高光谱图像和深度学习的菠菜新鲜度检测[J]. 农业工程学报, 2019, 35(13): 277-284. DOI: 10.11975/j.issn.1002-6819.2019.13.033
    引用本文: 谢忠红, 徐焕良, 黄秋桂, 王培. 基于高光谱图像和深度学习的菠菜新鲜度检测[J]. 农业工程学报, 2019, 35(13): 277-284. DOI: 10.11975/j.issn.1002-6819.2019.13.033
    Xie Zhonghong, Xu Huanliang, Huang Qiugui, Wang Pei. Spinach freshness detection based on hyperspectral image and deep learning method[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(13): 277-284. DOI: 10.11975/j.issn.1002-6819.2019.13.033
    Citation: Xie Zhonghong, Xu Huanliang, Huang Qiugui, Wang Pei. Spinach freshness detection based on hyperspectral image and deep learning method[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(13): 277-284. DOI: 10.11975/j.issn.1002-6819.2019.13.033

    基于高光谱图像和深度学习的菠菜新鲜度检测

    Spinach freshness detection based on hyperspectral image and deep learning method

    • 摘要: 针对传统机器视觉在实现菠菜新鲜度检测精度偏低的问题,该文提出了一种基于高光谱和深度学习技术的圆叶菠菜新鲜度识别新方法。以10 ℃常温贮存的圆叶菠菜为研究对象,以天为单位,综合考虑影响菠菜新鲜度的6个因素:贮藏天数、外观、含水率、叶绿素a、叶绿素b和胡萝卜素,将菠菜划分为新鲜、次新鲜和腐败3个等级。拍摄菠菜叶片的高光谱图像,计算ROI(region of interest)反射率均值后,基于分组精英策略遗传算法, 结合2种分组策略,筛选出含6个波长的组合。定义训练集R和测试集合T,使用SVM分类器,基于波长对应的反射率,分别进行基于光谱特性界定菠菜的新鲜度分类试验。找出了识别率均值最高的3个波长,分别是389.55、742.325和1 025.662 nm。由于基于光谱特性进行菠菜新鲜度检测时识别率偏低。尝试基于菠菜的高光谱图像特征进一步进行菠菜新鲜度识别研究。从高光谱图像集中抽取这3个波长对应的菠菜图像,构成菠菜图像样本库(NormImg389、NormImg742、NormImg1 025和NormImg_merge),基于深度学习技术建立菠菜新鲜度识别模型,对图像样本库中4类图像进行识别试验,平均识别准确率79.69%、68.75%、69.27%和80.99%。而NormImg389测试集识别正确率接近80%,NormImg_merge测试集识别正确率最高达到了80.99%,说明融合3个波长对应的图像进行等级识别效果最好。该研究实现了圆叶菠菜新鲜度的无损检测,具有实践和理论意义。

       

      Abstract: Abstract: Aiming at the problem that the traditional machine vision has low discrimination accuracy when realizing the fresh level recognition of spinach, A new method for fresh grade recognition of spinach based on hyperspectral and deep learning was conducted in this study. Round leaf spinach stored in room temperature 10oC on a daily basis was regarded as research objects. The spinach was divided into three grades of fresh, relatively fresh and corruption according to the score calculated by considering 6 factors: fresh spinach days of storage, appearance, water content, chlorophyll a, chlorophyll b, and carotenoids. After 6 ROI areas was obtained from the hyperspectral image of spinach leaves shot with high spectrum imaging instrument, the mean reflectance of ROI region was calculated. Based on the grouping elite strategy genetic algorithm, an adaptive grouping strategy was used to screen out a set of wavelengths A, A=389.55 nm, 401.629 nm, 742.325 nm, 949.939 nm, 1 025.662 nm. Then the artificial grouping strategy was also used for wavelength screening. The number of statistical groups was the wavelength selected by n = 1, 2, 3...n, and the four frequencies with the highest frequency were placed in the set B, B=389.55 nm, 536.365 nm, 742.325 nm, 1 025.662 nm . The six wavelengths in the A∪B set were combined as the final selected wavelengths, and these wavelengths were better able to identify the fresh grade of spinach. Define training set R and test set T, R and T each containing 240 spinach samples. Using the SVM classifier, based on the spine reflectance corresponding to the six wavelengths, a fresh grade classification test based on the spectral characteristics to define spinach was separately performed. After 10 trials, the mean value of recognition accuracy was obtained, and the three wavelengths with the highest recognition rate were found, which were 389.55, 742.325 and 1 025.662 nm, respectively. The corresponding recognition rates were 62.08%, 60.00% and 60.42%, respectively. This indicated that the recognition rate of spinach fresh grade was low based on spectral characteristics. In addition to the spectral properties, spinach's hyperspectral image also contains rich image information corresponding to all wavelengths, so further spine fresh grade recognition based on image features can be performed. The spinach images corresponding to the three wavelengths extracted from the hyperspectral image set constituted an image sample library. Based on the deep learning technology, the spine fresh grade recognition model was established. The recognition experiments were carried out on four types of images (NormImg389、NormImg742、NormImg1 025和NormImg_merge) in the image sample library. The average recognition accuracy of the three experiments was 79.69%, 68.75%, 69.27% and 80.99%. The NormImg389 and NormImg_merge test sets had higher recognition rates, which were close to 80%. The image recognition rate of spinach in NormImg_merge was up to 80.99%, which indicated that when the spinach fresh level recognition was performed, the images corresponding to the three wavelengths were merged. Identifying can get the best classification results. This study achieved the non-destructive testing of the fresh grade of round leaf spinach, and the research results provided quality assurance for industrial processing and marketing, which has practical and theoretical significance.

       

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