红外热成像技术在作物病害早期检测方面的应用研究

发布时间：2018-04-25 08:46

本文选题：红外热成像技术 + 水稻稻瘟病　；参考：《河北农业大学》2015年硕士论文

【摘要】：为了防治病害,保证粮食产量,我国在农业生产中存在过量使用农药的情况,导致土壤和水源的污染日益严重。与此同时,大量使用农药带来的食品安全问题也得到全社会广泛关注。为了保护环境实现农业可持续发展,国家对农业的水、肥、药的使用提出了控制用量的要求。2015年3月5日,两会上的政府报告中强调“综合治理农药兽药残留问题,全面提高农产品质量和食品安全水平”。其中病虫害的早期发现和早期施治是降低农药使用量的有效措施。传统的病害检测主要基于肉眼观察。为了提早发现病害,近年来人们进行了大量的探索研究,寻找病害早期发现的方法途径,如显微技术、光谱技术等。本文对红外热成像技术在作物病害早期检测方面进行了研究试验。本课题研究主要内容如下:1.总结了国内外采用红外热成像技术对作物病害和胁迫方面进行检测的研究进展和现状,并分析了该技术在国内外同类研究中的不足之处;对红外热成像技术进行概述,着重阐述了非制冷红外探测器的原理及构造,并对其热流量方程进行推导;通过分析作物感染病害后水分变化与温度的关系,得出了红外热成像技术应用于作物病害检测具有可行性的结论。2.通过查阅大量资料并咨询扬州农科院的水稻专家和中国农业大学的小麦组专家,进行多次预试验,对比确定了水稻稻瘟病喷雾接种法和小麦条锈病涂抹接种法。对病菌的特点及侵染机理进行了分析;结合实际操作对病菌的培养、病害接种过程等水稻和小麦各自试验材料的制备方法进行了归纳整理;正式试验选择水稻稻瘟病和小麦条锈病为试验材料。3.对系统需求进行分析,搭建了红外热成像试验系统,包括德国Vario CAM#174;hr红外热像仪、图像存储卡、上位机和可见光图像采集系统。图像正式采集之前,通过对全天不同时刻作物红外热图像采集,分析对比了环境温度和水分对成像效果的影响,最终确定了图像采样时间及检测方法。4.在可控条件下,运用红外热成像技术对水稻稻瘟病叶片和小麦条锈病叶片进行初步检测,分析红外热图像中病原对叶片的影响。采用IRBIS 3红外数据分析软件对获取的200幅图像进行分析,提取其特征值可得,在干燥环境中,水稻稻瘟病叶片感病后的温差为0.62℃~2℃,其健康叶片温差小于0.2℃;小麦条锈病的叶片感病后的温差为1℃~1.5℃,其健康叶片温差小于0.3℃。5.利用红外分析软件IRBIS 3对2000余幅图像进行分析,结果表明:(1)对接种水稻稻瘟病的80个水稻样本进行连续、无损检测,发现在肉眼很难观测到病变时,红外热图像中已经能发现叶片感病部位和健康部位间约有0.36℃~0.63℃的温度特征差值,基本可以于发病前一天初步实现对水稻稻瘟病的早期检测。(2)小麦在遭受条锈菌侵染后,叶片病害部位的温度低于健康部位的温度,在病斑明显可见前,即小麦刚进入褪绿期,此时还未产孢,而在红外热图像中的标注点处,经过红外热图像特征提取可得此处比周围正常部位温度特征值低0.62℃~0.87℃。(3)本试验在利用红外热成像技术检测作物病害的同时,使用叶绿素含量测定仪SPAD-502对其叶绿素相对值进行测定。与叶片的温度、病情发展进行综合分析后发现,叶绿素相对含量随病情的发展产生变化。试验结果表明,在可控条件下,叶绿素相对含量可以作为鉴别叶片是否感染病害的一个指标。上述研究结果表明采用红外热成像技术可以实现作物病害的快速、无损检测。本研究为作物病害的快速检测仪器和传感器的开发提供了理论基础。
[Abstract]:In order to prevent and control diseases and ensure grain yield, there is a situation of excessive use of pesticides in agricultural production in China, which leads to more and more serious pollution of soil and water. At the same time, the problem of food safety caused by a large number of pesticides has also been widely concerned. In order to protect the environment and realize the sustainable development of agriculture, the state has made the water and fertilizer of agriculture. The use of drug use put forward the requirement to control the dosage in March 5th.2015. In the government report of the two conferences, the government report of the two conferences stressed "comprehensive control of pesticide and veterinary drug residues, improving the quality of agricultural products and the level of food safety in an all-round way". Based on the naked eye observation. In order to find the disease early, a lot of research and research have been carried out in recent years to find ways of early detection of disease, such as microtechnology and spectral technology. This paper studies the early detection of crop disease by infrared thermal imaging technology. The main contents of this research are as follows: 1. summarized the domestic The research progress and status of the detection of crop disease and stress by infrared thermal imaging technology are adopted, and the shortcomings of the technology in the same kind of research at home and abroad are analyzed. The infrared thermal imaging technology is summarized, the principle and structure of uncooled infrared detector are expounded, and the heat flow equation is deduced. The relationship between water change and temperature after crop infection was analyzed, and the feasibility of applying infrared thermal imaging technology to crop disease detection.2. was concluded by consulting a lot of data and consulting the experts of the rice experts in Yangzhou Academy of agriculture and the experts of the wheat group of China Agricultural University, and the rice blast was determined by comparison. The spray inoculation method and the wheat stripe rust smear inoculation method were used to analyze the characteristics of the pathogen and the mechanism of the infection. The preparation methods of the experimental materials of rice and wheat were summed up in combination with the cultivation of the pathogens, the inoculation process of the disease and so on in combination with the actual operation. The formal test selected the rice blast and the wheat stripe rust as the test material.3.. The system requirements are analyzed and the infrared thermal imaging test system is set up, including the German Vario CAM#174, the HR infrared thermograph, the image storage card, the upper computer and the visible light image acquisition system. Before the image is collected, the image effect of the environment temperature and water on the imaging effect is analyzed and compared through the collection of the infrared thermal images of the crops at different times of the day. When the image sampling time and the detection method.4. were determined, the infrared thermal imaging technique was used to detect the leaves of rice blast and wheat stripe rust under the controllable condition. The effect of pathogen on the leaves in the infrared thermal image was analyzed. The 200 images obtained by the IRBIS 3 infrared data analysis software were analyzed and extracted. Its characteristic value can be obtained. In the dry environment, the temperature difference of rice blast leaves after the disease is 0.62 ~2 C, the temperature difference of the healthy leaves is less than 0.2 degrees C, the difference of temperature difference between the leaves of wheat stripe rust after the disease is 1 C ~1.5 C, the temperature difference of the healthy leaves is less than 0.3 C.5., and the infrared analysis software IRBIS 3 is used to analyze the 2000 images. The results show that: (1) 80 rice samples inoculated with rice blast were tested continuously and nondestructive. It was found that when the naked eye was difficult to observe the pathological changes, the temperature characteristic difference between the infected parts of the leaves and the healthy parts at about 0.36 ~0.63 C had been found in the infrared thermal image, and the early detection of rice blast was preliminarily realized on the day before the onset of the disease. 2) when the wheat was infected with stripe rust, the temperature of the site of leaf disease was lower than that of the healthy part. Before the spot was visible, the wheat had just entered the fading period and did not produce the sporulation at this time. At the point of the infrared thermal image, the feature extraction by infrared thermal image was 0.62 ~0.87 lower than the temperature characteristic value of the normal part around the surrounding area. (3) (3) while using infrared thermal imaging to detect crop diseases, the chlorophyll relative value was measured by the chlorophyll content analyzer. After comprehensive analysis of the temperature of the leaves and the development of the disease, the relative content of chlorophyll changed with the development of the disease. The experimental results showed that under controlled conditions, The relative content of chlorophyll can be used as an indicator to identify the infection of leaves. The above results show that the infrared thermal imaging technology can achieve rapid and nondestructive detection of crop diseases. This study provides a theoretical basis for the development of rapid detection instruments and sensors for crop diseases.

【学位授予单位】：河北农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S431;TN219;S123

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