叶片偏振高光谱特征及叶绿素含量估算模型研究

发布时间：2018-06-14 12:16

本文选题：偏振遥感 + 植物叶片　；参考：《广西师范学院》2017年硕士论文

【摘要】：植物是地球表面广泛存在的一种地物,而叶片是植物进行光合作用、养分转化、呼吸及蒸腾作用的重要器官。植物叶片的叶绿素含量是反映植物的光合作用能力和营养供给情况的重要生理指标,是农作物生长发育和受灾状况的指示器。遥感技术因其获取信息量大、周期短、客观等特点和在持续、动态跟踪监测方面的优势,被广泛应用于农作物生化参数的估算当中。与传统光学和辐射遥感方法相比,偏振光遥感由于偏振信息的多维特性,因而在农作物自动观测中具有更独特的优势。为此,本文通过对多种植物和叶片的偏振光谱观测实验,对不同植物叶片的偏振高光谱及其与叶绿素含量之间的关系进行了研究,以期找出两者的相关关系。并通过偏振反射光谱反演植物的叶绿素含量,进而了解作物的生长状况和受灾情况。该研究可为应用偏振光对农作物进行遥感自动观测,以及作物的偏振光遥感识别、分类和应用研究提供科学依据和技术支撑。完成的主要研究工作如下:(1)利用偏振成像地面实验平台,从不同方位对植物目标进行了偏振观测实验。通过对前向、侧向、后向三个方位的ri图像对比,发现前向的图像中目标的偏振度较大,信息最为丰富,侧向次之,而后向图像中所包含的信息最少,因此,针对植物目标特性的偏振探测应以前向方位为主。(2)利用室内多角度观测平台和加装了偏振片的ASD光谱仪,对具有毛刺、绒毛和蜡质层等不同表面特征的植物叶片进行了偏振光谱实验研究。通过对实验结果的对比及分析,发现叶片表面毛刺越多、绒毛越多、蜡质层越薄,其偏振反射越低;叶片的三种特征中对偏振度的影响最大是蜡质层,毛刺次之,绒毛的影响相对较小;蜡质层对偏振反射和偏振度的影响均非常明显。(3)利用室内多角度观测平台、加装了偏振片的ASD光谱仪和叶绿素仪,对多种光滑叶片的叶绿素含量与偏振高光谱的相关关系进行了实验研究。通过分析偏振高光谱与叶绿素含量的关系,建立了基于绿峰偏振光特性的叶绿素含量估算模型,并进行了精度评价。结果表明,对于光滑叶片而言,在420~720nm测量范围内,550nm附近绿峰波段的偏振度与叶绿素含量的关系最好,其次为偏振反射,再次为最高反射和总反射,最低反射的关系最不明显。基于偏振度的指数形式叶绿素含量估算模型,其R2和RMSE分别为0.7527和9.5759,且通过了信度0.01的显著性检验,可用于叶绿素含量的估算。
[Abstract]:Plant is one of the most important organs of photosynthesis, nutrient transformation, respiration and transpiration on the surface of the earth. The chlorophyll content of plant leaves is an important physiological index to reflect the photosynthesis ability and nutrition supply of plants. It is also an indicator of the growth and development of crops and the disaster condition. Remote sensing technology is widely used in the estimation of biochemical parameters of crops because of its characteristics of large amount of information, short period, objective and so on, as well as its advantages in continuous and dynamic tracking and monitoring. Compared with traditional optical and radiometric remote sensing methods, polarized remote sensing has more unique advantages in crop automatic observation because of the multidimensional characteristics of polarization information. In order to find out the correlation between the polarization hyperspectrum and chlorophyll content of different plant leaves, this paper studied the relationship between the polarization hyperspectrum and chlorophyll content of different plant leaves by means of the polarizing spectrum observation experiments of many kinds of plants and leaves in order to find out the correlation between the polarization hyperspectrum and the chlorophyll content of different plant leaves. The chlorophyll content of the plant was retrieved by polarization reflectance spectroscopy, and then the crop growth and the disaster situation were understood. The research can provide scientific basis and technical support for remote sensing automatic observation of crops with polarized light, as well as the recognition, classification and application of polarized light for crops. The main work of this paper is as follows: (1) Polarimetric observation experiments on plant targets are carried out from different directions using polarization imaging ground experiment platform. By comparing the ri images with three directions: forward, lateral and backward, it is found that the polarization degree of the target in the forward image is large, the information is the most abundant, the side is the second, and the information in the backward image is the least, so, The polarization detection of plant target should be based on forward azimuth.) the indoor multi-angle observation platform and the ASD spectrometer with polarizer are used. The polarizing spectra of plant leaves with different surface characteristics, such as fluff and waxy layer, were studied experimentally. Through the comparison and analysis of the experimental results, it is found that the more burr, the more fluff, the thinner the waxy layer, and the lower the polarization reflection of the leaf surface, the more the waxy layer is the most important one among the three characteristics of the leaf, the second is the burr. The effect of fluff on polarization reflection and degree of polarization is very obvious.) using indoor multi-angle observation platform, ASD spectrometer and chlorophyll meter with polarizer are added. The correlation between chlorophyll content and polarization hyperspectral of various smooth leaves was studied experimentally. Based on the analysis of the relationship between the polarization hyperspectrum and chlorophyll content, the estimation model of chlorophyll content based on the characteristics of green peak polarized light was established and the accuracy was evaluated. The results show that, for smooth leaves, the relationship between the degree of polarization and chlorophyll content in the green band around 550 nm is the best in the 420~720nm measurement range, followed by the polarization reflection, the highest reflection and the total reflection, and the lowest reflection is the least obvious. The estimation model of chlorophyll content in exponential form based on polarization is 0.7527 and 9.5759 for R2 and 9.5759, respectively, and it can be used to estimate chlorophyll content through the significance test of reliability 0.01.
【学位授予单位】：广西师范学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S127

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