Detection of early plant stress responses in hyperspectral images
Detection of early plant stress responses in hyperspectral images
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DOI：
10.1016/j.isprsjprs.2014.03.016
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发表时间：
2014-07-01
影响因子：
12.7
通讯作者：
Pluemer, Lutz
中科院分区：
文献类型：
--
作者：
Behmann, Jan;Steinruecken, Joerg;Pluemer, Lutz
农作物的早期压力检测是非常相关的，但很难实现。我们假设，近距离高光谱成像能够在早期阶段无损地发现与压力相关的过程，这是人眼看不见的。我们提出了一种结合无监督和有监督方法的方法，以便从一系列高光谱图像中识别渐进应力发展的几个阶段。整个植物的胁迫是通过像素尺度上的胁迫响应水平来检测的。研究的重点是大麦(Hordeum Uggare)的干旱胁迫。无监督学习被用来将高光谱特征分成与应激反应和渐进性衰老的不同阶段相关的簇。虽然所有这些特征都可以在水分充足和干旱胁迫的植物中找到，但它们各自的分布不同。基于支持向量机的有序分类方法用于量化和可视化衰老进程阶段的分布，并将水分充足的植物从干旱胁迫中分离出来。对于每个衰老阶段，确定了一组最相关的独特植被指数(VIS)。该方法已应用于温室盆栽大麦植株的两个试验，分别在水分充足和干旱胁迫条件下进行。比使用NDVI更早检测到干旱胁迫，时间长达10天。此外，研究还表明，一些VI具有全局性，而另一些VI则特定于特定的衰老阶段。通过对玉米(Zea Mays)的田间试验，说明了该方法在田间的可移植性。(C)2014年国际摄影测量和遥感学会(ISPR)，由Elsevier B.V.出版。保留所有权利。
Early stress detection in crop plants is highly relevant, but hard to achieve. We hypothesize that close range hyperspectral imaging is able to uncover stress related processes non-destructively in the early stages which are invisible to the human eye. We propose an approach which combines unsupervised and supervised methods in order to identify several stages of progressive stress development from series of hyperspectral images. Stress of an entire plant is detected by stress response levels at pixel scale. The focus is on drought stress in barley (Hordeum vulgare). Unsupervised learning is used to separate hyperspectral signatures into clusters related to different stages of stress response and progressive senescence. Whereas all such signatures may be found in both, well watered and drought stressed plants, their respective distributions differ. Ordinal classification with Support Vector Machines (SVM) is used to quantify and visualize the distribution of progressive stages of senescence and to separate well watered from drought stressed plants. For each senescence stage a distinctive set of most relevant Vegetation Indices (VIs) is identified. The method has been applied on two experiments involving potted barley plants under well watered and drought stress conditions in a greenhouse. Drought stress is detected up to ten days earlier than using NDVI. Furthermore, it is shown that some VIs have overall relevance, while others are specific to particular senescence stages. The transferability of the method to the field is illustrated by an experiment on maize (Zea mays). (C) 2014 International Society for Photogrammetry and Remote sensing, Inc. (ISPRS) Published by Elsevier B.V. All rights reserved.