title: Highly sensitive image-derived indices of water-stressed plants using hyperspectral imaging in SWIR and histogram analysis.
abstract: The optical signature of leaves is an important monitoring and predictive parameter for a variety of biotic and abiotic stresses, including drought. Such signatures derived from spectroscopic measurements provide vegetation indices - a quantitative method for assessing plant health. However, the commonly used metrics suffer from low sensitivity. Relatively small changes in water content in moderately stressed plants demand high-contrast imaging to distinguish affected plants. We present a new approach in deriving sensitive indices using hyperspectral imaging in a short-wave infrared range from 800 nm to 1600 nm. Our method, based on high spectral resolution (1.56 nm) instrumentation and image processing algorithms (quantitative histogram analysis), enables us to distinguish a moderate water stress equivalent of 20% relative water content (RWC). The identified image-derived indices 15XX nm/14XX nm (i.e. 1529 nm/1416 nm) were superior to common vegetation indices, such as WBI, MSI, and NDWI, with significantly better sensitivity, enabling early diagnostics of plant health.
authors.affiliation: Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: David M
authors.initials: DM
authors.lastname: Kim
authors.affiliation: Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: Hairong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: Haiying
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: Tommy
authors.initials: T
authors.lastname: Du
authors.affiliation: Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Donald Danforth Plant Science Center, St. Louis, MO 63132.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Mockler
authors.affiliation: Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: Mikhail Y
authors.initials: MY
authors.lastname: Berezin
mesh_terms: D000465:Algorithms; D031235:Buxus / Q000502:physiology*; D003681:Dehydration; D003952:Diagnostic Imaging / Q000379:methods; D055864:Droughts; D018515:Plant Leaves / Q000737:chemistry / Q000502:physiology*; D013057:Spectrum Analysis / Q000379:methods*; D013312:Stress, Physiological / Q000502:physiology*; D014867:Water / Q000032:analysis; D014868:Water Deprivation / Q000502:physiology*
chemical_list: D014867:Water