Measuring Leaf Water Content with Dual-Wavelength Intensity Data from Terrestrial Laser Scanners

Research output: Contribution to journalArticleScientificpeer-review

Standard

Measuring Leaf Water Content with Dual-Wavelength Intensity Data from Terrestrial Laser Scanners. / Junttila, Samuli; Vastaranta, Mikko; Liang, Xinlian; Kaartinen, Harri; Kukko, Antero; Kaasalainen, Sanna; Holopainen, Markus; Hyyppä, Hannu; Hyyppä, Juha.

In: Remote Sensing, Vol. 9, No. 1, 8, 2017.

Research output: Contribution to journalArticleScientificpeer-review

Harvard

APA

Vancouver

Author

Junttila, Samuli ; Vastaranta, Mikko ; Liang, Xinlian ; Kaartinen, Harri ; Kukko, Antero ; Kaasalainen, Sanna ; Holopainen, Markus ; Hyyppä, Hannu ; Hyyppä, Juha. / Measuring Leaf Water Content with Dual-Wavelength Intensity Data from Terrestrial Laser Scanners. In: Remote Sensing. 2017 ; Vol. 9, No. 1.

Bibtex - Download

@article{315a2cb13c48438b9410f4f661e5b79b,
title = "Measuring Leaf Water Content with Dual-Wavelength Intensity Data from Terrestrial Laser Scanners",
abstract = "Decreased leaf moisture content, typically measured as equivalent water thickness (EWT), is an early signal of tree stress caused by drought, disease, or pest insects. We investigated the use of two terrestrial laser scanners (TLSs) employing different wavelengths for improving the understanding how EWT can be retrieved in a laboratory setting. Two wavelengths were examined for normalizing the effects of varying leaf structure and geometry on the measured intensity. The relationship between laser intensity features, using red (690 nm) and shortwave infrared (1550 nm) wavelengths, and the EWT of individual leaves or groups of needles were determined with and without intensity corrections. To account for wrinkles and curvatures of the leaves and needles, a model describing the relationship between incidence angle and backscattered intensity was applied. Additionally, a reflectance model describing both diffuse and specular reflectance was employed to remove the fraction of specular reflectance from backscattered intensity. A strong correlation (R2 = 0.93, RMSE = 0.004 g/cm2) was found between a normalized ratio of the two wavelengths and the measured EWT of samples. The applied intensity correction methods did not significantly improve the results of the study. The backscattered intensity responded to changes in EWT but more investigations are needed to test the suitability of TLSs to retrieve EWT in a forest environment.",
keywords = "forest health, forestry, terrestrial laser scanning, lidar, multispectral lidar, leaf water content, monitoring, time series",
author = "Samuli Junttila and Mikko Vastaranta and Xinlian Liang and Harri Kaartinen and Antero Kukko and Sanna Kaasalainen and Markus Holopainen and Hannu Hyypp{\"a} and Juha Hyypp{\"a}",
year = "2017",
doi = "10.3390/rs9010008",
language = "English",
volume = "9",
journal = "Remote Sensing",
issn = "2072-4292",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",
number = "1",

}

RIS - Download

TY - JOUR

T1 - Measuring Leaf Water Content with Dual-Wavelength Intensity Data from Terrestrial Laser Scanners

AU - Junttila, Samuli

AU - Vastaranta, Mikko

AU - Liang, Xinlian

AU - Kaartinen, Harri

AU - Kukko, Antero

AU - Kaasalainen, Sanna

AU - Holopainen, Markus

AU - Hyyppä, Hannu

AU - Hyyppä, Juha

PY - 2017

Y1 - 2017

N2 - Decreased leaf moisture content, typically measured as equivalent water thickness (EWT), is an early signal of tree stress caused by drought, disease, or pest insects. We investigated the use of two terrestrial laser scanners (TLSs) employing different wavelengths for improving the understanding how EWT can be retrieved in a laboratory setting. Two wavelengths were examined for normalizing the effects of varying leaf structure and geometry on the measured intensity. The relationship between laser intensity features, using red (690 nm) and shortwave infrared (1550 nm) wavelengths, and the EWT of individual leaves or groups of needles were determined with and without intensity corrections. To account for wrinkles and curvatures of the leaves and needles, a model describing the relationship between incidence angle and backscattered intensity was applied. Additionally, a reflectance model describing both diffuse and specular reflectance was employed to remove the fraction of specular reflectance from backscattered intensity. A strong correlation (R2 = 0.93, RMSE = 0.004 g/cm2) was found between a normalized ratio of the two wavelengths and the measured EWT of samples. The applied intensity correction methods did not significantly improve the results of the study. The backscattered intensity responded to changes in EWT but more investigations are needed to test the suitability of TLSs to retrieve EWT in a forest environment.

AB - Decreased leaf moisture content, typically measured as equivalent water thickness (EWT), is an early signal of tree stress caused by drought, disease, or pest insects. We investigated the use of two terrestrial laser scanners (TLSs) employing different wavelengths for improving the understanding how EWT can be retrieved in a laboratory setting. Two wavelengths were examined for normalizing the effects of varying leaf structure and geometry on the measured intensity. The relationship between laser intensity features, using red (690 nm) and shortwave infrared (1550 nm) wavelengths, and the EWT of individual leaves or groups of needles were determined with and without intensity corrections. To account for wrinkles and curvatures of the leaves and needles, a model describing the relationship between incidence angle and backscattered intensity was applied. Additionally, a reflectance model describing both diffuse and specular reflectance was employed to remove the fraction of specular reflectance from backscattered intensity. A strong correlation (R2 = 0.93, RMSE = 0.004 g/cm2) was found between a normalized ratio of the two wavelengths and the measured EWT of samples. The applied intensity correction methods did not significantly improve the results of the study. The backscattered intensity responded to changes in EWT but more investigations are needed to test the suitability of TLSs to retrieve EWT in a forest environment.

KW - forest health

KW - forestry

KW - terrestrial laser scanning

KW - lidar

KW - multispectral lidar

KW - leaf water content

KW - monitoring

KW - time series

U2 - 10.3390/rs9010008

DO - 10.3390/rs9010008

M3 - Article

VL - 9

JO - Remote Sensing

JF - Remote Sensing

SN - 2072-4292

IS - 1

M1 - 8

ER -

ID: 10229621