title: Radiometric Calibration of a Dual-Wavelength, Full-Waveform Terrestrial Lidar.
abstract: Radiometric calibration of the Dual-Wavelength Echidna(®) Lidar (DWEL), a full-waveform terrestrial laser scanner with two simultaneously-pulsing infrared lasers at 1064 nm and 1548 nm, provides accurate dual-wavelength apparent reflectance (ρ(app)), a physically-defined value that is related to the radiative and structural characteristics of scanned targets and independent of range and instrument optics and electronics. The errors of ρ(app) are 8.1% for 1064 nm and 6.4% for 1548 nm. A sensitivity analysis shows that ρ(app) error is dominated by range errors at near ranges, but by lidar intensity errors at far ranges. Our semi-empirical model for radiometric calibration combines a generalized logistic function to explicitly model telescopic effects due to defocusing of return signals at near range with a negative exponential function to model the fall-off of return intensity with range. Accurate values of ρ(app) from the radiometric calibration improve the quantification of vegetation structure, facilitate the comparison and coupling of lidar datasets from different instruments, campaigns or wavelengths and advance the utilization of bi- and multi-spectral information added to 3D scans by novel spectral lidars.
authors.affiliation: Department of Earth and Environment, Boston University, 675 Commonwealth Avenue, Boston, MA 02215, USA. zhanli86@bu.edu.|School for the Environment, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA. zhanli86@bu.edu.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Li
authors.affiliation: CSIRO Land &amp; Water, GPO Box 1666, Canberra, ACT 2601, Australia. David.Jupp@csiro.au.
authors.forename: David L B
authors.initials: DL
authors.lastname: Jupp
authors.affiliation: Department of Earth and Environment, Boston University, 675 Commonwealth Avenue, Boston, MA 02215, USA. alan@bu.edu.
authors.forename: Alan H
authors.initials: AH
authors.lastname: Strahler
authors.affiliation: School for the Environment, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA. Crystal.Schaaf@umb.edu.
authors.forename: Crystal B
authors.initials: CB
authors.lastname: Schaaf
authors.affiliation: Department of Physics and Applied Physics, University of Massachusetts Lowell, 600 Suffolk Street, Lowell, MA 01854, USA. ghowephysics@gmail.com.
authors.forename: Glenn
authors.initials: G
authors.lastname: Howe
authors.affiliation: Department of Physics and Applied Physics, University of Massachusetts Lowell, 600 Suffolk Street, Lowell, MA 01854, USA. Kuravi_Hewawasam@student.uml.edu.
authors.forename: Kuravi
authors.initials: K
authors.lastname: Hewawasam
authors.affiliation: Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA. douglase@bu.edu.
authors.forename: Ewan S
authors.initials: ES
authors.lastname: Douglas
authors.affiliation: Department of Physics and Applied Physics, University of Massachusetts Lowell, 600 Suffolk Street, Lowell, MA 01854, USA. Supriya_Chakrabarti@uml.edu.
authors.forename: Supriya
authors.initials: S
authors.lastname: Chakrabarti
authors.affiliation: Department of Physics and Applied Physics, University of Massachusetts Lowell, 600 Suffolk Street, Lowell, MA 01854, USA. Timothy_Cook@uml.edu.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Cook
authors.affiliation: School for the Environment, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA. Ian.Paynter@umb.edu.
authors.forename: Ian
authors.initials: I
authors.lastname: Paynter
authors.affiliation: School for the Environment, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA. Edward.Saenz@umb.edu.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Saenz
authors.affiliation: CSIRO Land &amp; Water, GPO Box 1666, Canberra, ACT 2601, Australia. michael.schaefer@csiro.au.|Precision Agriculture Research Group, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia. michael.schaefer@csiro.au.
authors.forename: Michael
authors.initials: M
authors.lastname: Schaefer
keywords: DWEL; dual-wavelength lidar; full-waveform lidar; radiometric calibration; terrestrial lidar; vegetation structure