DWEL: A Dual-Wavelength Echidna Lidar for ground-based forest scanning

Douglas, Ewan S.; Strahler, Alan H.; Martel, Jason; Cook, Timothy A.; Mendillo, Christopher B.; Marshall, R. A.; Chakrabarti, Supriya; Schaaf, Crystal B.; Woodcock, Curtis E.; Ли, Жан; Yang, Xiaoyuan; Culvenor, Darius; Jupp, David L.B.; Newnham, Glenn; Lovell, Jenny

doi:10.1109/igarss.2012.6352489

Cited by 41 publications

(34 citation statements)

References 4 publications

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“…Additionally, laser scanning techniques continue to improve all the time and the new scanner systems are faster and have a longer range than their predecessors. Furthermore, new types of scanners are also emerging: multiple wavelength and hyperspectral laser scanners that are able to collect both spatial and spectral information simultaneously [53][54][55]. Moreover, some of these systems collect spectral data with full waveform.…”

Section: Discussionmentioning

confidence: 99%

Improved Sampling for Terrestrial and Mobile Laser Scanner Point Cloud Data

et al. 2013

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Abstract:We introduce and test the performance of two sampling methods that utilize distance distributions of laser point clouds in terrestrial and mobile laser scanning geometries. The methods are leveled histogram sampling and inversely weighted distance sampling. The methods aim to reduce a significant portion of the laser point cloud data while retaining most characteristics of the full point cloud. We test the methods in three case studies in which data were collected using a different terrestrial or mobile laser scanning system in each. Two reference methods, uniform sampling and linear point picking, were used for result comparison. The results demonstrate that correctly selected distance-sensitive sampling techniques allow higher point removal than the references in all the tested case studies.

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Section: Discussionmentioning

confidence: 99%

Improved Sampling for Terrestrial and Mobile Laser Scanner Point Cloud Data

et al. 2013

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“…Multispectral three-dimensional (3D) target characteristics can be measured using dual or multi-wavelength terrestrial light detection and ranging (lidar) instruments, which have become available through active research in the field during recent years (Gaulton et al, 2013, Douglas et al, 2012, Tan and Narayanan, 2004, Wallace et al, 2012, Wei et al, 2012, Woodhouse et al, 2011. New applications using multi or hyperspectral laser scanning have increased quite recently, and the high future potential of these instruments has been widely acknowledged.…”

Section: Introductionmentioning

confidence: 99%

Hyperspectral lidar in non-destructive 4D monitoring of climate variables

Kaasalainen

Hakala

Nevalainen

et al. 2014

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:The first applications of a prototype 8-channel full waveform active hyperspectral lidar (HSL) show a possibility to determine various target 3D characteristics with remote observations. The results open up a prospect for four-dimensional (4D -a three dimensional target representation with time as a fourth dimension) monitoring of important climate variables, such as those related to tree physiology or snow pollution. * Corresponding author. BACKGROUNDMultispectral three-dimensional (3D) target characteristics can be measured using dual or multi-wavelength terrestrial light detection and ranging (lidar) instruments, which have become available through active research in the field during recent years (Gaulton et al., 2013, Douglas et al., 2012, Tan and Narayanan, 2004, Wallace et al., 2012, Wei et al., 2012, Woodhouse et al., 2011. New applications using multi or hyperspectral laser scanning have increased quite recently, and the high future potential of these instruments has been widely acknowledged. Three-dimensional (3D) distributions of vegetation biochemical properties were measured together with spectral indices using the Salford Advanced Laser Canopy Analyser (SALCA), a dualwavelength terrestrial laser scanner (Gaulton et al., 2013). The Dual-Wavelength Echidna Lidar (DWEL) (Douglas et al., 2012) is also a full-waveform ground based laser scanner, and it was shown to improve the retrieval of forest structural parameters. A tunable 4-channel canopy lidar has also been introduced for simultaneous retrieval of vegetation structure and spectral indices (Woodhouse et al., 2011).A spaceborne dual-wavelength lidar application has also been presented by Hancock et al., (2012) to separate ground and canopy returns using the spectral ratio to complement the canopy height from laser scanning. This paper presents preliminary results for an 8-channel hyperspectral lidar for full-waveform laser scanning (Hakala et al., 2012). The hyperspectral scanning lidar is based on supercontinuum technology (see Manninen et al., 2014 and references therein), and combines active hyperspectral imaging and full-waveform laser scanning with the same instrument in one measurement. Thus, by including spectral data in each member of the point cloud, we can get information on the surface material of the target in three dimensions (3D). Repeating the measurement over time, a 4D representation, i.e., a time series, of the object is possible. The instrument and measurements are presented in Sect. 2. The results and conclusion are in Sections 3 and 4, respectively. THE HYPERSPECTRAL LIDARThe HSL prototype has 8 spectral channels in 500-1600 nm. The continuous laser spectrum allows the selection of spectral channels from this range according to the application. The time of flight is recorded for the reflected laser pulses for retrieving the range distance, and the spectrum for each point is recorded with a spectrograph and a 16-element avalanche photodiode (APD) array connected to an 8-channel high-speed digitizer (see Hakala et al., ...

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“…Respectively, Suomalainen et al [24] has demonstrated the use of a simulated hyperspectral Lidar in classification of needles and branches [24]. Terrestrial dual-wavelength Lidar systems, operating at 1064 nm and 1540 nm wavelengths, have been developed and tested in laboratory conditions [25,26]. The first prototype of a full waveform hyperspectral Lidar instrument utilizing a supercontinuum laser source has been developed and constructed at the Finnish Geospatial Research Institute [27].…”

Section: Introductionmentioning

confidence: 99%

Investigating Bi-Temporal Hyperspectral Lidar Measurements from Declined Trees—Experiences from Laboratory Test

et al. 2015

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Global warming is posing a threat to the health and condition of forests as the amount and length of biotic and abiotic disturbances increase. Most methods for detecting disturbances and measuring forest health are based on multi-and hyperspectral imaging. We conducted a test with spruce and pine trees using a hyperspectral Lidar instrument in a laboratory to determine the capability of combined range and reflectance measurements to investigate forest health. A simple drought treatment was conducted by leaving the harvested trees outdoors without a water supply for 12 days. The results showed statistically significant variation in reflectance after the drought treatment for both species. However, the changes differed between the species, indicating that drought-induced alterations in spectral characteristics may be species-dependent. Based on our results, hyperspectral Lidar has the potential to detect drought in spruce and pine trees.

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DWEL: A Dual-Wavelength Echidna Lidar for ground-based forest scanning

Cited by 41 publications

References 4 publications

Improved Sampling for Terrestrial and Mobile Laser Scanner Point Cloud Data

Improved Sampling for Terrestrial and Mobile Laser Scanner Point Cloud Data

Hyperspectral lidar in non-destructive 4D monitoring of climate variables

Investigating Bi-Temporal Hyperspectral Lidar Measurements from Declined Trees—Experiences from Laboratory Test

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