Categorisation of full waveform data provided by laser scanning devices

2011 ◽  
Author(s):  
Andreas Ullrich ◽  
Martin Pfennigbauer
Keyword(s):  
Laser Scanning ◽  
Waveform Data ◽  
Full Waveform

scholarly journals VOXEL BASED REPRESENTATION OF FULL-WAVEFORM AIRBORNE LASER SCANNER DATA FOR FORESTRY APPLICATIONS

2016 ◽  
Vol XLI-B8 ◽  
pp. 755-762
Author(s):  
N. Stelling ◽  
K. Richter
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Biomass Estimation ◽  
Full Potential ◽  
Scanner Data ◽  
Waveform Data ◽  
Geometric Transformations ◽  
Full Waveform ◽  
Voxel Representation ◽  
Attenuation Corrected

The advantages of using airborne full-waveform laser scanner data in forest applications, e.g. for the description of the vertical vegetation structure or accurate biomass estimation, have been emphasized in many publications. To exploit the full potential offered by airborne full-waveform laser scanning data, the development of voxel based methods for data analysis is essential. In contrast to existing approaches based on the extraction of discrete 3D points by a Gaussian decomposition, it is very promising to derive the voxel attributes from the digitised waveform directly. For this purpose, the waveform data have to be transferred into a 3D voxel representation. This requires a series of radiometric and geometric transformations of the raw full-waveform laser scanner data. Thus, the paper deals with the geometric aspects and describes a processing chain from the raw waveform data to an attenuationcorrected volumetric forest stand reconstruction. <br><br> The integration of attenuation-corrected waveform data into the voxel space is realised with an efficient parametric voxel traversal method operating on an octree data structure. The voxel attributes are derived from the amplitudes of the attenuation-corrected waveforms. Additionally, a new 3D filtering approach is presented to eliminate non-object voxel. Applying these methods to real full-waveform laser scanning data, a voxel based representation of a spruce was generated combining three flight strips from different viewing directions.

scholarly journals Correcting attenuation effects caused by interactions in the forest canopy in full-waveform airborne laser scanner data

2014 ◽  
Vol XL-3 ◽  
pp. 273-280 ◽  
Author(s):  
K. Richter ◽  
N. Stelling ◽  
H.-G. Maas
Keyword(s):  
Laser Scanning ◽  
Forest Canopy ◽  
Canopy Structure ◽  
Integral Approach ◽  
Space Representation ◽  
Real World Data ◽  
Waveform Data ◽  
Full Waveform ◽  
Airborne Laser ◽  
Lower Amplitude

Full-waveform airborne laser scanning offers a great potential for various forestry applications. Especially applications requiring information on the vertical structure of the lower canopy parts benefit from the great amount of information contained in waveform data. To enable the derivation of vertical forest canopy structure, the development of suitable voxel based data analysis methods is straightforward. Beyond extracting additional 3D points, it is very promising to derive the voxel attributes from the digitized waveform directly. For this purpose, the differential backscatter cross sections have to be projected into a Cartesian voxel structure. Thereby the voxel entries represent amplitudes of the cross section and can be interpreted as a local measure for the amount of pulse reflecting matter. However, the "history" of each laser echo pulse is characterized by attenuation effects caused by reflections in higher regions of the crown. As a result, the received waveform signals within the canopy have a lower amplitude than it would be observed for an identical structure without the previous canopy structure interactions (Romanczyk et al., 2012). If the biophysical structure is determined from the raw waveform data, material in the lower parts of the canopy is thus under-represented. <br><br> To achieve a radiometrically correct voxel space representation the loss of signal strength caused by partial reflections on the path of a laser pulse through the canopy has to be compensated. In this paper, we present an integral approach correcting the waveform at each recorded sample. The basic idea of the procedure is to enhance the waveform intensity values in lower parts of the canopy for portions of the pulse intensity, which have been reflected (and thus blocked) in higher parts of the canopy. The paper will discuss the developed correction method and show results from a validation both with synthetic and real world data.

scholarly journals VOXEL BASED REPRESENTATION OF FULL-WAVEFORM AIRBORNE LASER SCANNER DATA FOR FORESTRY APPLICATIONS

2016 ◽  
Vol XLI-B8 ◽  
pp. 755-762
Author(s):  
N. Stelling ◽  
K. Richter
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Biomass Estimation ◽  
Full Potential ◽  
Scanner Data ◽  
Waveform Data ◽  
Geometric Transformations ◽  
Full Waveform ◽  
Voxel Representation ◽  
Attenuation Corrected

The advantages of using airborne full-waveform laser scanner data in forest applications, e.g. for the description of the vertical vegetation structure or accurate biomass estimation, have been emphasized in many publications. To exploit the full potential offered by airborne full-waveform laser scanning data, the development of voxel based methods for data analysis is essential. In contrast to existing approaches based on the extraction of discrete 3D points by a Gaussian decomposition, it is very promising to derive the voxel attributes from the digitised waveform directly. For this purpose, the waveform data have to be transferred into a 3D voxel representation. This requires a series of radiometric and geometric transformations of the raw full-waveform laser scanner data. Thus, the paper deals with the geometric aspects and describes a processing chain from the raw waveform data to an attenuationcorrected volumetric forest stand reconstruction. <br><br> The integration of attenuation-corrected waveform data into the voxel space is realised with an efficient parametric voxel traversal method operating on an octree data structure. The voxel attributes are derived from the amplitudes of the attenuation-corrected waveforms. Additionally, a new 3D filtering approach is presented to eliminate non-object voxel. Applying these methods to real full-waveform laser scanning data, a voxel based representation of a spruce was generated combining three flight strips from different viewing directions.

Utilization of full-waveform data in airborne laser scanning applications

2007 ◽  
Author(s):  
Andreas Ullrich ◽  
Markus Hollaus ◽  
Christian Briese ◽  
Wolfgang Wagner ◽  
Michael Doneus
Keyword(s):  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
Waveform Data ◽  
Full Waveform ◽  
Airborne Laser

Archaeological prospection of forested areas using full-waveform airborne laser scanning

2008 ◽  
Vol 35 (4) ◽  
pp. 882-893 ◽  
Author(s):  
Michael Doneus ◽  
Christian Briese ◽  
Martin Fera ◽  
Martin Janner
Keyword(s):  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
Archaeological Prospection ◽  
Full Waveform ◽  
Airborne Laser ◽  
Forested Areas

scholarly journals REFINED SIMULATION OF SATELLITE LASER ALTIMETER FULL ECHO WAVEFORM

2018 ◽  
Vol XLII-3 ◽  
pp. 1267-1273
Author(s):  
H. Men ◽  
Y. Xing ◽  
G. Li ◽  
X. Gao ◽  
Y. Zhao ◽  
...  
Keyword(s):  
Laser Energy ◽  
Vital Role ◽  
Data Simulation ◽  
Laser Altimeter ◽  
Validation Data ◽  
Simulation Accuracy ◽  
Waveform Data ◽  
Full Waveform ◽  
Ground Target ◽  
Echo Simulation

The return waveform of satellite laser altimeter plays vital role in the satellite parameters designation, data processing and application. In this paper, a method of refined full waveform simulation is proposed based on the reflectivity of the ground target, the true emission waveform and the Laser Profile Array (LPA). The ICESat/GLAS data is used as the validation data. Finally, we evaluated the simulation accuracy with the correlation coefficient. It was found that the accuracy of echo simulation could be significantly improved by considering the reflectivity of the ground target and the emission waveform. However, the laser intensity distribution recorded by the LPA has little effect on the echo simulation accuracy when compared with the distribution of the simulated laser energy. At last, we proposed a refinement idea by analyzing the experimental results, in the hope of providing references for the waveform data simulation and processing of GF-7 satellite in the future.

scholarly journals Processing and analysis of airborne full-waveform laser scanning data for the characterization of forest structure and fuel properties

2020 ◽  
pp. 95
Author(s):  
P. Crespo-Peremarch ◽  
L. A. Ruiz
Keyword(s):  
Forest Structure ◽  
Laser Scanning ◽  
Software Tool ◽  
Understory Vegetation ◽  
Airborne Laser Scanning ◽  
Vegetation Density ◽  
Regression Methods ◽  
Full Waveform ◽  
Airborne Laser ◽  
Pulse Density

<p class="Bodytext">This PhD thesis addresses the development of full-waveform airborne laser scanning (ALS<sub>FW</sub>) processing and analysis methods to characterize the vertical forest structure, in particular the understory vegetation. In this sense, the influence of several factors such as pulse density, voxel parameters (voxel size and assignation value), scan angle at acquisition, radiometric correction and regression methods is analyzed on the extraction of ALS<sub>FW</sub> metric values and on the estimate of forest attributes. Additionally, a new software tool to process ALS<sub>FW</sub> data is presented, which includes new metrics related to understory vegetation. On the other hand, occlusion caused by vegetation in the ALS<sub>FW</sub>, discrete airborne laser scanning (ALS<sub>D</sub>) and terrestrial laser scanning (TLS) signal is characterized along the vertical structure. Finally, understory vegetation density is detected and determined by ALS<sub>FW</sub> data, as well as characterized by using the new proposed metrics.</p>

scholarly journals Spectral and spatial information from a novel dual-wavelength full-waveform terrestrial laser scanner for forest ecology

2018 ◽  
Vol 8 (2) ◽  
pp. 20170049 ◽  
Author(s):  
F. Mark Danson ◽  
Fadal Sasse ◽  
Lucy A. Schofield
Keyword(s):  
Field Experiments ◽  
Forest Ecology ◽  
Laser Scanner ◽  
Dual Wavelength ◽  
Leaf Biomass ◽  
Terrestrial Laser Scanner ◽  
Area Index ◽  
Waveform Data ◽  
Full Waveform ◽  
Wide Range

The Salford Advanced Laser Canopy Analyser (SALCA) is an experimental terrestrial laser scanner designed and built specifically to measure the structural and biophysical properties of forest canopies. SALCA is a pulsed dual-wavelength instrument with co-aligned laser beams recording backscattered energy at 1063 and 1545 nm; it records full-waveform data by sampling the backscattered energy at 1 GHz giving a range resolution of 150 mm. The finest angular sampling resolution is 1 mrad and around 9 million waveforms are recorded over a hemisphere above the tripod-mounted scanner in around 110 min. Starting in 2010, data pre-processing and calibration approaches, data analysis and information extraction methods were developed and a wide range of field experiments conducted. The overall objective is to exploit the spatial, spectral and temporal characteristics of the data to produce ecologically useful information on forest and woodland canopies including leaf area index, plant area volume density and leaf biomass, and to explore the potential for tree species identification and classification. This paper outlines the key challenges in instrument development, highlights the potential applications for providing new data for forest ecology, and describes new avenues for exploring information-rich data from the next generation of terrestrial laser scanners instruments like SALCA.

Sign in / Sign up

Export Citation Format

Share Document