scholarly journals ON GROUND SURFACE EXTRACTION USING FULL-WAVEFORM AIRBORNE LASER SCANNER FOR CIM

2015 ◽  
Vol XL-4/W5 ◽  
pp. 159-163
Author(s):  
K. Nakano ◽  
H. Chikatsu
Keyword(s):  
Spatial Information ◽  
Laser Scanner ◽  
Ground Surface ◽  
Positioning Systems ◽  
Surface Extraction ◽  
Airborne Laser Scanner ◽  
Full Waveform ◽  
Airborne Laser ◽  
Laser Scanners ◽  
Forested Areas

Satellite positioning systems such as GPS and GLONASS have created significant changes not only in terms of spatial information but also in the construction industry. It is possible to execute a suitable construction plan by using a computerized intelligent construction. Therefore, an accurate estimate of the amount of earthwork is important for operating heavy equipment, and measurement of ground surface with high accuracy is required. A full-waveform airborne laser scanner is expected to be capable of improving the accuracy of ground surface extraction for forested areas, in contrast to discrete airborne laser scanners, as technological innovation. For forested areas, fundamental studies for construction information management (CIM) were conducted to extract ground surface using full-waveform airborne laser scanners based on waveform information.

scholarly journals MULTI-TARGET DETECTION FROM FULL-WAVEFORM AIRBORNE LASER SCANNER USING PHD FILTER

2016 ◽  
Vol XLI-B5 ◽  
pp. 647-652
Author(s):  
T. Fuse ◽  
D. Hiramatsu ◽  
W. Nakanishi
Keyword(s):  
Target Detection ◽  
A Priori ◽  
Laser Scanner ◽  
Real Data ◽  
Bayesian Filtering ◽  
Probability Hypothesis Density ◽  
Airborne Laser Scanner ◽  
Full Waveform ◽  
Airborne Laser ◽  
A New Technique

We propose a new technique to detect multiple targets from full-waveform airborne laser scanner. We introduce probability hypothesis density (PHD) filter, a type of Bayesian filtering, by which we can estimate the number of targets and their positions simultaneously. PHD filter overcomes some limitations of conventional Gaussian decomposition method; PHD filter doesn’t require a priori knowledge on the number of targets, assumption of parametric form of the intensity distribution. In addition, it can take a similarity between successive irradiations into account by modelling relative positions of the same targets spatially. Firstly we explain PHD filter and particle filter implementation to it. Secondly we formulate the multi-target detection problem on PHD filter by modelling components and parameters within it. At last we conducted the experiment on real data of forest and vegetation, and confirmed its ability and accuracy.

On analysis and visualization of full-waveform airborne laser scanner data

2005 ◽  
Author(s):  
Ulf Soederman ◽  
Asa Persson ◽  
Johanna Toepel ◽  
Simon Ahlberg
Keyword(s):  
Laser Scanner ◽  
Scanner Data ◽  
Airborne Laser Scanner ◽  
Full Waveform ◽  
Airborne Laser

scholarly journals MULTI-TARGET DETECTION FROM FULL-WAVEFORM AIRBORNE LASER SCANNER USING PHD FILTER

2016 ◽  
Vol XLI-B5 ◽  
pp. 647-652
Author(s):  
T. Fuse ◽  
D. Hiramatsu ◽  
W. Nakanishi
Keyword(s):  
Target Detection ◽  
A Priori ◽  
Laser Scanner ◽  
Real Data ◽  
Bayesian Filtering ◽  
Probability Hypothesis Density ◽  
Airborne Laser Scanner ◽  
Full Waveform ◽  
Airborne Laser ◽  
A New Technique

We propose a new technique to detect multiple targets from full-waveform airborne laser scanner. We introduce probability hypothesis density (PHD) filter, a type of Bayesian filtering, by which we can estimate the number of targets and their positions simultaneously. PHD filter overcomes some limitations of conventional Gaussian decomposition method; PHD filter doesn’t require a priori knowledge on the number of targets, assumption of parametric form of the intensity distribution. In addition, it can take a similarity between successive irradiations into account by modelling relative positions of the same targets spatially. Firstly we explain PHD filter and particle filter implementation to it. Secondly we formulate the multi-target detection problem on PHD filter by modelling components and parameters within it. At last we conducted the experiment on real data of forest and vegetation, and confirmed its ability and accuracy.

scholarly journals TOWARDS AUTOMATIC SINGLE-SENSOR MAPPING BY MULTISPECTRAL AIRBORNE LASER SCANNING

2016 ◽  
Vol XLI-B3 ◽  
pp. 155-162 ◽  
Author(s):  
E. Ahokas ◽  
J. Hyyppä ◽  
X. Yu ◽  
X. Liang ◽  
L. Matikainen ◽  
...  
Keyword(s):  
Land Cover ◽  
Tree Species ◽  
Forest Inventory ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Ground Surface ◽  
Airborne Laser Scanning ◽  
Forest Mapping ◽  
Airborne Laser Scanner ◽  
Airborne Laser

This paper describes the possibilities of the Optech Titan multispectral airborne laser scanner in the fields of mapping and forestry. Investigation was targeted to six land cover classes. Multispectral laser scanner data can be used to distinguish land cover classes of the ground surface, including the roads and separate road surface classes. For forest inventory using point cloud metrics and intensity features combined, total accuracy of 93.5% was achieved for classification of three main boreal tree species (pine, spruce and birch).When using intensity features – without point height metrics - a classification accuracy of 91% was achieved for these three tree species. It was also shown that deciduous trees can be further classified into more species. We propose that intensity-related features and waveform-type features are combined with point height metrics for forest attribute derivation in area-based prediction, which is an operatively applied forest inventory process in Scandinavia. It is expected that multispectral airborne laser scanning can provide highly valuable data for city and forest mapping and is a highly relevant data asset for national and local mapping agencies in the near future.

scholarly journals Effects of harvester positioning errors on merchantable timber volume predicted and estimated from airborne laser scanner data in mature Norway spruce forests

Silva Fennica ◽  
2022 ◽  
Vol 56 (1) ◽  
Author(s):  
Lennart Noordermeer ◽  
Erik Næsset ◽  
Terje Gobakken
Keyword(s):  
Forest Inventory ◽  
Laser Scanner ◽  
Grid Cell ◽  
Grid Cells ◽  
Timber Volume ◽  
Positioning Systems ◽  
Airborne Laser Scanner ◽  
Positioning Errors ◽  
Airborne Laser ◽  
Mean Square Errors

Newly developed positioning systems in cut-to-length harvesters enable georeferencing of individual trees with submeter accuracy. Together with detailed tree measurements recorded during processing of the tree, georeferenced harvester data are emerging as a valuable tool for forest inventory. Previous studies have shown that harvester data can be linked to airborne laser scanner (ALS) data to estimate a range of forest attributes. However, there is little empirical evidence of the benefits of improved positioning accuracy of harvester data. The two objectives of this study were to (1) assess the accuracy of timber volume estimation using harvester data and ALS data acquired with different scanners over multiple years and (2) assess how harvester positioning errors affect merchantable timber volume predicted and estimated from ALS data. We used harvester data from 33 commercial logging operations, comprising 93 731 harvested stems georeferenced with sub-meter accuracy, as plot-level training data in an enhanced area-based inventory approach. By randomly altering the tree positions in Monte Carlo simulations, we assessed how prediction and estimation errors were influenced by different combinations of simulated positioning errors and grid cell sizes. We simulated positioning errors of 1, 2, …, 15 m and used grid cells of 100, 200, 300 and 400 m. Values of root mean square errors obtained for cell-level predictions of timber volume differed significantly for the different grid cell sizes. The use of larger grid cells resulted in a greater accuracy of timber volume predictions, which were also less affected by positioning errors. Accuracies of timber volume estimates at logging operation level decreased significantly with increasing levels of positioning error. The results highlight the benefit of accurate positioning of harvester data in forest inventory applications. Further, the results indicate that when estimating timber volume from ALS data and inaccurately positioned harvester data, larger grid cells are beneficial.2

scholarly journals REFERENCE VALUE PROVISION SCHEMES FOR ATTENUATION CORRECTION OF FULL-WAVEFORM AIRBORNE LASER SCANNER DATA

2015 ◽  
Vol II-3/W5 ◽  
pp. 65-72 ◽  
Author(s):  
K. Richter ◽  
R. Blaskow ◽  
N. Stelling ◽  
H.-G. Maas
Keyword(s):  
Laser Pulse ◽  
Attenuation Correction ◽  
Laser Scanner ◽  
Reference Value ◽  
Space Representation ◽  
Airborne Laser Scanner ◽  
Full Waveform ◽  
Airborne Laser ◽  
Lower Amplitude ◽  
Pulse Echo

The characterization of the vertical forest structure is highly relevant for ecological research and for better understanding forest ecosystems. Full-waveform airborne laser scanner systems providing a complete time-resolved digitization of every laser pulse echo may deliver very valuable information on the biophysical structure in forest stands. To exploit the great potential offered by full-waveform airborne laser scanning data, the development of suitable voxel based data analysis methods is straightforward. Beyond extracting additional 3D points, it is very promising to derive voxel attributes from the digitized waveform directly. However, the ’history’ of each laser pulse echo 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). <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 by applying suitable attenuation correction models. The basic idea of the correction procedure is to enhance the waveform intensity values in lower parts of the canopy for portions of the pulse intensity, which have been reflected in higher parts of the canopy. To estimate the enhancement factor an appropriate reference value has to be derived from the data itself. Based on pulse history correction schemes presented in previous publications, the paper will discuss several approaches for reference value estimation. Furthermore, the results of experiments with two different data sets (leaf-on/leaf-off) are presented.

scholarly journals TOWARDS AUTOMATIC SINGLE-SENSOR MAPPING BY MULTISPECTRAL AIRBORNE LASER SCANNING

2016 ◽  
Vol XLI-B3 ◽  
pp. 155-162 ◽  
Author(s):  
E. Ahokas ◽  
J. Hyyppä ◽  
X. Yu ◽  
X. Liang ◽  
L. Matikainen ◽  
...  
Keyword(s):  
Land Cover ◽  
Tree Species ◽  
Forest Inventory ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Ground Surface ◽  
Airborne Laser Scanning ◽  
Forest Mapping ◽  
Airborne Laser Scanner ◽  
Airborne Laser

This paper describes the possibilities of the Optech Titan multispectral airborne laser scanner in the fields of mapping and forestry. Investigation was targeted to six land cover classes. Multispectral laser scanner data can be used to distinguish land cover classes of the ground surface, including the roads and separate road surface classes. For forest inventory using point cloud metrics and intensity features combined, total accuracy of 93.5% was achieved for classification of three main boreal tree species (pine, spruce and birch).When using intensity features – without point height metrics - a classification accuracy of 91% was achieved for these three tree species. It was also shown that deciduous trees can be further classified into more species. We propose that intensity-related features and waveform-type features are combined with point height metrics for forest attribute derivation in area-based prediction, which is an operatively applied forest inventory process in Scandinavia. It is expected that multispectral airborne laser scanning can provide highly valuable data for city and forest mapping and is a highly relevant data asset for national and local mapping agencies in the near future.

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