XXII ISPRS Congress 2012: Technical Commission VII

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Multivolume work

Persistent identifier:: 1663813779

Title:: XXII ISPRS Congress 2012

Sub title:: Melbourne, Australia, 25 August-1 September 2012

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663813779

Language:: English

Additional Notes:: Kongress-Thema: Imaging a sustainable future

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1663821976

Title:: Technical Commission VII

Scope:: 546 Seiten

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663821976

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(39,B7)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist ermittelt.; Literaturangaben

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [VII/7, III/2, V/3: WAVEFORM LIDAR FOR REMOTE SENSING]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: FULL WAVEFORM LIDAR EXPLOITATION TECHNIQUE AND ITS EVALUATION IN THE MIXED FOREST HILLY REGION S. Chhatkuli, K. Mano, T. Kogure, K. Tachibana, H. Shimamura

Document type:: Multivolume work

Structure type:: Chapter

International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012 XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia Discrete time system Processed signal y(n) Observed signal x(n) ———4» hn) ha) = ast 110,9,16,2124,25242116,9,0,-11] Figure 3. Block diagram of FIR filter 3. ACCURACY EVALUATION OF LIDAR DERIVED TERRAIN DATA We performed a test to evaluate and to compare the vertical accuracy of LiDAR derived terrain data constructed from the discrete LiDAR pulses and the proposed full waveform exploitation technique obtained during autumn and winter. For the accuracy evaluation, a typical hilly area with varying topography covered by Japanese cedar (Sugi) trees, Japanese cypress (Hinoki) trees and other deciduous trees was selected. Ground truth data were measured by performing total station survey. Figure 4 shows the terrain model of the site and total station surveyed check points. The check points were collected from the stripe of about 400m x 10 m area at the density of about 1pt/ 4.5 sqm. The area was covered with both evergreen and deciduous tree varieties and the topography of the area varied from flat plane to rolling hill. The maximum slope of the test site was about 30 %. To evaluate the accuracy of LiDAR derived ground elevation, DTM of the ground terrain with 1 m grid size was constructed from the discrete LIDAR pulses obtained during September, full waveform LiDAR pulses obtained during September, discrete LiDAR pulses obtained during December and full waveform LiDAR pulses obtained during December respectively. The elevation of the ground on each DTM that corresponds to the horizontal location of the total station surveyed check points were then calculated directly by using ArcGis’s Surface Spot tool. The difference between measured point elevation data and LiDAR derived DTM elevations for the four cases are presented in Table 1. The RMSE between measured data and DTM data obtained by using discrete LiDAR pulses was 0.73 m during September, when deciduous trees were full of leaves. By using the full waveform exploitation technique, the DTM thus constructed showed an increase in the terrain data accuracy. The RMSE for the terrain data obtained by using full waveform LiDAR pulses was 0.59 m. During December, when the leaves fall off from the deciduous trees, RMSE between measured data and DTM constructed by using discrete LiDAR pulses was 0.22 m. For the same winter data set, the RMSE of the terrain data obtained by using full waveform LiDAR pulses was 0.21 m. 507 Figure 4. TIN of terrain model and ground truth surveyed points (blue dots) A NSSDA Accuracy; (m) DTM model UR (NSSDA Accuracy — * (RMSE, m) RN) September 0.73 143 discrete September «m 0.59 TIS waveform December 0.22 0.43 discrete December EIE 0.21 0.41 waveform Table 1. Accuracy evaluation of LiDAR derived terrain data 4. RESULTS AND DISCUSSION Point cloud generated from the discrete return pulses and full waveform return pulses along, a part of, the longitudinal section of the concerned area are compared and demonstrated in Figure 5 for autumn and winter. The white dots in Figure 5 represent discrete return pulses and yellow dots represent the full waveform return pulses. For both seasons, we can see that the point cloud generated from the full waveform return pulses increased the vegetation/canopy detection and moreover increased the ground penetration significantly. To quantify the increment in the ground penetration, the point cloud generated from the full waveform return pulses and discrete return pulses were filtered automatically by using commercial software, TerraScan, to separate the ground points and vegetation points. The ground points obtained from the full waveform point cloud and the discrete return pulses are compared for autumn and winter respectively and presented below. During autumn, the ground penetration by discrete LIDAR was relatively poor with large gaps or missing ground points in some of the topographically complex terrains. However, by using the full waveform exploitation technique, ground point detection was considerably increased throughout the region.

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