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/1, V/3, ICWG V/I: LOW-COST UAVS (UVSS) AND MOBILE MAPPING SYSTEMS]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: ASSESSING THE FEASIBILITY OF UAV-BASED LIDAR FOR HIGH RESOLUTION FOREST CHANGE DETECTION L. O. Wallace, A. Lucieer and C. S. Watson

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 The objectives of this paper are to assess the ability of UAV plat- forms for monitoring high resolution change within a Eucalyptus Nitens plantation. This will be achieved by examining the capa- bilities of a UAV-borne LiDAR system, carrying the same model scanner as described in (Jaakkola et al., 2010), to resolve plot level forest metrics and assess the repeatability of these metrics. The effects of the spatial accuracy of these systems, varying beam width, point density and scan angle will be assessed by altering the system's altitude and then manipulating the resultant point clouds to isolate the effects of each factor. 2 METHODS 2.1 Hardware The capabilities of the TerraLuma UAV-borne LiDAR system de- veloped at the University of Tasmania will be assessed in this study (shown in Figure 1). The platform consists of a multi- rotor UAV (OktoKopter Droidworx/Mikrokopter AD-8) which is used to carry the sensor payload. This particular system is capa- ble of carrying up to 2.8 kg for a duration of 3- 4 min which is sufficient time to cover a plot sized area within 100 m of the take off point. The system is equipped with an on-board autopilot allowing predefined flight paths to be followed which ensure an efficient use of this flight time. Figure 1. The multi-rotor UAV platform used within this study. The laser scanner on-board this system is an Ibeo LUX automotive scanner. The sensor payload is vibration isolated from the main platform through 4 silicon mounts. This payload consists of a position and orientation system (POS), a laser scanner and a data logging pc. The POS consists of a MEMs based IMU, a dual frequency GPS receiver and an HD Video camera. The high rate measurements from the IMU are fused with observations of position and velocity from the GPS and orientation from the camera to ensure high accuracy observations of position and orientation are made for use in the generation of a point cloud (as outlined in Wallace et al. (2011)). This payload is stand-alone from the sensors used in the auto-pilot and all processing is performed offline. The on-board laser scanner is an Ibeo LUX automotive sensor which measures points in four scanning layers and in doing so can record up to 22000 returns/s. The scanner has a measurement range of up to 200 m with a repeatability of 0.10 m. The beam divergence of the Ibeo LUX laser scanner is 0.08 ^ across track and 1.6? along track. The Ibeo LUX can record up to 3 returns per pulse and records a pulse length measurement for each return. 500 Flight 1 2 3 4 Altitude (m) 30 50 70 90 points/m 77 45 19 10 Footprint Diameter 0.83 1.30 1.95 2.38 across(along) (m) (0.04) (0.07) (0.10) (0.12) Motion 9975 2175 205 925 Angle (°) Table 1. Flight conditions over the field measured pre-pruning assessment plot. 2.2 Study Area and Data Collection A 5 year old Eucalyptus Nitens plantation coup was chosen as the study area. The coup is located near the town of Franklin in Tasmania, Australia (Figure 2). The area has a mean elevation of 450 m and consists of terrain with a 20 ^ east facing slope. The trees stand approximately 10 m tall and were due to be pruned within 2 months of the LiDAR survey. N A g 25 50 100 mm Kilo m ets rs Figure 2. The state of Tasmania with a dot showing the location of the study area. UAV-borne LiDAR data was collected from four flights follow- ing a 120 m transect in both forward and reverse directions. In each flight this transect was flown in both forward and reverse directions. Each flight was flown with an average velocity of 4.0 m/s at a constant height above the take-off point. Four 12.62 m radius circular plots were extracted from each of the point clouds for use in this analysis. One of these areas is located over a future pre-pruning assessment plot. This ground inven- tory will be used in future analysis of the collected data. The properties of the data acquisition are given in Table 1 based on the above ground flying height over this ground inventory plot. The slope of the terrain and constant flying height above take-off allowed a variety of flying heights to be assessed over the remain- ing plots. These four flying heights show the significant variation in footprint diameter, point density and scan angle of the UAV system. The footprint diameter at 30 m can be considered simi- lar to some modern full scale data as used in (Yu et al., 2011) for example. However, all other data is collected with a significantly larger footprint. The lowest flying height of 30 m ensured safe operating distance of approximately 10 m above the trees the top of the slope. Generating point clouds separately for the forward and reverse transects allowed comparison both at the various flying height, as

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