XXII ISPRS Congress 2012: Technical Commission VII

Bibliographic data

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

and cise rield nt of ling. ; via 14^ The and note van, x for nics /S in y of with {igh DOI: nage sian ems. uav- nera | 7th ities ing. doi: 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 ASSESSING THE FEASIBILITY OF UAV-BASED LIDAR FOR HIGH RESOLUTION FOREST CHANGE DETECTION L. O. Wallace *, A. Lucieer and C. S. Watson Survey and Spatial Science Group School of Geography and Environmental Studies University of Tasmania Hobart, Tasmania, Australia Luke.Wallace Q utas.edu.au KEY WORDS: Unmanned Aerial Systems, LiDAR, Forestry, Change Detection ABSTRACT: Airborne LiDAR data has become an important tool for both the scientific and industry based investigation of forest structure. The uses of discrete return observations have now reached a maturity level such that the operational use of this data is becoming increasingly common. However, due to the cost of data collection, temporal studies into forest change are often not feasible or completed at infrequent and at uneven intervals. To achieve high resolution temporal LiDAR surveys, this study has developed a micro- Unmanned Aerial Vehicle (UAV) equipped with a discrete return 4-layer LiDAR device and miniaturised positioning sensors. This UAV has been designed to be low-cost and to achieve maximum flying time. In order to achieve these objectives and overcome the accuracy restrictions presented by miniaturised sensors a novel processing strategy based on a Kalman smoother algorithm has been developed. This strategy includes the use of the structure from motion algorithm in estimating camera orientation, which is then used to restrain IMU drift. The feasibility of such a platform for monitoring forest change is shown by demonstrating that the pointing accuracy of this UAV LiDAR device is within the accuracy requirements set out by the Australian Intergovernmental Committee on Surveying and Mapping (ICSM) standards. 1 INTRODUCTION Airborne Light Detecting and Ranging (LiDAR) data has become an increasingly important tool for the scientific investigation of forest structure. The use of discrete return observations have reached a level of maturity which allows the accurate generation of forest resource inventories for operational use to become in- creasingly common (Woods et al., 2011). Limited multi-temporal studies using LiDAR data have also shown potential for assess- ing forest dynamics such as changes in biomass, gap fractions (Vepakomma et al., 2008) as well as for assessing the uncer- tainty in growth prediction models (Hopkinson, 2008). The use of LiDAR data for multi-temporal forest surveys are, however, restricted by the high cost of data collection as well as restric- tions on flying seasons in some areas. Data collected from repeat surveys are further complicated by the often large time periods between surveys. As such these surveys are often performed us- ing different sensor sets at different flying conditions. For exam- ple, Vepakomma et al. (2008) used data from surveys with two different sensors flown at different altitudes (700 m and 1000 m). It has been shown that these datasets are not directly com- parable as different instruments produce data with different prop- erties (Nasset, 2009). These restrictions make the assessment of forest change using full scale airborne data difficult, restrict- ing scientific investigation and making practical use for forestry management infeasible. Mini-Unmanned Aerial Vehicles (UAV) are a platform which can be used within targeted very high spatial and temporal resolution surveys at a low cost. The use of these systems in combination with miniaturised laser scanners has been highlighted as a plat- form which will allow high frequency multi-temporal forest stud- ies to be performed with the same instrumentation set (Jaakkola et al., 2010). The UAV-borne LiDAR system outlined in Jaakkola et al. (2010), for example, highlights the key advantages of UAVs. However, the effect of flight conditions for measuring forest met- rics is yet to be thoroughly examined. The use of mini-UAVs 499 suggest that survey conditions will typically include lower fly- ing heights, higher point densities, and a smaller survey areas. Furthermore, the miniaturised laser scanner has been developed for applications other than mapping (automotive and robotics ap- plications for example) and are not as highly developed as laser scanners used on-board full scale systems. The effect of different flying conditions on the collection of dis- crete return LiDAR data within forest has been well studied (Lovell et al., 2005; Goodwin et al., 2006; Disney et al., 2010). Such stud- ies have often been completed with the aim of determining opti- mum flying conditions for LiDAR surveys. These studies have shown that point density, beam divergence, scan angle as well as the internal properties of the scanner, such as the triggering mech- anism all have an effect on the derivation of tree metrics and that these effects are more pronounced at finer measurement scales (i.e. the individual tree level). Lovell et al. (2005), for example, suggests that tree height measurements are improved in data sets with higher point density due to the increased likelihood that the tree top will be sampled. Furthermore, it has been shown that the use of large scan angles will result in a reduction in the number of lower canopy returns and effect canopy cover estimates (Mors- dorf et al., 2006). The effect of survey conditions are important to consider for UAV-borne LiDAR surveys. These systems offer higher point densities and depending on the chosen survey con- ditions and area of interest may require the use of higher scan angles to capture an area of interest. Furthermore, the minia- turised sensors on these systems typically have a higher beam di- vergence, less sensitive diodes, different triggering mechanisms and the ability to utilise higher scanning angles (up to 180 ^). As such the optimum flying conditions, using these low-cost sensors mounted on UAVs, for repeatable determination of forest met- rics from LiDAR data requires further investigation. This analy- sis can assume similar effects of flying height as shown in these prior studies to provide an initial hypothesis for determining the optimum conditions for performing UAV-borne surveys.

Access restriction

Copyright

fullscreen: Technical Commission VII (B7)

Multivolume work

Volume

Chapter

Chapter

Table of contents

Cite and reuse

Volume

Chapter

Image

Image fragment

Citation links

Citation recommendation