UAV data acquisition and processing

127 Pages·2015·16.76 MB·English

SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

Deliverable D.2.02
UAV data acquisition and processing
WP 2 – Forest information collection and analysis
Task 2.02- UAV data acquisition and processing

Revision: Final
Authors: Enda Nolan
Participant: Coastway Surveys
Dissemination level PU (Public)
Enda Nolan (Coastway), David O’Reilly
Contributor(s)
Liam Murphy (Coastway),
Reviewer(s) Federico Prandi
Editor(s)
Raffaele De Amicis (Graphitech)
Partner in charge(s) FLY, CNR, COAST,TRE
Due date 31-MAR-15
Submission Date 17-APR-15

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European Commission
SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

REVISION HISTORY AND STATEMENT OF ORIGINALITY

Revision History

Revision Date Author Organisation Description
Definition of the
Coastway
06/07/2014 Enda Nolan document
1.0 Surveys
Chapters
Coastway Content and
17/10/2014 Enda Nolan
2.0 Surveys Revision
Coastway
12/12/2014 Enda Nolan Revision
3.0 Surveys
31/03/2015
4.0 Federico Prandi Graphitech Revision

Statement of originality

This deliverable contains original unpublished work except where clearly indicated otherwise.
Acknowledgement of previously published material and of the work of others has been made through
appropriate citation, quotation or both.

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European Commission
SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

Table of contents
REVISION HISTORY AND STATEMENT OF ORIGINALITY .................................................. 2
Revision History .............................................................................................................. 2

Statement of originality .................................................................................................. 2

Table of contents ............................................................................................................ 3

List of figures .................................................................................................................. 5

Acronyms ........................................................................................................................ 6

1 Introduction ............................................................................................................. 7

2 Overview of UAV data collection for forestry applications ...................................... 8

2.1 Payloads: Cameras and sensors ........................................................................ 9

2.2 Processing and Outcomes ................................................................................. 9

2.3 Regulation & Licencing ...................................................................................... 9

3 Pilot Test Sites ........................................................................................................ 11

3.1 Test Site Locations Ireland & Italy Phase 1 (Phase 2 Austria in 2015) ............ 11

3.1.1 Gortahile................................................................................................... 11

3.1.2 Trento –Italy (site 2) ................................................................................. 12

4 Survey Equipment .................................................................................................. 15

4.1 UAV .................................................................................................................. 15

4.2 Image Sensors ................................................................................................. 16

4.2.1 IXUS/ELPH RGB ......................................................................................... 16

4.2.26 S110 NIR Standard .................................................................................. 17

4.3 GNSS ................................................................................................................ 18

4.3.1 GEO 7X ...................................................................................................... 18

5 Flight Methodology ................................................................................................ 20

5.1 Pre Flight Checks ............................................................................................. 20

5.2 Flight ................................................................................................................ 20

5.3 Post-Flight Checks and Comments .................................................................. 22

6 Processing and Outputs ......................................................................................... 25

6.1 Processing Chain ............................................................................................. 25

6.2 Software Tools Adopted .................................................................................. 25

6.3 Operations and Processing Methodology ....................................................... 26

6.4 Data Outputs ................................................................................................... 32

6.5 Additional Outputs .......................................................................................... 36

7 Summary of Survey Results .................................................................................... 37

7.1 Piscine (RGB) ................................................................................................... 37

7.2 Piscine (NIR) .................................................................................................... 41

7.3 Montesover (RGB) ........................................................................................... 44

7.4 Montesover (NIR) ............................................................................................ 48

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European Commission
SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

8 Annex...................................................................................................................... 52
8.1 Quality Report Outputs ................................................................................... 52

9 Checklist ............................................................................................................... 123

10 Bibliography ....................................................................................................... 127

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European Commission
SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

List of figures
Figure 1: Fixed wing e-Bee UAV sistem ........................................................................................................ 8
Figure 3 Flight plan. .................................................................................................................................... 11
Figure 4 Flight plan ..................................................................................................................................... 12
Figure 5 UAV transport box ........................................................................................................................ 13
Figure 6 eBee UAV system .......................................................................................................................... 15
Figure 8 S110 NIR camera ........................................................................................................................... 18
Figure 9 Trimble geo 7x .............................................................................................................................. 19
Figure 10 Flight path Ireland ....................................................................................................................... 21
Figure 12 Process chain .............................................................................................................................. 25
Figure 13 New project ................................................................................................................................ 26
Figure 15 Import images ............................................................................................................................. 27
Figure 19 Window to locate the GCPs ........................................................................................................ 30
Figure 20 Colored point cloud obtained for the test site on Italy .............................................................. 31
Figure 22 Undistorted image ...................................................................................................................... 32
Figure 23 Low resolution ortomosaic ......................................................................................................... 33
Figure 25 Dense matching raster DSM ....................................................................................................... 34
Figure 26 Dense matching grid point DSM ................................................................................................. 35

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European Commission
SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

Acronym
CA Consortium Agreement
DM Data Manager
GA Grant Agreement
GA General Assembly
OM Operational Manager
PC Project Coordinator
QRM Quality and Risk Manager
SB Stakeholders Board
TB Technical Board
TL Task Leader
WPL Work Package Leader
DTM Digital Terrain Model
SqKm Square Kilometre
RPAS Remotely Piloted Aerial Systems
IAA Irish Aviation Authority
CAA Civil Aviation Authority
EC European Commission

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European Commission
SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

1 Introduction

Precision Agriculture and forestry applications require access to high spatial and temporal resolution
and up to date images. Using traditional techniques such as satellite and airborne remote sensing data
this could be difficult and expensive. The use of Airborne Lidar over the last 10 to 15 years has proven
advantageous but limited in its capability to create a DTM due to the varied level of undergrowth,
leading to the creation of a very sparse DTM.

Advances in the last five years in the capabilities of lightweight UAV/UAS equipment and payloads for
civilian use have brought massive improvements in the methods used to survey large land parcels
agriculture including forestry. These systems provide a potential alternative to satellite and airborne
data acquisition ensuring low cost, high spatial and temporal resolution, and high flexibility in image
acquisition programming.

Lightweight battery powered UAV’s have proven to be a great leap forward and an excellent
cost effective Surveyors tool for land flat parcels up to 10sqkm, which do not need extensive
clearing of scrum and undergrowth to determine the DTM, the Slope project will determine the
true value of this equipment in mountainous areas. In an agricultural or forestry scenario, in order
to produce valid photogrammetric outputs, the fixed wing UAV with autonomous navigation system uses
GPS and inertial measuring technology which are the preferred methods with respect to the RPAS
systems currently available.

The SLOPE projects intention is to investigate the application of UAV systems for locating harvesting
sites, planning and supporting forestry operations. The extent of the area of interest is in general
relatively small (less than 1500 ha) thus it is required to obtain data and analysis in a relatively short
time. Furthermore the positional accuracy is generally low (< 1m) and a visual analysis of the images is
important so the availability of high-resolution orthophotos is quite important.

This document will analyse the use of a UAV system to collect and collate information to support forest
harvest planning in mountainous areas. In particular the field operations will be investigated focusing on
the collection of raw data, the generation of the DSM and orthophotos and the general evaluation of
the accuracies achieved. Furthermore a section highlighting the pros and cons of the overall workflow
will be provided.

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SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

2 Overview of UAV data collection for forestry applications

Unmanned aerial vehicles (UAV) are becoming a feasible and low cost method for remote-sensing data
acquisition, mostly aerial images and derived products such as DSM and orthophotos. Thanks to the
development, reliability and miniaturization of the sensors modern UAVs systems enable a relative safe
operation. However their application on forestry and mountain environment pose some challenges that
will be face off during SLOPE projects, first of all the weather conditions (wind) but also the GNSS signal
quality or the visibility of the terrain under the canopy coverage in absence DTM availability.
Despite these limitations the potentiality of UAVs on forestry applications in terms of spatial and
temporal resolution and costs paves the way to the wide usage of these instruments especially in case
like mountain forest harvesting planning where precision farming could be very useful to exploit the
potential of the wood preserving the natural resource.

Figure 1: Fixed wing e-Bee UAV sistem
One of the possible classifications of UAVs system is based on the different type of flying vehicles able to
transport camera and/or other sensors. There are the fixed wing UAVs and multi rotor helicopter; both
systems can be piloted by an operator via Remote Control (RC) or by an on-board autopilot.
In case of Auto piloted UAV the mission is planned in advance defining path, height velocity and photo
trigger. The vehicle is then navigated by on-board GNSS/INS unit, in case of problem like signal loss the
system switch on the semiautomatic mode and for these reasons the flight has to be controlled by a
qualified pilot able to take the control in every moment.
In case of forestry application and precision farming when the area to be covered is relatively big and
there is not particular requirements to survey on vertical surfaces the fixed wing system are preferred.

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SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

2.1 Payloads: Cameras and sensors

Due their nature small commercial UAVs (especially fixed wing ones) have reduced payload and space,
for these reasons these systems are typically equipped with compact consumer cameras. The resolution
of these cameras can be very high ensuring a high spatial resolution of the acquired images, however
some problems related to the stability of the inner orientation parameters as well as the rolling shutter
effect can be affect the final product.
For agricultural and forestry applications other sensors like multi/hyperspectral ones can be mounted
on the UAVs for vegetation analysis.
2.2 Processing and Outcomes

The first outcome of the UAV forest images is the production of Digital Surface Model (DSM) obtained
by image matching and the related orthorectified image mosaic. Thanks to the high-resolution aerial
images acquired this products can became the basis for subsequent geospatial analysis.
Within SLOPE particular attention will be dedicated to the in single-tree-extraction (Cfr. D2.3), tree
crown detection, tree density, age-classes and further structure parameters, like stem or timber
volume. These parameters can be derived either from object-based image analysis or from point cloud
data as a result of image matching.
Forest parameters estimated using UAV derived information and refined by the other SLOPE survey will
be a valuable support for the forestry inventory and the forest information system at the base of SLOPE
project.
2.3 Regulation & Licencing

The absence of an EU wide regulatory framework limits the possibility to fly UAV’s in European airspace.
It is a severe limitation for the development of UAV market, which requires careful consideration.
A pilot project carried out in 2009 has set in place developments which will eventually lead to a single
regulation and licencing agreement for UAV’s / RPAS.
At the beginning of the Slope Project each test site has its own regulatory body, Ireland – IAA Irish
Aviation Authority, Italy - ENAC Italian Civil Aviation Authority, Austria – Austro Control.

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SLOPE - Integrated proceSsing and controL systems fOr sustainable forest Production in
mountain arEas – FP7-NMP-2013-SME-7 --604129
WP 2. – Forest Information collection and Analysis
Deliverable D.2.02 – UAV data acquisition and processing

Figure 2: Foreseen roadmap for UAV EU regulamentation
Every private operator must obtain a licence to fly from several of the Aviation Authorities in Europe,
Coastway Surveys is licenced by the CAA & IAA.

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