Activities of the WG4 presented by Matthew Perks during our last Workshop in Prague.

1. HARMONIOUS
WG4 Description of Activities: River Flow
M. Perks, M. Kohv – Prague 28 Feb 2019
matthew.perks@ncl.ac.uk @catchmentSci

2. 2
WG4: River flow monitoring using non-
contact methods and traditional techniques

3. 3
§ Assessing methodologies and procedures for
pre-processing analysis including pixel
calibration, frame correction and frame matching
in order to improve the performance of the
image-based flow velocity estimation
§ Providing a selection of methods and procedures
for monitoring streamflow appropriate for the
objective of the study, financial and physical
resources, expertise availability.
Objectives

4. 4
Task 1: Inter-comparison exercises with different algorithms
and procedures to reproduce 3D morphological survey
(A) (B)
(D)
(C)
(F)(E)
Manfreda et al. (2019)

5. 5
Task 1: Inter-comparison exercises with different algorithms
and procedures to reproduce 3D morphological survey
Flight Flight
Plan
Take-off
AGL (m)
Average
AGL (m)
Camera
Tilt
(degree)
Average
GSD
(cm/px )
Number
of
Images
N.1 60 74 0° 1.9 276
N.2 60 74 0° 1.9 268
N.3 60 74 70° - 271
N.4 60 74 20° 2.0 273
N.5 60 74 0° 1.9 257
N.6 120 134 0° 3.3 85
Manfreda et al. (2019)

6. 6
Task 1: Inter-comparison exercises with different algorithms
and procedures to reproduce 3D morphological survey
N. GCPs
3 4 5 6 7 8 9
RMSEX,Y
(m)
10
-4
10
-3
10
-2
10
-1
100
N. GCPs
3 4 5 6 7 8 9
RMSEZ
(m)
10
-2
10
-1
100
101
(B)
RMSEX,Y
= 0.2cm RMSE
Z
= 10cm
RMSE
Z
= 3.5cm
(A)
Single Flight
Combined Flights
Single Flight
Combined Flights
Manfreda et al. (2019)

7. 7
Task 1: Inter-comparison exercises with different algorithms
and procedures to reproduce 3D morphological survey
Optimization of both the choice and combination of flight plans
can reduce the relative error of the 3D model:
• Within two meters without the need to include GCPs
• GCPs reduce the error to within a few cm
The combined use of images extracted from two different flight
config. improved the 3D model, especially z component
• One with a camera at nadir and the second with a 20°
angle

8. 8
Task 1: Inter-comparison exercises with different algorithms
and procedures to reproduce 3D morphological survey

9. 9
Task 2: Assessing methods for monitoring river flow velocity
and discharge

10. 10
Task 2: Assessing methods for monitoring river flow velocity
and discharge
Focus of two short term scientific missions:
• Sophie Pearce (Loughborough Uni.) to Tuscia Uni.
• Robert Ljubicic (Uni. of Belgrade) to Newcastle Uni.
Processing imagery collected with differing flight config:
• Platform (Phantom 4/Matrice), altitude (30 – 56m),
with range of view angles
Processing using differing image velocimetry software:
• LSPIV, LSPTV, Optical flow, KLT-PIV, DischargeApp

11. 11
Task 2: Assessing methods for monitoring river flow velocity
and discharge
Source: Sophie Pearce

12. 12
Task 3: Inter-comparison of different optical sensors, site
characteristics, and algorithms for discharge assessment
Compilation of contributions from research groups across
Europe using fixed and UAS platforms. To to be submitted to
Earth System Science Data (ESSD)

13. 13
Task 3: Inter-comparison of different optical sensors, site
characteristics, and algorithms for discharge assessment
Source: Flavia Tauro
Unfiltered Filtered

14. 14
Future Tasks
Continuing assessment of UAS techniques for velocity
assessment and development of guidelines for best-practise
Workshop on the methods for monitoring river flow velocity
Expansion of UAS monitoring for morphological components of
discharge quantification – stage, water extent, remote
assessment of bathymetry? Change detection?
Discussion between this WG4 and WG1 for identifying and
testing additional approaches for image pre-processing,
specifically geometric correction and image enhancement