UEF Traditional Christmas Seminar on Forest Inventory - PowerPoint Presentation

Slide1

UEF Traditional Christmas Seminar on Forest Inventory

Full-waveform

LiDAR research at the Hyytiälä siteIlkka Korpela, Docent

Outline

What is FWF LiDAR all about? Hyytiälä status, 12/2011 Foreseeable FWF research Other optical-RS-projects in HyytiäläSlide2

LiDAR

Time-stamped photons

C

amera 1

Target

Free photons

C

amera 2

C

amera 3

What is FWF LiDAR all about? Slide3

Ilkka Korpela

t

0

P

TX

Time

TX:

Pulse, 4



10 ns (1.2

 3 m), e.g. 1064 nm (NIR),

0.15  1 mrad (15 100 cm/km)

RX:

Optics & Photondetector & Amplifier & ”

Fast correlator

”

System:

Time, Position, Attitude of equipment & mirror

[

X, Y, Z]

(

t

)

+

et

L

×

R(rX, rY, rZ)(t) × [sin(L)cos(L), sin(L)sin(



L

),cos(



L

)]

Illuminated area

Divergence,

e.g. 1/e

2

What is FWF LiDAR all about? Slide4

Ilkka Korpela

Transmitted pulse (t)

Sum wave thru the receiver optics (t)

Inherent noise ”smuggles”

Sum-wave: front, maxima, back edge.

 Unambiguous distance?

What is FWF LiDAR all about? Slide5

Ilkka Korpela

P

target

[W/m

2

]

 Ptransmitted

 illumination  Losses

Atmosphere, canopy

P

received



f (

P

target

,

Silhouette area, Reflectance, Losses

Atmosphere

, Optics)

Volumetric

backscatter

What is FWF LiDAR all about? Slide6

Maximum amplitude

Distance perpendicular to power line, m

”Illumination”Slide7

H < 1 m

”Reflectance”Slide8

”Structure”

Ilkka KorpelaSlide9

Ilkka Korpela

Reflectance ~ P

Backscatter

/P

illumination

1. Echo

Perforated

Lambertia

surface,

LOSSES

2. EchoSlide10

First interaction (echo) has most information (intensity/amplitude),

the subsequent data is inherently contaminated by losses. What can we do with the rest of the waveform?Slide11

Hyytiälä Status 12/2011

Hyytiälä experiment

http://www.helsinki.fi/~korpela/HYDE_REF/ Pseudosystematic field plot measurements since 1996, last 2011 (student work in future?). ’Optimized’ for tree-level analyses

25000+ trees & 125+ plots to be ’LiDAR-updated’ 2/11-1/12

LiDAR data sets 2004, 1 km, 1-3 p/m2 (DR) Optech 2006, 1 km, 6-8 p/m2 (DR) Optech 2007, 1 km, 6-9 p/m2 (DR) Leica 2008, 1,2,3,4 km 0.2-1.5 p/m2 (DR) Leica 2010, 1,2,3 km, 1-8 p/m2 (DR + FWF) Leica

2011a, 1, 1.5, 2 km, 1-8 p/m2 (DR + FWF) Leica 2011b, 750 m, 8 p/m2, (DR+FWF), leaf-off, Riegl

2011 density map

10 x 15 kmSlide12

Hyytiälä Status 12/2011Slide13

Foreseeable FWF research (Hyytiälä)

Seedling stand vegetation & DEM –analyses

Tree species classification using FWF features (radiometric & new geometric) Descriptive study on pulse-target interactions

(interpretation of field photos) LAI & stuff (Lauri)

What else could be studied with the experiment? Change detection (2004-2011) Peatlands (Lakkasuo 2006 + 2011 LiDAR)

Old forests (Susimäki 2011, Kuivajärvi old growth)

Leaf-off vs. Leaf-on (+ sensor effects)

Gain of FWF in area-based inventory? (1-3 km LiDAR)Slide14

Other (optical) RS projects in Hyytiälä

VHR satellite imagery exists (check with Miina Rautiainen et al. (UH), Tuomas Häme VTT)

Airborne Hyperspectral was acquired 2011 (Paras Pant -presentation)

Radar? Slide15

Future of Hyytiälä experiment

2012: airborne imaging campaigns for BRDF research

(Can BRDF of the atmosphere be eliminated using normalization of at-sensor radiance images, in one image block?) Links to presentation by Anne Seppänen. Multidivergent LiDAR acquisitions: what can be gained thru 20, 60 and 120 cm footprint data (structure & species)

Collaboration/teamwork is always welcome (share the workload in forest, invoices of RS campaigns, data analyses and writing).Slide16

Airborne

imaging campaigns for BRDF research

KRÅNGLIGT

Refl.

”BRDF” or reflectance anisotropy varies between pine, spruce and birch (

λ

)

No studies exist that utilize this, Seppänen et al. (UEF + UH), tries it!

Reflectance calibration seems to be the bottleneck, and within sp- variation.Slide17

Ilkka Korpela

Thanks!