Presentation on theme: "UEF Traditional Christmas Seminar on Forest Inventory Full-waveform LiDAR research at the Hyytiälä site Ilkka Korpela, Docent Outline What is FWF LiDAR."— Presentation transcript:
UEF Traditional Christmas Seminar on Forest Inventory Full-waveform LiDAR research at the Hyytiälä site Ilkka Korpela, Docent Outline What is FWF LiDAR all about? Hyytiälä status, 12/2011 Foreseeable FWF research Other optical-RS-projects in Hyytiälä
LiDAR Time-stamped photons Camera 1 Target Free photons Camera 2 Camera 3 What is FWF LiDAR all about?
Ilkka Korpela t0t0 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?
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?
Ilkka Korpela P target [W/m 2 ] P transmitted illumination Losses Atmosphere, canopy P received f (P target, Silhouette area, Reflectance, Losses Atmosphere, Optics) Volumetric backscatter What is FWF LiDAR all about?
Maximum amplitude Distance perpendicular to power line, m ”Illumination”
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?
Hyytiälä Status 12/2011 Hyytiälä experiment http://www.helsinki.fi/~korpela/HYDE_REF/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 km
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)
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?
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).
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.