IGARSS11_WANG_v2.ppt

INVESTIGATION ON THE ORIENTATION AND STRUCTURE PARAMETERS OF CANOPY USING POLSAR OBSERVATIONS Yanting Wang, Thomas Ainsworth and Jong-Sen Lee Remote Sensing Division Naval Research Laboratory

Objectives ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Volume of Spheroid Scatterers ,[object Object],Each elementary scatterer features a body of revolution w.r.t. the symmetric axis, ON. The projected symmetry axis on the polarization plane is oriented towards angle  ; The local incidence angle w.r.t. the symmetry axis is  ; The principal scattering components are S a and S b . O X Y Z N

Circular Polarization Representation ,[object Object],[object Object],[object Object],If  and  are separable, Advantage: Orientation parameters readily separable as phase terms. Symmetric distribution Orientation dispersion Mean orientation angle Independent of orientation 0: sphere 1: dipole Relates to both shape variation and orientation dispersion

Circular Polarization Representation ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Orientation Distribution ,[object Object],Orientation distribution (  ): symmetric, zero mean Incidence angle distribution (  ): shows same dispersion

Orientation Distribution ,[object Object],Established a relation between  2 and  4 . The orientation parameters, mean and dispersion, can be determined and removed, which leaves only scatterer shape information.

Physical Parameters Retrieval ,[object Object],[object Object],We get mean shape, r, and shape variation, Re (  ab ). Size Shape Orientation

Forest Observations ,[object Object],Tropical Rainforest [Guyana] Jun. 93 - Broad leaf - Thick foliage - Random branches Temperate Conifer [Germany] Jun. 91 - Needle leaf - Oriented branches ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],* Image source: Google Earth

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],C-band Forest Observations C-band Blue: rain forest (Guyana) Black: conifer (Germany) Cyan: deciduous (Michigan)

L-band Forest Observations ,[object Object],[object Object],[object Object],[object Object],[object Object],L-band Blue: rain forest (Guyana) Black: conifer (Germany) Cyan: deciduous (Michigan)

Vegetation Observations ,[object Object],[object Object],[object Object],C-band L-band

stem branchy dipole; random uniform shape sphere; broader needle; thinner Scatter plots @ 50 th percentile, C-band leafy ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Scatter plots @ 50 th percentile, L-band At L-band, scattering component from structure – good separation. Anisotropic dipole: stembeans, lucerne; Thin column: wheat; Broad shape: potatoes, beet, grass; Mixed structure: forest; Uniform structure: rapeseed, peas dipole; random uniform shape stem branchy sphere; broader needle; thinner leafy

Potential Physical Characterization ,[object Object],[object Object],[object Object],[object Object],[object Object],Size Shape Orientation

[object Object],Supervised Wishart Classification Experimental Wishart Classification (with extra step of segmentation)

Unsupervised Classification ,[object Object],[object Object],[object Object],Initial Segmentation: start with dense, discrete, gridded divisions  4 at 0.15, 0.25, and 0.5  ab from -0.9 to 0.9 with 0.2 intervals Primary divisions Secondary divisions: mean shape ratio, pixel intensity 100+ initial divisions

Unsupervised Classification ,[object Object],[object Object],[object Object],Merge the secondary divisions based on inter-class Wishart distance. From sample X to C m : Inter-class: Secondary divisions: Merge if the classes are close, leaving 38 classes for the AIRSAR Flevoland dataset ,[object Object],[object Object],[object Object],[object Object],Final result: 20 classes for the AIRSAR Flevoland dataset Class centers: C m , C n , …

Unsupervised Classification Re-colored Unsupervised Wishart Classification Map Supervised Wishart Classification Map Iterations not necessary, Wishart classification converges fast (pixel change < 10%) C-band L-band

Unsupervised Classification ,[object Object],Sault Saint Marie, Lake Superior, Michigan C-band, Pauli RGB Composition Black: Low Backscatter, SPAN<-10 dB Gray: Surface Green: Deciduous Forest Blue: Coniferous Forest Yellow: Mixed Type

Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

IGARSS11_WANG_v2.ppt

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