polarization signature analysis of paddy rice in southern china
DESCRIPTION
Presented in “China – Thailand Geo-Informatics Workshop Series I: Agricultural Applications” 30 June - 2 July 2010 at Pattaya, ThailandTRANSCRIPT
Polarization Signature Analysis of Paddy Rice in Southern China
Chou Xie, Yun Shao, Kun Li, Fengli Zhang, Junna YuanInstitute of Remote Sensing Applications,
Chinese Academy of Sciences, China
Maosong Xu, Xuejun Wang, Zhongsheng XiaState Forestry Administration, China
Outlines
Introduction
Objectives
Radarsat 2: Polarimetric Signature Analysis of Paddy Rice in Guizhou Test Site
Airborne SAR Data: Polarization Behavior Analysis of Paddy Rice in Hainan Test Site
Conclusions
Outlines
Introduction
Rice is the staple food of more than half population of the world.
Most of Rice grows in cloud-prone and rainy areas : great potential of SAR, especially polarimetric SAR.
Two test sites were selected for this study in southern China
Guizhou
Hainan
One step forward from Multitemporal Radarsat 1 rice mapping
Understand the polarimetric signature of paddy rice in south China
Explore the potentiality of polarimetric Radarsat 2 in rice mapping
Rice acreage survey Rice yield estimation
Objectives
Radarsat 2: Polarimetric Signature Analysis of Paddy Rice in Guizhou Test Site
Guizhou Test Site:
Located in Zhazuo, Guizhou province, typical mountainous area with Karst Landform Small rice fields distribute in the flat bottom area of valleys Two type of rice: hybrid rice and japonica rice One rice crop a year, Growing season: May to October
Hybrid rice Japonica rice
RADARSAT-2 Acquisitions (supported by SOAR Program)
Acquisitiontime
BeamMode
Incidenceangle
(degrees)
Resolution (m)
Range Azimuth
July 26,2009 FQ 40.34 12m 8m
August 19,2009 FQ 40.34 12m 8m
September 12,2009
FQ 40.34 12m 8m
October 6,2009 FQ 40.34 12m 8m
Rice fields
Rice fields
Linear Polarization Combination
HH – HV space:
good combination of polarizations
Linear Polarization RatiosThe HH/HV improves the discrimination between rice and other targets;
Combination of HH and HH/HV is the best combination
HH and HH/HV Color Composite Image (R:HH G:VH B:HH/HV)
Rice=purple magenta=building1 yellow=buiding2 green=forest
Polarization information is a unique advantage of SAR
Polarization decomposition can be use to analyze the physical scattering mechanisms of the targets, and then carry out a variety of processing and applications.
Polarization decomposition methods are mainly divided into
two categories, one is coherent decomposition, the other is
incoherent decomposition.
The Pauli decomposition (coherent decomposition) and
Cloude decomposition (incoherent decomposition) were
applied in this study,
Radarsat 2: Polarimetric Signature Analysis of Paddy Rice in Guizhou Test Site
Pauli Decomposition
Color composite image red=a scattering mechanism characterized by double- or even-bouncegreen= those scatters which are able to return the orthogonal polarization, from which, one of the best examples is the volume scattering produced by the forest canopy. blue =power scattered by targets characterized by single- or odd-bounce.
Rice fields
Rice fields
Polarimetric signature of four major targets
rice forest
urban water
H-Alpha space of four major targets
forestrice
urban water
Entropy, Anisotropy and combinations
Entropy H Anisotropy A
HA H(1-A)
Color composite image highlighting rice ( R :HA , G:Pauli-G , B: Pauli-B )
Rice=red magenta=building1 yellow=buiding2 green=forest
image
So far, parameter does not have very clear physical meaning to explain scattering mechanisms of rice. But it shows rice fields correctly.
It is sensitivity to terrain. In the test site (mountainous area), rice fields are relatively flat compared to other features.
Color composite image highlighting rice ( R : , G:Pauli-G , B: Pauli-B )
Rice=red magenta =building1 yellow=buiding2 green=forest water=black
Temporal Polarization signature of rice
July 26th,2009 Aug 19th,2009
Sep 12th,2009 Oct 6th,2009
Temporal H-Alpha space of rice
July 26th,2009
Aug 19th,2009
Sep 12th,2009
Oct 6th,2009
Located in southeast of
Hainan province
Large-scale rice cultivation
Large,regular rice fields
Three rice crops a year
Growing season:
February to June,
late June to September,
October to next January
Airborne SAR Data: Polarization Behavior Analysis of Paddy Rice in Hainan Test Site
Airborne SAR data acquisitions
Acquisition time Incidence angle (degrees)
Resolution (meter) Polarization
Range Azimuth
February 21th,2009 44.0—50.9 2 2 HH/HV/VH/VV
February 27th,2009 33.0—44.0 2 2 HH/HV/VH/VV
February 28th,2009 33.9—44.8 2 2 HH/HV/VH/VV
March 9th,2009 54.0—65.5 2 2 HH/HV/VH/VV
March 9th,2009 50.5—63.4 2 2 HH/HV/VH/VV
March 9th,2009 48.3—62.0 2 2 HH/HV/VH/VV
March 9th,2009 47.5—66.8 2 2 HH/HV/VH/VV
March 10th,2009 47.5—66.8 2 2 HH/HV/VH/VV
Color composite image ( R:HH G:HV B:VV )
Rice on different polarization images
HH
VH
HV
VV
rice
Linear Polarization Ratios image—HH/VV
Rice in different growth stages<HH>/ <VV> of ri ce wi th di ff erent stages
0
0. 5
1
1. 5
2
2. 5
3
3. 5
4
58. 5 60 61 70 80 85The hei ght of ri ce (cm)
<HH>
/<VV
> (d
B)
<HH>/ <VV>
<HH> / <VV> of rice increases with rice growthdistinguish rice in different growing stages
rice1=60 days rice2= 40 days rice3=30 days rice4=20 days The accuracy of rice extraction is 90%, and the precision of classification is 71%.
Liner polarization combination, Polarization decomposition is effective in rice discrimination
Paddy rice mapping is feasible with polarimetric Radarsat 2 data in mountainous areas
Polarimetric signature, parameters delivered from polarization decomposition (coherent or incoherent decomposition) need further study, understanding and exploring
It is better to provide final results, maps and services to the end users instead of provide SAR data to them
Conclusions
ThanksThanks!!Chou XieChou Xie
Institute of Remote Sensing Applications, Institute of Remote Sensing Applications, Chinese Academy of SciencesChinese Academy of Sciences
Tel:86-10-64876313Tel:86-10-64876313Email:[email protected]:[email protected]