Polarization signature analysis of paddy rice in southern china


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Presented in “China – Thailand Geo-Informatics Workshop Series I: Agricultural Applications” 30 June - 2 July 2010 at Pattaya, Thailand

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Polarization signature analysis of paddy rice in southern china

  1. 1. Polarization Signature Analysis of Paddy Rice in Southern China <ul><li>Chou Xie, Yun Shao, Kun Li, Fengli Zhang, Junna Yuan </li></ul><ul><li>Institute of Remote Sensing Applications, </li></ul><ul><li>Chinese Academy of Sciences, China </li></ul><ul><li>Maosong Xu, Xuejun Wang, Zhongsheng Xia </li></ul><ul><li>State Forestry Administration, China </li></ul>
  2. 2. Outlines <ul><li>Introduction </li></ul><ul><li>Objectives </li></ul><ul><li>Radarsat 2: Polarimetric Signature Analysis of Paddy Rice in Guizhou Test Site </li></ul><ul><li>Airborne SAR Data: Polarization Behavior Analysis of Paddy Rice in Hainan Test Site </li></ul><ul><li>Conclusions </li></ul>Outlines
  3. 3. Introduction <ul><li>Rice is the staple food of more than half population of the world. </li></ul><ul><li>Most of Rice grows in cloud-prone and rainy areas : great potential of SAR, especially polarimetric SAR. </li></ul><ul><li>Two test sites were selected for this study in southern China </li></ul><ul><li>Guizhou </li></ul><ul><li>Hainan </li></ul>
  4. 4. <ul><li>One step forward from Multitemporal Radarsat 1 rice mapping </li></ul><ul><li>Understand the polarimetric signature of paddy rice in south China </li></ul><ul><li>Explore the potentiality of polarimetric Radarsat 2 in rice mapping </li></ul><ul><li>Rice acreage survey </li></ul><ul><li>Rice yield estimation </li></ul>Objectives
  5. 5. Radarsat 2: Polarimetric Signature Analysis of Paddy Rice in Guizhou Test Site <ul><li>Guizhou Test Site: </li></ul><ul><li>Located in Zhazuo, Guizhou province, typical mountainous area with Karst Landform </li></ul><ul><li>Small rice fields distribute in the flat bottom area of valleys </li></ul><ul><li>Two type of rice: hybrid rice and japonica rice </li></ul><ul><li>One rice crop a year, </li></ul><ul><li>Growing season: May to October </li></ul>
  6. 6. Hybrid rice Japonica rice
  7. 7. RADARSAT-2 Acquisitions (supported by SOAR Program) Acquisition time Beam Mode Incidence angle (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
  8. 8. Rice fields Rice fields
  9. 9. Linear Polarization Combination HH – HV space: good combination of polarizations
  10. 10. Linear Polarization Ratios <ul><li>The HH/HV improves the discrimination between rice and other targets; </li></ul><ul><li>Combination of HH and HH/HV is the best combination </li></ul>
  11. 11. HH and HH/HV Color Composite Image (R:HH G:VH B:HH/HV) Rice=purple magenta=building1 yellow=buiding2 green=forest
  12. 12. <ul><li>Polarization information is a unique advantage of SAR </li></ul><ul><li>Polarization decomposition can be use to analyze the physical scattering mechanisms of the targets, and then carry out a variety of processing and applications. </li></ul><ul><li>Polarization decomposition methods are mainly divided into two categories, one is coherent decomposition, the other is incoherent decomposition. </li></ul><ul><li>The Pauli decomposition (coherent decomposition) and Cloude decomposition (incoherent decomposition) were applied in this study, </li></ul>Radarsat 2: Polarimetric Signature Analysis of Paddy Rice in Guizhou Test Site
  13. 13. Pauli Decomposition Color composite image red=a scattering mechanism characterized by double- or even-bounce green= 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
  14. 14. Polarimetric signature of four major targets rice forest urban water
  15. 15. H-Alpha space of four major targets forest water rice urban
  16. 16. Entropy, Anisotropy and combinations Entropy H Anisotropy A HA H(1-A)
  17. 17. Color composite image highlighting rice ( R :HA , G:Pauli-G , B: Pauli-B ) Rice=red magenta=building1 yellow=buiding2 green=forest
  18. 18. image <ul><li>So far, parameter does not have very clear physical meaning to explain scattering mechanisms of rice. But it shows rice fields correctly. </li></ul><ul><li>It is sensitivity to terrain. In the test site (mountainous area), rice fields are relatively flat compared to other features. </li></ul>
  19. 19. Color composite image highlighting rice ( R : , G:Pauli-G , B: Pauli-B ) Rice=red magenta =building1 yellow=buiding2 green=forest water=black
  20. 20. Temporal Polarization signature of rice July 26th,2009 Aug 19th,2009 Sep 12th,2009 Oct 6th,2009
  21. 21. Temporal H-Alpha space of rice July 26th, 2009 Aug 19th, 2009 Sep 12th, 2009 Oct 6th, 2009
  22. 22. <ul><li>Located in southeast of Hainan province </li></ul><ul><li>Large-scale rice cultivation </li></ul><ul><li>Large,regular rice fields </li></ul><ul><li>Three rice crops a year </li></ul><ul><li>Growing season: </li></ul><ul><li>February to June, </li></ul><ul><li>late June to September, </li></ul><ul><li>October to next January </li></ul>Airborne SAR Data: Polarization Behavior Analysis of Paddy Rice in Hainan Test Site
  23. 23. 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
  24. 24. Color composite image ( R:HH G:HV B:VV )
  25. 25. Rice on different polarization images HH VH HV VV rice
  26. 26. <ul><li>Linear Polarization Ratios image—HH/VV </li></ul>
  27. 27. Rice in different growth stages <HH> / <VV> of rice increases with rice growth distinguish rice in different growing stages
  28. 28. 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%.
  29. 29. <ul><li>Liner polarization combination, Polarization decomposition is effective in rice discrimination </li></ul><ul><li>Paddy rice mapping is feasible with polarimetric Radarsat 2 data in mountainous areas </li></ul><ul><li>Polarimetric signature, parameters delivered from polarization decomposition (coherent or incoherent decomposition) need further study, understanding and exploring </li></ul><ul><li>It is better to provide final results, maps and services to the end users instead of provide SAR data to them </li></ul>Conclusions
  30. 30. Thanks ! Chou Xie Institute of Remote Sensing Applications, Chinese Academy of Sciences Tel:86-10-64876313 Email:xiechou@irsa.ac.cn