On The Use of Polarimetric Orientation for POLSAR Classification and Decomposition Hiroshi Kimura Gifu University, Japan IGARSS 2011 Vancouver, Canada July 25, 2011

ＩIGARSS 2011, Vancouver, Canada Contents Background Polarization Orientation in Built-up Areas Method to Discriminate Built-up and Non-built-up Areas ALOS PALSAR Experiment Conclusion ＩIGARSS 2011, Vancouver, Canada

ＩIGARSS 2011, Vancouver, Canada Background Agricultural field Built-up Area Freeman&Durden decomposition of ALOS PALSAR　data (Descend.) Double-bounce, Volume, Surface From map “Isezaki” by The Geospatial Information Authority of Japan (GSI) Objective: To discriminate built-up and non-built-up areas ＩIGARSS 2011, Vancouver, Canada

Polarization Orientation in Built-up Areas Radar x (azimuth) y (range) V H k a f From L-band Pi-SAR data of Gifu • PO angle shift of built-up areas: azimuth slope angle: w a , ground range angle: g =0, radar look angel: f p/2-f . a: wall orientation angle from the normal of radar beam H. Kimura, “Radar polarization orientation shifts in built-up areas,” IEEE GRSL, vol. 5, no. 2, 2008. • PO angle shift of terrain slopes: w : azimuth slope angle, g : ground range slope angle, f : radar look angle. ＩIGARSS 2011, Vancouver, Canada

Method to Discriminate Built-up and Non-built-up Area • Detection of built-up areas facing away from the radar (|a|ac) • Method to discriminate Built-up areas: |qa|>c or |qd|>c. Not built-up but level surface areas: |qa|c and |qd|c. qa, qd : PO angles from ascending and descending orbits c : PO angle threshold from wall orientation angle threshold ac DETECTABLE zone of built-up areas Illumination Illumination ASCENDING UNDETECTABLE zone of built-up areas DESCENDING ＩIGARSS 2011, Vancouver, Canada

In case of SMALL threshold ac DETECTABLE zone of built-up areas DETECTABLE = + (OR) UNDETECTABLE ASCENDING DESCENDING • NO undetectable zone of built-up area • COMMISSION error (Non-built-up areas are assigned to built-up areas) increases. • OMSSION error (Built-up areas are assigned to non-built-up areas) decreases. ＩIGARSS 2011, Vancouver, Canada

In case of LARGE threshold ac DETECTABLE zone of built-up areas DETECTABLE = + (OR) UNDETECTABLE zone UNDETECTABLE ASCENDING DESCENDING • Undetectable zone of built-up area exists. • COMMISSION error (Non-built-up areas are assigned to built-up areas) decreases. • OMSSION error (Built-up areas are assigned to non-built-up areas) increases. ＩIGARSS 2011, Vancouver, Canada

ALOS PALSAR Experiment: PALSAR Scenes The Atsugi area: about 50 km south- west from Tokyo Radar illumination azimuth: 99 (Ascending) 261 (Descending) Expected ac is 9 (No undetectable zone and the max. ac), then the PO angle threshold c will be 10. ＩIGARSS 2011, Vancouver, Canada

ALOS PALSAR Experiment: Images Pauli color code Freeman&Durden decomposition PO angle |HH-VV|, |HV|, |HH+VV| Double-bounce, Volume, Surface -p/4 p/4 ＩIGARSS 2011, Vancouver, Canada

ＩIGARSS 2011, Vancouver, Canada Study Area ( 5.2km by 3.1 km ) F3 F3 F2 F2 B3 B3 B2 B2 B1 B1 F1 F1 © Google Earth Google Earth image Map by GSI, Japan ＩIGARSS 2011, Vancouver, Canada

Freeman&Durden Decomposition B3 B2 B1 F1 © Google Earth Double-bounce Volume Surface Google Earth image Ascending Descending ＩIGARSS 2011, Vancouver, Canada

ＩIGARSS 2011, Vancouver, Canada H a H-Alpha Segmentation F3 F2 B3 B2 B1 F1 © Google Earth Google Earth image Ascending Descending ＩIGARSS 2011, Vancouver, Canada

ＩIGARSS 2011, Vancouver, Canada PO Angle Images F3 F2 B3 B2 B1 F1 © Google Earth -p/4 p/4 Google Earth image Ascending Descending ＩIGARSS 2011, Vancouver, Canada

Discrimination Results F3 F2 B3 B2 B1 F1 White: Built-up area, Black: Non-built-up area c=5(ac=5 ) c=10(ac=9) c=12(ac=11) ＩIGARSS 2011, Vancouver, Canada

Discrimination Results (Built-up areas) Google Earth image c=5(ac=5 ) c=10(ac=9) c=12(ac=11) B1 B2 B3 © Google Earth © Google Earth © Google Earth Omission errors White: Built-up area Black: Non-built-up area ＩIGARSS 2011, Vancouver, Canada

Discrimination Results (Non-built-up areas) Google Earth image c=5(ac=5 ) c=10(ac=9) c=12(ac=11) F1 F2 F3 © Google Earth © Google Earth © Google Earth Commission errors White: Built-up area Black: Non-built-up area ＩIGARSS 2011, Vancouver, Canada

Discrimination Results Agricultural field Built-up Area Freeman&Durden decomposition of ALOS PALSAR　data (Descend.) Double-bounce, Volume, Surface Built-up Areas (white) and non-built-up areas (black) by c=10(ac=9). ＩIGARSS 2011, Vancouver, Canada

Discrimination Results Agricultural field Built-up Area Freeman&Durden decomposition of ALOS PALSAR　data (Ascend.) Double-bounce, Volume, Surface Built-up Areas (white) and non-built-up areas (black) by c=10(ac=9). ＩIGARSS 2011, Vancouver, Canada

ＩIGARSS 2011, Vancouver, Canada Conclusion PO from ascending and descending orbits can be used to discriminate built-up and non-built-up areas. Radar illumination direction influences POLSAR data aanlysis. The discrimination prevents misleading of POLSAR decomposition and classification. (Volume scattering in urban areas, double bounce in agricultural fields, et al.) The expected threshold with no undetectable zone of built-up areas and the maximum number seems to be good, but a further study is required for the best one . Slopes should be separated. ＩIGARSS 2011, Vancouver, Canada

Rotation of Coherence Matrix (Yamaguchi) Ascending 　　　　Descending Agricultural fields BEFORE Rotation AFTER |HH-VV| |HV| |HH+VV| |HH-VV| |HV| |HH+VV| Ascending 　　　　Descending Built-up Areas ＩIGARSS 2011, Vancouver, Canada

PO Angle Shifts of Slopes Range Slope Angle (degrees) ＩIGARSS 2011, Vancouver, Canada