1. imaginlabs.com Patent U.S. 8,121,433 B2 California Institute of Technology Monitoring Urban Changes from Digital Surface Models: Generating DSM using Worldview Imagery and COSI-Corr Processing vs. Airborne LiDAR Acquisitions Sebastien Leprince Francois Ayoub Jiao Lin Jean-Philippe Avouac leprincs@caltech.edu Office: 626-395-2912 Cell: 626-240-9041 California Institute of Technology

2. Case Study: City of Christchurch, NZ Data: Worldview panchromatic stereo-pairs (courtesy of DigitalGlobe): - Acquired in September 2009 - Acquired in August 2011 LiDAR acquisitions (courtesy of GNS Science, NZ): - 1m gridded LiDAR acquired mid-2010 - 1m gridded LiDAR acquired late-2011 Goal: Comparing the digital surface models produced using COSI-Corr on pairs of 0.5m stereo Worldview images with state-of-the-art airborne LiDAR acquisitions. Applications: City planning, urbanism, insurance, rapid response to catastrophic events (e.g., earthquakes, liquefactions).

3. Eastern part of downtown Christchurch, NZ, zoom on a small 650x350m area 2009 Worldview DSM generated with COSI-Corr 1m GSD 2011 Worldview DSM generated with COSI-Corr 1m GSD 2010 LiDAR DSM, 1m GSD2011 LiDAR DSM, 1m GSD COSI-Corr DSM extraction using Worldview stereo imagery competes with LiDAR

4. 2010 LiDAR DSM 1m GSD 2011 LiDAR DSM 1m GSD

5. 2009 Worldview DSM generated with COSI-Corr 1m GSD 2011 Worldview DSM generated with COSI-Corr 1m GSD

6. Comparison of height profiles on buildings (2011 data) All heights in meters Dotted Profiles = COSI-Corr + Worldview DSM Solid Profiles = LiDAR

7. Comparison of height profiles on buildings (2011 data) All heights in meters Dotted Profiles = COSI-Corr + Worldview DSM Solid Profiles = LiDAR

8. Comparison of height profiles on buildings (2011 data) All heights in meters Dotted Profiles = COSI-Corr + Worldview DSM Solid Profiles = LiDAR

9. Looking at Building Height Change 2009/2011 Difference between Worldview DEM generated by COSI-Corr 2010/2011 Difference between LiDAR DSM Blue areas are negative changes in height in excess of 3m (building destruction) Red areas are positive changes in height in excess of 3m (building construction) Building destruction after the Feb. 2011 Christchurch earthquake Building destruction after the Sept. 2010 Canterbury earthquake? Building construction after the Feb. 2011 Christchurch earthquake Building construction after the Sept. 2010 Canterbury earthquake

10. Comparison with other Software (2011 data): ERDAS LPS - eATE 2011 Worldview DSM generated with COSI-Corr 1m GSD 2011 Worldview DSM generated with ERDAS LPS eATE 1m GSD

11. Comparison with other Software (2011 data): ERDAS LPS - eATE 2011 Worldview DSM generated with ERDAS LPS eATE 1m GSD

12. Comparison with other Software (2011 data): ERDAS LPS - eATE 2011 Worldview DSM generated with COSI-Corr 1m GSD

13. Comparison with other Software (2011 data): ERDAS LPS - eATE All heights in meters White Profiles = COSI-Corr Green Profiles: ERDAS LPS eATE Red Profiles = LiDAR

14. Comparison with other Software (2011 data): ERDAS LPS - eATE All heights in meters White Profiles = COSI-Corr Green Profiles: ERDAS LPS eATE Red Profiles = LiDAR

15. Comparison with other Software (2011 data): ERDAS LPS - eATE All heights in meters White Profiles = COSI-Corr Green Profiles: ERDAS LPS eATE Red Profiles = LiDAR

16. Comparison with other Software (2011 data): ERDAS LPS - eATE All heights in meters White Profiles = COSI-Corr Green Profiles: ERDAS LPS eATE Red Profiles = LiDAR

17. Conclusions COSI-Corr processing of Worldview stereo-pairs can compete with LiDAR DSM acquisition Cost advantage of COSI-Corr + stereo processing with respect to LiDAR: stereo acquisition + processing costs ~$100/km 2 vs. ~$1000/km 2 for LiDAR acquisitions Satellite imagery more responsive than airborne LiDAR survey. Can deliver imagery quickly and globally without need for flight authorizations Can repeat satellite survey more often than LiDAR surveys: better monitoring in time of surface evolution. Typical applications: disaster monitoring and assessment, city planning, mining, etc.