Geomatica 2015 - DEM Results

transcript

DEM Extraction ResultsGeomatica 2015

Work Performed in this release• 2x to 4x improvement in DEM extraction performance• Special handling of high-res satellites• Improved correlation: Fewer blunders and failed areas• Sharper edges, more detail• Better handling of rapid changes in elevation (steep

slopes, tops of tall buildings)• New smoothing filters that preserve detail• Improved merging of tri-stereo DEMs

2Copyright PCI Geomatics 2015

Performance Improvements

• DEM extraction specifically improved (epi-polar generation and geocoding unchanged)

• With all steps included total times are 1.5x to 2x faster

Source Original Current Improvement

Ultracam airphoto 160s 40s 4x

World View 2 (hi-res satellite) 35m 11m 3x

WV-2 50cm ortho-image of Greenland

Copyright PCI Geomatics 2015 4

WV-2 2m DTM of Greenland

High-Res Satellites• Sub-metre (50cm and below) satellites

– e.g. GeoEye 2, WorldView 3• Now using methodologies similar to aerial

photography• Higher detail and fewer blunders than

previous methods

GeoEye 2 (50cm Satellite)• 50cm, 1m and 2m DEMs extracted automatically• No manual editing was performed• Control was a single GCP yielding 10cm

accuracy• Subject area is a mining site with high relief

Copyright PCI Geomatics 2015

• Full DEM shown at left• 34k x 53k pixels• 17km x 26km area• Note high detail at

50cm DEM• Red box indicates

study area8

Mining site – GeoEye 2 image at 50cm

Mining site – GeoEye 2 DEM at 2m

Mining site – GeoEye 2 DEM at 1m

Mining site – GeoEye 2 DEM at 50cm (1 point-per-pixel density)

World View 3 (30cm Satellite)• 30cm and 60cm DEMs extracted automatically• Water areas were manually flattened. No other

editing was performed• No GCPs: Geometry based on ephemeris and

tie-points only• Subject area is a new volcanic island in the

South Pacific ocean

Volcano – WV3 DEM using older extraction method

Note many blunders/failures and lack of detail

Volcano – WV3 DEM at 30cm using current extraction method

Fewer blunders and higher detail in less time

Volcano – WV3 imagery at 30cm

Comparison of DEM and image results

Before & after eruption (via BBC News)

Air Photo• 20cm DEM extracted automatically from

10cm imagery• Better detail, fewer failures

– Buildings have sharper edges– Captures tops of high buildings– Smoother roads and surfaces

• 3x faster18Copyright PCI Geomatics 2015

20cm DSM overview 20cm DSM detail (raw, unedited)

UltraCam 30cm DSM of Graz, Austria

UltraCam 7.5cm ortho-image of Graz, Austria

220-image, 15cm UltraCam project: 30cm DSM overview

220-image, 15cm UltraCam project: 30cm DSM detail

220-image, 15cm UltraCam project: 30cm DSM detail (maximum zoom)

220-image, 15cm UltraCam project: Image detail

Contact PCI Geomatics

www.pcigeomatics.cominfo@pcigeomatics.com

Geomatica 2015 - DEM Results

Documents