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TitleDEM Extraction from High Resolution Imagery
DownloadDownloads (Preprint)
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorToutin, Th
SourceGeospatial Today; 2, 3, 2003 p. 31-36, Open Access logo Open Access
Alt SeriesEarth Sciences Sector, Contribution Series 20043266
Mediapaper; on-line; digital
File formatpdf
Released2003 01 01
AbstractDigital elevation models (DEMs) extracted from high-resolution stereo images (SPOT-5, EROS and IKONOS) using a three-dimensional (3-D) multi-sensor physical model developed at the Canada Centre for Remote Sensing, Natural Resources Canada were evaluated. Firstly, the photogrammetric stereo-bundle adjustment was set-up with few accurate ground control points. DEMs were then generated using an area-based multi-scale image matching method and then compared to 0.2-m accurate lidar elevation data. Elevation linear errors with 68% confidence level (LE68) of 6.5 m, 20 m and 6.4 m were achieved for SPOT, EROS and IKONOS, respectively. The worse results for EROS are mainly due to its asynchronous orbit, which generate large geometric and radiometric differences between the stereo-images. When these differences are not large (such as in the middle of the stereo-pair), 10-m LE68 was achieved. Since SPOT and IKONOS DEMs were in fact a digital terrain surface model where the elevation of land covers (trees, houses) is included, the elevation accuracy is performed depending on the land cover types. LE68 of 1-2 m were obtained for bare surfaces and lakes. However, when compared to sensor resolution, SPOT achieved better results than IKONOS: half-pixel versus 1.5 pixels. On the other hand, LE68 of 4 m to 6.6 m were obtained depending on the forest types (deciduous, conifer, mixed or sparse) and its surface elevation.

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