Browsing by Author "Teo, T. A."

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COLLOCATION-AIDED ADJUSTMENT OF HETEROGENEOUS MODELS FOR SATELLITE IMAGES
(2010)
Chang, W. C.
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Chen, L. C.
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Teo, T. A.
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土木工程學系
;
Department of Civil Engineering
The geometric correction for satellite images is an important task in remote sensor applications. The geometric correction methods for satellite images include rigorous sensor model (RSM) and rational function model (RFM). RSM describes the relationship between object points and image coordinates through exterior orientation parameters (EOPs). RFM uses the Rational Polynomial Coefficients (RPCs) to transform object coordinates into image space. Thus, treated parameters in the block adjustment for those two models are heterogeneous. In fact, the availability of those parameters is satellite dependent. Thus, the heterogeneous models between RSM and RFM should be combined in the block adjustment when those two types of images are integrated. Considering the global geometry, the block adjustment for all images is to keep the geometrical registration consistent. There might still remain local systematic errors. Thus, this paper proposes a collocation-aided block adjustment for multi-sensor images. The Direct Georeferencing, which is one of RSM, and the RFM are combined a mathematical model for block adjustment. Then the least squares collocation is included to compensate the systematic errors for those heterogeneous models. Besides, to adapt for the weakly convergent geometry, which happens frequently, a digital elevation model is employed as the elevation control in the block adjustment. The test data set includes GeoEye, QuickBird, WorldView-1, Kompsat-2, and Formosat-2 satellite images. The validation includes the checks for absolute accuracy and relative discrepancy among those images. Experimental results indicate that the proposed block adjustment significantly improved both the absolute accuracy and relative discrepancy.
DIGITAL ELEVATION QUALITY DERIVED FROM MEDIUM-FORMAT DIGITAL CAMERAS
(2013-12-01)
Shih, P. T. Y.
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Wu, J. Y.
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Teo, T. A.
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Tsai, J. C.
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交大名義發表
Medium-format digital cameras are a useful tool in airborne lidar missions to produce digital ortho-images. This study investigates the quality of digital elevation models (DEMs) and digital surface models (DSMs) derived from such cameras. An image-matching strategy is used to produce height information from highly overlapping images and the quality of the derived height information is analysed using synchronous lidar point clouds as the reference data. The evaluation focused on various types of land cover and DEM generation methods. The RMSE between lidar and image-derived height information for two datasets was 0054% and 0027% of the flying height in flat, bare-earth areas, but studies with manually edited vegetated areas using stereo photogrammetry revealed high uncertainties, especially in steep terrain.