Abstract
Abstract. As the linear array sensor such as multispectral and hyperspectral sensor has great potential in disaster monitoring and geological survey, the quality of the image geometric rectification should be guaranteed. Different from the geometric rectification of airborne planar array images or multi linear array images, exterior orientation elements need to be determined for each scan line of single linear array images. Internal distortion persists after applying GPS/IMU data directly to geometrical rectification. Straight lines may be curving and jagged. Straight line feature -based geometrical rectification algorithm was applied to solve this problem, whereby the exterior orientation elements were fitted by piecewise polynomial and evaluated with the straight line feature as constraint. However, atmospheric turbulence during the flight is unstable, equal piecewise can hardly provide good fitting, resulting in limited precision improvement of geometric rectification or, in a worse case, the iteration cannot converge. To solve this problem, drawing on dynamic programming ideas, unequal segmentation of line feature-based geometric rectification method is developed. The angle elements fitting error is minimized to determine the optimum boundary. Then the exterior orientation elements of each segment are fitted and evaluated with the straight line feature as constraint. The result indicates that the algorithm is effective in improving the precision of geometric rectification.
Highlights
Airborne linear array pushbroom sensors are becoming increasingly of interest for multispectral and hyperspectral applications
The geometric rectification of linear images is different from airborne planar array images or multi linear array images, because there are no geometric constraints among each scan line, and each line is independently acquired with a different exterior orientation, so a classic bundle adjustment is not realistic, owing to the huge number of unknowns
In order to eliminate POS data errors, (Tuo et al, 2005) used POS data to coarse correct first, and applied polynomial model based on the reference images for further correct. (Wang et al, 2013) presented a geometric correction method which can be used to correct the linear array image based on the bias matrix
Summary
Airborne linear array pushbroom sensors are becoming increasingly of interest for multispectral and hyperspectral applications. Straight line feature-based geometrical rectification algorithm was applied to solve this problem (Lee et al, 2000), whereby the exterior orientation elements are fitted by piecewise polynomial and evaluated with the straight line feature as constraint. Atmospheric turbulence during the flight is unstable, equal piecewise can hardly provide good fitting, resulting in limited precision improvement of geometric rectification or, in a worse case, the iteration cannot converge. To solve this problem, drawing on dynamic programming ideas, unequal segmentation of line feature-based geometric rectification method is developed
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