REAL TIME PROCESSING FOR EPIPOLAR RESAMPLING OF LINEAR PUSHBROOM IMAGERY BASED ON THE FAST ALGORITHM FOR BEST SCAN LINE SEARCHING
Keywords: Linear CCD, Differential rectification, Back projection of ground points, Best scan line searching, ADS40
Abstract. The epipolar resampling of linear pushbroom imagery is essential for automatic DEM extraction and feature collection. Due to the special imaging geometry of linear array scanners, the epipolar geometry of linear pushbroom imagery is very complex. In this paper, a fast algorithm for epipolar resampling of linear pushbroom imagery is proposed which can satisfy the real time processing demand of automatic DEM extraction and feature collection. The differential rectification of linear pushbroom imagery based on the rigorous geometric model is the basis for epipolar resampling. The back projection of ground points is essential for the differential rectification of linear pushbroom imagery and its main objective is searching the best scan line. The traditional best scan line searching methodology based on collinearity equation iterations needs a lot of calculation which has little practical use. According to the geometric constraints of the central perspective plane of scan line, the best scan line is determined efficiently within several iterations which just calculating the distance of ground point to the central perspective planar in object space. Based on our fast back projection algorithm, the epipolar resampling processing efficiency of linear pushbroom imagery can be improved greatly. The ADS40 airborne linear pushbroom imagery is tested and experiment results show that our algorithm has the merits of both high accuracy and efficiency which is suitable for real time processing of epipolar resampling.