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Figure 4: Comparative analysis between the proposed fish-eye correction approach and fish-eye correction with calibration patterns. (a) The reprojection errors attained using a calibration pattern (CB) to correct fish-eye distortion and using the proposed method. Notice the residual difference with the traditional calibration approach. The reprojected pixel locations are illustrated in (b) and (c) for CB and for our approach, respectively. (d) Comparative analysis of the height estimation error in different locations of the scene. (f) The pan-tilt angle error when observing a human being in different scene locations.