void KLTUpdateTCBorder(
KLT_TrackingContext tc);

KLTUpdateTCBorder() is a convenience function that automatically recomputes and updates the borderx and bordery fields of the tracking context, so that the user doesn't have to ever touch these fields. Unless the user desires direct control over the border, this function should be called whenever smooth_sigma_fact, pyramid_sigma_fact, window_width, window_height, or subsampling is changed.