deletions | additions       diff --git a/section_Pillar_I_Training_Set__.tex b/section_Pillar_I_Training_Set__.tex  index 0902fc7..f148798 100644  --- a/section_Pillar_I_Training_Set__.tex  +++ b/section_Pillar_I_Training_Set__.tex 
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orthorectified by estimating the most probable viewing angle based on  the set of all images. Since a downward-looking camera is attached to  the UAV, most images will be roughly aligned with the z-axis, given  slow flight.For both steps, the software Agisoft  PhotoScan~\cite{agisoft2013agisoft} was used. The stitching process  can be time-consuming and error-prone. In some environments, an image  from a top view point can be taken capturing the entire area with  high-resolution camera, circumventing the need for stitching together  multiple images. Yet another method starts with an existing image and  modifies the environment accordingly---for example by painting the  floor or printing posters--to correspond to the image. In all cases,  we will describe the environment as \emph{map image}.