The input may be inaccurate and obstacle points may not be determined as obstacles.įill in the point where the obstacle point is located with occupied.The obstacle point cloud is processed and may not match the raw pointcloud.It is unlikely that a point on the ground will be immediately behind an obstacle.There are three reasons for setting a distance margin. Therefore, the unknown are assumed to be the cells that are more than a distance margin from each obstacle point. Initialize freespace to the farthest point of each bin.Īssume that unknown is behind the obstacle, since the back of the obstacle is a blind spot. The ray trace is done by Bresenham's line algorithm. The ray trace is performed in three steps for each cell. The following figure shows each of the bins from side view. The bin contains the following information for each point In addition, the x,y information in the map coordinate is also stored for ray trace on map coordinate. First of all, obstacle and raw pointcloud as input are transformed into a polar coordinate system and divided into bin per angle_increment.Īt this time, each point belonging to each bin is stored as range data.
