Free Space Estimation

A free space determination module and method for estimating free space in an occupancy grid. The free space estimation unit comprises a memory configured to store object detection data relating to one or more object detections by an object detection system; and a controller configured to: obtain one or more object detections in a field of view of the object detection system 5.1; divide the field of view of the object detection system into multiple segments 5.2; select an object detection of the object detection system in each of the multiple segments of the field of view containing an object detection 5.3; use locations of the selected object detections to plot a polygon representing a free space envelope 5.4; and designate cells of an occupancy grid as representing free space by applying a triangle rasterization algorithm to the polygon representing the free space envelope 5.5. The controller preferably selects the object detection determined to be closest to the sensor in each of the segments of the field of view containing an object detection. Determining that no object detections are present in a segment of the field of view if no objects are detected within a threshold distance of a sensor.