Method and apparatus for generating an orthorectified tile

摘要

A method is disclosed for generating an orthorectified tile. In at least one embodiment, the method includes retrieving source images obtained by way of a terrestrial based camera; retrieving position data associated with the source images; retrieving orientation data associated with the source images; and converting source image by means of corresponding position data and orientation data to obtain the orthorectified tile. Orthorectified tiles are used to generate an orthorectified mosaic. As such, images recorded by terrestrial based camera may be used to generate a map of a road surface with corresponding road signs.

主权项

1. Method for generating a geo-positioned orthorectified tile, comprising:
retrieving a sequence of source images obtained at different times by a terrestrial based camera mounted on a moving vehicle when driving across a road surface; retrieving position data associated with each of the retrieved source images and representative of the position of the vehicle in a geographic coordinate reference system, wherein the position data includes constant position parameters defining the position of the camera with respect to a reference position within the vehicle and variable position parameters defining the position of the vehicle's reference position in said geographical coordinate reference system; retrieving orientation data associated with each of the retrieved source images and representative of the orientation of the vehicle within the geographic coordinate reference system, wherein the orientation data includes constant orientation parameters defining the orientation of the camera with respect to a reference orientation of the vehicle and variable orientation parameters defining the orientation of the vehicle's reference orientation in said geographic coordinate reference system; using the position and orientation data associated with the retrieved source images to determine the position and orientation of the road surface below the vehicle at the time each source image is obtained; estimating the plane of the road surface seen in a first source image using the position and orientation of the road surface below the vehicle determined from a second source image in which the vehicle is positioned over the road surface seen in the first image; and converting the first source image using the estimated plane of the road surface seen in the first source image and an angle defined by a difference in elevation between two sides of the road surface with respect to a horizontal plane to obtain the geo-positioned orthorectified tile and corresponding metadata defining a conversion of pixel coordinates in the geo-positioned orthorectified tile to a position in the geographic coordinate reference system.