| 摘要 |
A method and apparatus for identifying and analysing an aircraft landing site during flight is provided and is intended for use with UAVs possibly required to make an emergency or forced landing. The method includes the steps of using image capture means such as an infrared camera to capture in-flight images of the ground in the region of a possible landing site, using a database of computer modelled images of possible aircraft landing sites mapped to a global co-ordinate reference frame to compare the in-flight images with a modelled image of the possible landing site and optimising correspondence between the two images to obtain an in-flight image optimally mapped to the global co-ordinate reference frame possibly using a Kalman filter. From this modelled image a landing site which corresponds to the optimally mapped in-flight image is analysed to ascertain the presence of any obstructions such as life forms, vehicles or newly erected buildings thereon. The analysis may involve the use of pixel intensity thresholding, convex hull calculation and back projection to determine the area of the obstruction. A number of time varying in-flight images may also be taken to determine the relative frequency of a detected obstruction and consequent probability of the obstruction being present on the landing site. The terrain characteristics/presence of obstructions may also be determined by obtaining a measure of randomness of spatial information present in the in-flight image based on a statistical measure of said randomness estimated based on intensity estimated from a grey-level histogram. |
