The paper introduces a method of semiautomatic extraction of linear objects from aerial images that has good interactive performance

robustness

accuracy and real time response. A linear object is extracted as a consecutive parabola between each input two seed points. First

through fast binary template matching by correlation and optimize algorithm

the initial parameters of the parabola which have eliminated the blunders caused by shadow and other noises are calculated

and then the least squares template matching is used for accurate positioning by evaluating the adjusted precise parameters of the parabola. This paper specifies the mathematical model of least square template matching and the self adaptive template generation to overcome the effects of changes of the width and contrast of the linear feature. The least squares template matching could also be seen as an optimal algorithm that integrates the image feature and geometrical constraints together and has been studied well for long terms. If the proper initial values have been given

the least square method works well and is often applied to solve the accurate positioning problem. The experimental results indicate that the method could gain high accuracy and is robust and ready to practical mapping production from aerial images.