| 摘要 |
The invention relates to a method and a device for extracting contours from sonar images u 0 using the level-set-function &phis; n (x,y) both for areas in the sonar image designated as highlight and areas designated as shadow. While the highlight develops by means of iteration of the level-set-function for the highlight according to the equation &phis; n+1 (x,y) = &phis; n (x,y) + Deltat s (K(x,y) - d i (x,y) + d o (x,y)), the level-set-function for the shadow iterates according to the equation &phis; n+1 (x,y) = &phis; n (x,y) + Deltat s (K(x,y) - f s - d i (x,y) + d o (x,y)). The two equations differ by the term, formula (I), which decreases with the number of iteration steps t and causes shadow contours to be elaborated during the following iteration steps. |
