A Topdown Algorithm for Computation of Level Line Trees

We introduce an optimal topdown algorithm for computing and representing level line trees of 2-D intensity images. The running time of the algorithm is ${\rm O}(n + t)$, where $n$ is the size of the input image and $t$ is the total length of all level lines. The properties of level line trees are also investigated. The efficiency of the algorithm is illustrated by experiments on images of different sizes and scenes.