The invention provides a self-adaptive valley and
ridge line extraction method and
system based on a
scale space. The self-adaptive valley
ridge line extraction method comprises the following steps: firstly, carrying out
oversampling on an original DEM (
Digital Elevation Model) to serve as processed initial DEM, and establishing a zeroth group of
scale space according to the initial DEM; according to a total layer number of a
pyramid, firstly selecting the DEM with a highest spatial scale in the zeroth group of
scale space as the bottom layer of the
pyramid, then, carrying out downsampling on the zeroth layer of DEM, correspondingly establishing a first group of scale space, and selecting the DEM with the highest scale as the first layer of the DEM
pyramid and so on; and starting with the top layer of the DEM pyramid to carry out self-adaptive multi-angle topographic section elevation extremum method extraction, carrying out postprocessing to obtain a
ridge line and a valley line, and finally, carrying out the layer-by-layer refining extraction of a result. Compared with the prior art, the self-adaptive valley and ridge line extraction method not only can give both consideration to the integral tendency and the detail change of ridge (valley) extraction, guarantees extraction precision, but also can quickly obtain an extraction result and guarantee extraction efficiency.