对于四种未修补裂缝分类问题，研究它们在方向以及分布密度上的差异性来进行裂缝类型
的划分。(For　the　problem of unrepaired crack classification, we use the differences of them on the crack　direction　and　the　distribution　for　crack　classification.　Using　2D　feature　mapping,　Delaunay　triangular　subdivision　and　other　methods,　we　will　calculate　some　relevant　characteristic　parameters　of　these　features　to　characterize　differences　of　the　crack　to　achieve　the　purpose　of　classification.)