如何查找圖像中矩形的角點座標

Question

在對原始圖像進行預處理後，我得到了該圖像。現在，我的問題是如何獲得矩形（最大）的四角的座標。對不起，如果這是如此noob問題。

更新：由於我跟OpenCV的開發，結束了使用this answer

Answer 1

一個簡單的方法是：

1. 找到所有連接組件
2. 計算的凸包對於每個組件
3. 選擇凸包最大的組件區域
4. 簡化凸包多邊形
5. 簡化多邊形的頂點是你要找的

快速&髒數學解決方案要點：

(* find all connected components, calculate the convex hull for each component *) 
convexHulls = ComponentMeasurements[ColorNegate[Binarize[src]], {"ConvexArea", "ConvexVertices"}]; 

(* pick the component where the convex hull has the largest area *) 
vertices = SortBy[convexHulls[[All, 2]], First][[-1, 2]] 

(* simplify the convex hull polygon, by iteratively removing the vertex with the lowest distance to the line through the vertex before and after it *) 
distanceToNeighbors[vertices_] := MapThread[Abs[(#1 - #2).Cross[#1 - #3]/Norm[#1 - #3]]&, RotateLeft[vertices, #] & /@ {-1, 0, 1}] 
removeVertexWithLowestDistance[vertices_] := With[{removeIndex = Ordering[distanceToNeighbors[vertices], 1]}, Drop[vertices, removeIndex]] 
verticesSimplified = NestWhile[removeVertexWithLowestDistance, vertices, Min[distanceToNeighbors[#]] < 10&] 

(* the vertices of the simplified polygon are the points you're looking for *) 
Show[src, Graphics[ 
    { 
    {EdgeForm[Red], Transparent, Polygon[verticesSimplified]}, 
    {Red, PointSize[Large], Point[verticesSimplified]} 
    }]]