如何在图像中找到矩形的角落坐标

Question

如何在图像中找到矩形的角落坐标

image-processing

3

我通过对原始图像进行预处理得到了这张图片。现在我的问题是如何获得矩形（最大）的四个角点的坐标。如果这是一些初学者的问题，那我很抱歉。

enter image description here

更新：由于我正在使用OpenCV进行开发，所以最终使用这个答案

- Tae-Sung Shin

1个回答

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- Niki · Accepted Answer

一个简单的方法是：

找到所有连通组件
为每个组件计算凸包
选择凸包面积最大的组件
化简凸包多边形
化简后的多边形顶点即为所需点

快速且简便的Mathematica解决方案:

(* 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]}
   }]]

Result