如何使用“keySelector” for“OrderBy（）”函数用于在openCV中对轮廓进行排序 [英] How to use "keySelector" for "OrderBy()"function for sorting contours in openCV

问题描述

大家好，



我需要在二进制图像中找到N个最大区域轮廓。 br />
我想尝试 OrderBy（）函数按区域排序轮廓。

但是，我无法理解 keySelector 的语法用作中的参数OrderBy（）



虽然我使用的是EmguCV，但C ++语法也很有帮助。

Hello all,

I need to find N largest area contours available in a binary image.
I wanted to try the OrderBy() function to sort the contours by Area.
However, I am unable to understand the the syntax for keySelector used as a parameter in OrderBy()

Although I am using EmguCV, but a C++ syntax will also be helpful.

Contour<Point> contours = inputImage.FindContours();
contours.Orderby( ???? ); // OrderBy(Func<Point,TKey> keySelector)

非常感谢任何帮助。

Any help is much appreciated.

推荐答案

您好。

您应该注意，在您的代码中 - 您将只获得一个轮廓。

为了您的目的，您应该握紧所有轮廓，然后命令它们。

检查此代码：

Hello.
You should notice, that in your code - you will get only one contour.
For your purpose you should fistly get all contours, and after that order them.
Check this code:

var allContours = new List<Contour<Point>>();
         for (var contours = image.FindContours(); contours != null; contours = contours.HNext)
             allContours.Add(contours);
         allContours.OrderBy(x => x.Area);       // by ascending
         allContours.OrderByDescending(x => x.Area); // by descending

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