C# - Opencv应用（3） 之矩阵Mat使用[图像截取粘贴、ROI操作、位运算、数学计算]

• 图像读取，大小、截取、位运算
• 图像ROI操作：粘贴+赋值、滤波
• 图像数学计算
• 部分结果如下：
  

1.图像读取，大小、截取、位运算

        //图像显示private static void showImg(string w_name,Mat img,int flg=0){Cv2.NamedWindow(w_name, 0);Cv2.ImShow(w_name, img);Cv2.WaitKey(flg);}private static void SubMat(){var src = Cv2.ImRead("./images/Lenna.png");if(src.Empty()){Console.WriteLine("请检查图像输入！\n");}else{Console.WriteLine("读取图像大小：[" + src.Rows + "," + src.Cols + "]");}showImg("src", src);// Assign small image to matvar small = new Mat();Cv2.Resize(src, small, new Size(100, 100));src[10, 110, 10, 110] = small;showImg("src1", src);src[370, 470, 400, 500] = small.T();showImg("src2", src);// ↑ This is same as the following://small.T().CopyTo(src[370, 470, 400, 500]);// Get partial mat (similar to cvSetImageROI)Mat part = src[200, 400, 200, 360];// Invert partial pixel valuesCv2.BitwiseNot(part, part);// Fill the region (50..100, 100..150) with color (128, 0, 0)part = src.SubMat(50, 100, 400, 450);part.SetTo(128);using (new Window("SubMat", src)){Cv2.WaitKey();}part.Dispose();}

2. 图像ROI操作：粘贴+赋值、滤波

• 针对不同范围的区域即ROI进行不同的操作，根本上是像素/灰度值的改变

        //图像行列中的某些范围做操作private void RowColRangeOperation(){using var src = Cv2.ImRead(ImagePath.Lenna);Cv2.GaussianBlur(src.RowRange(100, 200),src.RowRange(200, 300),new Size(7, 7), 20);Cv2.GaussianBlur(src.ColRange(200, 300),src.ColRange(100, 200),new Size(7, 7), 20);using (new Window("RowColRangeOperation", src)){Cv2.WaitKey();}}/// <summary>/// Submatrix expression operations/// </summary>private void RowColOperation(){using var src = Cv2.ImRead(ImagePath.Lenna);var rand = new Random();for (int i = 0; i < 200; i++){int c1 = rand.Next(100, 400);int c2 = rand.Next(100, 400);using Mat temp = src.Row(c1).Clone();src.Row(c2).CopyTo(src.Row(c1));temp.CopyTo(src.Row(c2));}((Mat)~src.ColRange(450, 500)).CopyTo(src.ColRange(0, 50));src.RowRange(450, 460).SetTo(new Scalar(0, 0, 255));using (new Window("RowColOperation", src)){Cv2.WaitKey();}}

3.图像数学计算

• 通过矩阵进行普通与归一化矩阵计算

//数学计算/// <summary>/// Solve equation AX = Y/// </summary>private static void ByMat(){// x + y = 10// 2x + 3y = 26// (x=4, y=6)double[,] av = {{1, 1},{2, 3}};double[] yv = { 10, 26 };var a = new Mat(2, 2, MatType.CV_64FC1, av);var y = new Mat(2, 1, MatType.CV_64FC1, yv);var x = new Mat();Cv2.Solve(a, y, x, DecompTypes.LU);Console.WriteLine("ByMat:");Console.WriteLine("X1 = {0}, X2 = {1}", x.At<double>(0), x.At<double>(1));}/// <summary>/// Solve equation AX = Y/// </summary>private static void ByNormalArray(){// x + y = 10// 2x + 3y = 26// (x=4, y=6)double[,] a = {{1, 1},{2, 3}};double[] y = { 10, 26 };var x = new System.Collections.Generic.List<double>();Cv2.Solve(InputArray.Create(a), InputArray.Create(y),OutputArray.Create(x),DecompTypes.LU);Console.WriteLine("ByNormalArray:");Console.WriteLine("X1 = {0}, X2 = {1}", x[0], x[1]);}

完整代码

• 主要代码结构如下：

using System;
using OpenCvSharp;namespace SamplesCore
{/// <summary>/// /// </summary>class MatOperations{static void Main(string[] args){ByMat();ByNormalArray();SubMat();RowColRangeOperation();RowColOperation();return;}//函数定义。。。。。。}
}