OpenCV进行图像卷积

$$图像卷积$$

1.视频教程：
B站、网易云课堂、腾讯课堂
2.代码地址：
Gitee
Github
3.存储地址：
Google云
百度云：
提取码：

• 1.卷积
• 2.实现均值卷积
• 3.blur函数
• 4.卷积边缘填充
• 5.图像模糊
• 6.自定义滤波

1.卷积

卷积的概念最早出现在，数字信号处理，而不是图像处理。

2.实现均值卷积

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);
	int h = src.rows;
	int w = src.cols;
	Mat result = src.clone();
	for (int row = 1; row < h - 1; row++) {
		for (int col = 1; col < w - 1; col++) {
			// 3*3卷积核
			int sb = src.at<Vec3b>(row, col)[0] + src.at<Vec3b>(row - 1, col - 1)[0] + src.at<Vec3b>(row - 1, col)[0] +
				src.at<Vec3b>(row-1, col+1)[0] + src.at<Vec3b>(row, col - 1)[0] + src.at<Vec3b>(row, col+1)[0] +
				src.at<Vec3b>(row+1, col-1)[0] + src.at<Vec3b>(row+1, col)[0] + src.at<Vec3b>(row + 1, col+1)[0];

			int sg = src.at<Vec3b>(row, col)[1] + src.at<Vec3b>(row - 1, col - 1)[1] + src.at<Vec3b>(row - 1, col)[1] +
				src.at<Vec3b>(row - 1, col + 1)[1] + src.at<Vec3b>(row, col - 1)[1] + src.at<Vec3b>(row, col + 1)[1] +
				src.at<Vec3b>(row + 1, col - 1)[1] + src.at<Vec3b>(row + 1, col)[1] + src.at<Vec3b>(row + 1, col + 1)[1];

			int sr = src.at<Vec3b>(row, col)[2] + src.at<Vec3b>(row - 1, col - 1)[2] + src.at<Vec3b>(row - 1, col)[2] +
				src.at<Vec3b>(row - 1, col + 1)[2] + src.at<Vec3b>(row, col - 1)[2] + src.at<Vec3b>(row, col + 1)[2] +
				src.at<Vec3b>(row + 1, col - 1)[2] + src.at<Vec3b>(row + 1, col)[2] + src.at<Vec3b>(row + 1, col + 1)[2];

			result.at<Vec3b>(row, col)[0] = sb / 9;
			result.at<Vec3b>(row, col)[1] = sg / 9;
			result.at<Vec3b>(row, col)[2] = sr / 9;
		}
	}
	imshow("result", result);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

3.blur函数

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);
	Mat dst;
	blur(src, dst, Size(3, 3), Point(-1, -1), BORDER_DEFAULT);
	imshow("dst", dst);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);
	Mat dst;
	blur(src, dst, Size(12, 12), Point(-1, -1), BORDER_DEFAULT);
	imshow("dst", dst);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

4.卷积边缘填充

常用的边缘像素填充方法

1.constant填充
2.replicate
3.wrap
4.reflect
5.default

卷积核大小最好为奇数，让锚定点位于中心

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);

	// 边缘填充
	int border = 8;
	Mat border_m;
	copyMakeBorder(src, border_m, border, border, border, border, BORDER_DEFAULT);
	imshow("border fill", border_m);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);

	// 边缘填充
	int border = 8;
	Mat border_m;
	copyMakeBorder(src, border_m, border, border, border, border, BORDER_CONSTANT);
	imshow("border fill", border_m);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);

	// 边缘填充
	int border = 8;
	Mat border_m;
	copyMakeBorder(src, border_m, border, border, border, border, BORDER_CONSTANT,Scalar(255,0,0));
	imshow("border fill", border_m);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

5.图像模糊

5.1 高斯模糊

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);

	Mat dst;
	GaussianBlur(src, dst, Size(5, 5), 0);
	imshow("gaussina blur", dst);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

5.2 盒子模糊（均值模糊）

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);

	Mat dst;
	// 盒子模糊，即均值模糊
	boxFilter(src, dst,-1, Size(5, 5),Point(-1,-1),true,BORDER_DEFAULT);
	imshow("boxFilter blur", dst);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

上下模糊

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);

	Mat dst;
	// 盒子模糊，即均值模糊
	boxFilter(src, dst,-1, Size(1, 25),Point(-1,-1),true,BORDER_DEFAULT);
	imshow("boxFilter blur", dst);

	waitKey(0);
	destroyAllWindows();
	return 0;
}

6.自定义滤波

针对不同卷积核系数，图像输出类型数值范围
CV_32F/CV_32S
类型转换与显示支持

#include 
#include 

using namespace cv;
using namespace std;

int main(int argc, char** argv) {

	Mat src = imread("E:/cats.jpg", IMREAD_COLOR);

	if (src.empty()) {
		printf("image is empty!!!");
		return -1;
	}
	imshow("src", src);
	// 自定义滤波 - 均值卷积
	int k = 15;
	Mat mkernel = Mat::ones(k, k, CV_32F) / (float)(k*k);
	Mat dst;
	filter2D(src, dst, -1, mkernel, Point(-1, -1), 0, BORDER_DEFAULT);
	imshow("custom mean filter", dst);

	// 非均值滤波
	Mat robot = (Mat_ <int>(2, 2) << 1, 0, 0, -1);
	Mat result;
	filter2D(src, result, CV_32F, robot, Point(-1, -1), 127, BORDER_DEFAULT);
	convertScaleAbs(result, result);
	imshow("robot filter", result);
	
	waitKey(0);
	destroyAllWindows();
	return 0;
}