【opencv六】利用opencv做边缘提取，并展示像素级操作

Bertha 。 2022-04-03 10:52 211阅读 0赞

利用opencv做一些计算机视觉的操作。实现的功能就是将彩色图片变成灰白的，并对灰度图片作边缘化提取操作。下图展示的是灰度图和边缘图。

#include "opencv2/highgui/highgui.hpp"
    #include "opencv2/imgproc/imgproc.hpp"
    
    using namespace cv;
    
    int main()
    {
    	Mat img_rgb, img_gry, img_cny;
    
    	namedWindow("Example Gray",WINDOW_AUTOSIZE);
    	namedWindow("Example Canny",WINDOW_AUTOSIZE);
    
    	img_rgb = imread("H:\\vs2017\\opencv_learning\\ConsoleApplication1\\img.jpg");
    	
    	cvtColor(img_rgb,img_gry,COLOR_BGR2GRAY);
    	imshow("Example Gray",img_gry);
    
    	Canny(img_gry,img_cny,10,100,3,true);
    	imshow("Example Canny",img_cny);
    
    
    
    	waitKey(0);
    
    	return 0;
    
    }

![aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy81NTI5OTk3LTY3NWI1YTFlYjdhYTEwNDQucG5n][]

--------------------

对图片的某一个像素进行读取，并修改该像素值。下边代码展示的是对衣服全灰的图，在某一个像素位置使其变成一个小白点。

#include "opencv2/highgui/highgui.hpp"
    #include "opencv2/imgproc/imgproc.hpp"
    #include <iostream>
    using namespace cv;
    
    int main()
    {
    	Mat img_rgb, img_gry, img_cny;
    
    	namedWindow("Example Gray",WINDOW_AUTOSIZE);
    	namedWindow("Example Canny",WINDOW_AUTOSIZE);
    
    	img_rgb = imread("H:\\vs2017\\opencv_learning\\ConsoleApplication1\\img.png");
    	
    	cvtColor(img_rgb,img_gry,COLOR_BGR2GRAY);
    	int x = 16, y = 32;
    	Vec3b intensity = img_rgb.at< Vec3b >(y, x);
    	// ( Note: We could write img_rgb.at< cv::Vec3b >(x,y)[0] )
    	//
    	uchar blue = intensity[0];
    	uchar green = intensity[1];
    	uchar red = intensity[2];
    
    	std::cout << "At (x,y) = (" << x << ", " << y <<
    		"): (blue, green, red) = (" <<
    		(unsigned int)blue <<
    		", " << (unsigned int)green << ", " <<
    		(unsigned int)red << ")" << std::endl;
    
    
    	std::cout << "Gray pixel there is: " <<
    		(unsigned int)img_gry.at<uchar>(y, x) << std::endl;
    
    	img_gry.at<uchar>(x, y) = 255; // Set the gray pixel
    
    	imshow("Example Gray",img_gry);
    
    	Canny(img_gry,img_cny,10,100,3,true);
    	imshow("Example Canny",img_cny);
    
    	waitKey(0);
    
    	getchar();
    	return 0;
    
    }

![aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy81NTI5OTk3LTk1MDA4OGRmMDVjYjQ4YjkucG5n][]

![aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy81NTI5OTk3LTFkMDllYjk0Y2E2ZTFjYTQucG5n][]

[aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy81NTI5OTk3LTY3NWI1YTFlYjdhYTEwNDQucG5n]: /images/20220403/de005b919fa34dcd8f4d085b67c95232.png
[aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy81NTI5OTk3LTk1MDA4OGRmMDVjYjQ4YjkucG5n]: /images/20220403/e870b65ca1024ac9935d4f1c54cab3f4.png
[aHR0cHM6Ly91cGxvYWQtaW1hZ2VzLmppYW5zaHUuaW8vdXBsb2FkX2ltYWdlcy81NTI5OTk3LTFkMDllYjk0Y2E2ZTFjYTQucG5n]: /images/20220403/c2db7f8c8419475b80eed0bc1e91c1ad.png