opencv笔记

显示图像

#include"opencv2/highgui/highgui.hpp"  
  
int main()  
{  
    IplImage* img = cvLoadImage("123.jpg");  
    cvNamedWindow("Demo1",CV_WINDOW_AUTOSIZE);  
    cvShowImage("Demo1", img);  
      
    cvWaitKey(0);  
    cvReleaseImage(&img);  
    cvDestroyWindow("Demo1");

    return 0;

}

cvNamedWindow(）第一个参数指定了该窗口的标题，同时也作为该窗口的索引。第二个参数可选0或CV_WINDOW_AUTOSIZE，为0时图像根据窗口大小进行伸缩，为CV_WINDOW_AUTOSIZE时，窗口根据图片大小伸缩。

#include"opencv2/highgui/highgui.hpp"  
using namespace cv;  
  
int main()  
{  
    Mat image = imread("123.jpg");  
    imshow("Demo2", image);  
    cvWaitKey(0);  
}  


imread和cvloadimage有什么异同
OpenCV提供C接口和C++接口，功能是一样的。选用何种接口，完全取决于个人爱好。
如果你的程序是C风格的，最好选用C接口，如果是C++风格的，最好选用C++接口。
C接口的很多函数需要配对使用，比如：创建矩阵后需要释放矩阵，相对来说，代码量要大一些，一个不小心就会出现内存泄漏。

在图像上画矩形框

cvRectangle与cv::rectangle的用法cvRentangle和cv::rectangle函数原型对比：C:       void cvRectangle(CvArr* img, CvPoint pt1, CvPoint pt2, CvScalar color, int thickness=1, int line_type=8, int shift=0 )C++: void rectangle(Mat& img, Point pt1,Point pt2,const Scalar& color, int thickness=1, int lineType=8, int shift=0)C++: void rectangle(Mat& img, Rect rec, const Scalar& color, int thickness=1, int lineType=8, int shift=0 )参数介绍：img图像.pt1矩形的一个顶点。pt2矩形对角线上的另一个顶点color线条颜色 (RGB) 或亮度（灰度图像 ）(grayscale image）。thickness组成矩形的线条的粗细程度。取负值时（如 CV_FILLED）函数绘制填充了色彩的矩形。line_type线条的类型。见cvLine的描述shift坐标点的小数点位数。代码：#include <iostream>#include <opencv2\highgui\highgui.hpp>using namespace std;using namespace cv;int main(){char *imageSrc = "I:\\OpenCV Learning\\picture\\sumpalace.jpg";Mat matImage = imread(imageSrc,-1);        IplImage *iplImage = cvLoadImage(imageSrc,-1);if(matImage.data==0||iplImage->imageData ==0){cout<<"图片加载失败"<<endl;return -1;}cv::rectangle(matImage,cvPoint(20,200),cvPoint(200,300),Scalar(255,0,0),1,1,0);//Rect(int a,int b,int c,int d)a,b为矩形的左上角坐标,c,d为矩形的长和宽cv::rectangle(matImage,Rect(100,300,20,200),Scalar(0,0,255),1,1,0);cvRectangle(iplImage,cvPoint(20,200),cvPoint(200,300),Scalar(0,255,255),1,1,0);imshow("matImage",matImage);cvShowImage("IplImage",iplImage);waitKey();return 0;}

如果需要在Mat类型的图上绘制矩形，选择cv::trctangle()在IplImage*类型的图上绘制矩形，选择cvRectangle()

opencv document

OpenCV Tutorials

opencv中文网站

OpenCV基础数据结构

学习OPENCV（二）：操作像素

访问IplImage数据时的注意事项

图像处理和图像识别中常用的OpenCV函数（整理）

OpenCV学习笔记（9）利用MFC的Picture控件显示图像+播放视频和捕获摄像头画面

OpenCV中使用神经网络 CvANN_MLP

OpenCV - Mat、CvMat、IplImage类型浅析

Cximage<---->Mat 、Cximage<---->lplImage 以及 lplImage<----->Mat的转换、像素位深度

OpenCV:初试牛刀-带滚动条的视频播放-2

截取图像

#include "opencv2/imgproc/imgproc.hpp"  
#include "opencv2/highgui/highgui.hpp"  
using namespace cv;
// Define our callback which we will install for  
// mouse events.  
//  
void my_mouse_callback(
	int event, int x, int y, int flags, void* param
	);
CvRect box;
bool drawing_box = false;
bool isRectDrawn = false;

// A litte subroutine to draw a box onto an image_copy  
void draw_box(IplImage* img, CvRect rect) {
	cvRectangle(
		img,
		cvPoint(box.x, box.y),
		cvPoint(box.x + box.width, box.y + box.height),
		cvScalar(0xff, 0x00, 0x00), /* blue */
		2);
}

void draw_box_green(IplImage* img, CvRect rect) {
	cvRectangle(
		img,
		cvPoint(box.x, box.y),
		cvPoint(box.x + box.width, box.y + box.height),
		cvScalar(0x00, 0xff, 0x00), /* green */
		2);
}
// This is our mouse callback. If the user  
// presses the left button, we start a box.  
// when the user releases that button, then we  
// add the box to the current image_copy. When the  
// mouse is dragged (with the button down) we  
// resize the box.  
//  
void my_mouse_callback(int event, int x, int y, int flags, void* param)
{
	IplImage* image_copy = (IplImage*)param;
	switch (event) {
	case CV_EVENT_MOUSEMOVE:
	{
							   if (drawing_box) {
								   box.width = x - box.x;
								   box.height = y - box.y;
							   }
	}
		break;
	case CV_EVENT_LBUTTONDOWN: {
								   drawing_box = true;
								   box = cvRect(x, y, 0, 0);
	}
		break;
	case CV_EVENT_LBUTTONUP: {
								 drawing_box = false;
								 isRectDrawn = true;
								 if (box.width < 0) {
									 box.x += box.width;
									 box.width *= -1;
								 }
								 if (box.height < 0) {
									 box.y += box.height;
									 box.height *= -1;
								 }
								 draw_box(image_copy, box);
	}
		break;
	}
}






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

	box = cvRect(-1, -1, 0, 0);
	IplImage* image_input = cvLoadImage(argv[1]);
	IplImage* image = cvCloneImage(image_input);
	IplImage* image_copy = cvCloneImage(image);
	IplImage* temp = cvCloneImage(image_copy);
	cvNamedWindow(argv[1], 0);
	// Here is the crucial moment that we actually install  
	// the callback. Note that we set the value ‘param’ to  
	// be the image_copy we are working with so that the callback  
	// will have the image_copy to edit.  
	//  
	cvSetMouseCallback(
		argv[1],
		my_mouse_callback,
		(void*)image_copy
		);
	// The main program loop. Here we copy the working image_copy  
	// to the ‘temp’ image_copy, and if the user is drawing, then  
	// put the currently contemplated box onto that temp image_copy.  
	// display the temp image_copy, and wait 15ms for a keystroke,  
	// then repeat…  
	//  
	while (1) {
		//cvCopyImage( image_copy, temp );  
		cvCopy(image_copy, temp);
		if (drawing_box) draw_box(temp, box);
		cvShowImage(argv[1], temp);
		//if( cvWaitKey( 15 )==27 ) break;  
		int key = cvWaitKey(15);
		if (key == 27) break;
		if (isRectDrawn)
		{
			if (key == 's' || key == 'S')
			{
				// draw green box  
				draw_box_green(image_copy, box);
				cvCopy(image_copy, image);

				// save roi image  
				static int index = 0;
				char save_image_name[128];
				string sa = string(argv[1]);
				string fn=string(sa.begin()+sa.length()-10,sa.end()-4);
				
				sprintf(save_image_name, (fn+string("rect_%d.jpg")).c_str(), index++);
				cvSetImageROI(image_input, box);
				cvSaveImage(save_image_name, image_input);
				cvResetImageROI(image_input);

				isRectDrawn = false;
			}

			if (key == 'q' || key == 'Q')
			{
				cvCopy(image, image_copy);
				isRectDrawn = false;
			}
		}
	}
	// Be tidy  
	//  
	cvReleaseImage(&image_copy);
	cvReleaseImage(&temp);
	cvDestroyWindow("Box Example");
}

opencv中各种矩阵乘的区别

修改opencv源码的方法