环境：CentOS7
g++ (GCC) 4.8.5 0623 (Red Hat 4.8.5-16)
$ pkg-config --modversion opencv2.4.13
以下程序的编译方法相同：
$g++ main.cpp `pkg-config --cflags --libs opencv`
1.创建\分配图像内存
#include<stdlib.h>#include<stdio.h>#include<math.h>#include<cv.h>#include<highgui.h>#include<iostream>using namespace std;int main(int argc,char**argv){/**IplImage* cvCreateImage(CvSize size, int depth, int channels);size: cvSize(width,height);depth: 像素深度: IPL_DEPTH_8U, IPL_DEPTH_8S, IPL_DEPTH_16U,IPL_DEPTH_16S, IPL_DEPTH_32S, IPL_DEPTH_32F, IPL_DEPTH_64Fchannels: 像素通道数. Can be 1, 2, 3 or 4.各通道是交错排列的. 一幅彩色图像的数据排列格式如下：b0 g0 r0 b1 g1 r1 ...**//*******分配内存给一个新图像******///分配一个1channel的字节图像IplImage * img1 = cvCreateImage(cvSize(200,200), IPL_DEPTH_8U, 1);//分配一个3channel的浮点图像IplImage * img2 = cvCreateImage(cvSize(200,200), IPL_DEPTH_32F,3);//复制图像IplImage * img3 = cvCloneImage(img1);//释放图像cvReleaseImage(&img1);cvShowImage("win1",img3);cvWaitKey(0);return 0;}
2.图像读写、保存
#include<stdlib.h>#include<stdio.h>#include<math.h>#include<cv.h>#include<highgui.h>#include<iostream>using namespace std;int main(int argc,char**argv){/******图像读写******///从文件读如图像IplImage *img4 = 0;//此种方法默认强制转换为三通道彩色图像img4 = cvLoadImage("wongrgb.jpg");/*img=cvLoadImage(fileName,flag);flag>0:三通道彩色图像flag=0:单通道灰度图像flag<0:读如的通道与图片相同*///强制转换为单通道图img4 = cvLoadImage("wongrgb.jpg",0);if(!img4)printf("ERROR load Image.\n");/******保存图像******///cvSaveImage(outFileName,img);保存的格式由扩展名确定if(!cvSaveImage("wongrgb2.jpg",img4))printf("Could not save image.\n");//cvWaitKey(0);return 0;}
3.图像像素点访问与修改
#include<stdlib.h>#include<stdio.h>#include<math.h>#include<cv.h>#include<highgui.h>#include<iostream>using namespace std;//首先定义一个 c++ wrapper ‘Image’，然后基于Image定义不同类型的图像:template<class T> class Image{private:IplImage* imgp;public:Image(IplImage* img=0) {imgp=img;}~Image(){imgp=0;}void operator=(IplImage* img) {imgp=img;} inline T* operator[](const int rowIndx) {return ((T *)(imgp->imageData + rowIndx*imgp->widthStep));}};typedef struct{unsigned char b,g,r;} RgbPixel;typedef struct{float b,g,r;} RgbPixelFloat;typedef Image<RgbPixel> RgbImage;typedef Image<RgbPixelFloat> RgbImageFloat;typedef Image<unsigned char> BwImage;typedef Image<float> BwImageFloat;int main(int argc,char**argv){/*****访问图像像素******//*间接访问*///对于单通道字节型图像IplImage *img5 = cvCreateImage(cvSize(200,200),IPL_DEPTH_8U,1);CvScalar s = cvGet2D(img5,50,50);//访问第50行第50列的像素printf("intensity = %f\n",s.val[0]);s.val[0] = 111;cvSet2D(img5,50,50,s);//设定（50，50）点的像素值cvShowImage("win1",img5);cvSaveImage("a.jpg",img5);//对多通道字节型/浮点型图像IplImage *img6 = cvCreateImage(cvSize(200,200),IPL_DEPTH_32F,3);CvScalar s6 = cvGet2D(img6,50,50);printf("blue=%f, green=%f, red=%f\n",s6.val[0],s6.val[1],s6.val[2]);s6.val[0] = 111;s6.val[1] = 111;s6.val[2] = 111;cvSet2D(img6,50,50,s);cvShowImage("win2",img6);/*直接访问*///对于单通道字节型图像（效率高，但容易出错）IplImage* img7=cvCreateImage(cvSize(200,200),IPL_DEPTH_8U,1);((uchar *)(img7->imageData + 50*img7->widthStep))[40] = 255;//第50行40列cvShowImage("win3",img7);//对于多通道字节型图像:IplImage* img8=cvCreateImage(cvSize(200,200),IPL_DEPTH_8U,3);((uchar *)(img8->imageData + 50*img8->widthStep))[100*img8->nChannels + 0]=111; ((uchar *)(img8->imageData + 50*img8->widthStep))[100*img8->nChannels + 1]=112; ((uchar *)(img8->imageData + 50*img8->widthStep))[100*img8->nChannels + 2]=113;cvShowImage("win4",img8);//对于多通道浮点型图像:IplImage* img9=cvCreateImage(cvSize(200,200),IPL_DEPTH_32F,3);((float *)(img9->imageData + 100*img9->widthStep))[50*img9->nChannels + 0]=111; ((float *)(img9->imageData + 100*img9->widthStep))[50*img9->nChannels + 1]=112; ((float *)(img9->imageData + 100*img9->widthStep))[50*img9->nChannels + 2]=113;cvShowImage("win5",img9);int i, j, k;i = 50;j = 90;k = 1;/*基于指针的直接访问*///对于单通道字节型图像:IplImage* img10 = cvCreateImage(cvSize(200,200),IPL_DEPTH_8U,1);int height = img10->height;int width = img10->width;int step = img10->widthStep/sizeof(uchar);uchar* data = (uchar *)img10->imageData;data[i*step+j] = 111;cvShowImage("win6",img10);//对于多通道字节型图像:IplImage* img11 = cvCreateImage(cvSize(200,200),IPL_DEPTH_8U,1);int height11 = img11->height;int width11 = img11->width;int step11 = img11->widthStep/sizeof(uchar);uchar* data11 = (uchar *)img11->imageData;data11[i*step11+j] = 111;cvShowImage("win7",img11);//对于多通道浮点型图像:（假设图像数据采用4字节（32bit）行对齐方式）IplImage* img12 = cvCreateImage(cvSize(200,200),IPL_DEPTH_32F,1);int height12 = img12->height;int width12 = img12->width;int step12 = img12->widthStep/sizeof(float);float* data12 = (float *)img12->imageData;data12[i*step12+j] = 111;cvShowImage("win8",img12);/*基于 c++ wrapper 的直接访问: （更简单高效）：类：见程序开头*///对于单通道字节型图像:IplImage* img13=cvCreateImage(cvSize(200,200),IPL_DEPTH_8U,1);BwImage imgA(img13);imgA[i][j] = 111;cvShowImage("win9",img13);//对于多通道字节型图像:IplImage* img14=cvCreateImage(cvSize(200,200),IPL_DEPTH_8U,3);RgbImage imgA14(img14);imgA14[i][j].b = 111;imgA14[i][j].g = 111;imgA14[i][j].r = 111;cvShowImage("win10",img14);//对于多通道浮点型图像:IplImage* img15=cvCreateImage(cvSize(200,200),IPL_DEPTH_32F,3);RgbImageFloat imgA15(img15);imgA15[i][j].b = 111;imgA15[i][j].g = 111;imgA15[i][j].r = 111;cvShowImage("win11",img15);cvWaitKey(0);return 0;}
代码来源：《OpenCV中文参考手册》
