【转载】opencv2 一个窗口显示多幅图片（windows7和bunutu系统）

1.ubuntu系统
【摘自】http://blog.csdn.net/csd_ct/article/details/51686100
opencv 版本:2.4.12

操作系统:ubuntu 16.04
编辑器:atom 1.8

为了将源图像和结果图像数据对比，常常要将多幅图片在一个窗口中显示。方法是首先声明一个大的Mat 作为最后显示的窗口，然后在这个大Mat中提取ＲＯＩ，然后将原图和结果图拷贝到这两个ROI中。这里用到的函数是Rect 提取ROI区域，然后CopyTo　拷贝原图到ROI区域。源代码如下:

#include <iostream>  #include <opencv2/opencv.hpp>  using namespace std;  using namespace cv;  void mergeImg(Mat & dst,Mat &src1,Mat &src2)  {      int rows = src1.rows+5+src2.rows;      int cols = src1.cols+5+src2.cols;      CV_Assert(src1.type () == src2.type ());      dst.create (rows,cols,src1.type ());      src1.copyTo (dst(Rect(0,0,src1.cols,src1.rows)));      src2.copyTo (dst(Rect(src1.cols+5,0,src2.cols,src2.rows)));  }  int main(int argc, char *argv[])  {      Mat src1 = imread("/home/ct/Pictures/cat.jpg");      Mat src2 = imread("/home/ct/Pictures/cat.jpg");      Mat outImg;      mergeImg (outImg,src1,src2);      imshow("img",outImg);      waitKey();      return 0;  }

2.windows7系统
【摘自】http://blog.csdn.net/Augusdi/article/details/9019473
这个以前的时候，采取的是把要显示的图片copy到一张大图片上去~ 这个也忒麻烦了点

然后 在 http://download.csdn.net/detail/zhazhiqiang2010/3614993#comment 这里发现一个好用的代码。。。。

感谢上传者，记录在这里只为了以后方便使用~~~

#include <cv.h>  #include <highgui.h>  #include <stdio.h>  #include <stdarg.h>  #include <time.h>  #include <iostream>  #pragma comment(lib, "cv.lib")  #pragma comment(lib, "cxcore.lib")  #pragma comment(lib, "highgui.lib")  void cvShowManyImages(char* title, int nArgs, ...)   {      // img - Used for getting the arguments       IplImage *img;      // DispImage - the image in which input images are to be copied      IplImage *DispImage;      int size;      int i;      int m, n;      int x, y;      // w - Maximum number of images in a row       // h - Maximum number of images in a column       int w, h;      // scale - How much we have to resize the image      float scale;      int max;      // If the number of arguments is lesser than 0 or greater than 12      // return without displaying       if(nArgs <= 0)      {          printf("Number of arguments too small....\n");          return;      }      else if(nArgs > 12)      {          printf("Number of arguments too large....\n");          return;      }      // Determine the size of the image, and the number of rows/cols  from number of arguments       else if (nArgs == 1)      {          w = h = 1;          size = 300;      }      else if (nArgs == 2)      {          w = 2; h = 1;          size = 300;      }      else if (nArgs == 3 || nArgs == 4)      {          w = 2; h = 2;          size = 300;      }      else if (nArgs == 5 || nArgs == 6) {          w = 3; h = 2;          size = 200;      }      else if (nArgs == 7 || nArgs == 8)      {          w = 4; h = 2;          size = 200;      }      else      {          w = 4; h = 3;          size = 150;      }      // Create a new 3 channel image0      DispImage = cvCreateImage( cvSize( 100+ size*w, 60 + size*h), 8, 3 );      // Used to get the arguments passed      va_list args;      va_start(args, nArgs);      // Loop for nArgs number of arguments      for (i = 0, m = 20, n = 20; i < nArgs; i++, m += (20 + size))       {          // Get the Pointer to the IplImage          img = va_arg(args, IplImage*);          // Check whether it is NULL or not          // If it is NULL, release the image, and return          if(img == 0)          {              printf("Invalid arguments");              cvReleaseImage(&DispImage);              return;          }          // Find the width and height of the image          x = img->width;          y = img->height;          // Find whether height or width is greater in order to resize the image          max = (x > y)? x: y;          // Find the scaling factor to resize the image          scale = (float) ( (float) max / size );          // Used to Align the images          if( i % w == 0 && m!= 20)          {              m = 20;              n+= 0 + size;          }          // Set the image ROI to display the current image          //cvSetImageROI(DispImage, cvRect(m, n, (int)( x/scale ), (int)( y/scale )));          cvSetImageROI(DispImage, cvRect(m, n, (int)( x/scale ), (int)( y/scale )));          //      cout<<"x="<<m<<"y="<<n<<endl;          // Resize the input image and copy the it to the Single Big Image          cvResize(img, DispImage);          // Reset the ROI in order to display the next image          cvResetImageROI(DispImage);      }      // Create a new window, and show the Single Big Image      //cvNamedWindow( title, 1 );      cvShowImage( title, DispImage);      /*cvWaitKey(0);*/      //cvDestroyWindow(title);      // End the number of arguments      va_end(args);      // Release the Image Memory      cvReleaseImage(&DispImage);  }  int main(int argc,char **argv)   {      /*   CvCapture *capture;*/      int i=0;      IplImage *frame=cvLoadImage(".\\test.png");      cvNamedWindow("video",1);      cvResizeWindow("video",700,660);      IplImage *frame_not=cvCreateImage(cvGetSize(frame),frame->depth,frame->nChannels);      cvNot(frame,frame_not);      IplImage *frame_gray=cvCreateImage(cvGetSize(frame),frame->depth,1);      IplImage *frame1=cvCreateImage(cvGetSize(frame),frame->depth,frame->nChannels);      IplImage *frame_canny=cvCreateImage(cvGetSize(frame),frame->depth,1);      IplImage *frame2=cvCreateImage(cvGetSize(frame),frame->depth,frame->nChannels);      cvCvtColor(frame,frame_gray,CV_RGB2GRAY);      cvCvtColor(frame_gray,frame1,CV_GRAY2BGR);      cvCanny(frame_gray,frame_canny,20,75,3);      cvCvtColor(frame_canny,frame2,CV_GRAY2BGR);      cvShowManyImages("video",4,frame,frame_not,frame1,frame2);      cvWaitKey();      cvReleaseImage(&frame_not);      cvReleaseImage(&frame1);      cvReleaseImage(&frame_gray);      cvReleaseImage(&frame2);      cvReleaseImage(&frame_canny);      cvDestroyWindow("video");      return 0;  } 

【Note：】

注意 这个函数显示的图像是 nChannels = 3 的。
你看见 cvShowManyImages 函数中的

// Create a new 3 channel image0DispImage = cvCreateImage( cvSize( 100+ size*w, 60 + size*h), 8, 3 );

了么~吼吼， 如果想要 显示 单通道 的，把 3 改为 1 就OK了
【起初我 cvLoadImage( “tutu”); 读入了之前

【cvLoadImage( ,0) 读入了一张图像，然后用 cvSaveImage(); 保存图像】

得到的一张图像

】 这样是可以显示的。 然后就误导了我以为 可以显示灰度图。。。。。。

后来，发现 cvLoadImage( ,0) 读入的 灰度图 老是 出错。。。。。。

后来发现 【cvLoadImage( ,0) 读入了一张图像，然后用 cvSaveImage(); 保存图像】 之后的图像 nChanels = 3 ！

才发现：

cvSaveImage（）保存的 图像只能为深度为8U的1通道或者3通道(RGB)的图像。

也就是说 nChanels = 3 ， R=G=B 的 3 通道的 灰度图

总之，函数只显示 通道为3 的 图像！

=========================================================================================================================================

从文件中读入一幅图像可以使用imread函数来读取图像，
Mat img=imread(filename);
该语句将filename所指定路径的指定文件读取到img数组中，该函数读取的是默认的三通道图像，读取的顺序默认情况下是BGR顺序，如果想得到单通道（灰度级的）图像，则可以使用下面的方式：
Mat img=imread(filename,0);
另一个版本：【摘自】http://blog.csdn.net/yang_xian521/article/details/7915396

/************************************************************************ * Copyright(c) 2012  Yang Xian * All rights reserved. * * File: showManyImage.cpp * Brief:  * Version: 1.0 * Author: Yang Xian * Email: [e-mail] * Date: 2012/08/28 * History: ************************************************************************/  #include"cv.h"  #include "highgui.h"  using namespace cv;  using namespace std;  void imshowMany(const std::string& _winName, const vector<Mat>& _imgs);  int main(void)  {      vector<Mat> imgs(6);      imgs[0] = imread("cm.png");      imgs[1] = imread("wr.png");      imgs[2] = imread("lina.png");      imgs[3] = imread("dr.png");      imgs[4] = imread("pom.png");      imgs[5] = imread("qop.png");      imshowMany("DOTA2_Hero", imgs);      waitKey();      return 0;  }  void imshowMany(const std::string& _winName, const vector<Mat>& _imgs)  {      int nImg = (int)_imgs.size();      Mat dispImg;      int size;      int x, y;      // w - Maximum number of images in a row       // h - Maximum number of images in a column       int w, h;      // scale - How much we have to resize the image      float scale;      int max;      if (nImg <= 0)       {          printf("Number of arguments too small....\n");          return;      }      else if (nImg > 12)      {          printf("Number of arguments too large....\n");          return;      }      else if (nImg == 1)      {          w = h = 1;          size = 300;      }      else if (nImg == 2)      {          w = 2; h = 1;          size = 300;      }      else if (nImg == 3 || nImg == 4)      {          w = 2; h = 2;          size = 300;      }      else if (nImg == 5 || nImg == 6)      {          w = 3; h = 2;          size = 200;      }      else if (nImg == 7 || nImg == 8)      {          w = 4; h = 2;          size = 200;      }      else      {          w = 4; h = 3;          size = 150;      }      dispImg.create(Size(100 + size*w, 60 + size*h), CV_8UC3);      for (int i= 0, m=20, n=20; i<nImg; i++, m+=(20+size))      {          x = _imgs[i].cols;          y = _imgs[i].rows;          max = (x > y)? x: y;          scale = (float) ( (float) max / size );          if (i%w==0 && m!=20)          {              m = 20;              n += 20+size;          }          Mat imgROI = dispImg(Rect(m, n, (int)(x/scale), (int)(y/scale)));          resize(_imgs[i], imgROI, Size((int)(x/scale), (int)(y/scale)));      }      namedWindow(_winName);      imshow(_winName, dispImg);  }

以下是整理成OpenCV 1,0后的代码版本：

/************************************************************************ * Copyright(c) 2012  Yang Xian * All rights reserved. * * File: showManyImage.cpp * Brief:  * Version: 1.0 * Author: Yang Xian * Email: [e-mail] * Date: 2012/08/28 * History: ************************************************************************/  #include <cv.h>  #include <highgui.h>  #include <vector>  using namespace std;  #pragma comment(lib, "cv.lib")  #pragma comment(lib, "cxcore.lib")  #pragma comment(lib, "highgui.lib")  void imshowMany(const std::string& _winName, const vector<IplImage*>& _imgs);  int main(void)  {      std::vector<IplImage*> imgs(6);      imgs[0] = cvLoadImage("test.png");      imgs[1] = cvLoadImage("test.png");      imgs[2] = cvLoadImage("test.png");      imgs[3] = cvLoadImage("test.png");      imgs[4] = cvLoadImage("test.png");      imgs[5] = cvLoadImage("test.png");      imshowMany("DOTA2_Hero", imgs);      cvWaitKey();      return 0;  }  void imshowMany(const std::string& _winName, const vector<IplImage*>& _imgs)  {      int nImg = (int)_imgs.size();      IplImage* dispImg;      int size;      int x, y;      // w - Maximum number of images in a row       // h - Maximum number of images in a column       int w, h;      // scale - How much we have to resize the image      float scale;      int max;      if (nImg <= 0)       {          printf("Number of arguments too small....\n");          return;      }      else if (nImg > 12)      {          printf("Number of arguments too large....\n");          return;      }      else if (nImg == 1)      {          w = h = 1;          size = 300;      }      else if (nImg == 2)      {          w = 2; h = 1;          size = 300;      }      else if (nImg == 3 || nImg == 4)      {          w = 2; h = 2;          size = 300;      }      else if (nImg == 5 || nImg == 6)      {          w = 3; h = 2;          size = 200;      }      else if (nImg == 7 || nImg == 8)      {          w = 4; h = 2;          size = 200;      }      else      {          w = 4; h = 3;          size = 150;      }      dispImg = cvCreateImage(cvSize(100 + size*w, 60 + size*h), IPL_DEPTH_8U, 3);      for (int i= 0, m=20, n=20; i<nImg; i++, m+=(20+size))      {          x = _imgs[i]->height;          y = _imgs[i]->width;          max = (x > y)? x: y;          scale = (float) ( (float) max / size );          if (i%w==0 && m!=20)          {              m = 20;              n += 20+size;          }          cvSetImageROI(dispImg,cvRect(m, n, (int)(x/scale), (int)(y/scale)));          cvResize(_imgs[i], dispImg);          cvResetImageROI(dispImg);      }      cvNamedWindow(_winName.c_str());      cvShowImage(_winName.c_str(), dispImg);  }