opencv提取截获图像（总结摘来）

快来打我* 2021-11-15 12:08 725阅读 0赞

**截取**

Rect rect(10, 20, 100, 50);

Mat image\_roi = image(rect);

**分割/聚合颜色平面**

split( );

merge( );

**案例一、得到由矩形提取到的图像**

*第一步，把截取图像中需要的区域存入矩阵。*

CvMat\* cvGetSubRect(const CvArr\* arr, CvMat\* submat, CvRect rect);

把IplImage \*传给arr，IplImage \*指向所要截取的图像；

把CvMat \*传给submat；

rect是要截取的区域；

返回指向所存矩阵。  
例如：  
CvMat \*pMat = cvCreateMatHeader(100, 100, CV\_8UC1); //创建一个100\*100的矩阵头  
CvRect rect = cvRect(0, 0, 100, 100); //要截取的区域，与创建的矩阵大小一样  
cvGetSubRect(pImg, pMat, rect); //pImg为指向图像的指针，pMat指向存储所接图像的矩阵，返回值和pMat相等  
也可以简化为：  
CvMat \*pMat = cvGetSubRect(pImg, cvCreateMatHeader(100, 100, CV\_8UC1), cvRect(0, 0, 100, 100));  
  
*第二步，把刚才存入矩阵的数据转存为图像。*

IplImage\* cvGetImage( const CvArr\* arr, IplImage\* image\_header );

把CvMat \*传给arr；image\_header;

只需为图像头就行，不用分配数据存储空间 ；

返回所存图像的指针。  
例如：  
IplImage \*pSubImg = cvCreateImageHeader(cvSize(100, 100), 8, 1); //创建一个100\*100的图像头  
cvGetImage(pMat, pSubImg); //pMat为存储数据的矩阵，pSubImg指向图像，返回值与pSubImg相等  
也可以简化为：  
IplImage \*pSubImg = cvGetImage(pMat, cvCreateImageHeader(cvSize(100, 100), 8, 1));

**案例二、得到任意形状区域**

**第一步、在图片上画出来**

**\[cpp\]** [ view plain][view plain] [copy][view plain] [print][view plain] [?][view plain]

1.  \#include "cv.h" 
2.  \#include "highgui.h" 
3.  \#include <stdio.h> 
4.  \#include <stdlib.h> 
5.  
6.  IplImage\* inpaint\_mask = 0;
7.  IplImage\* img0 = 0, \*img = 0, \*inpainted = 0;
8.  CvPoint prev\_pt = \{-1,-1\};
9.  
10. void on\_mouse( int event, int x, int y, int flags, void\* zhang)
11. \{
12. if( !img )
13. return;
14. if( event == CV\_EVENT\_LBUTTONUP || !(flags & CV\_EVENT\_FLAG\_LBUTTON) )
15. prev\_pt = cvPoint(-1,-1);//初始化 
16. else if( event == CV\_EVENT\_LBUTTONDOWN )
17. prev\_pt = cvPoint(x,y);
18. else if( event == CV\_EVENT\_MOUSEMOVE && (flags & CV\_EVENT\_FLAG\_LBUTTON) )
19. \{ //手一直在绘画 
20. CvPoint pt = cvPoint(x,y);
21. if( prev\_pt.x < 0 )
22. prev\_pt = pt;
23. cvLine( inpaint\_mask, prev\_pt, pt, cvScalarAll(255), 5, 8, 0 );
24. cvLine( img, prev\_pt, pt, cvScalarAll(255), 5, 8, 0 );
25. prev\_pt = pt;
26. cvShowImage( "image", img );
27. \}
28. \}
29. 
30. int main( int argc, char\*\* argv )
31. \{
32. char\* filename = argc >= 2 ? argv\[1\] : (char\*)"fruits.jpg";
33. if( (img0 = cvLoadImage(filename,-1)) == 0 )
34. return 0;
35. printf( "Hot keys: \\n"
36. cvNamedWindow( "image", 1 );
37. img = cvCloneImage( img0 );
38. inpainted = cvCloneImage( img0 );
39. inpaint\_mask = cvCreateImage( cvGetSize(img), 8, 1 );
40. cvZero( inpaint\_mask );
41. cvZero( inpainted );
42. cvShowImage( "image", img );
43. cvShowImage( "watershed transform", inpainted );
44. cvSetMouseCallback( "image", on\_mouse, 0 );
45. \}

#include "cv.h"
    #include "highgui.h"
    #include <stdio.h>
    #include <stdlib.h>
    
    IplImage* inpaint_mask = 0;
    IplImage* img0 = 0, *img = 0, *inpainted = 0;
    CvPoint prev_pt = {-1,-1};
    
    void on_mouse( int event, int x, int y, int flags, void* zhang)
    {
      if( !img )
       return;
      if( event == CV_EVENT_LBUTTONUP || !(flags & CV_EVENT_FLAG_LBUTTON) )
        prev_pt = cvPoint(-1,-1);//初始化
      else if( event == CV_EVENT_LBUTTONDOWN )
        prev_pt = cvPoint(x,y);
      else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON) )
      {//手一直在绘画
        CvPoint pt = cvPoint(x,y);
        if( prev_pt.x < 0 )
        prev_pt = pt;
        cvLine( inpaint_mask, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
        cvLine( img, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
        prev_pt = pt;
        cvShowImage( "image", img );
      }
    }
    
    int main( int argc, char** argv )
    {
       char* filename = argc >= 2 ? argv[1] : (char*)"fruits.jpg";
       if( (img0 = cvLoadImage(filename,-1)) == 0 )
         return 0;
       printf( "Hot keys: \n"
       cvNamedWindow( "image", 1 );
       img = cvCloneImage( img0 );
       inpainted = cvCloneImage( img0 );
       inpaint_mask = cvCreateImage( cvGetSize(img), 8, 1 );
       cvZero( inpaint_mask );
       cvZero( inpainted );
       cvShowImage( "image", img );
       cvShowImage( "watershed transform", inpainted );
       cvSetMouseCallback( "image", on_mouse, 0 );   
    }

![0_1330496677cpCG.gif][]

第二步、将选择的区域提取出来

**\[cpp\]** [ view plain][view plain] [copy][view plain] [print][view plain] [?][view plain]

1.  if(event == CV\_EVENT\_RBUTTONUP)
2.  \{
3.  cvFloodFill(maskImg,cvPoint(x,y),cvScalarAll(255));
4.  cvSaveImage("maskImg.bmp",maskImg);
5.  IplImage \*segImage=cvCreateImage(cvGetSize(img),8,3);;
6.  cvCopy(img,segImage,maskImg);
7.  cvSaveImage("segImage.bmp",segImage);
8.  cvCopy(segImage,proc->img);
9.  cvReleaseImage(&segImage);
10. cvDestroyWindow("Key Image");
11. \}

if(event == CV_EVENT_RBUTTONUP)
        {
            cvFloodFill(maskImg,cvPoint(x,y),cvScalarAll(255));
            cvSaveImage("maskImg.bmp",maskImg);
            IplImage *segImage=cvCreateImage(cvGetSize(img),8,3);;
            cvCopy(img,segImage,maskImg);
            cvSaveImage("segImage.bmp",segImage);
            cvCopy(segImage,proc->img);
            cvReleaseImage(&segImage);
            cvDestroyWindow("Key Image");
        }

![0_1330496781n18N.gif][]

[view plain]: http://blog.csdn.net/wuxiaoyao12/article/details/7305865#
[0_1330496677cpCG.gif]: /images/20211115/2d26c22aedbc498789a7cc70e1ef0e33.png
[0_1330496781n18N.gif]: /images/20211115/7c65ab8284be4cac9d716198e9e1ceaa.png