OpenCV选择图像中矩形区域并保存分享！

本文实例为大家分享了OpenCV选择图像中矩形区域并保存的具体代码，供大家参考，具体内容如下

根据《Learning OpenCV》中的example4.1改写:

  // An example program in which the  // user can draw boxes on the screen.  //  //#include <cv.h>  //#include <highgui.h>  #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(0x00,0x00,0xff) /* blue */   );  }     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 */   );  }     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( "Box Example" );   // 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(   "Box Example",   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( "Box Example", 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];   sprintf(save_image_name, "rect_%d.jpg", 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" );  }     // 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;   }  }

使用方法：

载入图像后，用鼠标在图像上点击确定矩形起始点，拖动鼠标画矩形，抬起鼠标键时会画出一个红色矩形区域。按下s或S键，红色矩形变成绿色，并保存这个ROI区域。如果按下q或Q键，将会取消这次选择，红色矩形框消失。可以连续选取多个区域。按ESC键退出程序。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持<计算机技术网(www.ctvol.com)!!>。

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