OpenCV實現(xiàn)鼠標在圖像上框選單目標和多目標

更新時間：2019年08月10日 10:44:30 作者：yanglong890124

這篇文章主要為大家詳細介紹了OpenCV實現(xiàn)鼠標在圖像上框選單目標和多目標，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文實例為大家分享了OpenCV實現(xiàn)鼠標框選并顯示框選區(qū)域的具體代碼，供大家參考，具體內(nèi)容如下

鼠標在圖像上框選目標：

1. 用到鼠標回調(diào)函數(shù)

2. 回調(diào)函數(shù)里面分三部分

(1)鼠標按下左鍵

(2)鼠標按下的同時移動左鍵

(3)鼠標左鍵彈起

3. 圖像顯示的刷新

單目標：

#include <cv.h>
#include <highgui.h>
#include <stdio.h>
 
IplImage* src = 0; 
IplImage* tmp = 0; 
void on_mouse( int event, int x, int y, int flags, void* ustc)
{
 static CvPoint pre_pt = {-1,-1};
 static CvPoint cur_pt = {-1,-1};
 CvFont font;
 cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, 0.5, 0.5, 0, 1, CV_AA);//初始化字體
 char temp[16];
 
 if( (event == CV_EVENT_LBUTTONDOWN)&&(flags) )//鼠標左鍵按下時
 {
 sprintf(temp,"(%d,%d)",x,y);//格式化字符串
 pre_pt = cvPoint(x,y);//獲取當前點坐標值
 cvPutText(src,temp, pre_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvCircle( src, pre_pt, 2,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );//在圖像上畫圓
 cvShowImage( "src", src );
 //cvCopy(src,tmp);//這句有沒有，就是單目標和多目標的問題 
 }
 else if( (event == CV_EVENT_MOUSEMOVE) && (flags & CV_EVENT_LBUTTONDOWN))
 {//鼠標移動并且鼠標左鍵按下
 sprintf(temp,"(%d,%d)",x,y);//格式化字符串
 cur_pt = cvPoint(x,y);//獲取當前點坐標值 
 cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvRectangle(src, pre_pt, cur_pt, cvScalar(0,255,0,0), 2, 8, 0 );//在圖像上畫矩形
 cvShowImage( "src", src );
 cvCopy(tmp,src);//將img復制到臨時圖像tmp上，用于實時顯示
 }
 else if( event == CV_EVENT_LBUTTONUP )
 {//鼠標左鍵彈起
 sprintf(temp,"(%d,%d)",x,y);//字體格式化
 cur_pt = cvPoint(x,y);//獲取當前點坐標值 
 cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvCircle( src, cur_pt, 2,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );//在圖像上畫圓
 cvRectangle( src, pre_pt, cur_pt, cvScalar(0,255,0,0), 2, 8, 0 );//在圖像上畫矩形
 cvShowImage( "src", src );
 }
}
int main()
{
 src=cvLoadImage("lena.jpg",1);//讀入圖像
 tmp=cvCloneImage(src);//復制圖像到臨時圖像上
 cvNamedWindow("src",1);//新建窗口
 cvSetMouseCallback( "src", on_mouse, 0 );//注冊鼠標響應回調(diào)函數(shù)
 
 cvShowImage("src",src);//顯示圖像
 cvWaitKey(0);//等待按鍵按下 
 cvDestroyAllWindows();//銷毀所有窗口
 cvReleaseImage(&src);//釋放圖像
 cvReleaseImage(&tmp);//釋放圖像
 return 0;
}

多目標：

#include <cv.h>
#include <highgui.h>
#include <stdio.h>
 
IplImage* src = 0; 
IplImage* tmp = 0; 
void on_mouse( int event, int x, int y, int flags, void* ustc)
{
 static CvPoint pre_pt = {-1,-1};
 static CvPoint cur_pt = {-1,-1};
 CvFont font;
 cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, 0.5, 0.5, 0, 1, CV_AA);//初始化字體
 char temp[16];
 
 if( (event == CV_EVENT_LBUTTONDOWN)&&(flags) )//鼠標左鍵按下時
 {
 sprintf(temp,"(%d,%d)",x,y);//格式化字符串
 pre_pt = cvPoint(x,y);//獲取當前點坐標值
 cvPutText(src,temp, pre_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvCircle( src, pre_pt, 2,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );//在圖像上畫圓
 cvShowImage( "src", src );
 cvCopy(src,tmp);//這句有沒有，就是單目標和多目標的問題
 }
 else if( (event == CV_EVENT_MOUSEMOVE) && (flags & CV_EVENT_LBUTTONDOWN))
 {//鼠標移動并且鼠標左鍵按下
 sprintf(temp,"(%d,%d)",x,y);//格式化字符串
 cur_pt = cvPoint(x,y);//獲取當前點坐標值 
 cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvRectangle(src, pre_pt, cur_pt, cvScalar(0,255,0,0), 2, 8, 0 );//在圖像上畫矩形
 cvShowImage( "src", src );
 cvCopy(tmp,src);//將img復制到臨時圖像tmp上，用于實時顯示
 }
 else if( event == CV_EVENT_LBUTTONUP )
 {//鼠標左鍵彈起
 sprintf(temp,"(%d,%d)",x,y);//字體格式化
 cur_pt = cvPoint(x,y);//獲取當前點坐標值 
 cvPutText(src,temp, cur_pt, &font, cvScalar(0,0, 0, 255));//在圖像是打印字符
 cvCircle( src, cur_pt, 2,cvScalar(255,0,0,0) ,CV_FILLED, CV_AA, 0 );//在圖像上畫圓
 cvRectangle( src, pre_pt, cur_pt, cvScalar(0,255,0,0), 2, 8, 0 );//在圖像上畫矩形
 cvShowImage( "src", src );
 }
}
int main()
{
 src=cvLoadImage("lena.jpg",1);//讀入圖像
 tmp=cvCloneImage(src);//復制圖像到臨時圖像上
 cvNamedWindow("src",1);//新建窗口
 cvSetMouseCallback( "src", on_mouse, 0 );//注冊鼠標響應回調(diào)函數(shù)
 
 cvShowImage("src",src);//顯示圖像
 cvWaitKey(0);//等待按鍵按下 
 cvDestroyAllWindows();//銷毀所有窗口
 cvReleaseImage(&src);//釋放圖像
 cvReleaseImage(&tmp);//釋放圖像
 return 0;
}