opencv进阶-检测使用鼠标框选的自定义区域
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API-setMouseCallback
鼠标响应处理函数
void setMousecallback(const string& winname, MouseCallback onMouse, void* userdata=0)
- winname:窗口的名字
- onMouse:鼠标响应函数，回调函数。指定窗口里每次鼠标时间发生的时候，被调用的函数指针。
这个函数的原型应该为void on_Mouse(int event, int x, int y, int flags, void* param);
onMouse的函数原型：
void on_Mouse(int event, int x, int y, int flags, void* param);
event是 CV_EVENT_*变量之一
x和y是鼠标指针在图像坐标系的坐标（不是窗口坐标系）
flags是CV_EVENT_FLAG的组合， param是用户定义的传递到setMouseCallback函数调用的参数。- userdate：传给回调函数的参数
event鼠标事件总共有10中，从0-9依次代表如下:
#define CV_EVENT_MOUSEMOVE 0 滑动
#define CV_EVENT_LBUTTONDOWN 1 左键点击
#define CV_EVENT_RBUTTONDOWN 2 右键点击
#define CV_EVENT_MBUTTONDOWN 3 中间点击
#define CV_EVENT_LBUTTONUP 4 左键释放
#define CV_EVENT_RBUTTONUP 5 右键释放
#define CV_EVENT_MBUTTONUP 6 中间释放
#define CV_EVENT_LBUTTONDBLCLK 7 左键双击
#define CV_EVENT_RBUTTONDBLCLK 8 右键双击
#define CV_EVENT_MBUTTONDBLCLK 9 中间释放
一、选区矩形区域实时显示相机视频
代码
//---------------------------------【头文件、命名空间包含部分】-----------------------------
// 描述：包含程序所使用的头文件和命名空间
//-------------------------------------------------------------------------------------------------
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace cv;
using namespace std;
//-----------------------------------【宏定义部分】--------------------------------------------
// 描述：定义一些辅助宏
//------------------------------------------------------------------------------------------------
#define WINDOW_NAME "【程序窗口】" //为窗口标题定义的宏
//-----------------------------------【全局函数声明部分】------------------------------------
// 描述：全局函数的声明
//------------------------------------------------------------------------------------------------
void on_MouseHandle(int event, int x, int y, int flags, void* param); //鼠标回调函数
//-----------------------------------【全局变量声明部分】-----------------------------------
// 描述：全局变量的声明
//-----------------------------------------------------------------------------------------------
Rect select;
bool select_flag = false, flag = true;
Point origin;
Mat org, dst, gray_image;
//-----------------------------------【main( )函数】--------------------------------------------
// 描述：控制台应用程序的入口函数，我们的程序从这里开始执行
//-------------------------------------------------------------------------------------------------
int main(int argc, char** argv)
VideoCapture capture(0);
capture >> org;
select = Rect(-1, -1, 0, 0);
namedWindow(WINDOW_NAME);//定义一个img窗口
namedWindow("dst");
setMouseCallback(WINDOW_NAME, on_MouseHandle, 0);//调用回调函数
while (1)
if (!capture.read(org)) //获取视频帧失败
cout << "Cannot read the frame from video file" << endl;
break;
resize(org, org, Size(org.cols / 2, org.rows / 2), (0, 0), (0, 0), 3);
if (flag)
flag = false;
select = Rect(10, org.rows / 6, org.cols - 20, org.rows * 3 / 4);//第一次进入循环，记录起始点
cout << select.x << "--" << select.y << "--" << select.width << "--" << select.height << endl;
rectangle(org, select, Scalar(255, 0, 0), 1, 8, 0);//能够实时显示在画矩形窗口时的痕迹
dst = org(Rect(select.x, select.y, select.width, select.height)); //将感兴趣区域复制到tmp1
//img = dst.clone();
cvtColor(dst, gray_image, COLOR_BGR2GRAY); //彩色图片转换成黑白图片
//addWeighted(dst,0.1,img,0.7,0.,dst);
select = Rect(select.x + 10, select.y + 10, select.width - 20, select.height - 20);//记录起始点
rectangle(org, select, Scalar(255, 0, 0), 1, 8, 0);//能够实时显示在画矩形窗口时的痕迹
select = Rect(select.x - 10, select.y - 10, select.width + 20, select.height + 20);//记录起始点
rectangle(gray_image, Rect(10, 10, select.width - 20, select.height - 20), Scalar(255, 0, 0), 1, 8, 0);//能够实时显示在画矩形窗口时的痕迹
cout << select.x << "--" << select.y << "--" << select.width << "--" << select.height << endl;
imshow(WINDOW_NAME, org);
imshow("dst", gray_image);
if (waitKey(10) == 27) break;//按下ESC键，程序退出
waitKey(0);
destroyAllWindows();
return 0;
//--------------------------------【on_MouseHandle( )函数】-----------------------------
// 描述：鼠标回调函数，根据不同的鼠标事件进行不同的操作
//--------------------------------------------------------------------------------------
void on_MouseHandle(int event, int x, int y, int, void* param)
//Point origin;//不能在这个地方进行定义，因为这是基于消息响应的函数，执行完后origin就释放了，所以达不到效果。
if (select_flag)
select.x = MIN(origin.x, x);//不一定要等鼠标弹起才计算矩形框，而应该在鼠标按下开始到弹起这段时间实时计算所选矩形框
select.y = MIN(origin.y, y);
select.width = abs(x - origin.x);//算矩形宽度和高度
select.height = abs(y - origin.y);
select &= Rect(0, 0, org.cols, org.rows);//保证所选矩形框在视频显示区域之内
if (event == EVENT_LBUTTONDOWN)
select_flag = true;//鼠标按下的标志赋真值
origin = Point(x, y);//保存下来单击是捕捉到的点
select = Rect(x, y, 0, 0);//这里一定要初始化，宽和高为(0,0)是因为在opencv中Rect矩形框类内的点是包含左上角那个点的，但是不含右下角那个点
else if (event == EVENT_LBUTTONUP)
select_flag = false;
二、基于SSD检测特定区域内的多种物体
#include <opencv2\\opencv.hpp>
#include <opencv2\\dnn.hpp>
#include <iostream>
using namespace cv;
using namespace cv::dnn;
using namespace std;
const size_t width = 300;
const size_t height = 300;
const float meanVal = 127.5;
const float scaleFactor = 0.007843f;
const char* classNames[] = "background",
"aeroplane", "bicycle", "bird", "boat",
"bottle", "bus", "car", "cat", "chair",
"cow", "diningtable", "dog", "horse",
"motorbike", "person", "pottedplant",
"sheep", "sofa", "train", "tvmonitor" ;
String labelFile = "D:/opencv-4.4.0/models/ssd/labelmap_det.txt";
String model_text_file = "D:/opencv-4.4.0/models/ssd/MobileNetSSD_deploy.prototxt";
String modelFile = "D:/opencv-4.4.0/models/ssd/MobileNetSSD_deploy.caffemodel";
#define WINDOW_NAME "【程序窗口】"
void on_MouseHandle(int event, int x, int y, int flags, void* param);
Rect select;
bool select_flag = false, flag = true;
Point origin;
Mat org, frame, gray_image, binary_image;
int main(int argc, char** argv)
select = Rect(-1, -1, 0, 0);
namedWindow(WINDOW_NAME);//定义一个img窗口
namedWindow("dst");
setMouseCallback(WINDOW_NAME, on_MouseHandle, 0);//调用回调函数
VideoCapture capture(0);
capture >> org;
Net net = readNetFromCaffe(model_text_file, modelFile);
while (1)
if (!capture.read(org)) //获取视频帧失败
cout << "Cannot read the frame from video file" << endl;
break;
if (flag)
flag = false;
select = Rect(10, org.rows / 6, org.cols - 20, org.rows * 3 / 4);//第一次进入循环，记录起始点
//cout << select.x << "--" << select.y << "--" << select.width << "--" << select.height << endl;
rectangle(org, select, Scalar(255, 0, 0), 1, 8, 0);//能够实时显示在画矩形窗口时的痕迹
frame = org(Rect(select.x, select.y, select.width, select.height)); //将感兴趣区域复制到tmp1
Mat inputblob = blobFromImage(frame, scaleFactor, Size(width, height), meanVal, false);
net.setInput(inputblob, "data");
net.setPreferableBackend(DNN_BACKEND_OPENCV);
net.setPreferableTarget(DNN_TARGET_CPU);
Mat detection = net.forward("detection_out");
Mat detectionMat(detection.size[2], detection.size[3], CV_32F, detection.ptr<float>());
float confidence_threshold = 0.25;
for (int i = 0; i < detectionMat.rows; i++)
float confidence = detectionMat.at<float>(i, 2);
if (confidence > confidence_threshold)
size_t objIndex = (size_t)(detectionMat.at<float>(i, 1));
float tl_x = detectionMat.at<float>(i, 3) * frame.cols;
float tl_y = detectionMat.at<float>(i, 4) * frame.rows;
float br_x = detectionMat.at<float>(i, 5) * frame.cols;
float br_y = detectionMat.at<float>(i, 6) * frame.rows;
Rect object_box((int)tl_x, (int)tl_y, (int)(br_x - tl_x), (int)(br_y - tl_y));
rectangle(frame, object_box, Scalar(0, 0, 255), 2, 8, 0);
printf("%s:%.2f\\n", classNames[objIndex], confidence);//打印出检测的消息
putText(frame, format("%s:%.2f,%d", classNames[objIndex], confidence, i + 1), Point(tl_x, tl_y + 20), FONT_HERSHEY_SIMPLEX, 0.7, Scalar(255, 255, 0), 2);//并且在输出的图像上打上标记
vector < double>layerstimings;
double freq = getTickFrequency() / 1000;
double time = net.getPerfProfile(layerstimings) / freq;
ostringstream ss;
//ss << "FPS" << 1000 / time << ";time:" << time << "ms";
//putText(frame, ss.str(), Point(20, 20), FONT_HERSHEY_PLAIN, 1, Scalar(0, 0, 255), 2, 8);
//select = Rect(select.x + 10, select.y + 10, select.width - 20, select.height - 20);//记录起始点
//rectangle(org, select, Scalar(255, 0, 0), 1, 8, 0);//能够实时显示在画矩形窗口时的痕迹
//select = Rect(select.x - 10, select.y - 10, select.width + 20, select.height + 20);//记录起始点
//rectangle(frame, Rect(10, 10, select.width - 20, select.height - 20), Scalar(255, 0, 0), 1, 8, 0);//能够实时显示在画矩形窗口时的痕迹
//cout << select.x << "--" << select.y << "--" << select.width << "--" << select.height << endl;
imshow(WINDOW_NAME, org);
imshow("dst", frame);
if (waitKey(10) == 27) break;//按下ESC键，程序退出
waitKey(200);//窗口切换延迟需要满足实时检测的要求，这个时间要大于读取每一帧的时间
waitKey(0);
destroyAllWindows();
return 0;
void on_MouseHandle(int event, int x, int y, int, void* param)
if (select_flag)
select.x = MIN(origin.x, x);//不一定要等鼠标弹起才计算矩形框，而应该在鼠标按下开始到弹起这段时间实时计算所选矩形框
select.y = MIN(origin.y, y);
select.width = abs(x - origin.x);//算矩形宽度和高度
select.height = abs(y - origin.y);
select &= Rect(0, 0, org.cols, org.rows);//保证所选矩形框在视频显示区域之内
if (event == EVENT_LBUTTONDOWN)
select_flag = true;//鼠标按下的标志赋真值
origin = Point(x, y);//保存下来单击是捕捉到的点
select = Rect(x, y, 0, 0)以上是关于opencv进阶-检测使用鼠标框选的自定义区域的主要内容，如果未能解决你的问题，请参考以下文章