应用场景：跟踪摄像头中的目标物体，目标物体由鼠标选出，跟踪搜索框的大小和方向搜跟踪物体的变化而变换，目前仅支持单一物体跟踪。
视频效果：http://mpvideo.qpic.cn/0b78f4aamaaaruadcwgtabpfal6dayxqabqa.f10002.mp4?dis_k=a80f46fdbcd39e9c5a3593148bd2a64a&dis_t=1655366484&vid=wxv_1364128112354885633&format_id=10002&support_redirect=0&mmversion=false
代码实现：
代码语言：javascript复制#include <opencv2/core/utility.hpp>
#include "opencv2/video/tracking.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>
#include <ctype.h>
using namespace cv;
using namespace std;
Mat image;
bool backprojMode = false;
bool selectObject = false;
int trackObject = 0;
bool showHist = true;
Point origin;
Rect selection;
int vmin = 10, vmax = 256, smin = 30;
static void onMouse( int event, int x, int y, int, void* )
{
if( selectObject )
{
selection.x = MIN(x, origin.x);
selection.y = MIN(y, origin.y);
selection.width = std::abs(x - origin.x);
selection.height = std::abs(y - origin.y);
selection &= Rect(0, 0, image.cols, image.rows);
}
switch( event )
{
case EVENT_LBUTTONDOWN:
origin = Point(x,y);
selection = Rect(x,y,0,0);
selectObject = true;
break;
case EVENT_LBUTTONUP:
selectObject = false;
if( selection.width > 0 && selection.height > 0 )
trackObject = -1; // 启动画框
break;
}
}
string hot_keys =
"nnHot keys: n"
"tESC - quit the programn"
"tc - stop the trackingn"
"tb - switch to/from backprojection viewn"
"th - show/hide object histogramn"
"tp - pause videon"
"To initialize tracking, select the object with mousen";
static void help()
{
cout << "nThis is a demo that shows mean-shift based trackingn"
"You select a color objects such as your face and it tracks it.n"
"This reads from video camera (0 by default, or the camera number the user entersn"
"Usage: n"
" ./camshiftdemo [camera number]n";
cout << hot_keys;
}
const char* keys =
{
"{help h | | show help message}{@camera_number| 0 | camera number}"
};
int main( int argc, const char** argv )
{
VideoCapture cap;
Rect trackWindow;
int hsize = 16;
float hranges[] = {0,180};
const float* phranges = hranges;
CommandLineParser parser(argc, argv, keys);
if (parser.has("help"))
{
help();
return 0;
}
int camNum = parser.get<int>(0);
cap.open(camNum);
if( !cap.isOpened() )
{
help();
cout << "***Could not initialize capturing...***n";
cout << "Current parameter's value: n";
parser.printMessage();
return -1;
}
cout << hot_keys;
namedWindow( "Histogram", 0 );
namedWindow( "CamShift Demo", 0 );
setMouseCallback( "CamShift Demo", onMouse, 0 );
createTrackbar( "Vmin", "CamShift Demo", &vmin, 256, 0 );
createTrackbar( "Vmax", "CamShift Demo", &vmax, 256, 0 );
createTrackbar( "Smin", "CamShift Demo", &smin, 256, 0 );
Mat frame, hsv, hue, mask, hist, histimg = Mat::zeros(200, 320, CV_8UC3), backproj;
bool paused = false;
for(;;)
{
if( !paused )
{
cap >> frame;
if( frame.empty() )
break;
}
frame.copyTo(image);
if( !paused )
{
cvtColor(image, hsv, COLOR_BGR2HSV);
if( trackObject )
{
int _vmin = vmin, _vmax = vmax;
inRange(hsv, Scalar(0, smin, MIN(_vmin,_vmax)),
Scalar(180, 256, MAX(_vmin, _vmax)), mask);//确保h s v在范围内 返回标志mask 在255 否则0
int ch[] = {0, 0};
hue.create(hsv.size(), hsv.depth());
mixChannels(&hsv, 1, &hue, 1, ch, 1);//提取h通道到hue中 复制hsv[0]->hue[0]
if( trackObject < 0 )
{
//这个直方图除非被重新框选 否则在循环中只计算和绘制一次
Mat roi(hue, selection), maskroi(mask, selection);
calcHist(&roi, 1, 0, maskroi, hist, 1, &hsize, &phranges);//16个条 范围0-180
normalize(hist, hist, 0, 255, NORM_MINMAX);//计算直方图后又归一化0-255
trackWindow = selection;
trackObject = 1; // 只设置一次
histimg = Scalar::all(0);
int binW = histimg.cols / hsize;//一个bin占的宽度
Mat buf(1, hsize, CV_8UC3);//定义一个缓冲单bin矩阵 1×16
for( int i = 0; i < hsize; i )
buf.at<Vec3b>(i) = Vec3b(saturate_cast<uchar>(i*180./hsize), 255, 255);
cvtColor(buf, buf, COLOR_HSV2BGR);
for( int i = 0; i < hsize; i )
{
int val = saturate_cast<int>(hist.at<float>(i)*histimg.rows/255);//获取直方图的相对高度
rectangle( histimg, Point(i*binW,histimg.rows),
Point((i 1)*binW,histimg.rows - val),
Scalar(buf.at<Vec3b>(i)), -1, 8 );//画出直方图
}
}
// 反向投影
calcBackProject(&hue, 1, 0, hist, backproj, &phranges);
backproj &= mask;
//关键函数 目标追踪: 反向投影 搜索矩形框 迭代终止条件
RotatedRect trackBox = CamShift(backproj, trackWindow,
TermCriteria( TermCriteria::EPS | TermCriteria::COUNT, 10, 1 ));
if( trackWindow.area() <= 1 )
{
int cols = backproj.cols, rows = backproj.rows, r = (MIN(cols, rows) 5)/6;
trackWindow = Rect(trackWindow.x - r, trackWindow.y - r,
trackWindow.x r, trackWindow.y r) &
Rect(0, 0, cols, rows);
}
if( backprojMode )
cvtColor( backproj, image, COLOR_GRAY2BGR );
ellipse( image, trackBox, Scalar(0,0,255), 3, LINE_AA );
}
}
else if( trackObject < 0 )
paused = false;
if( selectObject && selection.width > 0 && selection.height > 0 )
{
Mat roi(image, selection);
bitwise_not(roi, roi);
}
imshow( "CamShift Demo", image );
imshow( "Histogram", histimg );
char c = (char)waitKey(10);
if( c == 27 )
break;
switch(c)
{
case 'b':
backprojMode = !backprojMode;
break;
case 'c':
trackObject = 0;
histimg = Scalar::all(0);
break;
case 'h':
showHist = !showHist;
if( !showHist )
destroyWindow( "Histogram" );
else
namedWindow( "Histogram", 1 );
break;
case 'p':
paused = !paused;
break;
default:
;
}
}
return 0;
}
