学习camshiftdemo小记

 参考自：http://blog.csdn.net/koriya/article/details/3347365

#ifdef _CH_

#pragma package <opencv>

#endif



#define CV_NO_BACKWARD_COMPATIBILITY



#ifndef _EiC

#include "cv.h"

#include "highgui.h"

#include <stdio.h>

#include <ctype.h>

#endif



//用HSV中的Hue分量进行跟踪

IplImage *image = 0, *hsv = 0, *hue = 0, *mask = 0, *backproject = 0, *histimg = 0;

CvHistogram *hist = 0;          //直方图类



int backproject_mode = 0;

int select_object = 0;

int track_object = 0;

int show_hist = 1;

CvPoint origin;

CvRect selection;

CvRect track_window;

CvBox2D track_box;              //Meanshift跟踪算法返回的Box类

CvConnectedComp track_comp;

int hdims = 16;                 //划分直方图bins的个数，越多越精确

float hranges_arr[] = {0,180};  //像素值的范围

float* hranges = hranges_arr;   //用于初始化CvHistogram类

int vmin = 10, vmax = 256, smin = 30;



void on_mouse( int event, int x, int y, int flags, void* param ) //该函数用于选择跟踪目标

{

	if( !image )

		return;



	if( image->origin )

		y = image->height - y;



	if( select_object ) //如果处于选择跟踪物体阶段，则对selection用当前的鼠标位置进行设置

	{

		selection.x = MIN(x,origin.x);

		selection.y = MIN(y,origin.y);

		selection.width = selection.x + CV_IABS(x - origin.x);

		selection.height = selection.y + CV_IABS(y - origin.y);



		selection.x = MAX( selection.x, 0 );

		selection.y = MAX( selection.y, 0 );

		selection.width = MIN( selection.width, image->width );

		selection.height = MIN( selection.height, image->height );

		selection.width -= selection.x;

		selection.height -= selection.y;

	}



	switch( event )

	{

	case CV_EVENT_LBUTTONDOWN:        //开始点击选择跟踪物体

		origin = cvPoint(x,y);

		selection = cvRect(x,y,0,0);  //坐标

		select_object = 1;            //表明开始进行选取

		break;

	case CV_EVENT_LBUTTONUP:

		select_object = 0;            //选取完成

		if( selection.width > 0 && selection.height > 0 )

			track_object = -1;        //如果选择物体有效，则打开跟踪功能

		break;

	}

}





CvScalar hsv2rgb( float hue )         //用于将Hue量转换成RGB量

{

	int rgb[3], p, sector;

	static const int sector_data[][3]=

	{{0,2,1}, {1,2,0}, {1,0,2}, {2,0,1}, {2,1,0}, {0,1,2}};

	hue *= 0.033333333333333333333333333333333f;

	sector = cvFloor(hue);

	p = cvRound(255*(hue - sector));

	p ^= sector & 1 ? 255 : 0;



	rgb[sector_data[sector][0]] = 255;

	rgb[sector_data[sector][1]] = 0;

	rgb[sector_data[sector][2]] = p;



	return cvScalar(rgb[2], rgb[1], rgb[0],0);  //返回对应的颜色值

}



int main( int argc, char** argv )

{

	CvCapture* capture = 0;



	if( argc == 1 || (argc == 2 && strlen(argv[1]) == 1 && isdigit(argv[1][0])))

		capture = cvCaptureFromCAM( argc == 2 ? argv[1][0] - '0' : 0 );//打开摄像头

	else if( argc == 2 )

		capture = cvCaptureFromAVI( argv[1] ); //打开AVI文件



	if( !capture )  //打开视频流失败处理

	{

		fprintf(stderr,"Could not initialize capturing...\n");

		return -1;

	}

                   //打印出程序功能列表

	printf( "Hot keys: \n"  

		"\tESC - quit the program\n"

		"\tc - stop the tracking\n"

		"\tb - switch to/from backprojection view\n"

		"\th - show/hide object histogram\n"

		"To initialize tracking, select the object with mouse\n" );



	cvNamedWindow( "Histogram", 1 );

	cvNamedWindow( "CamShiftDemo", 1 );

	cvSetMouseCallback( "CamShiftDemo", on_mouse, 0 );        // 设置鼠标回调函数

	cvCreateTrackbar( "Vmin", "CamShiftDemo", &vmin, 256, 0 );//建立滑动条

	cvCreateTrackbar( "Vmax", "CamShiftDemo", &vmax, 256, 0 );

	cvCreateTrackbar( "Smin", "CamShiftDemo", &smin, 256, 0 );



	for(;;)           //进入视频帧处理主循环

	{

		IplImage* frame = 0;

		int i, bin_w, c;



		frame = cvQueryFrame( capture );

		if( !frame )  

			break;



		if( !image )  //刚开始先建立一些缓冲区

		{

			/* allocate all the buffers */

			image = cvCreateImage( cvGetSize(frame), 8, 3 );

			image->origin = frame->origin;

			hsv = cvCreateImage( cvGetSize(frame), 8, 3 );

			hue = cvCreateImage( cvGetSize(frame), 8, 1 );

			mask = cvCreateImage( cvGetSize(frame), 8, 1 );       //分配掩膜图像空间

			backproject = cvCreateImage( cvGetSize(frame), 8, 1 );//分配反向投影图空间，大小一样，单通道

			hist = cvCreateHist( 1, &hdims, CV_HIST_ARRAY, &hranges, 1 );  //分配建立直方图空间

			histimg = cvCreateImage( cvSize(320,200), 8, 3 );              //分配用于画直方图的空间

			cvZero( histimg );   //背景为黑色

		}



		cvCopy( frame, image, 0 );

		cvCvtColor( image, hsv, CV_BGR2HSV );   // 把图像从RGB表色系转为HSV表色系



		if( track_object )  //   如果当前有需要跟踪的物体   

		{

			int _vmin = vmin, _vmax = vmax;

            //掩膜板，只处理像素值为H：0~180，S：smin~256，V：vmin~vmax之间的部分

			cvInRangeS( hsv, cvScalar(0,smin,MIN(_vmin,_vmax),0),

				cvScalar(180,256,MAX(_vmin,_vmax),0), mask );

			cvSplit( hsv, hue, 0, 0, 0 ); // 取得H分量



			if( track_object < 0 ) //如果需要跟踪的物体还没有进行属性提取，则进行选取框类的图像属性提取

			{

				float max_val = 0.f;

				cvSetImageROI( hue, selection );  // 设置原选择框

				cvSetImageROI( mask, selection ); // 设置Mask的选择框

				cvCalcHist( &hue, hist, 0, mask );// 得到选择框内且满足掩膜板内的直方图

				cvGetMinMaxHistValue( hist, 0, &max_val, 0, 0 );

				cvConvertScale( hist->bins, hist->bins, max_val ? 255. / max_val : 0., 0 );  // 对直方图转为0~255

				cvResetImageROI( hue );  // remove ROI

				cvResetImageROI( mask );

				track_window = selection;

				track_object = 1;



				cvZero( histimg );

				bin_w = histimg->width / hdims;

				for( i = 0; i < hdims; i++ )  //画直方图到图像空间

				{

					int val = cvRound( cvGetReal1D(hist->bins,i)*histimg->height/255 );

					CvScalar color = hsv2rgb(i*180.f/hdims);

					cvRectangle( histimg, cvPoint(i*bin_w,histimg->height),

						cvPoint((i+1)*bin_w,histimg->height - val),

						color, -1, 8, 0 );

				}

			}



			cvCalcBackProject( &hue, backproject, hist ); // 得到hue的反向投影图

			cvAnd( backproject, mask, backproject, 0 );   // 得到反向投影图mask内的内容

			cvCamShift( backproject, track_window,

				cvTermCriteria( CV_TERMCRIT_EPS | CV_TERMCRIT_ITER, 10, 1 ),

				&track_comp, &track_box );

			//使用MeanShift算法对backproject中的内容进行搜索，返回跟踪结果

			track_window = track_comp.rect; //得到跟踪结果的矩形框



			if( backproject_mode )

				cvCvtColor( backproject, image, CV_GRAY2BGR ); // 显示模式

			if( !image->origin )

				track_box.angle = -track_box.angle;

			cvEllipseBox( image, track_box, CV_RGB(255,0,0), 3, CV_AA, 0 ); //画出跟踪结果的位置

		}



		if( select_object && selection.width > 0 && selection.height > 0 ) //如果正处于物体选择，画出选择框

		{

			cvSetImageROI( image, selection );

			cvXorS( image, cvScalarAll(255), image, 0 );

			cvResetImageROI( image );

		}



		cvShowImage( "CamShiftDemo", image ); //显示视频和直方图

		cvShowImage( "Histogram", histimg );



		c = cvWaitKey(10);

		if( (char) c == 27 )

			break;

		switch( (char) c )

		{

		case 'b':

			backproject_mode ^= 1;

			break;

		case 'c':

			track_object = 0;

			cvZero( histimg );

			break;

		case 'h':

			show_hist ^= 1;

			if( !show_hist )

				cvDestroyWindow( "Histogram" );

			else

				cvNamedWindow( "Histogram", 1 );

			break;

		default:

			;

		}

	}



	cvReleaseCapture( &capture );

	cvDestroyWindow("CamShiftDemo");



	return 0;

}



#ifdef _EiC

main(1,"camshiftdemo.c");

#endif