OpenCV通过Harr分类器人脸识别

#include <cv.h>
#include <highgui.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h> //用于防御式编程
#include <math.h>
#include <float.h>//<float.h>与<limits.h>一样是定义边界值的,<float.h>定义的是浮点数的边界值
#include <limits.h>
#include <time.h>
#include <ctype.h>//在调用字符函数时，在源文件中包含的头文件

#pragma comment(lib, "cv.lib")
#pragma comment(lib, "cxcore.lib")
#pragma comment(lib, "highgui.lib")

static CvMemStorage *storage = 0;
static CvHaarClassifierCascade *cascade = 0;
void detect_and_draw( IplImage *image);
const char *cascade_name = "haarcascade_frontalface_alt.xml";
int main( int argc, char **argv)
{
	CvCapture *capture = 0;
	IplImage *frame, *frame_copy = 0;
	int optlen = strlen("--cascade=");
	const char *input_name;
	if (argc > 1 && strncmp ( argv[1], "--cascade=", optlen ) == 0 ) //如果有图像或者视频输入执行
	{
		cascade_name = argv[1] + optlen;
		input_name =  argc > 2 ? argv[2] : 0;
	}
	else   //实时视频
	{
		cascade_name = "haarcascade_frontalface_alt2.xml";
		input_name = argc > 1 ? argv[1] : "test.png";
	}
	cascade = (CvHaarClassifierCascade*)cvLoad( cascade_name, 0, 0, 0);
	if ( !cascade )
	{
		fprintf( stderr, "ERROR:could not load classifier cascade\n");
		fprintf( stderr, "Usage:facedetect --cascade=\"<cascade_path>\" [filename|camera_index]\n");
		return -1;
	}
	storage = cvCreateMemStorage(0);
	if ( !input_name || (isdigit(input_name[0]) && input_name[1] == '\0'))  //extern int isdigit(char c)判断字符c是否为数字
		capture = cvCaptureFromCAM( !input_name ? 0 : input_name[0] - '0');
	else
		capture = cvCaptureFromAVI( input_name );   //如果有视频文件，就读视频文件
	cvNamedWindow( "result", 1);
	if (capture)
	{
		for(;;)
		{
			if (!cvGrabFrame( capture ))
				break;
			frame = cvRetrieveFrame( capture ); //获得由cvGrabFrame函数抓取的图片
			if (!frame)
				break;
			if (!frame_copy)
				frame_copy = cvCreateImage( cvSize(frame->width,frame->height),
				IPL_DEPTH_8U,frame->nChannels);
			if (frame->origin == IPL_ORIGIN_TL)

				cvCopy (frame, frame_copy, 0);
			else
				cvFlip (frame, frame_copy, 0);////反转图像,沿着x-axis
			detect_and_draw( frame_copy ); // 检测并且画出人脸
			if(cvWaitKey (10) >= 0)
				break;
		}

		//释放指针
		cvReleaseImage( &frame_copy );
		cvReleaseCapture( &capture);
	}
	else  //如果不是视频，那就是图像呗！
	{

		const char *filename = input_name ? input_name : (char*)"Lena.jpg";
		IplImage *image = cvLoadImage(filename, 1);
		if (image)
		{
			detect_and_draw(image);
			cvWaitKey(0);
			cvReleaseImage(&image);
		}
		else
		{


			FILE *f = fopen(filename, "rt");
			if (f)
			{
				char buf[1000+1];
				while (fgets(buf, 1000 , f))
				{
					int len = (int)strlen(buf);

					while ( len > 0 && isspace(buf[len-1]))
						len--;
					buf[len] = '\0';
					image = cvLoadImage(buf, 1);
					if (image)
					{
						detect_and_draw(image);
						cvWaitKey(0);
						cvReleaseImage(&image);
					}
				}
				fclose(f);
			}
		}
	}

	cvDestroyWindow("result");
	return 0;
}

void detect_and_draw(IplImage *img) //检测和画出人脸的函数体
{
	static CvScalar colors[] =
	{
		{{0,0,255}},
		{{0,128,255}},
		{{0,255,255}},
		{{0,255,0}},
		{{255,128,0}},
		{{255,255,0}},
		{{255,0,0}},
		{{255,0,255}}
	};

	double scale = 1.3;
	IplImage *gray = cvCreateImage(cvSize(img->width,img->height), IPL_DEPTH_8U, 1);
	IplImage *small_img = cvCreateImage(cvSize(cvRound(img->width/scale),
		cvRound(img->height/scale)),
		8, 1);

	int i;
	cvCvtColor(img, gray, CV_BGR2GRAY);//把输入的彩色图像转化为灰度图像

	cvResize(gray, small_img,CV_INTER_LINEAR);
	cvEqualizeHist(small_img, small_img);//灰度图象直方图均衡化
	cvClearMemStorage(storage);
	if (cascade)
	{
		double t = (double)cvGetTickCount();
		CvSeq *faces = cvHaarDetectObjects(small_img, cascade,storage,1.1,2,0,cvSize(30, 30));
		t = (double)cvGetTickCount() - t; //计算的时间
		printf("detection time = %gms\n",t/((double)cvGetTickFrequency()*1000.));
		for (i = 0; i < (faces ? faces->total : 0); i++)
		{
			//返回索引所指定的元素指针
			CvRect *r = (CvRect*)cvGetSeqElem(faces, i);

			//用矩形
			//确定两个点来确定人脸位置，因为用cvRetangle嘛
			CvPoint pt1, pt2;
			//找到画矩形的两个点
			pt1.x = r->x*scale;
			pt2.x = (r->x+r->width)*scale;
			pt1.y = r->y*scale;
			pt2.y = (r->y+r->height)*scale;
			//画出矩形
			cvRectangle( img, pt1, pt2, colors[i%8], 3, 8, 0 );
		}
	}
	cvShowImage("result",img);
	cvReleaseImage(&gray);
	cvReleaseImage(&small_img);
}