使用OpenCV 2.4.5 Haar级联进行人脸检测：教程与示例

#include "cv.h"
#include "highgui.h"
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <math.h>
#include <float.h>
#include <limits.h>
#include <time.h>
#include <ctype.h>
#include <opencv.hpp>
#ifdef _EiC
#define WIN32
#endif
 
static CvMemStorage* storage = 0;
static CvHaarClassifierCascade* cascade = 0;
 
void detect_and_draw( IplImage* image );
 
const char* cascade_name =
    "haarcascade_frontalface_alt.xml";
/*    "haarcascade_profileface.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 )
    {
        cascade_name = argv[1] + optlen;
        input_name = argc > 2 ? argv[2] : 0;
    }
    else
    {
        cascade_name = "F:\\OPENCV\\opencv\\data\\haarcascades\\haarcascade_frontalface_alt2.xml";
        //opencv装好后haarcascade_frontalface_alt2.xml的路径,
       //也可以把这个文件拷到你的工程文件夹下然后不用写路径名cascade_name= "haarcascade_frontalface_alt2.xml";  
       //或者cascade_name ="C:\\Program Files\\OpenCV\\data\\haarcascades\\haarcascade_frontalface_alt2.xml"
        input_name = argc > 1 ? argv[1] : 0;
    }
 
    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') )
        capture = cvCaptureFromCAM( !input_name ? 0 : input_name[0] - '0' );