人脸检测

其实，这些代码都是《学习Opencv》这本书上的。


转自：http://www.cnblogs.com/ma6174/archive/2013/03/31/2991315.html
这个博客的Python代码是用CV写的，而我的是cv2,改过来之后有各种错误。
opencv写的这个有调用摄像头的部分，第一次运行的时候好像能行，但是之后就没结果了。
// face_detection.cpp : 定义控制台应用程序的入口点。
//

#define  _CRT_SECURE_NO_WARNINGS
#include "stdafx.h"
#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>

#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 = "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');
    else
        capture = cvCaptureFromAVI(input_name);

    cvNamedWindow("result", 1);

    if (capture)
    {
        for (;;)
        {
            if (!cvGrabFrame(capture))
                break;
            frame = cvRetrieveFrame(capture);
            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);

            detect_and_draw(frame_copy);

            if (cvWaitKey(10) >= 0)
                break;
        }

        cvReleaseImage(&frame_copy);
        cvReleaseCapture(&capture);
    }
    else
    {
        //const char* filename = input_name ? input_name : (char*)"lena.jpg";
        const char* filename = input_name ? input_name : (char*)"503.jpg";
        IplImage* image = cvLoadImage(filename, 1);

        if (image)
        {
            detect_and_draw(image);
            cvWaitKey(0);
            cvReleaseImage(&image);
        }
        else
        {
            /* assume it is a text file containing the
            list of the image filenames to be processed - one per line */
            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)
{
    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), 8, 1);
    IplImage* small_img = cvCreateImage(cvSize(cvRound(img->width / scale),
        cvRound(img->height / scale)),
        8, 1);
    int i;

    cvCvtColor(img, gray, CV_BGR2GRAY);
    cvResize(gray, small_img, CV_INTER_LINEAR);
    cvEqualizeHist(small_img, small_img);
    cvClearMemStorage(storage);

    if (cascade)
    {
        double t = (double)cvGetTickCount();
        CvSeq* faces = cvHaarDetectObjects(small_img, cascade, storage,
            1.1, 2, 0/*CV_HAAR_DO_CANNY_PRUNING*/,
            cvSize(30, 30));
        t = (double)cvGetTickCount() - t;
        printf("detection time = %gms\n", t / ((double)cvGetTickFrequency()*1000.));
        for (i = 0; i < (faces ? faces->total : 0); i++)
        {
            CvRect* r = (CvRect*)cvGetSeqElem(faces, i);
            CvPoint center;
            int radius;
            center.x = cvRound((r->x + r->width*0.5)*scale);
            center.y = cvRound((r->y + r->height*0.5)*scale);
            radius = cvRound((r->width + r->height)*0.25*scale);
            cvCircle(img, center, radius, colors[i % 8], 3, 8, 0);
        }
    }

    cvShowImage("result", img);
    cvReleaseImage(&gray);
    cvReleaseImage(&small_img);
}

//这个代码亲测能运行，更改cvHaarDetectObjects的参数能够检测不同的人脸个数，转自：http://www.cnblogs.com/mengdd/archive/2012/08/01/2619043.html
#include"stdafx.h"
#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>

#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)
{
    cascade_name = "haarcascade_frontalface_alt2.xml";
    cascade = (CvHaarClassifierCascade*)cvLoad(cascade_name, 0, 0, 0);

    if (!cascade)
    {
        fprintf(stderr, "ERROR: Could not load classifier cascade\n");
        return -1;
    }
    storage = cvCreateMemStorage(0);
    cvNamedWindow("result", 1);

    const char* filename = "96.jpg";
    IplImage* image = cvLoadImage(filename, 1);

    if (image)
    {
        detect_and_draw(image);
        cvWaitKey(0);
        cvReleaseImage(&image);
    }

    cvDestroyWindow("result");

    return 0;
}


void detect_and_draw(IplImage* img)
{
    double scale = 1.2;
    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 } }
    };//Just some pretty colors to draw with

    //Image Preparation 
    // 
    IplImage* gray = cvCreateImage(cvSize(img->width, img->height), 8, 1);
    IplImage* small_img = cvCreateImage(cvSize(cvRound(img->width / scale), cvRound(img->height / scale)), 8, 1);
    cvCvtColor(img, gray, CV_BGR2GRAY);
    cvResize(gray, small_img, CV_INTER_LINEAR);

    cvEqualizeHist(small_img, small_img); //直方图均衡

    //Detect objects if any 
    // 
    cvClearMemStorage(storage);
    double t = (double)cvGetTickCount();
    CvSeq* objects = cvHaarDetectObjects(small_img,
        cascade,
        storage,
        1.1,
        2,
        0/*CV_HAAR_DO_CANNY_PRUNING*/,
        cvSize(30, 30));

    t = (double)cvGetTickCount() - t;
    printf("detection time = %gms\n", t / ((double)cvGetTickFrequency()*1000.));

    //Loop through found objects and draw boxes around them 
    for (int i = 0; i<(objects ? objects->total : 0); ++i)
    {
        CvRect* r = (CvRect*)cvGetSeqElem(objects, i);
        cvRectangle(img, cvPoint(r->x*scale, r->y*scale), cvPoint((r->x + r->width)*scale, (r->y + r->height)*scale), colors[i % 8]);
    }
    for (int i = 0; i < (objects ? objects->total : 0); i++)
    {
        CvRect* r = (CvRect*)cvGetSeqElem(objects, i);
        CvPoint center;
        int radius;
        center.x = cvRound((r->x + r->width*0.5)*scale);
        center.y = cvRound((r->y + r->height*0.5)*scale);
        radius = cvRound((r->width + r->height)*0.25*scale);
        cvCircle(img, center, radius, colors[i % 8], 3, 8, 0);
    }

    cvShowImage("result", img);
    cvReleaseImage(&gray);
    cvReleaseImage(&small_img);
}