opencv人脸识别

发布网友 发布时间：2022-04-22 06:24

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热心网友 时间：2022-05-22 01:45

#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 = "Lena.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);
}

需要说明的几点:
1.图像和.xml文件要放在该程序的bin目录下（.sln所在的目录）。
2.《学习OpenCV》里面就是用矩形表示，但是书里面的代码不太对，原因是忽略了缩放因子，即void detect_and_draw(IplImage* img )里面的double scale=1.2;
这个缩放因子的作用是：拿到一个图像，首先将它缩放（scale=1.2即变为一个小图像），然后在缩放后的小图像上检测人脸，这样会比较快。
最基本的就这么多吧。

热心网友 时间：2022-05-22 03:03

你可以看看opencv,需要提取特征还有训练分类器