学习OpenCV——肤色检测

前三种方式转载：http://blog.csdn.net/onezeros/article/details/6342567

 

第一种：RGB color space

第二种：RG color space

第三种：Ycrcb之cr分量+otsu阈值化

第四种：YCrCb中133<=Cr<=173 77<=Cb<=127

第五种：HSV中 7<H<29

 下一步需要滤波操作 因为检测结果中有许多瑕疵

#include "highgui.h"
#include "cv.h"

// skin region location using rgb limitation
void SkinRGB(IplImage* rgb,IplImage* _dst)
{
    assert(rgb->nChannels==3&& _dst->nChannels==3);

    static const int R=2;
    static const int G=1;
    static const int B=0;

    IplImage* dst=cvCreateImage(cvGetSize(_dst),8,3);
    cvZero(dst);

    for (int h=0;h<rgb->height;h++) {
        unsigned char* prgb=(unsigned char*)rgb->imageData+h*rgb->widthStep;
        unsigned char* pdst=(unsigned char*)dst->imageData+h*dst->widthStep;
        for (int w=0;w<rgb->width;w++) {
            if ((prgb[R]>95 && prgb[G]>40 && prgb[B]>20 &&
                prgb[R]-prgb[B]>15 && prgb[R]-prgb[G]>15/*&&
                !(prgb[R]>170&&prgb[G]>170&&prgb[B]>170)*/)||//uniform illumination
                (prgb[R]>200 && prgb[G]>210 && prgb[B]>170 &&
                abs(prgb[R]-prgb[B])<=15 && prgb[R]>prgb[B]&& prgb[G]>prgb[B])//lateral illumination
                ) {
                    memcpy(pdst,prgb,3);
            }
            prgb+=3;
            pdst+=3;
        }
    }
    cvCopyImage(dst,_dst);
    cvReleaseImage(&dst);
}
// skin detection in rg space
void cvSkinRG(IplImage* rgb,IplImage* gray)
{
    assert(rgb->nChannels==3&&gray->nChannels==1);

    const int R=2;
    const int G=1;
    const int B=0;

    double Aup=-1.8423;
    double Bup=1.5294;
    double Cup=0.0422;
    double Adown=-0.7279;
    double Bdown=0.6066;
    double Cdown=0.1766;
    for (int h=0;h<rgb->height;h++) {
        unsigned char* pGray=(unsigned char*)gray->imageData+h*gray->widthStep;
        unsigned char* pRGB=(unsigned char* )rgb->imageData+h*rgb->widthStep;
        for (int w=0;w<rgb->width;w++)
        {
            int s=pRGB[R]+pRGB[G]+pRGB[B];
            double r=(double)pRGB[R]/s;
            double g=(double)pRGB[G]/s;
            double Gup=Aup*r*r+Bup*r+Cup;
            double Gdown=Adown*r*r+Bdown*r+Cdown;
            double Wr=(r-0.33)*(r-0.33)+(g-0.33)*(g-0.33);
            if (g<Gup && g>Gdown && Wr>0.004)
            {
                *pGray=255;
            }
            else
            {
                *pGray=0;
            }
            pGray++;
            pRGB+=3;
        }
    }

}
// implementation of otsu algorithm
// author: onezeros#yahoo.cn
// reference: Rafael C. Gonzalez. Digital Image Processing Using MATLAB
void cvThresholdOtsu(IplImage* src, IplImage* dst)
{
    int height=src->height;
    int width=src->width;

    //histogram
    float histogram[256]={0};
    for(int i=0;i<height;i++) {
        unsigned char* p=(unsigned char*)src->imageData+src->widthStep*i;
        for(int j=0;j<width;j++) {
            histogram[*p++]++;
        }
    }
    //normalize histogram
    int size=height*width;
    for(int i=0;i<256;i++) {
        histogram[i]=histogram[i]/size;
    }

    //average pixel value
    float avgValue=0;
    for(int i=0;i<256;i++) {
        avgValue+=i*histogram[i];
    }

    int threshold;
    float maxVariance=0;
    float w=0,u=0;
    for(int i=0;i<256;i++) {
        w+=histogram[i];
        u+=i*histogram[i];

        float t=avgValue*w-u;
        float variance=t*t/(w*(1-w));
        if(variance>maxVariance) {
            maxVariance=variance;
            threshold=i;
        }
    }

    cvThreshold(src,dst,threshold,255,CV_THRESH_BINARY);
}

void cvSkinOtsu(IplImage* src, IplImage* dst)
{
    assert(dst->nChannels==1&& src->nChannels==3);

    IplImage* ycrcb=cvCreateImage(cvGetSize(src),8,3);
    IplImage* cr=cvCreateImage(cvGetSize(src),8,1);
    cvCvtColor(src,ycrcb,CV_BGR2YCrCb);
    cvSplit(ycrcb,0,cr,0,0);

    cvThresholdOtsu(cr,cr);
    cvCopyImage(cr,dst);
    cvReleaseImage(&cr);
    cvReleaseImage(&ycrcb);
}

void cvSkinYUV(IplImage* src,IplImage* dst)
{
    IplImage* ycrcb=cvCreateImage(cvGetSize(src),8,3);
    //IplImage* cr=cvCreateImage(cvGetSize(src),8,1);
    //IplImage* cb=cvCreateImage(cvGetSize(src),8,1);
    cvCvtColor(src,ycrcb,CV_BGR2YCrCb);
    //cvSplit(ycrcb,0,cr,cb,0);

    static const int Cb=2;
    static const int Cr=1;
    static const int Y=0;

    //IplImage* dst=cvCreateImage(cvGetSize(_dst),8,3);
    cvZero(dst);

    for (int h=0;h<src->height;h++) {
        unsigned char* pycrcb=(unsigned char*)ycrcb->imageData+h*ycrcb->widthStep;
        unsigned char* psrc=(unsigned char*)src->imageData+h*src->widthStep;
        unsigned char* pdst=(unsigned char*)dst->imageData+h*dst->widthStep;
        for (int w=0;w<src->width;w++) {
            if (pycrcb[Cr]>=133&&pycrcb[Cr]<=173&&pycrcb[Cb]>=77&&pycrcb[Cb]<=127)
            {
                    memcpy(pdst,psrc,3);
            }
            pycrcb+=3;
            psrc+=3;
            pdst+=3;
        }
    }
    //cvCopyImage(dst,_dst);
    //cvReleaseImage(&dst);
}

void cvSkinHSV(IplImage* src,IplImage* dst)
{
    IplImage* hsv=cvCreateImage(cvGetSize(src),8,3);
    //IplImage* cr=cvCreateImage(cvGetSize(src),8,1);
    //IplImage* cb=cvCreateImage(cvGetSize(src),8,1);
    cvCvtColor(src,hsv,CV_BGR2HSV);
    //cvSplit(ycrcb,0,cr,cb,0);

    static const int V=2;
    static const int S=1;
    static const int H=0;

    //IplImage* dst=cvCreateImage(cvGetSize(_dst),8,3);
    cvZero(dst);

    for (int h=0;h<src->height;h++) {
        unsigned char* phsv=(unsigned char*)hsv->imageData+h*hsv->widthStep;
        unsigned char* psrc=(unsigned char*)src->imageData+h*src->widthStep;
        unsigned char* pdst=(unsigned char*)dst->imageData+h*dst->widthStep;
        for (int w=0;w<src->width;w++) {
            if (phsv[H]>=7&&phsv[H]<=29)
            {
                    memcpy(pdst,psrc,3);
            }
            phsv+=3;
            psrc+=3;
            pdst+=3;
        }
    }
    //cvCopyImage(dst,_dst);
    //cvReleaseImage(&dst);
}

int main()
{

    IplImage* img= cvLoadImage("D:/skin.jpg"); //随便放一张jpg图片在D盘或另行设置目录
    IplImage* dstRGB=cvCreateImage(cvGetSize(img),8,3);
    IplImage* dstRG=cvCreateImage(cvGetSize(img),8,1);
    IplImage* dst_crotsu=cvCreateImage(cvGetSize(img),8,1);
    IplImage* dst_YUV=cvCreateImage(cvGetSize(img),8,3);
    IplImage* dst_HSV=cvCreateImage(cvGetSize(img),8,3);


    cvNamedWindow("inputimage", CV_WINDOW_AUTOSIZE);
    cvShowImage("inputimage", img);
    cvWaitKey(0);

    SkinRGB(img,dstRGB);
    cvNamedWindow("outputimage1", CV_WINDOW_AUTOSIZE);
    cvShowImage("outputimage1", dstRGB);
    cvWaitKey(0);
    cvSkinRG(img,dstRG);
    cvNamedWindow("outputimage2", CV_WINDOW_AUTOSIZE);
    cvShowImage("outputimage2", dstRG);
    cvWaitKey(0);
    cvSkinOtsu(img,dst_crotsu);
    cvNamedWindow("outputimage3", CV_WINDOW_AUTOSIZE);
    cvShowImage("outputimage3", dst_crotsu);
    cvWaitKey(0);
    cvSkinYUV(img,dst_YUV);
    cvNamedWindow("outputimage4", CV_WINDOW_AUTOSIZE);
    cvShowImage("outputimage4", dst_YUV);
    cvWaitKey(0);
    cvSkinHSV(img,dst_HSV);
    cvNamedWindow("outputimage5", CV_WINDOW_AUTOSIZE);
    cvShowImage("outputimage5", dst_HSV);
    cvWaitKey(0);
    return 0;
}