学习OpenCV——肤色检测

前三种方式转载：/article/7910141.html

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

[cpp]
view plaincopyprint?

#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;
}