【肤色检测 (I)】实测Ycrcb之cr分量+otsu阈值化

效果还不错，不过问题就是代码都是用的较老的opencv语法，里面有一些处理不好容易报错。。

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

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/core/core.hpp>

#include <iostream>
#include <string>
#include <cstdio>

using namespace std;
using namespace cv;

// 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);
	//show ycrcb
	cvShowImage("ycrcb",ycrcb);

	cvSplit(ycrcb,0,cr,0,0);

	cvThresholdOtsu(cr,cr);
	cvShowImage("out2",cr);

	//cvWaitKey(0);
	//cvCopyImage(cr,dst);

	//cvReleaseImage(&cr);
	cvReleaseImage(&ycrcb);
}


int main()
{
	IplImage* img = cvLoadImage( "earth.jpg" );
	//out用以保存输出图像
	IplImage * out = cvCreateImage(
		cvGetSize(img),
		IPL_DEPTH_8U,
		3
	);

	cvShowImage("in",img);
	cvSkinOtsu(img,out);
	//cvShowImage("out",out);

	cvWaitKey(0);

	cvReleaseImage(&img);//用完清理
	cvReleaseImage(&out);//用完清理
	cvDestroyWindow("in");
	cvDestroyWindow("out");

	return 0;
}