opencv-图像二值化、阈值获取、直方图、轮廓提取（转）

#include <cv.h>
#include <highgui.h>
#include <windows.h>



// 获取直方图
// 1. pImageData   图像数据
// 2. nWidth       图像宽度
// 3. nHeight      图像高度
// 4. nWidthStep   图像行大小
// 5. pHistogram   直方图
BOOL GetHistogram(unsigned char *pImageData, int nWidth, int nHeight, int nWidthStep,
    int *pHistogram)
{
    int            i     = 0;
    int            j     = 0;
    unsigned char *pLine = NULL;
    // 清空直方图
    memset(pHistogram, 0, sizeof(int) * 256);
    for (pLine = pImageData, j = 0; j < nHeight; j++, pLine += nWidthStep)
    {
        for (i = 0; i < nWidth; i++)
        {
            pHistogram[pLine[i]]++;
        }
    }
    return TRUE;
}

// 大津法取阈值
// 1. pImageData   图像数据
// 2. nWidth       图像宽度
// 3. nHeight      图像高度
// 4. nWidthStep   图像行大小
// 函数返回阈值
int Otsu(unsigned char *pImageData, int nWidth, int nHeight, int nWidthStep)
{
    int    i          = 0;
    int    j          = 0;
    int    nTotal     = 0;
    int    nSum       = 0;
    int    A          = 0;
    int    B          = 0;
    double u          = 0;
    double v          = 0;
    double dVariance  = 0;
    double dMaximum   = 0;
    int    nThreshold = 0;
    int    nHistogram[256];
    // 获取直方图
    GetHistogram(pImageData, nWidth, nHeight, nWidthStep, nHistogram);
    for (i = 0; i < 256; i++)
    {
        nTotal += nHistogram[i];
        nSum   += (nHistogram[i] * i);
    }
    for (j = 0; j < 256; j++)
    {
        A = 0;
        B = 0;
        for (i = 0; i < j; i++)
        {
            A += nHistogram[i];
            B += (nHistogram[i] * i);
        }
        if (A > 0)
        {
            u = B / A;
        }
        else
        {
            u = 0;
        }
        if (nTotal - A > 0)
        {
            v = (nSum - B) / (nTotal - A);
        }
        else
        {
            v = 0;
        }
        dVariance = A * (nTotal - A) * (u - v) * (u - v);
        if (dVariance > dMaximum)
        {
            dMaximum = dVariance;
            nThreshold = j;
        }
    }
    return nThreshold;
}


// 二值化
// 1. pImageData   图像数据
// 2. nWidth       图像宽度
// 3. nHeight      图像高度
// 4. nWidthStep   图像行大小
// 5. nThreshold   阈值
BOOL Threshold(unsigned char *pImageData, int nWidth, int nHeight, int nWidthStep,
    unsigned int nThreshold)
{
    int            i     = 0;
    int            j     = 0;
    unsigned char *pLine = NULL;
    for (pLine = pImageData, j = 0; j < nHeight; j++, pLine += nWidthStep)
    {
        for (i = 0; i < nWidth; i++)
        {
            if (pLine[i] >= nThreshold)
            {
                pLine[i] = 0x00;
            }
            else
            {
                pLine[i] = 0xff;
            }
        }
    }
    return TRUE;
}


// 二值化图像取反
void Not(IplImage *edge)
{
    int i;
    int j;
    for(i=0;i<edge->height;i++)
      for(j=0;j<edge->width;j++)
      {
         if(edge->imageData[edge->height*i+j]==0)
            edge->imageData[edge->height*i+j]=1;
          else
            edge->imageData[edge->height*i+j]=0;

      }

}

BOOL FindContours(unsigned char *pImageData, int nWidth, int nHeight, int nWidthStep)
{
    int            i        = 0;
    int            j        = 0;
    unsigned char *pLine[3] = { NULL, NULL, NULL };
    for (j = 1; j < nHeight - 1; j++)
    {
        pLine[0]  = pImageData + nWidthStep * (j - 1);
        pLine[1]  = pImageData + nWidthStep * j;
        pLine[2]  = pImageData + nWidthStep * (j + 1);
        for (i = 1; i < nWidth - 1; i++)
        {
            if (pLine[0][i-1] == 0xFF && pLine[0][i] == 0xFF && pLine[0][i+1] == 0xFF &&
                pLine[1][i-1] == 0xFF && pLine[1][i] == 0xFF && pLine[1][i+1] == 0xFF &&
                pLine[2][i-1] == 0xFF && pLine[2][i] == 0xFF && pLine[2][i+1] == 0xFF)
            {
                pLine[0][i-1] = 0;
            }
            else
            {
                pLine[0][i-1] = pLine[1][i];
            }
        }
    }
    return TRUE;
}

int main(int argc, char* argv[])
{

    IplImage *src = cvLoadImage("e://five.jpg", CV_LOAD_IMAGE_GRAYSCALE);
    IplImage *dsc = cvCreateImage(cvSize(src->width*0.5,src->height*0.5), src->depth, src->nChannels);
    // 转换图像大小
    cvResize(src, dsc, CV_INTER_LINEAR);
    src->width*=0.5;
    src->height*=0.5;

    // 复制图像
    // 两个图像的大小类型通道数必须相同
    cvCopy(dsc, src );
    cvNamedWindow("src", CV_WINDOW_AUTOSIZE);
    cvShowImage("src", src);

    // 取图像阀值
    unsigned int threshold = Otsu((unsigned char *)src->imageData, src->width, src->height, src->widthStep);

    // 图像二值化
    if (TRUE == Threshold((unsigned char *)src->imageData, src->width, src->height, src->widthStep,
    threshold))
    {
        cvNamedWindow("dsc", CV_WINDOW_AUTOSIZE);
        cvShowImage("dsc", src);

        // 图像取反
        // cvNot(src, src);
        FindContours((unsigned char *)src->imageData,src->width , src->height, src->widthStep);
        cvNamedWindow("not", CV_WINDOW_AUTOSIZE);
        cvShowImage("not", src);
        cvWaitKey(0);


    }
    cvDestroyAllWindows();
    cvReleaseImage(&src);
    cvReleaseImage(&dsc);
    printf("Hello World!/n");
    return 0;
}