【AdaBoost算法】积分图代码实现

一、积分图介绍

定义：图像左上方的像素点值的和；

在Adaboost算法中可用于加速计算Haar或MB-LBP特征值，如下图：

二、代码实现

#include <opencv/highgui.h>
#include <opencv/cv.h>
#include <opencv2/imgproc/imgproc_c.h>

using namespace cv;

int calcIntImage(unsigned char *pucSrcImage, unsigned int *pucDstImage, int width, int height);

int main(int argv, char **argc)
{
    IplImage *pstImage = cvLoadImage("D:\test01.JPG", CV_LOAD_IMAGE_COLOR);
    IplImage *pstYUVImage = cvCreateImage(cvSize(pstImage->width, pstImage->height), IPL_DEPTH_8U, 3);
    unsigned char *pucImage = (unsigned char*)malloc(pstImage->width * pstImage->height * sizeof(unsigned char));
    unsigned int *puiIntImage = (unsigned int*)malloc((pstImage->width + 1) * (pstImage->height + 1) * sizeof(unsigned int));


    cvCvtColor(pstImage, pstYUVImage, CV_BGR2YUV);

    for(int i = 0; i < pstImage->width * pstImage->height; i++)
    {
        //提取Y分量
        pucImage[i] = pstYUVImage->imageData[i*3];
    }
    
    /* 计算积分图 */
    calcIntImage(pucImage, puiIntImage, pstImage->width, pstImage->height);


    /* 测试代码，测试是否计算正确 */
    for(int i = 0; i < 5; i++)
    {
        for(int j = 0; j < 5; j++)
        {
            printf("%d ", (int)(pucImage[i*pstImage->width + j]));
        }
        printf("
");
    }
    printf("
");
    for(int i = 0; i < 6; i++)
    {
        for(int j = 0; j < 6; j++)
        {
            printf("%4d ", (int)(puiIntImage[i*(pstImage->width + 1) + j]));
        }
        printf("
");
    }
    /* 测试代码结束 */

    cvShowImage("Win", pstImage);
    cvWaitKey(0);

    cvReleaseImage(&pstImage);
    cvReleaseImage(&pstYUVImage);
    if(NULL != pucImage)
    {
        free(pucImage);
        pucImage = NULL;
    }
    if(NULL != puiIntImage)
    {
        free(puiIntImage);
        puiIntImage = NULL;
    }
    return 0;
}

int calcIntImage(unsigned char *pucSrcImage, unsigned int *puiDstImage, int width, int height)
{
    int i= 0, j = 0, sum = 0;
    int iIntImageWidth = width + 1;
    int iIntImageHeight = height + 1;
    unsigned char *pucSrcImageTmp;
    unsigned int *puiDstImageTmp;
    
    pucSrcImageTmp = pucSrcImage;

    /* 存储每列的和 */
    unsigned int *puiImageRow = (unsigned int *)malloc(width * sizeof(unsigned int));
    memset(puiImageRow, 0, width * sizeof(unsigned int));
    puiDstImageTmp = puiDstImage;

    /* 积分图第一行清0 */
    memset(puiDstImageTmp, 0, iIntImageWidth);
    puiDstImageTmp += iIntImageWidth;

    /* 积分图第一列清0 */
    for(i = 0; i < height; i++)
    {
       *puiDstImageTmp = 0;
       puiDstImageTmp += iIntImageWidth;
    }

    puiDstImageTmp = puiDstImage + iIntImageWidth;
    /* 开始计算积分图 */
    for(i = 0; i < height; i++)
    {
        for(j = 0; j < width; j++)
        {
            puiImageRow[j] += pucSrcImageTmp[j];
            puiDstImageTmp[j+1] = puiDstImageTmp[j] + puiImageRow[j];
        }
        puiDstImageTmp += iIntImageWidth;
        pucSrcImageTmp += width;
    }

    if(NULL != puiImageRow)
    {
        free(puiImageRow);
        puiImageRow = NULL;
    }
    return 0;
}

三、计算结果

如下图，结果OK~