OpenCV中显示特征脸为黑色是什么原因
OpenCV中显示特征脸图片时是黑色是什么原因
特征脸矩阵数据如下（部分）：
0.000672752 -0.00398728 -4.23263e-005 -0.0150063 -0.0100655 -0.00682615 -0.0136038 -0.00788624 -0.0116071 -0.0170394 -0.0113726 -0.00329139 -0.00835479 -0.00103875 -0.0142026 -0.0157444 -0.00300682 -0.00911777 -0.00928913 -0.0149414 -0.00239133 -0.00676903 0.00255839 -0.0260086 -0.0176653 -0.00379464 -0.0136513 -0.000317007 0.00736613 -0.0228252 -0.0057197 0.000358763 0.00238805 0.00498493 -0.027213 -0.00735805 0.00357394 0.00700721 -0.00336265 0.00625503 -0.0144903 -0.000144143 0.00967291 0.00113688 0.00268168 -0.0240363 0.00871699 0.000356486 -0.00095915 -0.000674725 0.0107582 -0.00599353 0.00250839 -0.00294682 -0.00241268 0.00397216 0.0161414 0.00467632 -0.00419795 -0.00875254 0.000507923 0.00745908 0.00289604 -0.00840111 0.0064205 0.0132191 0.00565852 0.0171387 0.00387539 0.00292129 0.00613545 -0.00697766 0.00481558 0.000702915 0.00950864 0.00292367 0.0133789 0.00308503 0.0134737 0.00894141 0.00250446 0.00646444 0.00190217 0.00691703 0.00347312 0.00927087 0.00509597 0.00993473 0.00664872 0.0139689 0.00986597 0.0112875 0.00626067 0.00739277 0.0123023 0.0026249 0.0155314 0.0201914 0.0097147 0.00645924 0.00216852 0.00438826 0.0105113
......

程序如下：

C/C++ code

#include <stdio.h>#include <cv.h>#include <highgui.h>#include <iostream>using namespace std;void main(){    float Vector[10][92*112];    char fileName[40];    int img_num;    int start;    for(img_num=0;img_num<10;img_num++) //对每一张图片进行操作    {        sprintf(fileName, "trainData\\%d.pgm", img_num+1);        IplImage *img_src = cvLoadImage(fileName, CV_LOAD_IMAGE_GRAYSCALE);        IplImage *img_gray = cvCreateImage(cvSize(92,112), 8, 1);        cvResize(img_src, img_gray);        CvMat *Mat_tmp = cvCreateMat(img_gray->height, img_gray->width, CV_32FC1);        cvConvert(img_gray, Mat_tmp); //得到转换成100*100维图片后转换成矩阵；        //将矩阵数据转换成一行向量，有10副图，Vector[*][100*100] *处为10；        start = 0;        for(int i=0;i<Mat_tmp->cols;i++)        {            for(int j=0;j<Mat_tmp->rows;j++)            {                float value = cvmGet(Mat_tmp, j, i);                Vector[img_num][start] = value;                start++;            }        }        //内存释放；        cvReleaseImage(&img_src);        cvReleaseImage(&img_gray);        cvReleaseMat(&Mat_tmp);    }    //初始化CalcPCA参数    CvMat data;    cvInitMatHeader( &data, 10, 92*112, CV_32FC1, Vector);    CvMat *pAvgVector = cvCreateMat( 1, 92*112, CV_32FC1);     CvMat *pEigenValue = cvCreateMat( 1, 10, CV_32FC1);     CvMat *pEigenVector = cvCreateMat( 10, 92*112, CV_32FC1);    cvCalcPCA(&data, pAvgVector, pEigenValue, pEigenVector, CV_PCA_DATA_AS_ROW);     //输出特征值；    cout<<"特征值为："<<endl;    for(int i=0; i<10; i++)    {        printf("%f\n", cvmGet(pEigenValue, 0, i));    }    //求出特征脸；    CvMat *mat = cvCreateMat(92, 112, CV_32FC1);    start = 0;    for(i=0; i<112; i++)    {        for(int j=0; j<92; j++)        {            cvmSet(mat, j, i, cvmGet(pEigenVector, 0, start));            start++;        }    }    //标准化特征脸里面的数据；    cvNormalize(mat, mat, 255);    //显示特征脸    cvNamedWindow("FeatureFace",1);    cvShowImage("FeatureFace", mat);    cvWaitKey(0);    //释放内存空间；    cvReleaseMat(&mat);    cvReleaseMat(&pAvgVector);    cvReleaseMat(&pEigenValue);    cvReleaseMat(&pEigenVector); }