SVM在openCV中抛出“cv :: Exception at memory location” [英] SVM in openCV throws "cv::Exception at memory location"

问题描述

我试图用SVM，openCV，C ++和Visual Studio 2008（mfc app）创建一个简单的OCR应用程序。

我的训练样本是二进制图像机器印刷数字（0-9）。我想使用DAGSVM这个多类问题。所以我需要创建45个SVM，每个SVM是2类（SVM（0,1），SVM（0,2）... SVM（8,9））的SVM。

以下是操作方式：

SVM的参数：

 code> CvSVMParams params; 
 params.svm_type = CvSVM :: C_SVC; 
 params.kernel_type = CvSVM :: LINEAR; 
 params.term_crit = cvTermCriteria（CV_TERMCRIT_ITER，100，1e-6）; 
 

类i的训练图像的数据存储在矩阵trainData [i]的28x28图像，这意味着矩阵有784 cols）。
当训练每个SVM时，我创建两个矩阵，称为curTrainData& curTrainLabel。

  for（int i = 0; i <9; i ++）
 for +1; j <10; j ++）
 {
 curTrainData.create（trainData [i] .rows + trainData [j] .rows，784，CV_32FC1）; 
 curTrainLabel.create（curTrainData.rows，1，CV_32FC1）; 
 
 // merge 2 matrix：trainData [i]&对于（int k = 0; k  {
 curTrainLabel.at< float>（k，0）= 1.0; //数字类i 
 for（int l = 0; l <784; l ++）
 curTrainData.at< float>（k，l）= trainData [i] .at< float> k，l）; 
} 
 for（int k = 0; k  {
 curTrainLabel.at< float>（k + trainData [i] .rows，0）=  -  1.0; //数字类别j 
 for（int l = 0; l <784; l ++）
 curTrainData.at （k + trainData [i] .rows，l）= trainData [j ] .at< float>（k，l）; 
} 
 
 svms [i] [j] .train（curTrainData，curTrainLabel，Mat（），Mat（），params）; 
} 
  

我在调用时遇到错误 svms [i] [j] .train ... 。完整的错误是：

  svm.exe中0x75b5d36f处的未处理异常：Microsoft C ++异常：cv ::内存位置异常0x0022af8c .. 
  

说实话，我不完全理解在openCV中实现的SVM，找到他们使用图像中的对象的任何示例。

我真的很感激，如果有人能告诉我什么是错误：（

更新09/03 ：
我错了。错误来自：

  str.Format （_T（Results\trained_％d_％d.xml），i，j）; 
 svms [i] [j] .save（CT2A（str））; 
  
 
 
 
 str是一个CString变量。
 
 
 
 
  svms [i] [j] .save（Results\trained.xml）; 
  
我创建了文件夹Results和其他文件写入很好（方法fopen（），imwrite（）的文件。 
解决方案
 
 p>如果使用反斜杠\，则必须改为\\（或者可以使用frontslash/\").
 
I'm trying to create a simple OCR application with SVM, openCV, C++ and Visual Studio 2008 (mfc app).

My training samples are binary images of machine-printed digits (0-9). I want to use DAGSVM for this multi-class problem. So I need to create 45 SVMs, each of which is the SVM of 2 class (SVM(0,1), SVM(0,2)... SVM(8,9)).

Here's how things are going:

SVM's parameters:
CvSVMParams params;
params.svm_type    = CvSVM::C_SVC;
params.kernel_type = CvSVM::LINEAR;
params.term_crit   = cvTermCriteria(CV_TERMCRIT_ITER, 100, 1e-6);
Data of training images of class i are stored in matrix trainData[i] (each row is the pixels of a 28x28 image, which means the matrix has 784 cols).
When training each SVM, I create 2 matrix called curTrainData & curTrainLabel.
for (int i = 0; i < 9; i++)
    for (int j = i+1; j < 10; j++)
    {
        curTrainData.create(trainData[i].rows + trainData[j].rows, 784, CV_32FC1);
        curTrainLabel.create(curTrainData.rows, 1, CV_32FC1);

        // merge 2 matrix: trainData[i] & trainData[j]
        for (int k = 0; k < trainData[i].rows; k++)
        {
            curTrainLabel.at<float>(k, 0) = 1.0; // class of digit i
            for (int l = 0; l < 784; l++)
                curTrainData.at<float>(k,l) = trainData[i].at<float>(k,l);
        }
        for (int k = 0; k < trainData[j].rows; k++)
        {
            curTrainLabel.at<float>(k + trainData[i].rows, 0) = -1.0; // class of digit j
            for (int l = 0; l < 784; l++)
            curTrainData.at<float>(k + trainData[i].rows,l) = trainData[j].at<float>(k,l);
        }

        svms[i][j].train(curTrainData, curTrainLabel, Mat(), Mat(), params);
    }
I got error at the call svms[i][j].train.... The full error is:
Unhandled exception at 0x75b5d36f in svm.exe: Microsoft C++ exception: cv::Exception at memory location 0x0022af8c..
To tell the truth I don't fully understand SVM implemented in openCV and I can't find any example of them working with objects in images. 

I'm really grateful if someone can tell me what is (are) wrong :(

Update 09/03: 
I had mistaken. The error comes from:
str.Format(_T("Results\trained_%d_%d.xml"), i, j);  
svms[i][j].save(CT2A(str));
str is a CString variable.

It remains even if I change to:
svms[i][j].save("Results\trained.xml");
I've created the folder Results and others files are written well into it (files for methods fopen(), imwrite()...). I don't know why I can't add the folder when it comes to this save method of svm.
解决方案
If you use backslash "\", you have to put "\\" instead (or you can use a frontslash "/").

                        
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