segmentation fault with parallel_for_

edit

Please i have many problem with "parallel_for_" ( random segmentation fault). in the majority of cases, the code works but sometimes it displays segmentation error (random). I use parallel_for_ with opencv 3.1.0. My code is attached

    class Paralleltextzone : public ParallelLoopBody
{
public:
    Paralleltextzone  (vector <String> &_liste_files, const Mat &_mask_base,  int _mask_debug, const char* _debug_path, vector<float> &_param_image)
        :liste_files(_liste_files),  mask_base(_mask_base), mask_debug (_mask_debug), debug_path (_debug_path),  param_image (_param_image)
    {
    }
virtual void operator ()(const Range& range) const
{
    for (int r = range.start; r < range.end; r++)

    {    int resl=0;
        //get text zone
        cout<<"Processing the frame: "<<r<<endl;            
        Mat output_mat, mask, Kernel,  boxFilter;   
        string image_name=liste_files.at(r);            
        Mat image=imread(image_name);         
        threshold(mask_base,mask, 10, 255,  cv::THRESH_BINARY);
        resize(mask_base,mask_base,image.size());            
        image.copyTo(output_mat, mask_base);                     
         resl=text_recognition(output_mat, output_mat.rows, output_mat.cols, r, 0, "/home/krayni/Bureau/VTT/TextDetect/txt", 0,  (double)param_image.at(0),  (double)param_image.at(1), (int) param_image.at(2),  (int)param_image.at(3),(int)param_image.at(4));           

    }
}

Paralleltextzone& operator=(const Paralleltextzone  &) {
    return *this;
};



   /*Text Regions Detection*/
extern "C"  int text_recognition(Mat &image_orig, int rows, int cols, int stime, int Debug, const char *tempPath, int MULTI_CHANNEL, double alpha, double beta, int hue, int sat, int level)
{

Mat grey;
Mat image_processed = Mat::zeros(image_orig.size()*3, image_orig.type());
prepare_image_for_ocr1(image_orig, image_processed, alpha, beta); // enhance image contrast and brighteness

vector<Mat> channels(2); 
vector<vector<ERStat> > regions(2);   
cvtColor(image_processed, grey,COLOR_RGB2GRAY);  
channels.push_back(grey);
channels.push_back(255-grey);
regions[0].clear();
regions[1].clear();
vector< Ptr<ERFilter> > er_filters1;
vector< Ptr<ERFilter> > er_filters2;    
Ptr<ERFilter> er_filter1 = createERFilterNM1(loadClassifierNM1("trained_classifierNM1.xml"),8,0.00015f,0.13f,0.2f,true,0.1f);
Ptr<ERFilter> er_filter2 = createERFilterNM2(loadClassifierNM2("trained_classifierNM2.xml"),0.5);
// Create ERFilter objects with the 1st and 2nd stage default classifiers

 for (int i=0; i<2; i++)
{
//Ptr<ERFilter> er_filter1 = createERFilterNM1(loadClassifierNM1("/opt/exe/ASAP_TraitementPTT_python/trained_classifierNM1.xml"),8,0.00015f,0.13f,0.2f,true,0.1f);
//Ptr<ERFilter> er_filter2 = createERFilterNM2(loadClassifierNM2("/opt/exe/ASAP_TraitementPTT_python/trained_classifierNM2.xml"),0.5);
er_filters1.push_back(er_filter1);
er_filters2.push_back(er_filter2);
}

// Apply the default cascade classifier to each independent channel (could be done in parallel)


Extractfeatures extractfeatures(channels,regions,er_filters1,er_filters2);

parallel_for_(cv::Range(0,2), extractfeatures);    

//ananothe process 


return 1;

}

//valgrind erro
==25778== Invalid read of size 1
==25778==    at 0xD1D7445: cv::text::ERFilterNM::er_tree_extract(cv::_InputArray const&) (in /usr/local/lib/libopencv_text.so.3.1.0)
==25778==    by 0xD1D8D6A: cv::text::ERFilterNM::run(cv::_InputArray const&, std::vector<cv::text::ERStat, std::allocator<cv::text::ERStat> >&) (in /usr/local/lib/libopencv_text.so.3.1.0)
==25778==    by 0x14DFAA: text_recognition (in /home/krayni/Bureau/VTT/TextDetect/test_memory_leak/TEST_LOGO_DETECT)
==25778==    by 0x11CCFA: Paralleltextzone::operator()(cv::Range const&) const (in /home/krayni/Bureau/VTT/TextDetect/test_memory_leak/TEST_LOGO_DETECT)
==25778==    by 0x5D47961: tbb::interface7::internal::start_for<tbb::blocked_range<int>, (anonymous namespace)::ProxyLoopBody, tbb::auto_partitioner const>::execute() (in /usr/local/lib/libopencv_core.so.3.1.0)
==25778==    by 0x4E6067C: ??? (in /usr/lib/x86_64-linux-gnu/libtbb.so.2)
==25778==    by 0x4E5D83F: ??? (in /usr/lib/x86_64-linux-gnu/libtbb.so.2)
==25778==    by 0x5D47B74: cv::parallel_for_(cv::Range const&, cv::ParallelLoopBody const&, double) (in /usr ...