c++ - Blurring images of an image pyramid - Vector subscript out of range -

i trying load image, calculate image pyramid (save every image) , blur every single image of pyramid opencv 3.2 in c++. when run program receive error:

vector line:1740 expression: vector subscript out of range

here code:

#include "stdafx.h" #include <opencv2/highgui/highgui.hpp> #include <opencv2/xfeatures2d.hpp> #include <iostream> #include <opencv2/shape/shape.hpp>   using namespace std; using namespace cv; using namespace cv::xfeatures2d;   int main(int argc, char** argv) {       // read image     mat img_1;     img_1 = imread(argv[1], cv_load_image_grayscale);      // build image pyramid , save in vector of mat     vector<mat> img_1_pyramid;     int pyramid_octaves = 3;     buildpyramid(img_1, img_1_pyramid, pyramid_octaves);      /* void cv::buildpyramid (inputarray src, outputarrayofarrays dst, int      maxlevel, int bordertype = border_default) */         // initialize parameters first image pyramid     vector<mat> reduced_noise_1;     blur(img_1_pyramid[0], reduced_noise_1[0], size(3,3));     /* void cv::blur (inputarray src, outputarray dst, size ksize, point      anchor=point(-1,-1), int bordertype=border_default)*/  return 0; } 

i tried mat object: mat reduced_noise_1; or vector of predefined size vector<mat> reduced_noise(4);and can draw img_1_pyramid[0] imshow , receive right image...

when debug program receive error in line 621 of cvstd.hpp:

string::string(const char* s)     : cstr_(0), len_(0) {     if (!s) return;     size_t len = strlen(s);  // here appears error (only in german;))     memcpy(allocate(len), s, len); }