Heap Corruption using cv::FlannBasedMatcher and std::vector

Question

I am developing a breast imaging features for object recognition, using FlannBasedMatcher to compute spatial histograms.

Mat ComputeSpatialHistogram(Mat features, Mat vocabulary, int* region_index, int level, Ptr<DescriptorMatcher> flann_matcher)
{
   int vocab_size = vocabulary.rows;
   Mat descriptor = Mat::zeros(1, vocab_size*my_pow(4, level), CV_32FC1);
   if (features.rows > 0)
   {
        vector<DMatch> matches;
        flann_matcher->match(features, matches);
        int word_idx, region_idx, descr_idx;
        for (int i = 0; i < matches.size(); i++){
            word_idx = matches[i].trainIdx;
            region_idx = region_index[i];
            descr_idx = vocab_size*region_idx + word_idx;
            descriptor.at<float>(0, descr_idx) = descriptor.at<float>(0, descr_idx) + 1.0f;
        }
    }
    return descriptor;
}

I get an error when ending the execution of the if(features.rows > 0) scope. Can you helpme?

Answer 1

Try putting

matches.reserve(size) 

with the actually size of the vector, before insert any element. This is necessary if you're using the OpenCV 2.2, but not with the 2.9