Как правильно расставить mutex

void readImages(vector <Mat> &vectorOfImages, vector <string> &nameOfImages, vector <string> &nameOfTamplates, Mutex &mutex)
{
for (int i = 0; i < nameOfImages.size(); i++)
        {           
            cout << "start read image" << endl;
            vectorOfImages.push_back(imread(nameOfImages[i]));
            vectorOfImages.push_back(imread(nameOfTamplates[i]));
            cout << "stop read image" << endl;
            
        }
}

void processingImages(vector <Mat> &vectorOfImages, Mutex &mutex)
{
    Mat imageFound;
    double maxValue;
    int pixelsToBeCovered = 0;
 
    clock_t start = NULL;
 
    for (int start = clock(); ((double)(clock() - start) / CLOCKS_PER_SEC) < 5;)
    {
        if (!vectorOfImages.empty())
        {
            for (int i = 0; i < vectorOfImages.size() - 1; i+=2)
            {
                mutex.lock();
                FindImage(ref(vectorOfImages[i]), ref(vectorOfImages[i+1]), ref(imageFound), ref(maxValue), pixelsToBeCovered);
                cout << maxValue << endl;
                cout << "stop processing image" << endl;
                
                
            }
            vectorOfImages.clear();
            start = clock();
        }
    }
}

void Threads()
{   
    Mutex mutex;
    vector < cv::Mat > vectorOfImages;
    vector <string> nameOfImages;
    vector <string> nameOfTamplates;
    nameOfImages = { "image.bmp","image.bmp" ,"image.bmp" ,"image.bmp" ,"image.bmp" };
    nameOfTamplates = { "tamplateImage.bmp","tamplateImage.bmp", "tamplateImage.bmp", "tamplateImage.bmp", "tamplateImage.bmp" };
    thread threadReadImages(readImages, ref(vectorOfImages), ref(nameOfImages), ref(nameOfTamplates), ref(mutex));
    thread threadProcessingImages(processingImages, ref(vectorOfImages), ref(mutex));
    threadReadImages.join();
    threadProcessingImages.join();
}