c++读取文件中指定一行的图像数据并用opencv显示

#include <iostream>
#include <fstream>
#include<sstream>
#include <opencv2/opencv.hpp>
#include <string>
#include <vector>

using namespace std;
using namespace cv;

std::vector<int> split(std::string str, std::string pattern) {
    std::string::size_type pos;
    std::vector<int> result;
    str += pattern;//扩展字符串以方便操作
    int size = str.size();

    for (int i = 0; i < size; i++) {
        pos = str.find(pattern, i);
        if (pos < size) {
            std::string s = str.substr(i, pos - i);
            int number = 0;
            number = atoi(s.c_str());
            result.push_back(number);
            i = pos + pattern.size() - 1;
        }
    }
    return result;
}

int main() {
    string temp;
    bool find_i_need = false;
    string cai_filename = "/home/cai/bag/test1218bag/iamge_data.txt";
    //读txt文件
    ifstream infile;//定义文件变量
    infile.open(cai_filename, std::ios::app);
    int a = 0;
    while (getline(infile, temp)) //读取一行, 直到所有行读完
    {
        a++;
        unsigned long i = temp.find("1470");
       // std::cout<<i <<std::endl;
        if (temp.find("1470")==0) {
            std::cout << temp << std::endl;
            find_i_need = true;
            break;
        } else {
            continue;
        }
    }
    std::cout<<"a=" <<a<<std::endl;
    if (!find_i_need) {
        return 0;
    }
    std::vector<int> image_vector;
    int width = 0;
    int height = 0;
    image_vector = split(temp, "-");
    width = image_vector[2];
    height = image_vector[1];
    image_vector.erase(image_vector.begin());
    image_vector.erase(image_vector.begin());
    image_vector.erase(image_vector.begin());
    std::cout << image_vector.size() << std::endl;
    std::cout << "width" << width << std::endl;
    std::cout << "height" << height << std::endl;
    cv::Mat src = Mat::zeros(height, width, CV_8UC1);
    for (int i = 0; i < height; ++i) {
        for (int j = 0; j < width; ++j) {
            int Gray = image_vector[i * width + j];
            src.at<uchar>(i, j) = (uchar) Gray;
        }
    }

    cv::Mat dst;
    int new_width = width * 4;
    int new_height = height * 4;
    resize(src, dst, cv::Size(new_width, new_height));
    imshow("dst", dst);
    waitKey(0);
    return 0;
}