使用向量< vector< node>创建opencv mat到2d网格> [英] Creating opencv mat to 2d grid using vector<vector<node> >

问题描述

我正在构建一个使用OpenCV Mat的搜索算法，我将Mat转换为灰色图像，然后检查像素以使其坐标可行走或不可行走。我使用2D矢量来创建节点网格。 Node是一个包含像素信息的类。当我尝试从网格中打印nodeID时，程序突然关闭（例如

I am building a search algorithm using OpenCV Mat where I convert the Mat to gray image and then check the pixel to sign it to walkable or not walkable with their coordinate. I used a 2D vector to create a grid of node. The Node is a class to contain information about the pixel. when I try to print the nodeID from the grid the program sudden shutdown (e.g

grid.grid[10][10]->NodeID

）。

).

using namespace std;
int gridZise;
class location{
public:
    int x;
    int y;

};

class Node{
public:
    int gridX;
    int gridY;
    bool walkable;
    location worldPosition;
    int NodeID;


    int gCost;
    int hCost;
    Node *parent;

    Node(bool _walkable, int _gridX, int _gridY)
        {
            walkable = _walkable;
            gridX = _gridX;
            gridY = _gridY;
            NodeID = gridY * gridZise + gridX;
        }
    Node(int _gridX, int _gridY){
        gridX = _gridX;
        gridY = _gridY;
        NodeID = gridY * gridZise + gridX;
    }

    int fCost(){
        return gCost + hCost;
    }

};

class Grid{

public:
    cv::Mat map;
    vector<vector<Node*> > grid;
    int gridx;
    int gridy;


    Grid(cv::Mat _map){
        map = _map;
        gridx = map.cols;
        gridy = map.cols;
        gridZise = map.cols;
    }

    void CreateGrid(){
        // Set up sizes. (HEIGHT x WIDTH)
          grid.resize(gridy);
          for (int i = 0; i < gridy; ++i)
            grid[i].resize(gridx);

          // build up the grid
          for(int i=0; i <gridx;i++){
              for(int j=0; j < gridy;j++){
                  int pixel_val = map.at<int>(i,j);
                  bool _walkable = false;
                  if(pixel_val > 120){//if the value of the pixel is bigger than 120 is walkable
                       _walkable = true;
                  }
                  grid[i][j]->walkable = _walkable;
                  grid[i][j]->gridX = i;
                  grid[i][j]->gridY = j;
              }
          }
    }

    void PrintGrid(){
        for(int i=0; i <gridx;i++){
            for(int j=0; j < gridy;j++){
                cout << grid[i][j]->NodeID <<endl;
            }
        }
    }

    vector<Node> GetNeighbours(Node node)
        {
            vector<Node> neighbours;

            for (int x = -1; x <=1; x++)
            {
                for (int y = -1; y <= 1; y++)
                {
                    if (x == 0 && y == 0)
                        continue;

                    int checkX = node.gridX + x;
                    int checkY = node.gridY + y;

                    if(checkX >=0 && checkX < gridx && checkY >=0 && checkY < gridy)
                    {
                        Node neighbour(checkX,checkY);
                        neighbours.push_back(neighbour);
                    }
                }
            }
            return neighbours;
        }

    Node nodeFromLocation(location _node){
        Node currentNode = *grid[_node.x][_node.y];
        return currentNode;
    }

};


using namespace cv;
int main()
{
    cv::Mat img;
    img = imread("maze.jpg");

    if(img.empty()){
        cout<<"image not load "<<endl;
        return -1;
    }
    cvtColor(img,img,CV_BGR2GRAY);
    imshow("image",img);
    waitKey();
    Grid grid(img);

    grid.PrintGrid();

    return 0;
}

谢谢。



我尝试了什么：



我尝试使用迭代，如下所示。

Thank you.

What I have tried:

I try to use to use iterating as below this print nothing.

for(auto vec : grid)
       {
           for(auto x : vec)
               std::cout<<x->NodeID<<" , ";
           std::cout << std::endl;
       }

推荐答案

您的代码中有两个错误：

There are two errors in your code:

1. 你永远不会打电话给 CreateGrid（）（ Grid :: grid 是空的）
   
   
2. 从未分配 Grid :: grid 向量
   
   

修复构造函数中的第一个错误调用 CreateGrid（）：

To fix the first error call CreateGrid() in the constructor:

Grid(cv::Mat _map){
    map = _map;
    gridx = map.cols;
    gridy = map.cols;
    gridZise = map.cols;
    CreateGrid();
}

要修复第二个错误，请在 CreateGrid中初始化节点 （）：

To fix the second error initialise the Nodes in CreateGrid():

//grid[i][j]->walkable = _walkable;
//grid[i][j]->gridX = i;
//grid[i][j]->gridY = j;
grid[i][j] = new Node(i, j, _walkable);

但最好不要使用已分配的节点 s：

But it would be better to not use allocated Nodes:

vector<vector<Node> > grid;
// ...
grid[i][j].walkable = _walkable;
grid[i][j].gridX = i;
grid[i][j].gridY = j;
// ...
void PrintGrid(){
    for(int i=0; i <gridx;i++){
        for(int j=0; j < gridy;j++){
            cout << grid[i][j].NodeID <<endl;
        }
    }
}
// ... 
// Change other affected code too

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