OpenCV 2D阵列到图像的转换

Question

When I tried to convert a 2D array to image, the rows and columns are getting distorted. Same Image cant be made.

using namespace cv;
using namespace std;


int main()
{
     float val;
     int val1[3][3];

     Mat imm = (Mat_<float>(3,3) << 12, 13, 45, 11, 191, 255, 62, 27, 0);
     if (imm.empty()) //check whether the image is loaded or not
     {
         cout << "Error : Image cannot be loaded..!!" << endl;
         //system("pause"); //wait for a key press
         return -1;
     }

     for (int y = 0; y < imm.rows; ++y)
     {
         float* row_ptr = imm.ptr<float>(y);
         for (int x = 0; x < imm.cols; ++x)
         {
              val = row_ptr[x];
              val1[y][x]=val;
              if(x%3==0)
              cout<<"\n";
              cout<<val<<"\t";

         }
     }


     Mat out_img(3,3,CV_8U ,val1);
     cout<<"\n\n\n output= "<<out_img;
     cout<<"\n\n\n\n"<<"Input= "<<imm;
 }

The output we got is,

12  13  45  
11  191 255 
62  27  0   


 output= [ 12,   0,   0;
   0,  13,   0;
   0,   0,  45]



Input= [12, 13, 45;
 11, 191, 255;
 62, 27, 0]

We can see that output and input were not the same. So need help in reconstruction of the same data.

Thanks.

Answer 1

The reason for distorted output is you are trying to put 2d int (32bit) array into unsigned char(8 bit) mat. To correct this, you must either change mat type(CV_8U) to CV_32S or change 2d array to unsigned char

Answer 2

Mat im2;
imm.convertTo(CV_8U, im2);

This will give you the same image as uchar. No need to use the double for loop.