how to open a depth map from a file and transform it into a 3D point cloud - wanna convert c++ code to MATLAB script.

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Attaullah Shafiq 2021-4-30

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/818495-how-to-open-a-depth-map-from-a-file-and-transform-it-into-a-3d-point-cloud-wanna-convert-c-code

The following c++ code snippet show how to open a depth map from a file and transform it into a 3D point cloud:

FILE* inFile;
  //read the file
  fopen_s(&amp;amp;inFile,"depth.txt", "rb");
  fread(d, sizeof(UINT16), nVertices, inFile);
  fclose(inFile);
  for(int i=0 ; i &amp;lt; nVertices ; i++)
  {
    int r_i = i / (int)n_c;
    int c_i = i % (int)n_c;
    //normalize depth
    float d_i = (float)d[i] / (float)MAX_DEPTH;
    //color
    vertices[i].a = 255.;
    //the color of the point is a shade of gray proportional to the depth
    vertices[i].b = vertices[i].g = vertices[i].r = d_i;
    //calculate x-coordinate
    float alpha_h = (M_PI - theta_h) / 2;
    float gamma_i_h = alpha_h + (float)c_i*(theta_h / n_c);
    vertices[i].x = d_i / tan(gamma_i_h);
    //calculate y-coordinate
    float alpha_v = 2 * M_PI - (theta_v / 2);
    float gamma_i_v = alpha_v + (float)r_i*(theta_v / n_r);
    vertices[i].y = d_i * tan(gamma_i_v)*-1;
    //z-coordinate
    vertices[i].z = d_i;
  }