HW3 Submission -- Gaussian Blur

R2Image.cpp

void R2Image::
Blur(double sigma)
{
  R2Image *temp = new R2Image(width, height);

  // Generate 1D kernel
  int k_rad = 3 * sigma;
  int k_len = 6 * sigma + 1;
  double *k = (double *) malloc(k_len * sizeof(double));
  double sum = 0.0;

  double norm = 1.0 / 2.50662 * sigma;
  double coeff = 2.0 * sigma * sigma;

  for(int i=-1 * k_rad; i<=k_rad; i++) {
    double val = norm * std::exp(-i * i / coeff);
    k[i+k_rad] = val;
    sum += k[i+k_rad];
  }

  for(int i=0; i<k_len; i++) {
    k[i] /= sum;
    std::cout << "k[" << i << "] = " << k[i] << std::endl;
  }

  int x, y, i;

  for(y=0; y<height; y++) {
    for(x=0; x<width; x++) {
      double r = 0.0, g = 0.0, b = 0.0;
      for(i=-1*k_rad; i<=k_rad; i++) {
        r += Pixel(x, y+i).Red() * k[i+k_rad];
        g += Pixel(x, y+i).Green() * k[i+k_rad];
        b += Pixel(x, y+i).Blue() * k[i+k_rad];
      }
      // std::cout << val << std::endl;
      R2Pixel* p = new R2Pixel(r, g, b, 1);
      temp->SetPixel(x, y, *p);
    }
  }

  this->pixels = temp->pixels;
  temp->pixels = (R2Pixel *) malloc(npixels * sizeof(R2Pixel));

  for(y=k_rad; y<height-k_rad; y++) {
    for(x=k_rad; x<width-k_rad; x++) {
      double r = 0.0, g = 0.0, b = 0.0;
      for(i=-1*k_rad; i<=k_rad; i++) {
        r += Pixel(x+i, y).Red() * k[i+k_rad];
        g += Pixel(x+i, y).Green() * k[i+k_rad];
        b += Pixel(x+i, y).Blue() * k[i+k_rad];
      }
      // std::cout << val << std::endl;
      R2Pixel* p = new R2Pixel(r, g, b, 1);
      temp->SetPixel(x, y, *p);
    }
  }

  this->pixels = temp->pixels;
  temp->pixels = nullptr;
  free(k);
  delete temp;
}