Fixed_DIstortion_Corrector.java

private void crtLensDistor(double correctionFactor){
  lookUpTable = new ArrayList<>();

  double bOptimiz = 0.026731; // most cases only require b optimization
  double linearScal = 1.0 - bOptimiz - correctionFactor; // describes the linear scaling of the image

  int d = Math.min(width, height) / 2;    // radius of the circle

  for (int y = 0; y < height; y++) {
      for (int x = 0; x < width; x++) {
          // center of dst image
          double centerX = (width - 1) / 2.0;
          double centerY = (height - 1) / 2.0;
          // cartesian coordinates of the destination point (relative to the centre of the image)
          double deltaX = (x - centerX) / d;
          double deltaY = (y - centerY) / d;
          // distance or radius of dst image
          double dstR = Math.sqrt(deltaX * deltaX + deltaY * deltaY);
          // distance or radius of src image (with formula)
          double srcR = (bOptimiz * dstR * dstR + correctionFactor * dstR + linearScal) * dstR;
          // comparing old and new distance to get factor
          double factor = Math.abs(dstR / srcR);
          // coordinates in source image
          double srcXd = centerX + (deltaX * factor * d);
          double srcYd = centerY + (deltaY * factor * d);

          // no interpolation yet (just nearest point)
          short srcX = (short) 0;
          short srcY = (short) 0;

          if (srcX >= 0 && srcY >= 0 && srcX < width && srcY < height) {
              srcX = (short) srcXd;
              srcY = (short) srcYd;
          }

          lookUpTable.add(new Pair(srcX,srcY));
      }
  }
}

private void  matchingTable(Bitmap src){
    int[] srcPixels = new int[width*height];
    int[] dstPixels = new int[width*height];

    src.getPixels(srcPixels,0,width,0,0,width,height);

    for(int i=0;i<lookUpTable.size();i++){
        short srcX = lookUpTable.get(i).getFirst();
        short srcY = lookUpTable.get(i).getSecond();

        dstPixels[i] = srcPixels[srcY*width+srcX];
    }

    src.setPixels(dstPixels,0,width,0,0,width,height);
}