 The image is transformed into coordinates, using the multi-resolution pyramid technique, to copy the original image with Pyramidal Gaussian or Laplacian Pyramid shape to obtain an image with the same size but with reduced bandwidth.This achieves a special blurring effect on the original image, called Scale-Space and ensures that the points of interest are scale invariant.The SURF algorithm is based on the same principles and steps as SIFT; but details in each step are different.