The idea of selecting a characteristic scale disburdens the above mentioned detectors from the lack in scale invariance.
The properties of the scale space have been intensely studied by Lindeberg in. Based on his work on scale
space blobs the local extremum of the scale normalized Laplacian S is used as a scale selection criterion by different methods. Consequently in the literature they are often referred as Harris-Laplace or Hessian-Laplace detectors.