    CImg<Tfloat> get_blur(const float sigma, const unsigned int boundary_conditions=1,
                          const bool is_gaussian=true) const {
      return CImg<Tfloat>(*this,false).blur(sigma,boundary_conditions,is_gaussian);
    }
    CImg<Tfloat> get_blur(const float sigma, const unsigned int boundary_conditions=1,
                          const bool is_gaussian=true) const {
      return CImg<Tfloat>(*this,false).blur(sigma,boundary_conditions,is_gaussian);
    }