Spherical continuous wavelet transforms arising from sections of the Lorentz group

Abstract

We consider the conformal group of the unit sphere S n − 1 , the so-called proper Lorentz group Spin + ( 1 , n ) , for the study of spherical continuous wavelet transforms. Our approach is based on the method for construction of general coherent states associated to square integrable group representations over homogeneous spaces. The underlying homogeneous space is an extension to the whole of the group Spin + ( 1 , n ) of the factorization of the gyrogroup of the unit ball by an appropriate gyro-subgroup. Sections on it are constituted by rotations of the subgroup Spin ( n ) and Möbius transformations of the type φ a ( x ) = ( x − a ) ( 1 + a x ) − 1 , where a belongs to a given section on a quotient space of the unit ball. This extends in a natural way the work of Antoine and Vandergheynst to anisotropic conformal dilations on the unit sphere.