A device (D) is dedicated to the processing of data constituting initial tensor images, each tensor being a real symmetric and positive definite matrix representing an elementary part of a received tensor image. This device (D) comprises, on the one hand, a first calculating module (MC1) capable of performing a first selected, bijective and defined function of R*+ in R, and being associated with a selected metric definition, this first function allowing a second reciprocal function, and on the other, comprises a first processing module (MT1) provided for: i) constituting a first representation of a received tensor image; ii) calling the first calculating module (MC1) for applying the first function to a selected part of the first representation whereby obtaining a transformed part, and; iii) constituting, from the transformed part, a second representation of the tensor images ready to be processed.