The identification of directional energy distribution from the field measurement is an "ill-posed" problem. Using the wave distribution function (WDF) concept, this identification is done by finding an "inverse" of a non-bijective linear operator. We have developped an entropy regularization method to solve this problem. The use of entropy has many advantages : in particular, it allows to determine a solution with minimal information required by the data. A theoretical generalization of the method has been studied, as well. This method has been used to compute the WDF in the case of vaacum for simulated data and on experimental data from the FREJA satellite. The method is automatic, robust, and we obtain stable solutions. The obtained results are in accordance with those from other methods. However they are more diffuse, which seems preferable in this context.
