Before revision:  To promote jump sparsity, we use an isotropic and anisotropic \ell^{0 combined with a quadratic data fidelity, similarly as studied in [1] for general problems in signal recovery .
After revision:  To promote jump sparsity, we use an isotropic and an anisotropic \ell^0 regularisation on the image gradient combined with a quadratic data fidelity, similarly as studied in [1] for general problems in signal recovery .