1. A method for determining a voltage distribution on a surface of a cardiac tissue, comprising: transforming a received plurality of voltages collected by a plurality of electrodes adjacent to the surface into a digital representation of the plurality of voltages, with a computer; introducing a first and second regularization term to an error minimization formulation associated with the digital representation of the plurality of voltages; determining, by a processor associated with the computer, the voltage distribution according to said plurality of voltages and according to said regularization terms of the error minimization formulation; wherein the first of said regularization terms comprises a Laplacian smoothness operator and the second of said regularization terms comprises a Tikhonov regularization matrix; increasing a weight of one of the first and second regularization terms while decreasing a weight of the other one of the first and second regularization terms, wherein the weights of the first and second regularization terms each include a weighting parameter, and wherein the weighting parameter of the first regularization term is defined as τ and the weighting parameter of the second regularization term is defined as 1−τ, where τ is greater than zero and less than one; introducing to the error minimization formulation a confidence matrix, wherein a term of said confidence matrix is associated with at least one of a known first confidence that one or more of said plurality of voltages accurately measures a portion of said voltage distribution and a known second confidence that a portion of said voltage distribution exceeds a threshold and wherein the confidence matrix includes terms set to zero, the terms corresponding to one or more of said electrodes that are inoperable; and displaying a portion of the voltage distribution on a model of the cardiac tissue.