1. A method for determining at least one property of a subterranean formation, the method comprising: rotating a bottom hole assembly including a drill bit and an electromagnetic logging tool in a borehole penetrating the subterranean formation, the electromagnetic logging tool including a plurality of axially spaced transmitters and axially spaced receivers, at least one of the transmitters and at least one of the receivers including a transverse or tilted antenna; using the electromagnetic logging tool to acquire electromagnetic measurements of the subterranean formation while rotating the bottom hole assembly in the borehole; and causing a processor to process the acquired electromagnetic measurements using a pixel-based inversion to determine at least one formation property of the subterranean formation, wherein said pixel-based inversion processing comprises minimizing a cost function in an iterative manner, the cost function including a gradient penalization term having a gradient penalization constant, wherein an optimum gradient penalization constant value is selected using an adaptive regularization routine that optimizes the gradient penalization constant values.