“…Mathematical models that assume smoothness play an important role in a wide range of fields such as signal processing and pattern recognition. Smooth mathematical models are directly useful for noise reduction and interpolation of corrupted signals, and have many applications in time-series restoration [29], image restoration [12,13,21,24,35,36,40,53], color-image restoration [14,15,22,23,41,43], MR image reconstruction [19,20,30], dynamic PET reconstruction [17,18,45], and hyper spectral image restoration [16,48].…”