Fig. 2From: Guided block matching and 4-D transform domain filter projection denoising method for dynamic PET image reconstructionExample of a 3-D spectrum of a group in BM3D method performed on a single sinogram frame of dynamic PET transformed by 3-D linear transform b 4-D spectrum of the group in GBM4D method performed on a dynamic PET sinogram transformed by 4-D linear transform. The 4-D spectrum is sparser than the 3-D spectrumBack to article page