Jianwu Dong

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We study the marginal-MAP problem on graphical models, and present a novel approximation method based on direct approximation of the sum operation. A primary difficulty of marginal-MAP problems lies in the non-commutativity of the sum and max operations, so that even in highly structured models, marginalization may produce a densely connected graph over the(More)
Quantitative susceptibility mapping (QSM) is a magnetic resonance imaging technique that reveals tissue magnetic susceptibility. It relies on having a high quality field map, typically acquired with a relatively long echo spacing and long final TE. Applications of QSM outside the brain require the removal of fat contributions to the total signal phase.(More)
PURPOSE Existence of low SNR regions and rapid-phase variations pose challenges to spatial phase unwrapping algorithms. Global optimization-based phase unwrapping methods are widely used, but are significantly slower than greedy methods. In this paper, dual decomposition acceleration is introduced to speed up a three-dimensional graph cut-based phase(More)
With the extensive applications of Internet, the Internet data have grown at full speed. To directly reveal the relationship among mass data and the latent characteristics in information with visualization techniques has become an important research topic. Concerning small resource storage capacity and low data exchange efficiency of the traditionally(More)
We propose an efficient algorithm for finding the maximum a posteriori (MAP) configuration in Markov random fields (MRFs) under the framework of dual decomposition. In the framework, tractable subproblems like binary planar subproblems (BPSPs) have been introduced to obtain more accurate solutions than that of tree-structured subproblems. However, since(More)
Phase images derived from imaging devices are usually wrapped into discontinuous images, so phase unwrapping is needed for phase image reconstruction. The wrap counts of every voxel are determined by the assumption that the true phase is spatially continuous. However, it is difficult to distinguish whether the phase jump is caused by phase wrap or noise. In(More)
Dipole inversion is the final step of the QSM algorithm. In this step, the zero cone surface in the dipole kernel makes the field-to-susceptibility inverse problem ill-posed. Current solutions are mostly based on the Bayesian approach. Compared to the L1-norm, which has been used in previous techniques, the L2-norm converges faster. Therefore, we propose to(More)