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. Author manuscript; available in PMC: 2015 May 1.
Published in final edited form as: Magn Reson Med. 2013 Jul 2;71(5):1760–1770. doi: 10.1002/mrm.24840

Figure 6.

Figure 6

The sparsity-regularized L1-SPIRiT reconstruction for data set #2 with 14 dB input SNR yields lower WMSE (a) for both the WMSE-optimal and WSURE-optimized choices of γ, relative to the un-regularized SPIRiT reconstruction. The L1-SPIRiT reconstruction using the WSURE-optimized choice is within 0.056 dB of the true WMSE-optimal L1-SPIRiT reconstruction. The WMSE-optimal and WSURE-optimized choices for the L1-SPIRiT regularization parameter γ (b) tend to decrease slowly as the undersampling factor increases. The larger values of γ from the L-curve-like method increase the WMSE, but not as substantially as for DESIGN. The plotted values of R account for the central k-space calibration region.