English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The Approximate Message Passing (AMP) algorithm efficiently reconstructssignals which have been sampled with large i.i.d. sub-Gaussian sensingmatrices. Central to AMP is its "state evolution", which guarantees that thedifference between the current estimate and ground truth (the "aliasing") atevery iteration obeys a Gaussian distribution that can be fully characterizedby a scalar. However, when Fourier coefficients of a signal with non-uniformspectral density are sampled, such as in Magnetic Resonance Imaging (MRI), thealiasing is intrinsically colored, AMP's scalar state evolution is no longeraccurate and the algorithm encounters convergence problems. In response, wepropose the Variable Density Approximate Message Passing (VDAMP) algorithm,which uses the wavelet domain to model the colored aliasing. We presentempirical evidence that VDAMP obeys a "colored state evolution", where thealiasing obeys a Gaussian distribution that can be fully characterized with onescalar per wavelet subband. A benefit of state evolution is that Stein'sUnbiased Risk Estimate (SURE) can be effectively implemented, yielding analgorithm with subband-dependent thresholding that has no free parameters. Weempirically evaluate the effectiveness of VDAMP on three variations of FastIterative Shrinkage-Thresholding (FISTA) and find that it converges in around10 times fewer iterations on average than the next-fastest method, and to acomparable mean-squared-error.

Approximate Message Passing with a Colored Aliasing Model for Variable Density Fourier Sampled Images