MEM (‘xrayvision.mem’)#

The mem submodule contains the Maximum Entropy methods.

xrayvision.mem Module#

Implementation of Maximum Entropy Method

Functions#

_get_entropy(image, flux)

Return the entropy of an image.

_get_fourier_matrix(vis[, shape, pixel_size])

Return the complex Fourier matrix used to compute the value of the visibilities.

_estimate_flux(vis, shape, pixel[, maxiter, tol])

Estimate the total flux in the image by solving an optimisation problem.

_get_mean_visibilities(vis, shape, pixel)

Return the mean visibilities sampling the same call in the discretisation of the (u,v) plane.

_proximal_entropy(y, m, lamba, Lip[, tol])

This function computes the value of the proximity operator of the entropy function subject to positivity constraint, i.e. it solves the problem.

_proximal_operator(z, f, m, lamb, Lip[, niter])

Computes the value of the proximity operator of the entropy function subject to positivity constraint and flux constraint by means of a Dykstra-like proximal algorithm (see Combettes, Pesquet, "Proximal Splitting Methods in Signal Processing", (2011)).

_optimise_fb(Hv, Visib, Lip, flux, lambd, ...)

Solve the optimization problem using a forward-backward splitting algorithm

mem(vis, shape, pixel_size, *[, ...])

Maximum Entropy Method visibility based image reconstruction