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Diffstat (limited to 'Wrappers/Python/demos/PDHG_examples/GatherAll/PDHG_TV_Denoising.py')
| -rwxr-xr-x | Wrappers/Python/demos/PDHG_examples/GatherAll/PDHG_TV_Denoising.py | 280 |
1 files changed, 0 insertions, 280 deletions
diff --git a/Wrappers/Python/demos/PDHG_examples/GatherAll/PDHG_TV_Denoising.py b/Wrappers/Python/demos/PDHG_examples/GatherAll/PDHG_TV_Denoising.py deleted file mode 100755 index 6937fa0..0000000 --- a/Wrappers/Python/demos/PDHG_examples/GatherAll/PDHG_TV_Denoising.py +++ /dev/null @@ -1,280 +0,0 @@ -#======================================================================== -# Copyright 2019 Science Technology Facilities Council -# Copyright 2019 University of Manchester -# -# This work is part of the Core Imaging Library developed by Science Technology -# Facilities Council and University of Manchester -# -# Licensed under the Apache License, Version 2.0 (the "License"); -# you may not use this file except in compliance with the License. -# You may obtain a copy of the License at -# -# http://www.apache.org/licenses/LICENSE-2.0.txt -# -# Unless required by applicable law or agreed to in writing, software -# distributed under the License is distributed on an "AS IS" BASIS, -# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -# See the License for the specific language governing permissions and -# limitations under the License. -# -#========================================================================= - -""" - -Total Variation Denoising using PDHG algorithm: - - -Problem: min_{u}, \alpha * ||\nabla u||_{2,1} + Fidelity(u, g) - - \alpha: Regularization parameter - - \nabla: Gradient operator - - g: Noisy Data - - Fidelity = 1) L2NormSquarred ( \frac{1}{2} * || u - g ||_{2}^{2} ) if Noise is Gaussian - 2) L1Norm ( ||u - g||_{1} )if Noise is Salt & Pepper - 3) Kullback Leibler (\int u - g * log(u) + Id_{u>0}) if Noise is Poisson - - Method = 0 ( PDHG - split ) : K = [ \nabla, - Identity] - - - Method = 1 (PDHG - explicit ): K = \nabla - - - Default: ROF denoising - noise = Gaussian - Fidelity = L2NormSquarred - method = 0 - - -""" - -import numpy as np -import numpy -import matplotlib.pyplot as plt - -from ccpi.optimisation.algorithms import PDHG - -from ccpi.optimisation.operators import BlockOperator, Identity, Gradient -from ccpi.optimisation.functions import ZeroFunction, L1Norm, \ - MixedL21Norm, BlockFunction, L2NormSquared,\ - KullbackLeibler -from ccpi.framework import TestData -import os, sys -#import scipy.io -if int(numpy.version.version.split('.')[1]) > 12: - from skimage.util import random_noise -else: - from demoutil import random_noise - -# user supplied input -if len(sys.argv) > 1: - which_noise = int(sys.argv[1]) -else: - which_noise = 0 -print ("Applying {} noise") - -if len(sys.argv) > 2: - method = sys.argv[2] -else: - method = '0' -print ("method ", method) - - -loader = TestData(data_dir=os.path.join(sys.prefix, 'share','ccpi')) -data = loader.load(TestData.SHAPES, size=(50,50)) -ig = data.geometry -ag = ig - -# Create noisy data. -noises = ['gaussian', 'poisson', 's&p'] -noise = noises[which_noise] -if noise == 's&p': - n1 = random_noise(data.as_array(), mode = noise, salt_vs_pepper = 0.9, amount=0.2) -elif noise == 'poisson': - scale = 5 - n1 = random_noise( data.as_array()/scale, mode = noise, seed = 10)*scale -elif noise == 'gaussian': - n1 = random_noise(data.as_array(), mode = noise, seed = 10) -else: - raise ValueError('Unsupported Noise ', noise) -noisy_data = ig.allocate() -noisy_data.fill(n1) - -# Show Ground Truth and Noisy Data -plt.figure(figsize=(10,5)) -plt.subplot(1,2,1) -plt.imshow(data.as_array()) -plt.title('Ground Truth') -plt.colorbar() -plt.subplot(1,2,2) -plt.imshow(noisy_data.as_array()) -plt.title('Noisy Data') -plt.colorbar() -plt.show() - - -# Regularisation Parameter depending on the noise distribution -if noise == 's&p': - alpha = 0.8 -elif noise == 'poisson': - alpha = 1 -elif noise == 'gaussian': - alpha = .3 - -# fidelity -if noise == 's&p': - f2 = L1Norm(b=noisy_data) -elif noise == 'poisson': - f2 = KullbackLeibler(noisy_data) -elif noise == 'gaussian': - f2 = 0.5 * L2NormSquared(b=noisy_data) - -if method == '0': - - # Create operators - op1 = Gradient(ig, correlation=Gradient.CORRELATION_SPACE) - op2 = Identity(ig, ag) - - # Create BlockOperator - operator = BlockOperator(op1, op2, shape=(2,1) ) - - # Create functions - f = BlockFunction(alpha * MixedL21Norm(), f2) - g = ZeroFunction() - -else: - - operator = Gradient(ig) - f = alpha * MixedL21Norm() - g = f2 - - -# Compute operator Norm -normK = operator.norm() - -# Primal & dual stepsizes -sigma = 1 -tau = 1/(sigma*normK**2) - - -# Setup and run the PDHG algorithm -pdhg = PDHG(f=f,g=g,operator=operator, tau=tau, sigma=sigma) -pdhg.max_iteration = 2000 -pdhg.update_objective_interval = 100 -pdhg.run(2000) - - -if data.geometry.channels > 1: - plt.figure(figsize=(20,15)) - for row in range(data.geometry.channels): - - plt.subplot(3,4,1+row*4) - plt.imshow(data.subset(channel=row).as_array()) - plt.title('Ground Truth') - plt.colorbar() - plt.subplot(3,4,2+row*4) - plt.imshow(noisy_data.subset(channel=row).as_array()) - plt.title('Noisy Data') - plt.colorbar() - plt.subplot(3,4,3+row*4) - plt.imshow(pdhg.get_output().subset(channel=row).as_array()) - plt.title('TV Reconstruction') - plt.colorbar() - plt.subplot(3,4,4+row*4) - plt.plot(np.linspace(0,ig.shape[1],ig.shape[1]), data.subset(channel=row).as_array()[int(N/2),:], label = 'GTruth') - plt.plot(np.linspace(0,ig.shape[1],ig.shape[1]), pdhg.get_output().subset(channel=row).as_array()[int(N/2),:], label = 'TV reconstruction') - plt.legend() - plt.title('Middle Line Profiles') - plt.show() - -else: - plt.figure(figsize=(20,5)) - plt.subplot(1,4,1) - plt.imshow(data.subset(channel=0).as_array()) - plt.title('Ground Truth') - plt.colorbar() - plt.subplot(1,4,2) - plt.imshow(noisy_data.subset(channel=0).as_array()) - plt.title('Noisy Data') - plt.colorbar() - plt.subplot(1,4,3) - plt.imshow(pdhg.get_output().subset(channel=0).as_array()) - plt.title('TV Reconstruction') - plt.colorbar() - plt.subplot(1,4,4) - plt.plot(np.linspace(0,ig.shape[1],ig.shape[1]), data.as_array()[int(ig.shape[0]/2),:], label = 'GTruth') - plt.plot(np.linspace(0,ig.shape[1],ig.shape[1]), pdhg.get_output().as_array()[int(ig.shape[0]/2),:], label = 'TV reconstruction') - plt.legend() - plt.title('Middle Line Profiles') - plt.show() - - -#%% Check with CVX solution - -from ccpi.optimisation.operators import SparseFiniteDiff - -try: - from cvxpy import * - cvx_not_installable = True -except ImportError: - cvx_not_installable = False - - -if cvx_not_installable: - - ##Construct problem - u = Variable(ig.shape) - - DY = SparseFiniteDiff(ig, direction=0, bnd_cond='Neumann') - DX = SparseFiniteDiff(ig, direction=1, bnd_cond='Neumann') - - # Define Total Variation as a regulariser - regulariser = alpha * sum(norm(vstack([Constant(DX.matrix()) * vec(u), Constant(DY.matrix()) * vec(u)]), 2, axis = 0)) - - # choose solver - if 'MOSEK' in installed_solvers(): - solver = MOSEK - else: - solver = SCS - - # fidelity - if noise == 's&p': - fidelity = pnorm( u - noisy_data.as_array(),1) - elif noise == 'poisson': - fidelity = sum(kl_div(noisy_data.as_array(), u)) - solver = SCS - elif noise == 'gaussian': - fidelity = 0.5 * sum_squares(noisy_data.as_array() - u) - - obj = Minimize( regulariser + fidelity) - prob = Problem(obj) - result = prob.solve(verbose = True, solver = solver) - - diff_cvx = numpy.abs( pdhg.get_output().as_array() - u.value ) - - plt.figure(figsize=(15,15)) - plt.subplot(3,1,1) - plt.imshow(pdhg.get_output().as_array()) - plt.title('PDHG solution') - plt.colorbar() - plt.subplot(3,1,2) - plt.imshow(u.value) - plt.title('CVX solution') - plt.colorbar() - plt.subplot(3,1,3) - plt.imshow(diff_cvx) - plt.title('Difference') - plt.colorbar() - plt.show() - - plt.plot(np.linspace(0,ig.shape[1],ig.shape[1]), pdhg.get_output().as_array()[int(ig.shape[0]/2),:], label = 'PDHG') - plt.plot(np.linspace(0,ig.shape[1],ig.shape[1]), u.value[int(ig.shape[0]/2),:], label = 'CVX') - plt.legend() - plt.title('Middle Line Profiles') - plt.show() - - print('Primal Objective (CVX) {} '.format(obj.value)) - print('Primal Objective (PDHG) {} '.format(pdhg.objective[-1][0])) |