Code Record


[DOI: 10.21982/j9jg-vm40 _target: ] S2sharp
Ulfarsson, Magnus; Palsson, Frosti ; Mura, Mauro Dalla; Sveinsson, Johannes
% Usage [ Xhat_im , output ] = S2sharp(Yim,varargin) % % When using this code please refer to % % Sentinel-2 Sharpening Using a Reduced-Rank Method, M.O. Ulfarsson et al. % IEEE Transactions on Geoscience and Remote Sensing, 2019. % % This method sharpens bands the 60m bands B1,B9 and the 20m bands % B4,B5,B6,B7,B8a,B11,B12 to 10m resolution. We assume that % the noisy satellite images yi, i=1,...,L are related to the full % resolution target images by % % yi = Mi*Bi*xi + ni, i=1,...,L % % where Mi is a downsampling operator, Bi is a circulant blurring matrix, % and ni is noise. The method solves % min (1/2) sum_{i=1}^L || y_i - Mi*Bi*G*fi ||^2 + sum_{j=1}^r lam_j * phi(gj) % F, G % where phi is a regularizer function. % The function returns Xhat=G*F'. % % % Input: % Yim : 1x12 cell array containing the observed images for each of % the nb bands of the Sentinel 2 sensor. % CDiter: Number of cyclic descent iterations. % CDiter=10 is the default. % r: The subspace dimension, r=7 is the default. % lambda: The regularization parameter, lambda=0.005 is the % default. % Xm_im: nl x nc x nb 3D matrix containing the true (10m resolution) % q: penalty weights, if r=7 then q= [1, 1.5, 4, 8, 15, 15, 20 ]' % is the default otherwise the default is q=ones(p,1). Note % that lam_i = lam*q_i % X0: Initial value for X = G * F' % Gstep_only: If Gstep_only=1 then perform the G-step (once). Assuming that F is fixed % GCV: If GCV=1 then the GCV value is computed. % Output: output is a structure containing the following fields % Xhat_im: estimated image (3D) at high resolution (10m) for each % spectral channel % SAMm: mean SAM for the 60m and 20m bands (empty if Xm_im is not % available) % SAMm_2m: mean SAM for the 20m bands (empty if Xm_im is not available) % SRE: signal to reconstruction error for all the 12 bands % (empty if Xm_im is not available) % GCVscore: Contains the GCV score if it was GCV=1 otherwise GCV is % empty. % ERGAS_20m: ERGAS score for the 20 m bands % ERGAS_60m: ERGAS score for the 60 m bands % aSSIM: average Structural Similarity Index % RMSE: Root mean squared error % Time: computational time % Magnus O. Ulfarsson, September 2017. % Acknowledgement: % % S2sharp uses some code from % % C. Lanaras, J. Bioucas-Dias, E. Baltsavias, and K. Schindler, “Superresolution % of multispectral multiresolution images from a single sensor,” % in IEEE Conference on Computer Vision and Pattern Recognition % Workshops (CVPRW), 2017. % % % % The Manopt software % %

Code Site:

Code Access Instructions: The main code is S2sharp.m example.m shows how to use it.

Appears in: The method behind the code was published in

M.O. Ulfarsson, F. Palsson, M. Dalla Mura, JR Sveinsson, Sentinel-2 Sharpening Using a Reduced-Rank Method, Transactions on Geoscience and Remote Sensing, volume 57, issue 9, 2019.

Code Languages: Other - Matlab

To compile code: There is no need to compile. The software was developed in MATLAB Version: (R2017b)

Sensor Categories: Optical Imager, Optical Spectrometer

Geophysical Model: Inverse

Geophysical Categories: Land: Land Cover/Land Use

Keywords: Multispectral, Remote Sensing, Superresolution, inverse problem, Sentinel-2