.. _mrdegibbs:

mrdegibbs
===================

Synopsis
--------

Remove Gibbs Ringing Artifacts

Usage
--------

::

    mrdegibbs [ options ]  in out

-  *in*: the input image.
-  *out*: the output image.

Description
-----------

This application attempts to remove Gibbs ringing artefacts from MRI images using the method of local subvoxel-shifts proposed by Kellner et al. (see reference below for details).

This command is designed to run on data directly after it has been reconstructed by the scanner, before any interpolation of any kind has taken place. You should not run this command after any form of motion correction (e.g. not after dwipreproc). Similarly, if you intend running dwidenoise, you should run this command afterwards, since it has the potential to alter the noise structure, which would impact on dwidenoise's performance.

Note that this method is designed to work on images acquired with full k-space coverage. Running this method on partial Fourier ('half-scan') data may lead to suboptimal and/or biased results, as noted in the original reference below. There is currently no means of dealing with this; users should exercise caution when using this method on partial Fourier data, and inspect its output for any obvious artefacts. 

Options
-------

-  **-axes list** select the slice axes (default: 0,1 - i.e. x-y).

-  **-nshifts value** discretization of subpixel spacing (default: 20).

-  **-minW value** left border of window used for TV computation (default: 1).

-  **-maxW value** right border of window used for TV computation (default: 3).

Data type options
^^^^^^^^^^^^^^^^^

-  **-datatype spec** specify output image data type. Valid choices are: float32, float32le, float32be, float64, float64le, float64be, int64, uint64, int64le, uint64le, int64be, uint64be, int32, uint32, int32le, uint32le, int32be, uint32be, int16, uint16, int16le, uint16le, int16be, uint16be, cfloat32, cfloat32le, cfloat32be, cfloat64, cfloat64le, cfloat64be, int8, uint8, bit.

Standard options
^^^^^^^^^^^^^^^^

-  **-info** display information messages.

-  **-quiet** do not display information messages or progress status. Alternatively, this can be achieved by setting the MRTRIX_QUIET environment variable to a non-empty string.

-  **-debug** display debugging messages.

-  **-force** force overwrite of output files. Caution: Using the same file as input and output might cause unexpected behaviour.

-  **-nthreads number** use this number of threads in multi-threaded applications (set to 0 to disable multi-threading).

-  **-help** display this information page and exit.

-  **-version** display version information and exit.

References
^^^^^^^^^^

Kellner, E; Dhital, B; Kiselev, V.G & Reisert, M. Gibbs-ringing artifact removal based on local subvoxel-shifts. Magnetic Resonance in Medicine, 2016, 76, 1574–1581.

--------------



**Author:** Ben Jeurissen (ben.jeurissen@uantwerpen.be) & J-Donald Tournier (jdtournier@gmail.com)

**Copyright:** Copyright (c) 2008-2018 the MRtrix3 contributors.

This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, you can obtain one at http://mozilla.org/MPL/2.0/

MRtrix3 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty
of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

For more details, see http://www.mrtrix.org/


