.. _sh2response:

sh2response
===================

Synopsis
--------

Generate an appropriate response function from the image data for spherical deconvolution

Usage
--------

::

    sh2response [ options ]  SH mask directions response

-  *SH*: the spherical harmonic decomposition of the diffusion-weighted images
-  *mask*: the mask containing the voxels from which to estimate the response function
-  *directions*: a 4D image containing the direction vectors along which to estimate the response function
-  *response*: the output axially-symmetric spherical harmonic coefficients

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

The spherical harmonic coefficients are stored according the conventions described the main documentation, which can be found at the following link:  |br|
https://mrtrix.readthedocs.io/en/3.0.8/concepts/spherical_harmonics.html

Options
-------

-  **-lmax value** specify the maximum harmonic degree of the response function to estimate

-  **-dump file** dump the m=0 SH coefficients from all voxels in the mask to the output file, rather than their mean

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).

-  **-config key value** *(multiple uses permitted)* temporarily set the value of an MRtrix config file entry.

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

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

References
^^^^^^^^^^

Tournier, J.-D.; Smith, R. E.; Raffelt, D.; Tabbara, R.; Dhollander, T.; Pietsch, M.; Christiaens, D.; Jeurissen, B.; Yeh, C.-H. & Connelly, A. MRtrix3: A fast, flexible and open software framework for medical image processing and visualisation. NeuroImage, 2019, 202, 116137

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



**Author:** J-Donald Tournier (jdtournier@gmail.com)

**Copyright:** Copyright (c) 2008-2025 the MRtrix3 contributors.

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Covered Software is provided under this License on an "as is"
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See the Mozilla Public License v. 2.0 for more details.

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


