[Eeglablist] Creating new coordinates following bipolar re-referencing

[Makoto Miyakoshi]

Hello Knut,

I ran into the similar problem if I remember correctly. Please check
whetehr my tool linked below contains a solution. If not, I'll send you
another thing separately. Just let me know separately.
https://sccn.ucsd.edu/wiki/Makoto's_preprocessing_pipeline#Does_a_broad_dipole_layer_produce_a_depth_bias_when_fitted_with_a_single_dipole.3F_.28For_190.2C000_page_views.2C_02.2F22.2F2022_added.2C_07.2F18.2F2022_updated.29

Makoto

On Fri, Sep 1, 2023 at 12:38 PM Knut-André Skaug via eeglablist <
eeglablist at sccn.ucsd.edu> wrote:

> Hello,
>
> I struggle with understanding how to transform cartesian coordinates to
> spherical and polar coordinates following the rules used in EEGLAB.
>
> So far, I estimate the points of the bipolar references in cartesian space
> successfully, however when I try to use either:
> 'cart2sph.m.' or 'sph2cart.m' the output does not match the X, Y, Z
> variables in the chanlocs structure. In fact, only the radius matches the
> number.
>
> Do you have functions allowing me to transform from cartesian coordinates
> to spherical and polar coordinates?
>
> Any help is greatly appreciated.
>
> I am making the bipolar montage called 'banana' - if you would like to
> have the script to perform this re-referencing, I am happy to share.
>
> Some benefits to this bipolar reference scheme include more precise
> metrics aiming to show asymmetric spatial distributions, like left vs right
> hand EEG related activity.
>
> [cid:image001.png at 01D9DCBE.80F07700]
> Figure. Black dots show the location of the initial position of the
> electrodes as they were recorded. Green dots show the location of the
> bipolar re-referenced electrodes.
>
> Kind regards
> Knut Skaug
> PhD Cognitive Neuroscience
>
>
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