.. index:: 
   single: Parameters; 1D Field Size Infl

1D Field Size Infl
==================

The differential field size (*FS*) is defined as the distance from the :ref:`left inflection point<1D Left Infl>` to the  :ref:`right inflection point<1D Right Infl>`:

.. math:: FS = d(RE) - d(LE)

Where *d(RE)* and *d(LE)* are the linear distances from the profile centre to the right and left inflection points respectively.

**Protocol invocation name**: 1D Field Size Infl

|Note| Noisy data can lead to an inaccurate field size being reported.

|Note| The right and left inflection points are affected by the set window levels.

.. |Note| image:: _static/Note.png