  Energy resolved neutron transmission techniques can provide high-resolution
images of strain within polycrystalline samples allowing the study of residual
strain and stress in engineered components. Strain is estimated from such data
by analysing features known as Bragg-edges for which several methods exist. It
is important for these methods to provide both accurate estimates of strain and
an accurate quantification the associated uncertainty. Our contribution is
twofold. First, we present a numerical simulation analysis of these existing
methods, which shows that the most accurate estimates of strain are provided by
a method that provides inaccurate estimates of certainty. Second, a novel
Bayesian non-parametric method for estimating strain from Bragg-edges is
presented. The numerical simulation analysis indicates that this method
provides both competitive estimates of strain and accurate quantification of
certainty, two demonstrations on experimental data are then presented.
