  Materials characterization using electron backscatter diffraction (EBSD)
requires indexing the orientation of the measured region from Kikuchi patterns.
The quality of Kikuchi patterns can degrade due to pattern overlaps arising
from two or more orientations, in the presence of defects or grain boundaries.
In this work we employ constrained non-negative matrix factorization to segment
a microstructure with small grain misorientations,< 1 degree, and predict the
amount of pattern overlap. First we implement the method on mixed simulated
patterns - that replicates a pattern overlap scenario, and demonstrate the
resolution limit of pattern mixing or factorization resolution using a weight
metric. Subsequently, we segment a single-crystal dendritic microstructure and
compare the results with high resolution EBSD. By utilizing weight metrics
across a low angle grain boundary we demonstrate how very small
misorientations/low-angle grain boundaries can be resolved at a pixel level.
Our approach constitutes a versatile and robust tool, complementing other fast
indexing methods for microstructure characterization.
