Neighbor Pattern Averaging and Reindexing (NPAR™) is an innovative method for measuring crystallographic orientation from Electron Backscatter Diffraction (EBSD) patterns. Band detection performance relies on the signal to noise ratio (SNR) within the EBSD pattern. Noise and decreased SNR can be added into patterns via the use of camera gain to intensify the signal to obtain faster camera frame rates. Band detection becomes undependable and indexing performance suffers when the noise surpasses permissible limits. Noise levels can be dropped by decreasing the gain on the detector and also by averaging many frames together; however both of these methods extend the acquisition time needed for both EBSD pattern collection and orientation mapping.
NPAR™ allows the collected EBSD pattern to be averaged with all the closest immediate EBSD patterns on the mapping grid and then reindexed. This method minimizes the image noise akin to frame averaging, but without the related time penalty. This improves the SNR of the pattern and enables the EBSD detector to be operated at higher gain settings than conventionally used without compromising indexing performance.
Features and Benefits
- EBSD detectors can be operated at higher noise levels than conventional indexing
- Allows for rapid collection rates at constant beam current or constant collection rates at lower beam currents and energies
- Quicker acquisition rates compared to traditional frame indexing
- Ideal for in-situ and 3D experiments
- Ideal for non-conductive samples and beam-sensitive samples