Dave Mitchell's DigitalMicrograph™ Scripting Website

Function

A suite of tools to measure resolution and astigmatism in scanning microscope images

Version

version:20140524, v1.0

Author

D. R. G. Mitchell

Acknowledgements

This script is based on the SMART tools by : David Joy, Y-U Ko and J. Hwu, Proc SPIE, 06/2000, 'Metrics of resolution and performance for CD-SEMs'.

Comments

Although designed ostensibly for SEM images, this script will also work on images acquired from LaB6 STEMs where lattice resolution is not obtainable. Three different methods are provided. FFT and Auto-Correlation methods require only a single image while the Young's Fringes method requires two images with a small offset (ca 2% of image width) between them. Gold on carbon is an ideal reference specimen to use. In order to obtain sensible values the images analysed should be of sufficient magnification to be resolution (and not pixel) -limited. For a LaB6 STEM this might be at perhaps 100-300kx.

System Requirements

Tested on GMS 2.3 running under XP. Images can be any format which is readable into DigitalMicrograph. If these images do not have an inherent calibration then they will need to be calibrated. Images should be as well focused as possible, have astigmatism corrected and have high contrast and good signal to noise. For SEMs secondary electron images are prefered, while for STEMs HAADF images will be best although bright field images could also be used.

Known Issues

Refer to Joy's paper for a detailed description of the methods and limitations of the techniques. A list of instructions is provided by pressing the ? button. In the case of the Young's Fringes method, two images are required and these must be obtained one after the other with minimal delay - to minimise the effects of any drift in instrument performance.

Supported

Yes

Included Files

Script file.

Source Code