Dave Mitchell's DigitalMicrograph™ Scripting Website

Function

Levels out low frequency variations in brightness in the image, such as those due to thickness gradients in the specimen.

Version

version:20190520, v1.0

Author

D. R. G. Mitchell

Acknowledgements

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Comments

Thin areas of foils appear much brighter than thick areas in bright field and STEM HAADF images. This script extracts this low frequency variation of intensity in the image, by creating a gaussian blur of the image, using a guassian of very high standard deviation (30-200). This blurred image is then normalised to the average and the original image is divided by the normalised image to help flatten very bright and very dark areas. The standard deviation of the gaussian used can be set by running the script with the ALT key held down. This works well on areas of foil without local intensity variations (eg precipitates). If such features are present, then low standard deviation values (30-100) will result in bright haloes around the particles. In such circumstances it may be better to use larger values (eg 100-200).

The Digital Dodging script does something similar, albeit by normalising with a linear wedge created from the intensities at three user-selected points in the image.

System Requirements

This script has been tested using GMS 2.32, but should be compatible with all versions.

Known Issues

Haloes around discontinuities, such as precipitates, can be minimised by using larger blur values.

Supported

Yes.

Included Files

Main script.

Source Code