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FilteringAndCleaningTheData

Introduction

Filtering and cleaning the data is performed in several steps

1. calculate a median image,
2. remove the diamond spots,
3. remove the shadow of the DAC at high rotation angles,
4. replace images that really too dirty to do anything.

Calculate the median image

The background, from the detector, and smaller grains within the sample, is subtracted by calculating an ω-median image.

For each pixel on the detector, the median value of all intensities measured over the full ω-range. Those values are then combined into a median image, that includes the background signal from the detector and that of smaller grains. After subtracting this median ω-median image from each image, the spots from the bigger grains in the sample are clearly visible.

This is done using the image_math routine, from the Fable package.

image_math usage: image_math name_stem first_file last_file add|subtract|median