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processing:workflow_training
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| Both sides previous revision Previous revision Next revision | Previous revision | ||
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processing:workflow_training [2019/06/07 14:59] matthias |
processing:workflow_training [2019/09/04 16:47] (current) smerkel ↷ Links adapted because of a move operation |
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| * locate diffraction peaks, | * locate diffraction peaks, | ||
| * evaluate their intensity and that of the surrounding background, | * evaluate their intensity and that of the surrounding background, | ||
| - | * understand the [[processing:o_matrix|concept of the O-Matrix]]. | + | * understand the [[dac_experiments:geometry|concept of the O-Matrix]]. |
| [[software:fabian|Fabian]] allows you to zoom-in on a peak as well as browse through diffraction images as you increase or decrease ω. | [[software:fabian|Fabian]] allows you to zoom-in on a peak as well as browse through diffraction images as you increase or decrease ω. | ||
| Line 44: | Line 44: | ||
| ==== Working on background ==== | ==== Working on background ==== | ||
| - | To get rid of the background we now add up all the diffraction images and calculate an average and a median image. Then, every image is subtracted by this average/median image which should remove the background. Typically, with simulated data, background will not strongly affect your peak search. This point, however, is a good step to perform [[processing:background|median and average images]] calculations. But in case you have real data, this procedure is essential! | + | To get rid of the background we now add up all the diffraction images and calculate an average and a median image. Then, every image is subtracted by this average/median image which should remove the background. Typically, with simulated data, background will not strongly affect your peak search. This point, however, is a good step to perform [[processing:backgroundgeneral|median and average images]] calculations. But in case you have real data, this procedure is essential! |
| The average image is a representation of the data that includes | The average image is a representation of the data that includes | ||
| * the background, | * the background, | ||
| * the diffraction from the //surrounding matrix// or the //powder portion of the sample// that gives you continuous diffraction rings in the image, | * the diffraction from the //surrounding matrix// or the //powder portion of the sample// that gives you continuous diffraction rings in the image, | ||
| - | * the diffraction from the sample grains, that give rise to well-defined diffraction spots. | + | * the diffraction from the //sample grains//, that give rise to well-defined diffraction spots. |
| + | |||
| + | The median image is a representation of the data that includes | ||
| + | * the background, | ||
| + | * the diffraction from the //surrounding matrix// or the //powder portion of the sample// that gives you continuous diffraction rings in the image. | ||
| + | The diffraction from the //sample grains//, that give rise to well-defined diffraction spots are removed and **//do not contribute//** to the median image! | ||
| In [[software:fabian|Fabian]], you can subtract the median image from the original data. You will see the spots from the sample grains only. In theory, all background and contribution from the surrounding sample matrix should be removed. | In [[software:fabian|Fabian]], you can subtract the median image from the original data. You will see the spots from the sample grains only. In theory, all background and contribution from the surrounding sample matrix should be removed. | ||
processing/workflow_training.1559919573.txt.gz · Last modified: 2019/06/07 14:59 by matthias
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