Stitching issue from master pattern equator with get_patterns()

[hakonanes]

When sampling a hexagonal master pattern of a phase with point group 6mm, I get a stitching line where the "seam" between the two hemispheres is:

The detector normal is parallel to the sample normal (sample_tilt=0), and the crystal orientation is (30, 0, 0) degrees. The seam can be seen between the [1000] and [1100] zone axes.

The master pattern's northern and southern hemispheres in stereographic projection, generated with EMsoft v5.0:

Don't know the reason for this issue, and don't have the time to look into it at the moment. Reported it here so we can deal with this at a later time.

[CiosG]

I have seen something like this and it was related to fact that hemisphere size in pixels was even number while should be odd. But it was not EMsoft simulation but Dynamics.

Grzegorz

W dniu 2021-05-19 17:34, Håkon Wiik Ånes napisał(a):

When sampling a hexagonal master pattern of a phase with point group 6mm, I get a stitching line where the "seam" between the two hemispheres is:

[1]

The detector normal is parallel to the sample normal (sample_tilt=0), and the crystal orientation is (30, 0, 0) degrees. The seam can be seen between the [1000] and [1100] zone axes.

The master pattern's northern and southern hemispheres in stereographic projection, generated with EMsoft v5.0: [2]

Don't know the reason for this issue, and don't have the time to look into it at the moment. Reported it here so we can deal with this at a later time.

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[1] https://user-images.githubusercontent.com/12139781/118839435-c3074100-b8c6-11eb-938b-23d5c88b34bc.png [2] https://user-images.githubusercontent.com/12139781/118840047-53de1c80-b8c7-11eb-9181-0270dbc9abb6.png [3] https://github.com/pyxem/kikuchipy/issues/357 [4] https://github.com/notifications/unsubscribe-auth/AI3HGBQJW4KAQMUPYG3QWILTOPK73ANCNFSM45E54DDA

-- Cios Grzegorz Academic Centre for Materials and Nanotechnology (ACMiN) AGH University of Science and Technology, Krakow, Poland 30 Mickiewicza, 30-059 Krakow bldg. D-16 (Kawiory 30, 30-055 Krakow), room 2.23 tel: +48 12 617 52 78

[hakonanes]

Thanks for letting me know, @CiosG! Just so I understand you correctly, you saw this after sampling with another software than kikuchipy (MasterPattern.get_patterns())? Sampling with Bruker DynamicS?

I think the reason that I haven't seen this before is that I've mostly worked with centrosymmetric materials where we only need the northern hemisphere of the master pattern. So I think all sampling from non-centrosymmetric master patterns where we need both hemispheres have this issue...

The same pattern simulated with EMsoft with the exact same conditions:

[hakonanes]

The master patterns above had 1001 x 1001 pixels.

[CiosG]

After simulation with DynamicS we need to save the master pattern (stereographic projection) in odd number dimensions like 513x513 and then we stitch two the same hemispheres. When I once did 512x512 I have seen similar stitches.

I think EMSoft does something similar to keep the number odd.

In the EMEBSDmaster.nml:

! number of pixels along x-direction of the square master pattern
(2*npx+1 = total number) npx = 500,

best regards Grzegorz

W dniu 2021-05-19 18:10, Håkon Wiik Ånes napisał(a):

Thanks for letting me know, @CiosG [1]! Just so I understand you correctly, you saw this after sampling with another software than kikuchipy (MasterPattern.get_patterns()). Sampling with Bruker DynamicS?

I think the reason that I haven't seen this before is that I've mostly worked with centrosymmetric materials where we only need the northern hemisphere of the master pattern. So I think all sampling from non-centrosymmetric master patterns where we need both hemispheres have this issue...

The same pattern simulated with EMsoft with the exact same conditions:

[2]

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[1] https://github.com/CiosG [2] https://user-images.githubusercontent.com/12139781/118846831-652a2780-b8cd-11eb-87f9-cfcf9058ae92.png [3] https://github.com/pyxem/kikuchipy/issues/357#issuecomment-844252039 [4] https://github.com/notifications/unsubscribe-auth/AI3HGBX7OYZI5BLTRAFSD3TTOPPIVANCNFSM45E54DDA

-- Cios Grzegorz Academic Centre for Materials and Nanotechnology (ACMiN) AGH University of Science and Technology, Krakow, Poland 30 Mickiewicza, 30-059 Krakow bldg. D-16 (Kawiory 30, 30-055 Krakow), room 2.23 tel: +48 12 617 52 78