change scale of EBSD maps

[grandr...@gmail.com]

Hello I am importing .ctf files of EBSD data into Mtex, and have three quick questions;

1.  I would like to override the scale information (pixel:micron information) as the one in the .ctf is slightly incorrect due to a calibration issue we had last year.  Is there a way to do this via MTEX or do I have to edit the .ctf manually? 

2; Can MTEX correctly deal with EBSD data where the x and y grid spacing is different? 
3. Can the gridify function deal with EBSD data where the x and y grid spacing is different? 

Our SEM never outputs a perfectly square grid, it's always slightly rectangular which can be inconvenient.

Thank you, Jessica.

[Thomas Simm]

I also wanted to do something similar, change x and y values, as I recall I tried changing them using something like ebsd.x=ebsd.x*1.2 but this didn't work for some reason so I gave up because it wasn't important at the time.

An area where it would be useful for me is to correct for drift, so for example we could compare the SEM image with the EBSD map find the drift as a vector field and then change ebsd.x and ebsd.y to remove the drift

Tom

[Rüdiger Kilian]

Hello,
to change the scaling and strange rounding errors in the  ebsd stepsize, changing ebsd.unitCell sort of worked for me.
All the best,
Rüdiger

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From: mtex...@googlegroups.com [mtex...@googlegroups.com] on behalf of Thomas Simm [thoma...@gmail.com]
Sent: Thursday, May 05, 2016 10:37 AM
To: MTEX
Subject: {MTEX} Re: change scale of EBSD maps

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[grandr...@gmail.com]

So to answer my own questions,

1.  No, you cannot override the scale information using statements such as ebsd.x=ebsd.x*0.9108+0.0255.  For .ctf imports, editing the header (spacing in x or y) does not work either.  You must alter the location of each grid point, which can be done in excel.

2.  Yes, the ebsd workspace variable can handle different ebsd.x and ebsd.y spacings.

3.  I haven't checked gridify yet.

Jessica

[Ralf Hielscher]

Hi Jessica,

let me try to answer

1) overriding scale information should work as you did it. The important thing is to recompute the unitCell by

ebsd.x=ebsd.x*0.9108+0.0255
ebsd.unitCell = calcUnitCell([ebsd.prop.x(:),ebsd.prop.y(:)]);

I might try that unitCell is updated automatically in future releases. 

3) gridify should work as well

 

Ralf.