Concurrently segmenting for HAGB and LAGB?

[MTEXNewbie]

Currently, I segment once at the beginning of EBSD data processing. Is there a way to segment HAGB (>15°) and LAGB (2°-15°) at the beginning simultaneously?

Current workflow:

%% Import the Data

% create an EBSD variable containing the data

ebsd = loadEBSD(fname,CS,'interface','crc',...

  'convertSpatial2EulerReferenceFrame');

% % Take a look at the initial data without the non-indexed points

% plot(ebsd('indexed'))

% ######### Correction #########

% plot(ebsd,ebsd.mad)

% mtexColorbar

% % plot a MAD histogram

% hist(ebsd.mad)

% take only those measurements with MAD smaller than prescribed value set them to nonIndexed

ebsd(ebsd.mad>1.2).phase=0;

% ######### Adjust (rotate & crop) #########

% rotate the whole data set (orientations and spatial) about the z-axis by

% 90*degree to get vertical strut

ebsd = rotate(ebsd,-90*degree);

% % plot the band contrast

% plot(ebsd,ebsd.bc)

% colormap gray % this makes the image grayscale

% mtexColorbar

% segmentation angle typically 10 to 15 degrees

seg_angle = 15;

% minimum indexed points per grain between 5 and 10

min_points = 0;

% compute grains. either use 'angle' or 'unitcell' for segmentation

[grains,ebsd.grainId] = calcGrains(ebsd('indexed'),'unitcell');

% [grains,ebsd.grainId,ebsd.mis2mean] = calcGrains(ebsd,'angle',seg_angle*degree);

% ######### Clean #########

% Remove small grains with less than min_points indexed points

grains = grains(grains.grainSize > min_points);

% Re-calculate grain model to cleanup grain boundaries with less than minimum index points

% used ebsd points within grains having the minimum indexed number of points (e.g. 5~10 points)

ebsd = ebsd(grains);

[grains,ebsd.grainId] = calcGrains(ebsd('indexed'),'unitcell');

% [grains,ebsd.grainId,ebsd.mis2mean] = calcGrains(ebsd,'angle',seg_angle*degree,'boundary','tight');

% ######### Smooth #########

% Due to the measurement grid, the grain boundaries often show a typical staircase effect.

% This effect can be reduced by smoothing the grain boundaries.

grains = smooth(grains,4);

ebsd = ebsd(grains);

Another question, what is the segment angle set by the below code?

[grains,ebsd.grainId] = calcGrains(ebsd('indexed'),'unitcell');

[Rüdiger Kilian]

Hi,
you can segment initially with a fairly low angle and use an misorientitation angle as condition to select boundaries within a given interval. You'll find the procedure described in the forum it if you look for low angle boundaries.
Roughly like this:
gb = grains.boundary('x','x')
moriAngle = gb.misorientation.angle
LAB = gb(moriAngle > 1*degee & moriAngle < 10*degee)
LAB = gb(moriAngle >= 10*degree)

Cheers,
Rüdiger
________________________________________
From: mtex...@googlegroups.com <mtex...@googlegroups.com> on behalf of MTEXNewbie <rashed...@gmail.com>
Sent: Thursday, April 4, 2019 2:03:03 PM
To: MTEX
Subject: {MTEX} Concurrently segmenting for HAGB and LAGB?

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[MTEXNewbie]

Hi Rüdiger,

I have found a past solution here - https://groups.google.com/d/msg/mtexmail/OqS9OfSiWM0/cYcHX--ZBQAJ

I consider HAGB (>15°) = Grains and LAGB (2°-15°) = Sub-grains. If I calculate HAGB by segmenting at an high angle, I often encounter problem. But the other option to segment using 'unitcell' gives good result (the workflow shown above follows this procedure as the initial segmentation).

What is the segment angle set by the below code?

[Rüdiger Kilian]

The default segmentation angle is 10 degree.

Rüdiger
________________________________________
From: mtex...@googlegroups.com <mtex...@googlegroups.com> on behalf of MTEXNewbie <rashed...@gmail.com>

Sent: Friday, April 5, 2019 12:47:38 PM
To: MTEX
Subject: Re: {MTEX} Concurrently segmenting for HAGB and LAGB?

[MTEXNewbie]

Hi Rüdiger,

I am getting different result from,

[grains,ebsd.grainId] = calcGrains(ebsd('indexed'),'unitcell');

vs

seg_angle = 10;

[grains,ebsd.grainId,ebsd.mis2mean] = calcGrains(ebsd,'angle',seg_angle*degree,'boundary','tight');

Does the first line works in a different way even though the default segmentation angle is 10 degree there?

[Rüdiger Kilian]

Yes.

________________________________________
From: mtex...@googlegroups.com <mtex...@googlegroups.com> on behalf of MTEXNewbie <rashed...@gmail.com>

Sent: Friday, April 5, 2019 1:24:12 PM

To: MTEX
Subject: Re: {MTEX} Concurrently segmenting for HAGB and LAGB?

[MTEXNewbie]

Hi Rüdiger,

I was wondering if there is more detail available on how the 'unitcell' approach works, I believe it only gives HAGBs?

[grains,ebsd.grainId] = calcGrains(ebsd('indexed'),'unitcell');

Ref - https://mtex-toolbox.github.io/files/doc/EBSD.calcGrains.html

[Rüdiger Kilian]

Hi,
no, it simply ties boundaries to explicitly indexed pixels, has nothign to do with the threshold angle.
Cheers,
Rüdiger

________________________________________
From: mtex...@googlegroups.com <mtex...@googlegroups.com> on behalf of MTEXNewbie <rashed...@gmail.com>

Sent: Sunday, April 7, 2019 2:40:33 PM

To: MTEX
Subject: Re: {MTEX} Concurrently segmenting for HAGB and LAGB?

Hi Rüdiger,

I was wondering if there is more detail available on how the 'unitcell' approach works, I believe it only gives HAGBs?

[grains,ebsd.grainId] = calcGrains(ebsd('indexed'),'unitcell');