added option for minPixel

[vedadb]

Added option "minPixel" not to need to do Option 1.
Option 2. just skips the generation of grains object so slight speed up. (performs the same tesselation first run as second)
Option 3 and 4 perform first modified tesselation/graincalculation first run - either as scalar ebsd map (spatialDecomposition.m) or unit cell, and they produce the same grain map. - "major speed up".
Please try

e = ebsd;
e= e.gridify;
e1 = e;

Option 1:
tic
[g,e.grainId] = calcGrains(e);
e(g(g.grainSize<5)) = [];
e=e.gridify;
g=calcGrains(e);
toc

Option 2:
tic
g1 = calcGrains(e1,'minPixel',5);
toc

Option 3:
tic
g2 = calcGrains(e1,'minPixel',5,'byScalar');
toc

Option 4:
tic
g3 = calcGrains(e1,'minPixel',5,'byUnitCell');
toc

% Elapsed time is 29.616039 seconds.
% Elapsed time is 28.059836 seconds.
% Elapsed time is 19.381225 seconds.
% Elapsed time is 17.654077 seconds.

%
% Phase Grains Pixels Mineral Symmetry Crystal reference frame
% 1 3401 635157 Copper m-3m

% g1 = grain2d
%
% Phase Grains Pixels Mineral Symmetry Crystal reference frame
% 1 3401 635157 Copper m-3m
%

% g2 = grain2d
%
% Phase Grains Pixels Mineral Symmetry Crystal reference frame
% 1 3347 634138 Copper m-3m

% g3 = grain2d
%
% Phase Grains Pixels Mineral Symmetry Crystal reference frame
% 1 3347 634138 Copper m-3m

[vedadb]

Note: As the ebsd map is changed (pixels removed), the returned grainId size is different from the input ebsd-map size, thus the ebsd-map needs to be returned as well.

e.g.

[grains,ebsd] = calcGrains(ebsd,'minPixel',5);

A quick-fix I implemented for myself was to return the ebsd map instead of grainId if minPixel was specified