COMSOL Multiphysics™

flim2curve
Purpose
flim2curve
Create 2D curve object from image data.
Syntax
Description
[c,r] = flim2curve(I,fmt,...)
[c,r] = flim2curve(I,fmt,...) creates a curve2 object c and small curve2
objects r from the image I (gray-scale or RGB) operated upon by parameters
contained in the cell-array fmt. c is a curve2 object that approximates the contours
of I. r is a cell-array of curve2 objects containing small curves detected by the
argument. This is very useful for images containing noise. I is either an m-by-n
intensity image matrix or an m-by-n-by-3 RGB-image matrix as typically obtained
from the function imread. fmt is a cell-array of length 2 used to create contours
from I. If fmt{2} is empty then the scalar fmt{1} is used as a threshold value. If
instead, fmt{1} is empty, then the vector fmt{2} is used to specify the contour
levels of interest. See the function contourc for an explanation of the contour level
syntax in fmt{2}. All flmesh2spline properties are supported.
c = flim2curve(i,fmt,...) is an alternative syntax and is equivalent to c =
geomcsg({},{c,r{:}}) where the arguments c and r are those obtained from the
other call. This is less stable whenever i contain small structures.
Examples
Create contour-curves from function.
[x,y] = meshgrid(linspace(-3,3,50));
z = (x.^2+y.^2).*exp(-x.^2-y.^2)+cos(y)+sin(x);
figure
imagesc(z)
g = flim2curve(z,{[],[-1.5:0.5:2]});
figure
geomplot(g,'Pointmode','off');
Create curves from noisy picture. This example does not work in COMSOL Script
because it uses the mri.mat file available in MATLAB.
load mri
pic = D(:,:,1,10);
figure
image(pic)
v = axis;
[c,r] = flim2curve(pic,{[],1:30:91},'KeepFrac',0.10);
figure
geomplot(c,'Pointmode','off');
Plot all small curves in a green color.
for j = 1:length(r)
hold on
geomplot(r{j},'Pointmode','off','edgecolor','g')
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