patchSmooth

Below is a demonstration of the features of the patchSmooth function

Contents

```clear; close all; clc;
```

Syntax

[P]=patchSmooth(F,V,IND_V,optionStruct);

Description

This function can smoothen the input surface surface data specified by the faces F and the nodal/vertex data V. V is typically an nx3 vertex coordinate array, where n is the number of vertices. However V may represent a general nxm array where m>0. m=1 for instance for scalar nodal data, examples include vertex quantities such as displacement magnitude and temperature.

Examples

Plot settings

```fontSize=15;
cMap=gjet(250);
```

Example 1: Smoothing a triangulated surface

```% Creating example data
[F,V]=stanford_bunny; %Some graphics data
V_true=V;

V_noisy=V+5*randn(size(V));
```

Smoothen using patchSmooth. Two methods are shown here, 'LAP', which refers to Laplacian Smoothing, and 'HC' which refers to Humphreys-Classes smoothing

```%Set number of iterations to use
smoothParameters.n=25; %Number of iterations

%Smooth using Laplacian smoothing method
smoothParameters.Method='LAP';%Smooting method
V_smooth1=patchSmooth(F,V_noisy,[],smoothParameters);

%Smooth using HC method
smoothParameters.Method='HC'; %Smoothing method
V_smooth2=patchSmooth(F,V_noisy,[],smoothParameters);
```

Visualization to compare smoothening methods

```cFigure;

subplot(2,2,1); hold on;
title('True surface','FontSize',fontSize);
gpatch(F,V,'w','k',1);

subplot(2,2,2); hold on;
title('Noisy surface','FontSize',fontSize);
gpatch(F,V_noisy,'w','k',1);

subplot(2,2,3); hold on;
title('Laplacian smoothed noisy surface','FontSize',fontSize);
gpatch(F,V,'w','none',0.5);
gpatch(F,V_smooth1,'rw','k',1);

subplot(2,2,4); hold on;
title('Humpreys-Classes smoothed noisy surface','FontSize',fontSize);
gpatch(F,V,'w','none',0.5);
gpatch(F,V_smooth2,'rw','k',1);

drawnow;
```
```indRigid=find(V(:,1)>mean(V(:,1)));

%Smooth with constraints
smoothParameters.n=25; %Number of iterations
smoothParameters.Method='HC'; %Smoothing method
smoothParameters.RigidConstraints=indRigid; %Vertices to not keep constant
V_smooth_con=patchSmooth(F,V_noisy,[],smoothParameters);
```

Visualization to compare smoothening methods

```cFigure; hold on;
title('Constrained smoothing','FontSize',fontSize);
gpatch(F,V,'w','none',0.5);
gpatch(F,V_smooth_con,'rw','k',1);
plotV(V_smooth_con(indRigid,:),'b.','MarkerSize',25)
drawnow;
```

GIBBON www.gibboncode.org

Kevin Mattheus Moerman, [email protected]

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GIBBON: The Geometry and Image-based Bioengineering add-On. A toolbox for image segmentation, image-based modeling, meshing, and finite element analysis.

Copyright (C) 2006-2022 Kevin Mattheus Moerman and the GIBBON contributors

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