Image Processing and Analysis Image Gradient with Matlab

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Image Processing and Analysis Image Gradient
with Matlab

• Alexander Kolesnikov
• 03.11.2009

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Example Function 1
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Example Gradient field for the function 1
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Example Gradient magnitude
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Example Gradient magnitude
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Example 1 Matlab program
v -3.1253 X,Y meshgrid(v) Z
exp(-X.2 - Y.2) figure(21) white 1 1
1 set(gcf,'color',white') meshc(X,Y,Z) axis(-3
3 -3 3 0 1) set(gcf,'color',white') figure(22)
set(gcf,'color',white') px,py
gradient(Z,.2,.2) contour(v,v,Z), hold
on quiver(v,v,px,py), hold off figure(23)
set(gcf,'color',white') Mxpx.px
Mypy.py Msqrt(MxMy) meshz(X,Y,M)
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Example Function 2
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Example Gradient field for the functoin 2
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Function 2 Gradient Magnitude
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Function 2 Matlab program
v -3.1253 X,Y meshgrid(v) Z
X.exp(-X.2 - Y.2) figure(21) white 1 1
1 set(gcf,'color',white') meshc(X,Y,Z) axis(-3
3 -3 3 -0.4 0.5) set(gcf,'color',white') figure(
22) set(gcf,'color',white') px,py
gradient(Z,.2,.2) contour(v,v,Z), hold
on quiver(v,v,px,py), hold off
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Example Function 3
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Example Gradient field for the function 3
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Function 3 Matlab program
v -3.1253 X,Y meshgrid(v) Z
peaks(X,Y) figure(21) white 1 1
1 set(gcf,'color',white') meshc(X,Y,Z) axis(-3
3 -3 3 -10 5) set(gcf,'color',white') figure(22)
set(gcf,'color',white') px,py
gradient(Z,.2,.2) contour(v,v,Z), hold
on quiver(v,v,px,py), hold off
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Gradient operators in discrete space