Error Concealment*
damaged |
interpolated |
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Image Processing |
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Image Inpainting*
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Image Processing |
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Image Mosaicing*
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Geometric Transformation
In the virtual space, you can have any kind of apple you want! MATLAB functions: griddata, interp2, maketform, imtransform
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Basic Principle
• (x,y) (x’,y’) is a geometric 
transformation
• We are given pixel values at (x,y) and want to interpolate the unknown 
values at (x’,y’)
• Usually (x’,y’) are not integers and therefore we can use linear
interpolation to guess their values
MATLAB implementation: z’=interp2(x,y,z,x’,y’,method);
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Rotation
y’ |
y |
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x’
θ
x
x' |
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cos |
sin x |
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sin |
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y' |
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cos |
y |
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MATLAB Example
z=imread('cameraman.tif');
% original coordinates [x,y]=meshgrid(1:256,1:256);
%new coordinates a=2;
for i=1:256;for j=1:256; x1(i,j)=a*x(i,j); y1(i,j=y(i,j)/a;
end;end
%Do the interpolation z1=interp2(x,y,z,x1,y1,'cubic');
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Image Processing |
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Rotation Example
θ=3o
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Scale
a=1/2
x' |
a |
0 x |
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0 |
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y' |
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1/ a |
y |
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Affine Transform
square |
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parallelogram |
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x' |
a11 |
a12 |
x |
dx |
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y' |
a21 |
a22 |
y |
d y |
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