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boblsturm@0
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1 function [Y] = rot_kernel(kernel, deg)
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2
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3 N = size( kernel, 1 );
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4 max_rots = 4*(N-1);
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boblsturm@0
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5 deg_per_rot = 360 / max_rots;
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6
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7 % deg = deg - mod( deg, deg_per_rot );
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8 deg = deg_per_rot * ( round( deg / deg_per_rot ) );
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boblsturm@0
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9 num_of_rots = ceil( deg / deg_per_rot );
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boblsturm@0
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10
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11 if num_of_rots < 1
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12 Y = kernel;
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13 return
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14 else
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15 for r = 1:num_of_rots
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16 if mod( r, 2 ) == 0
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boblsturm@0
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17 kernel = rot_outer_layer( kernel );
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18 else
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19 kernel = rot_inner_layer( kernel );
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20 end
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boblsturm@0
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21 end
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22 end
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23
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24 Y = kernel;
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boblsturm@0
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25
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boblsturm@0
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26 end
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boblsturm@0
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27
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28 function [Y] = rot_outer_layer( A )
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boblsturm@0
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29 dim = size( A, 1 );
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30 top = A( 1, : );
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boblsturm@0
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31 right = A( 2:dim, dim )';
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32 bottom = fliplr( A( dim, 1:dim - 1 ) );
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boblsturm@0
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33 left = fliplr( A( 2:dim - 1, 1 )' );
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boblsturm@0
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34 shifted_layers = wshift('1D',[top,right,bottom,left],-1);
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35
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boblsturm@0
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36 top = shifted_layers( 1:length(top));
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boblsturm@0
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37 last_ind = length( top );
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boblsturm@0
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38
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39 right = shifted_layers( last_ind + 1 : last_ind + length(right));
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boblsturm@0
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40 last_ind = last_ind + length( right );
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boblsturm@0
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41
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boblsturm@0
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42 bottom = shifted_layers( last_ind + 1 : last_ind + length(bottom));
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boblsturm@0
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43 last_ind = last_ind + length( bottom );
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boblsturm@0
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44
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boblsturm@0
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45 left = shifted_layers( last_ind + 1 : end );
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boblsturm@0
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46
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boblsturm@0
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47 A( 1, : ) = top;
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48 A( 2:dim, dim ) = right';
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boblsturm@0
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49 A( dim, 1:dim - 1 ) = fliplr( bottom );
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boblsturm@0
|
50 A( 2:dim - 1, 1 ) = fliplr( left' );
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boblsturm@0
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51
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boblsturm@0
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52 Y = A;
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boblsturm@0
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53 end
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boblsturm@0
|
54
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boblsturm@0
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55 function [Y] = rot_inner_layer( kernel )
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boblsturm@0
|
56 % dim = size( kernel, 1 );
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boblsturm@0
|
57 % if dim < 2
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boblsturm@0
|
58 % Y = rot_outer_layer( kernel )
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boblsturm@0
|
59 % return;
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boblsturm@0
|
60 % else
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boblsturm@0
|
61 % Y = rot_inner_layer( kernel( 2:dim - 1, 2:dim - 1 ) )
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boblsturm@0
|
62 % end
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boblsturm@0
|
63 dim = size( kernel, 1 );
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boblsturm@0
|
64
|
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boblsturm@0
|
65 if mod( dim / 2, 2 ) == 0
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boblsturm@0
|
66 max_rots = dim / 2 - 1;
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boblsturm@0
|
67 else
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boblsturm@0
|
68 max_rots = dim / 2 - 0.5;
|
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boblsturm@0
|
69 end
|
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boblsturm@0
|
70
|
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boblsturm@0
|
71 low = 2;
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boblsturm@0
|
72 high = dim - 1;
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|
boblsturm@0
|
73 for i = 1:max_rots
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boblsturm@0
|
74 kernel( low:high, low:high ) = rot_outer_layer( kernel( low:high, low:high ) );
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boblsturm@0
|
75 low = low + 1;
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|
boblsturm@0
|
76 high = high - 1;
|
|
boblsturm@0
|
77 end
|
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boblsturm@0
|
78
|
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boblsturm@0
|
79 Y = kernel;
|
|
boblsturm@0
|
80 end |
