1 | % 'ima_filter': low-pass filter of an image followed by decimation
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2 |
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3 | %------------------------------------------------------------------------
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4 | %%%% Use the general syntax for transform fields with a single input and parameters %%%%
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5 | % OUTPUT:
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6 | % DataOut: output field structure
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7 | %
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8 | %INPUT:
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9 | % DataIn: input field structure
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10 | % Param: matlab structure whose field Param.TransformInput contains the filter parameters
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11 | %-----------------------------------
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12 |
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13 | %=======================================================================
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14 | % Copyright 2008-2019, LEGI UMR 5519 / CNRS UGA G-INP, Grenoble, France
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15 | % http://www.legi.grenoble-inp.fr
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16 | % Joel.Sommeria - Joel.Sommeria (A) legi.cnrs.fr
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17 | %
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18 | % This file is part of the toolbox UVMAT.
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19 | %
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20 | % UVMAT is free software; you can redistribute it and/or modify
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21 | % it under the terms of the GNU General Public License as published
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22 | % by the Free Software Foundation; either version 2 of the license,
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23 | % or (at your option) any later version.
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24 | %
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25 | % UVMAT is distributed in the hope that it will be useful,
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26 | % but WITHOUT ANY WARRANTY; without even the implied warranty of
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27 | % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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28 | % GNU General Public License (see LICENSE.txt) for more details.
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29 | %=======================================================================
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30 |
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31 | function DataOut=ima_filter(DataIn,Param)
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32 |
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33 | %% request input parameters
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34 | if isfield(DataIn,'Action') && isfield(DataIn.Action,'RUN') && isequal(DataIn.Action.RUN,0)
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35 | prompt = {'npx';'npy'};
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36 | dlg_title = 'get the filter size in x and y';
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37 | num_lines= 2;
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38 | def = { '20';'20'};
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39 | if isfield(Param,'TransformInput')&&isfield(Param.TransformInput,'FilterBoxSize_x')&&...
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40 | isfield(Param.TransformInput,'FilterBoxSize_y')
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41 | def={num2str(Param.TransformInput.FilterBoxSize_x);num2str(Param.TransformInput.FilterBoxSize_y)};
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42 | end
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43 | answer = inputdlg(prompt,dlg_title,num_lines,def);
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44 | DataOut.TransformInput.FilterBoxSize_x=str2num(answer{1}); %size of the filtering window
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45 | DataOut.TransformInput.FilterBoxSize_y=str2num(answer{2}); %size of the filtering window
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46 | return
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47 | end
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48 |
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49 | DataOut=DataIn; %default
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50 |
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51 | %definition of the cos shape matrix filter
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52 | bx=Param.TransformInput.FilterBoxSize_x;
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53 | by=Param.TransformInput.FilterBoxSize_y;
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54 | ix=1/2-bx/2:-1/2+bx/2;%
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55 | iy=1/2-by/2:-1/2+by/2;%
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56 | %del=np/3;
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57 | %fct=exp(-(ix/del).^2);
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58 | fct2_x=cos(ix/((Param.TransformInput.FilterBoxSize_x-1)/2)*pi/2);
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59 | fct2_y=cos(iy/((Param.TransformInput.FilterBoxSize_y-1)/2)*pi/2);
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60 | %Mfiltre=(ones(5,5)/5^2);
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61 | Mfiltre=fct2_y'*fct2_x;
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62 | Mfiltre=Mfiltre/(sum(sum(Mfiltre)));%normalize filter
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63 |
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64 | Atype=class(DataIn.A);% detect integer 8 or 16 bits
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65 | if numel(size(DataIn.A))==3
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66 | DataOut.A=filter2(Mfiltre,sum(DataIn.A,3));%filter the input image, after summation on the color component (for color images)
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67 | DataOut.A=uint16(DataOut.A); %transform to 16 bit images
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68 | else
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69 | DataOut.A=filter2(Mfiltre,DataIn.A);
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70 | DataOut.A=feval(Atype,DataOut.A);%transform to the initial image format
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71 | end
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72 | %reduce the size of the image
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73 | [npy,npx]=size(DataOut.A);
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74 | ind_y=ceil(by/2):by:npy-ceil(by/2);
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75 | ind_x=ceil(bx/2):bx:npx-ceil(bx/2);
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76 | B=DataOut.A(ind_y,ind_x);
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77 | DataOut.A=B;
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78 |
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