source: trunk/src/transform_field/ima_decimate.m @ 1027

Last change on this file since 1027 was 1027, checked in by g7moreau, 3 years ago
  • Update Copyright 2017 -> 2018
File size: 3.2 KB
Line 
1% 'ima_filter':  low-pass filter of an image followed by decimation
2
3%------------------------------------------------------------------------
4%%%%  Use the general syntax for transform fields with a single input and parameters %%%%
5% OUTPUT:
6% DataOut:   output field structure
7%
8%INPUT:
9% DataIn:  input field structure
10% Param: matlab structure whose field Param.TransformInput contains the filter parameters
11%-----------------------------------
12
13%=======================================================================
14% Copyright 2008-2018, LEGI UMR 5519 / CNRS UGA G-INP, Grenoble, France
15%   http://www.legi.grenoble-inp.fr
16%   Joel.Sommeria - Joel.Sommeria (A) legi.cnrs.fr
17%
18%     This file is part of the toolbox UVMAT.
19%
20%     UVMAT is free software; you can redistribute it and/or modify
21%     it under the terms of the GNU General Public License as published
22%     by the Free Software Foundation; either version 2 of the license,
23%     or (at your option) any later version.
24%
25%     UVMAT is distributed in the hope that it will be useful,
26%     but WITHOUT ANY WARRANTY; without even the implied warranty of
27%     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
28%     GNU General Public License (see LICENSE.txt) for more details.
29%=======================================================================
30
31function DataOut=ima_filter(DataIn,Param)
32
33%% request input parameters
34if isfield(DataIn,'Action') && isfield(DataIn.Action,'RUN') && isequal(DataIn.Action.RUN,0)
35    prompt = {'npx';'npy'};
36    dlg_title = 'get the filter size in x and y';
37    num_lines= 2;
38    def     = { '20';'20'};
39    if isfield(Param,'TransformInput')&&isfield(Param.TransformInput,'FilterBoxSize_x')&&...
40            isfield(Param.TransformInput,'FilterBoxSize_y')
41        def={num2str(Param.TransformInput.FilterBoxSize_x);num2str(Param.TransformInput.FilterBoxSize_y)};
42    end
43    answer = inputdlg(prompt,dlg_title,num_lines,def);
44    DataOut.TransformInput.FilterBoxSize_x=str2num(answer{1}); %size of the filtering window
45    DataOut.TransformInput.FilterBoxSize_y=str2num(answer{2}); %size of the filtering window
46    return
47end
48
49DataOut=DataIn; %default
50
51%definition of the cos shape matrix filter
52bx=Param.TransformInput.FilterBoxSize_x;
53by=Param.TransformInput.FilterBoxSize_y;
54ix=1/2-bx/2:-1/2+bx/2;%
55iy=1/2-by/2:-1/2+by/2;%
56%del=np/3;
57%fct=exp(-(ix/del).^2);
58fct2_x=cos(ix/((Param.TransformInput.FilterBoxSize_x-1)/2)*pi/2);
59fct2_y=cos(iy/((Param.TransformInput.FilterBoxSize_y-1)/2)*pi/2);
60%Mfiltre=(ones(5,5)/5^2);
61Mfiltre=fct2_y'*fct2_x;
62Mfiltre=Mfiltre/(sum(sum(Mfiltre)));%normalize filter
63
64Atype=class(DataIn.A);% detect integer 8 or 16 bits
65if numel(size(DataIn.A))==3
66    DataOut.A=filter2(Mfiltre,sum(DataIn.A,3));%filter the input image, after summation on the color component (for color images)
67    DataOut.A=uint16(DataOut.A); %transform to 16 bit images
68else
69    DataOut.A=filter2(Mfiltre,DataIn.A);
70    DataOut.A=feval(Atype,DataOut.A);%transform to the initial image format
71end
72%reduce the size of the image
73[npy,npx]=size(DataOut.A);
74ind_y=ceil(by/2):by:npy-ceil(by/2);
75ind_x=ceil(bx/2):bx:npx-ceil(bx/2);
76B=DataOut.A(ind_y,ind_x);
77DataOut.A=B;
78
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