source: trunk/src/transform_field/ima_filter.m @ 730

Last change on this file since 730 was 730, checked in by sommeria, 10 years ago

ima_filter put as example of transform function with input parameters

File size: 2.2 KB
Line 
1% 'ima_filter': example of image transform with input parameters: low-pass filter of an image
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%-------------------------------------
14function DataOut=ima_test(DataIn,Param)
15if isequal(DataIn,'*')
16    prompt = {'npx';'npy'};
17    dlg_title = 'get the filter size in x and y';
18    num_lines= 2;
19    def     = { '20';'20'};
20    if isfield(Param,'TransformInput')&&isfield(Param.TransformInput,'FilterBoxSize_x')&&...
21            isfield(Param.TransformInput,'FilterBoxSize_y')
22        def={num2str(Param.TransformInput.FilterBoxSize_x);num2str(Param.TransformInput.FilterBoxSize_y)};
23    end
24    answer = inputdlg(prompt,dlg_title,num_lines,def);
25    DataOut.TransformInput.FilterBoxSize_x=str2num(answer{1}); %size of the filtering window
26    DataOut.TransformInput.FilterBoxSize_y=str2num(answer{2}); %size of the filtering window
27    return
28end
29
30DataOut=DataIn; %default
31
32%definition of the cos shape matrix filter
33ix=[1/2-Param.TransformInput.FilterBoxSize_x/2:-1/2+Param.TransformInput.FilterBoxSize_x/2];%
34iy=[1/2-Param.TransformInput.FilterBoxSize_y/2:-1/2+Param.TransformInput.FilterBoxSize_y/2];%
35%del=np/3;
36%fct=exp(-(ix/del).^2);
37fct2_x=cos(ix/((Param.TransformInput.FilterBoxSize_x-1)/2)*pi/2);
38fct2_y=cos(iy/((Param.TransformInput.FilterBoxSize_y-1)/2)*pi/2);
39%Mfiltre=(ones(5,5)/5^2);
40Mfiltre=fct2_y'*fct2_x;
41Mfiltre=Mfiltre/(sum(sum(Mfiltre)));%normalize filter
42
43Atype=class(DataIn.A);% detect integer 8 or 16 bits
44if numel(size(DataIn.A))==3
45    DataOut.A=filter2(Mfiltre,sum(DataIn.A,3));%filter the input image, after summation on the color component (for color images)
46    DataOut.A=uint16(DataOut.A); %transform to 16 bit images
47else
48    DataOut.A=filter2(Mfiltre,DataIn.A)
49    DataOut.A=feval(Atype,DataOut.A);%transform to the initial image format
50end
51 
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