source: trunk/src/transform_field/ima_filter.m @ 742

% 'ima_filter': example of image transform with input parameters: low-pass filter of an image

%------------------------------------------------------------------------
%%%%  Use the general syntax for transform fields with a single input and parameters %%%%
% OUTPUT: 
% DataOut:   output field structure 

%INPUT:
% DataIn:  input field structure
% Param: matlab structure whose field Param.TransformInput contains the filter parameters
%-----------------------------------

%-------------------------------------
function DataOut=ima_test(DataIn,Param)
if isequal(DataIn,'*')
    prompt = {'npx';'npy'};
    dlg_title = 'get the filter size in x and y';
    num_lines= 2;
    def     = { '20';'20'};
    if isfield(Param,'TransformInput')&&isfield(Param.TransformInput,'FilterBoxSize_x')&&...
            isfield(Param.TransformInput,'FilterBoxSize_y')
        def={num2str(Param.TransformInput.FilterBoxSize_x);num2str(Param.TransformInput.FilterBoxSize_y)};
    end
    answer = inputdlg(prompt,dlg_title,num_lines,def);
    DataOut.TransformInput.FilterBoxSize_x=str2num(answer{1}); %size of the filtering window
    DataOut.TransformInput.FilterBoxSize_y=str2num(answer{2}); %size of the filtering window
    return
end

DataOut=DataIn; %default

%definition of the cos shape matrix filter
ix=[1/2-Param.TransformInput.FilterBoxSize_x/2:-1/2+Param.TransformInput.FilterBoxSize_x/2];%
iy=[1/2-Param.TransformInput.FilterBoxSize_y/2:-1/2+Param.TransformInput.FilterBoxSize_y/2];%
%del=np/3;
%fct=exp(-(ix/del).^2);
fct2_x=cos(ix/((Param.TransformInput.FilterBoxSize_x-1)/2)*pi/2);
fct2_y=cos(iy/((Param.TransformInput.FilterBoxSize_y-1)/2)*pi/2);
%Mfiltre=(ones(5,5)/5^2);
Mfiltre=fct2_y'*fct2_x;
Mfiltre=Mfiltre/(sum(sum(Mfiltre)));%normalize filter

Atype=class(DataIn.A);% detect integer 8 or 16 bits
if numel(size(DataIn.A))==3
    DataOut.A=filter2(Mfiltre,sum(DataIn.A,3));%filter the input image, after summation on the color component (for color images)
    DataOut.A=uint16(DataOut.A); %transform to 16 bit images
else
    DataOut.A=filter2(Mfiltre,DataIn.A)
    DataOut.A=feval(Atype,DataOut.A);%transform to the initial image format
end