rourou11's profile - activity

how to create SparseMat???

well M(rows)=256, N(cols)=320, T(number of frames"liste.size()")=2310

I definite my matrix like that and that change from sequence to other

cv::Mat output(rows*cols,liste.size(),CV_8UC3);

I get the best idea to express may self and I try to compute the Fourier transform with respect to the time coordinate. I try to reshape my 3D cube into a 2D matrix, where the vertical coordinate is the pixel index (in the range [0, MN-1]) and the horizontal coordinate the time (range [0, T-1]), i.e. each row contains the values of one pixel in the sequence.and then apply the DFT routine along each row with the cv::dft() function and the flag CV_DFT_ROWS.in which, M x N is the size of each frame and T is the total number of frames . but the code didn't run I suupose because of big size of mat output. How can I resolve this thdrksdfthmn???

YES thdrksdfthmn IT's probably near to my goal to applicate FFT on vector of size N (number of frame) at each (x,y) is changing in time but how in c++.

I read a lot fo tutorials but they always show how to compute FFT at 1 image "mat" i didn't find FFT of 3D and what about FFT means I have Idea

Hello, I want to computing FFT at 3D matin C++: I have n images that I want to calculate FFT at z axe for each pixel(x,y), and as a result the n images of amplitude and phase... but I have no idea how to make that please help me.

cv::Mat phase;
 cv::Mat magI;
 cv::Mat I;
 cv::Mat padded;
 cv::Mat output;     
  cv::Mat ampIm; 
  I = imread(liste[0].toStdString().c_str(), CV_LOAD_IMAGE_GRAYSCALE);
 int rows=I.rows;
 int cols=I.cols;

 for(int i=0;i<rows;i++){
for(int j=0;j<cols;j++){
     for(int k=0;k<liste.size();k++)
      {

        I = imread(liste[k].toStdString().c_str(), CV_LOAD_IMAGE_GRAYSCALE);
       Vec3b color = I.at<Vec3b>(Point(i,j));
        output.at<Vec3b>(Point(j+i*(rows-1),k))=color;


    }
    }
   }

   int m = cv::getOptimalDFTSize(output.rows );
  int n = getOptimalDFTSize( output.cols ); // on the border add zero values
  cv::copyMakeBorder(output, padded, 0, m - output.rows, 0, n - output.cols, BORDER_CONSTANT, Scalar::all(0));

cv::Mat planes[] = {Mat_<float>(padded), Mat::zeros(padded.size(), CV_32F)};
cv::Mat complexI;
merge(planes, 2, complexI);         // Add to the expanded another plane with zeros

dft(complexI, complexI,cv::DFT_ROWS|cv::DFT_COMPLEX_OUTPUT);            // this way the result may fit in the        source matrix


split(complexI, planes);                   // planes[0] = Re(DFT(I), planes[1] = Im(DFT(I))



  cv::cartToPolar   (planes[0],planes[1],magI,phase,true);
     magI += Scalar::all(1);                    // switch to logarithmic scale
        log(magI, magI);

     for(int k=0;k<liste.size();k++){
    for(int i=0;i<rows;i++){
     for(int j=0;j<cols;j++){
     Vec3b colorF =magI.at<Vec3b>(Point(j+i*(rows-1),k));
    ampIm.at<Vec3b>(Point(i,j))=colorF;
}
}     
   //save ampIm;
}

Hello, I want to rearrange values from planes[0] after computing FFT in image in order to display amplitude image but how to browser it. Thanks.

Mat magI;
 cv::Mat phase;
  img->load(liste[0]);
 *img = img->scaled(widget.imageLabel->width(), widget.imageLabel->height(),Qt::IgnoreAspectRatio,Qt::FastTransformation);
  QPixmap pixmap=QPixmap(QPixmap::fromImage(*img));
 int rows=pixmap.width();
 int cols=pixmap.height();
 cv::vector<int> pixels; 
 for(int i=0;i<rows;i++){
  for(int j=0;j<cols;j++){
      for(int k=0;k<liste.size();k++)
      {
       cv::Mat I = imread(liste[k].toStdString().c_str(), CV_LOAD_IMAGE_GRAYSCALE);
      int fftp = I.at<uchar>(j,i);
     pixels[k]=fftp;  }
 cv::Mat ff;
cv::dft(pixels, ff, cv::DFT_ROWS|cv::DFT_COMPLEX_OUTPUT);
 cv::Mat planes[] = {cv::Mat::zeros(pixels.size(),1, CV_32F), cv::Mat::zeros(pixels.size(),1, CV_32F)};
cv::split(ff, planes);                   
magnitude(planes[0], planes[1], planes[0]);
int m = planes[0].cols;
for(int l=0;l<m;l++)
      {
 magI.at<uchar>(j,i) = planes[0].0;//ERROR Iwant to put the first value of planes[0] in the first point in the image HOW
}

  }
}

ok thank you

hello, I want to applicate FFT at one pixel in image at get the complex composants with opencv. please help me. Thanks.

I want it with C++

well, this code display FFT amplitude and phase image but it didn't applicate FFT in all image's pixels it applicate like I said before at each pixel in the time pixel 1 of image1, pixel1 in image2..., pixel1 in image n and then pixel 2 in image1, pixel 2 in image2..., pixel 2 in image n... extract amplitude equation and phase from them and rearrange pixel in their images and display them. I hope this time my problem is clear to you ... and Thanks a lot.

function fft_img = get_FFT()

%Compute the FFT phase or Amplitude

CtrlFigHdl = GetFigHdl('CtrlFig'); ToggleButtonAmpHdl = findobj(CtrlFigHdl, 'Tag', 'ToggleButtonAmp'); ToggleButtonPhaseHdl = findobj(CtrlFigHdl, 'Tag', 'ToggleButtonPhase');

% detect if we want a Phase or Amplitude if get(ToggleButtonAmpHdl, 'Value') BufferType = 1; % FFT Amplitude type elseif get(ToggleButtonPhaseHdl, 'Value') BufferType = 2; % FFT Phase type else fft_img = []; return; end

CtrlFigUsrDat = get(CtrlFigHdl, 'UserData');

% Do we need to update the FFT? if (BufferType == CtrlFigUsrDat.Current.BufferType) && ~isempty(CtrlFigUsrDat.Current.Buffer) % No we don't fft_img = CtrlFigUsrDat.Current.Buffer; else % we need to compute a new fft % Notes: fft(uint16) is double; fft(single) is single; fft(double) is double

clear CtrlFigUsrDat; % Avoid duplication of data
CtrlFigUsrDat = ClearBuffer('main'); % makes room

% Get the ROI limits
[ROI_min_x ROI_max_x ROI_min_y ROI_max_y] = getROIlimits();

try
    h = [];

    % pre-allocation. We make it single as it's half the data needed and still good enough. 
    % The FFT computation below is converted in single as it is done, plane by plane
    fft_img = zeros(ROI_max_y-ROI_min_y+1, ROI_max_x-ROI_min_x+1, CtrlFigUsrDat.Current.z_dim, 'single');

    sizeOfSingle = 4;

    h = waitbar(0,[num2str(size(fft_img,2)) ' * ' num2str(size(fft_img,1)) ' pixels * ', ...
        num2str(size(fft_img,3)) ' frames * single (32 bpp) = ' num2str(numel(fft_img)*sizeOfSingle/(1024*1024),'%.2f'), ' MB'], ...
        'Name', 'Computing FFT...', 'WindowStyle', 'modal');
    set(h, 'HandleVisibility', 'off'); % do not integrate this into the line above
    pause(0.1); % allow refresh

    if BufferType == 1 % Amplitude
        for i = ROI_min_x:ROI_max_x % along x
            fft_img( : , i-ROI_min_x+1 , :) = abs(fft(single(get_RawData('ROI',i,':')),[],3));
             if ishandle(h)
                 waitbar((i-ROI_min_x+1)/(ROI_max_x-ROI_min_x+1), h);
             else
                 error('FFT aborted.');
             end                
        end
    else % Phase
        for i = ROI_min_x:ROI_max_x % along x
            fft_img( : , i-ROI_min_x+1 , :) = -angle(fft(single(get_RawData('ROI',i,':')),[],3));
             if ishandle(h)
                 waitbar((i-ROI_min_x+1)/(ROI_max_x-ROI_min_x+1), h);
             else
                 error('FFT aborted.');
             end
        end
    end

    % Update Buffer
    CtrlFigUsrDat.Current.BufferType = BufferType;
    CtrlFigUsrDat.Current.Buffer     = fft_img;
    setF(CtrlFigHdl, 'UserData', CtrlFigUsrDat);
catch FFTError
    messageBox(FFTError.message, 1, 'FFT Error');
    fft_img = []; % means it failed computing the FFT
end    

if ishandle(h)
    delete(h)
end

end

Is this better now???

well ,I try to expess my self better, in fact I have n images and I want to applicate FFT in order to dispaly magnitude and phase images but itsn't like mentioned in the tutorial image by image I want to applicate FFT in the time at pixel1 in im1 at 1t then pixel1 in im2 at t2 then at pixel 1 in im3 at t3... is it clear??? please help me if you can.

my problem here it's not how to extract magnitude or phase but how to applicate FFT on 3D image sequence of images????

ok but even with the tutorial it explains how to display FFT magnitude from one image however my application is to how display FFT magnitude and phase from many images, i explain more I should appliacte FFT for the same pixel of all images (like FFT signal) it means FFT for pixel 1.1 from im1 to imFinal and FFF for pixel 1.2 from im1 to imFinal... can you help me please.

thanks a lot

and what about the phase image I want just the phase please.

yes I found this tutorial, so this image displayed can be considered as amplitude and phase image in the same time???

function fft_img = get_FFT() % ****************************************************************************************************************************
% Compute the FFT phase or Amplitude

CtrlFigHdl              = GetFigHdl('CtrlFig');
ToggleButtonAmpHdl      = findobj(CtrlFigHdl, 'Tag', 'ToggleButtonAmp');
ToggleButtonPhaseHdl    = findobj(CtrlFigHdl, 'Tag', 'ToggleButtonPhase');

% detect if we want a Phase or Amplitude
if get(ToggleButtonAmpHdl, 'Value')
    BufferType = 1;  % FFT Amplitude type
elseif get(ToggleButtonPhaseHdl, 'Value')
    BufferType = 2;  % FFT Phase type
else
    fft_img = [];
    return;
end

CtrlFigUsrDat = get(CtrlFigHdl, 'UserData');

% Do we need to update the FFT?
if (BufferType == CtrlFigUsrDat.Current.BufferType) && ~isempty(CtrlFigUsrDat.Current.Buffer)
    % No we don't
    fft_img = CtrlFigUsrDat.Current.Buffer;
else
    % we need to compute a new fft
    % Notes: fft(uint16) is double; fft(single) is single; fft(double) is double

    clear CtrlFigUsrDat; % Avoid duplication of data
    CtrlFigUsrDat = ClearBuffer('main'); % makes room

    % Get the ROI limits
    [ROI_min_x ROI_max_x ROI_min_y ROI_max_y] = getROIlimits();

    try
        h = [];

        % pre-allocation. We make it single as it's half the data needed and still good enough. 
        % The FFT computation below is converted in single as it is done, plane by plane
        fft_img = zeros(ROI_max_y-ROI_min_y+1, ROI_max_x-ROI_min_x+1, CtrlFigUsrDat.Current.z_dim, 'single');

        sizeOfSingle = 4;

        h = waitbar(0,[num2str(size(fft_img,2)) ' * ' num2str(size(fft_img,1)) ' pixels * ', ...
            num2str(size(fft_img,3)) ' frames * single (32 bpp) = ' num2str(numel(fft_img)*sizeOfSingle/(1024*1024),'%.2f'), ' MB'], ...
            'Name', 'Computing FFT...', 'WindowStyle', 'modal');
        set(h, 'HandleVisibility', 'off'); % do not integrate this into the line above
        pause(0.1); % allow refresh

        if BufferType == 1 % Amplitude
            for i = ROI_min_x:ROI_max_x % along x
                fft_img( : , i-ROI_min_x+1 , :) = abs(fft(single(get_RawData('ROI',i,':')),[],3));
                 if ishandle(h)
                     waitbar((i-ROI_min_x+1)/(ROI_max_x-ROI_min_x+1), h);
                 else
                     error('FFT aborted.');
                 end                
            end
        else % Phase
            for i = ROI_min_x:ROI_max_x % along x
                fft_img( : , i-ROI_min_x+1 , :) = -angle(fft(single(get_RawData('ROI',i,':')),[],3));
                 if ishandle(h)
                     waitbar((i-ROI_min_x+1)/(ROI_max_x-ROI_min_x+1), h);
                 else
                     error('FFT aborted.');
                 end
            end
        end

        % Update Buffer
        CtrlFigUsrDat.Current.BufferType = BufferType;
        CtrlFigUsrDat.Current.Buffer     = fft_img;
        setF(CtrlFigHdl, 'UserData', CtrlFigUsrDat);
    catch FFTError
        messageBox(FFTError.message, 1, 'FFT Error');
        fft_img = []; % means it failed computing the FFT
    end    

    if ishandle(h)
        delete(h)
    end

end