Diff for "ScannerSynch" - CBU MRI facility Wiki
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Revision 35 as of 2017-03-17 11:34:11
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Editor: KristjanKalm
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Revision 36 as of 2017-08-08 15:53:15
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Editor: JohanCarlin
Comment: github link
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= ScannerSynch = = scansync =
For new projects, we recommend using [[https://github.com/MRC-CBU/mrisync/blob/master/scansync.m|this simple matlab function]] to synchronise with the scanner pulses. For existing projects we continue to support ScannerSynchClass, which is described further below.

= ScannerSynchClass =
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 * ScannerSynch is available on all relevant PCs (StimPCs, "mimic" PC)
 * From your desktop PC (Windows), you can also have a copy from `\\cbsu\data\Group\Imaging-Local\cbu\matlab`
 * You can also download it from [[attachment:ScannerSynchClass.m|here]] (right-click and "Save As...")
ScannerSynch is available on all relevant PCs (StimPCs, "mimic" PC). You can check out a local version for testing from [[https://github.com/MRC-CBU/mrisync|our github repo]].

scansync

For new projects, we recommend using this simple matlab function to synchronise with the scanner pulses. For existing projects we continue to support ScannerSynchClass, which is described further below.

ScannerSynchClass

ScannerSynch provides an interface for National Instruments PCI 6503 card used to capture all pulses (scanner synch pulse and button pulses alike) when using MATLAB.

For more information, type in MATLAB

help ScannerSynchClass

N.B.: National Instruments PCI 6503 card does not monitor pulses in the background, so you have to make sure that you wait for any pulse before it comes!

Any problems, report them to Johan Carlin.

Obtain ScannerSynch

ScannerSynch is available on all relevant PCs (StimPCs, "mimic" PC). You can check out a local version for testing from our github repo.

Using ScannerSynch

Initialise

  • Default. Use only if device (scanner, pulse emulator) is connected (only in StimPCs and mimic PC)!
  • SSO = ScannerSynchClass;
    
  • Emulations:
  • SSO = ScannerSynchClass(1);   % emulate scanner synch pulse
    
  • SSO = ScannerSynchClass(0,1); % emulate button box
    
  • SSO = ScannerSynchClass(1,1); % emulate scanner synch pulse and button box
    

Close

ScannerSynchClass has a destructor, which is automatically triggered if the object is deleted (e.g. clear, returning function). If you use a script, however, it does not perform any auto-clear, so you have to destroy the object manually:

  • SSO.delete;
    

Capture scanner synch pulse

  • Simple case
  • SSO.SetSynchReadoutTime(0.5); % make sure that you do not detect the same pule twice
    SSO.TR = 2;                   % allows detecting missing pulses
    while SSO.SynchCount < 10     % polls 10 pulses
        SSO.WaitForSynch;
        fprintf('Pulse %d: %2.3f. Measured TR = %2.3fs\n',...
            SSO.SynchCount,...
            SSO.TimeOfLastPulse,...
            SSO.MeasuredTR);
    end
    
  • Chance for missing pulse
  • SSO.SetSynchReadoutTime(0.5);  % make sure that you do not detect the same pule twice
    SSO.TR = 2;                    % allows detecting missing pulses
    while SSO.SynchCount < 10      % until 10 pulses
        WaitSecs(Randi(100)/1000); % in every 0-100 ms ...
        if SSO.CheckSynch(0.01)    % ... waits for 10 ms for a pulse
            fprintf('Pulse %d: %2.3f. Measured TR = %2.3fs. %d synch pulses has/have been missed\n',...
                SSO.SynchCount,...
                SSO.TimeOfLastPulse,...
                SSO.MeasuredTR,...
                SSO.MissedSynch);
        end
    end
    

Capture button presses

  • SSO.SetButtonReadoutTime(0.5);      % block individual buttons for 0.5s after button press so we will not detect the same button press twice
    % SSO.SetButtonBoxReadoutTime(0.5); % block the whole buttonbox for 0.5s after button press 
    % SSO.Keys = {'f1','f2','f3','f4'}; % emulation Buttons #1-#4 with F1-F4
    n = 0;
    % SSO.BBoxTimeout = 1.5;            % Wait for button press for 1.5s
    % SSO.BBoxTimeout = -1.5;           % Wait for button press for 1.5s even in case of response
    SSO.ResetClock;
    while n ~= 10                       % polls 10 button presses
        SSO.WaitForButtonPress;         % Wait for any button to be pressed
        % SSO.WaitForButtonRelease;       % Wait for any button to be released
        % SSO.WaitForButtonPress([],2); % Wait for Button #2
        % SSO.WaitForButtonPress(2);    % Wait for any button for 2s (overrides SSO.BBoxTimeout only for this event)
        % SSO.WaitForButtonPress(-2);   % Wait for any button for 2s even in case of response (overrides SSO.BBoxTimeout only for this event)
        % SSO.WaitForButtonPress(2,2);  % Wait for Button #2 for 2s (overrides SSO.BBoxTimeout only for this event)
        % SSO.WaitForButtonPress(-2,2); % Wait for Button #2 for 2s even in case of response (overrides SSO.BBoxTimeout only for this event)
        n = n + 1;
        fprintf('At %2.3fs, ',SSO.Clock);
        fprintf('Button %d ',SSO.LastButtonPress);
        fprintf('pressed: %2.3fs\n',SSO.TimeOfLastButtonPress);
    end
    

None: ScannerSynch (last edited 2017-08-08 15:53:15 by JohanCarlin)