hmrR_MotionCorrectTDDR

Adding TDDR motion correction function. Ref: https://www.sciencedirect.com/science/article/pii/S1053811918308103

FuncRegistry/UserFunctions/hmrR_MotionCorrectTDDR.m

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+% SYNTAX:
+% data_dod = hmrR_MotionCorrectTDDR(data_dod, mlActAuto, mlActMan)
+%
+% UI NAME:
+% Motion_Correct_TDDR
+%
+% DESCRIPTION:
+% Corrects motion artifacts by computing the temporal derivative of the dod signal, 
+% applying robust regression to reduce magnitude of outlying fluctuations, then 
+% integrating to get the corrected signal. This function follows the procedure described in:
+% Fishburn, F. A. et al. (2019). Temporal Derivative Distribution Repair (TDDR): A motion correction method for fNIRS. NeuroImage, 184, 171-179.
+%
+%
+% INPUTS:
+% data_dod: SNIRF data structure containing delta_OD 
+% mlActAuto:
+% mlActMan:
+%
+% OUTPUTS:
+% data_dod:   SNIRF data structure containing delta_OD after motion correction, 
+%        same size as dod (Channels that are not in the active ml remain unchanged)
+%
+% USAGE OPTIONS:
+% Motion_Correct_TDDR: dod = hmrR_MotionCorrectTDDR(dod, mlActAuto, mlActMan)
+%
+% PARAMETERS:
+%
+% PREREQUISITES:
+% Intensity_to_Delta_OD: dod = hmrR_Intensity2OD( intensity )
+% 
+% LOG:
+% Script by Frank Fishburn ([email protected]) 10/03/2018
+% Modified by Giulia Rocco ([email protected]) 20/02/2023
+
+function data_dod = hmrR_MotionCorrectTDDR(data_dod, mlActAuto, mlActMan)
+
+% mlAct = SD.MeasListAct; % prune bad channels
+t = data_dod.time;
+sample_rate = abs(1/(t(1)-t(2)));
+
+if isempty(mlActMan)
+    mlActMan = cell(length(data_dod),1);
+end
+if isempty(mlActAuto)
+    mlActAuto = cell(length(data_dod),1);
+end
+
+for kk = 1:length(data_dod)
+
+    dod         = data_dod(kk).GetDataTimeSeries();
+    MeasList    = data_dod(kk).GetMeasList();  
+
+    if isempty(mlActMan{kk})
+        mlActMan{kk} = ones(size(MeasList,1),1);
+    end
+    if isempty(mlActAuto{kk})
+        mlActAuto{kk} = ones(size(MeasList,1),1);
+    end
+
+    MeasListAct = mlActMan{kk} & mlActAuto{kk};
+
+    lstAct = find(MeasListAct==1);
+
+    for ii=1:length(lstAct)
+
+        idx_ch = lstAct(ii);
+
+        %% Preprocess: Separate high and low frequencies
+        filter_cutoff = .5;
+        filter_order = 3;
+        Fc = filter_cutoff * 2/sample_rate;
+        if Fc<1
+            [fb,fa] = butter(filter_order,Fc);
+            signal_low = filtfilt(fb,fa,dod(:,idx_ch));
+        else
+            signal_low = dod(:,idx_ch);
+        end
+        signal_high = dod(:,idx_ch) - signal_low;
+
+        %% Initialize
+        tune = 4.685;
+        D = sqrt(eps(class(dod)));
+        mu = inf;
+        iter = 0;
+
+        %% Step 1. Compute temporal derivative of the signal
+        deriv = diff(signal_low);
+
+        %% Step 2. Initialize observation weights
+        w = ones(size(deriv));
+
+        %% Step 3. Iterative estimation of robust weights
+        while iter < 50
+
+            iter = iter + 1;
+            mu0 = mu;
+
+            % Step 3a. Estimate weighted mean
+            mu = sum( w .* deriv ) / sum( w );
+
+            % Step 3b. Calculate absolute residuals of estimate
+            dev = abs(deriv - mu);
+
+            % Step 3c. Robust estimate of standard deviation of the residuals
+            sigma = 1.4826 * median(dev);
+
+            % Step 3d. Scale deviations by standard deviation and tuning parameter
+            r = dev / (sigma * tune);
+
+            % Step 3e. Calculate new weights accoring to Tukey's biweight function
+            w = ((1 - r.^2) .* (r < 1)) .^ 2;
+
+            % Step 3f. Terminate if new estimate is within machine-precision of old estimate
+            if abs(mu-mu0) < D*max(abs(mu),abs(mu0))
+                break;
+            end
+
+        end
+
+        %% Step 4. Apply robust weights to centered derivative
+        new_deriv = w .* (deriv-mu);
+
+        %% Step 5. Integrate corrected derivative
+        signal_low_corrected = cumsum([0; new_deriv]);
+
+        %% Postprocess: Center the corrected signal
+        signal_low_corrected = signal_low_corrected - mean(signal_low_corrected);
+
+        %% Postprocess: Merge back with uncorrected high frequency component
+        dod(:,idx_ch) = signal_low_corrected + signal_high;
+
+    end
+
+    data_dod(kk).SetDataTimeSeries(dod);
+end
+
+end