Added README.md, fixed a bug with orientation estimation, added examples.

+math/IntSignals.m

@@ -14,11 +14,11 @@ unitRotMat=eye(3);
 indexes = data.tMiddle(index):data.tMiddle(index+1);
 
 % Rotate the gyroscope data to Foot-frame.
-gyroLocal = (calibration.rotMatrix*data.filtGyr(indexes,:)');
+gyroLocal = (calibration.rotMatrix*data.filtGyr(indexes,:)')';
 
 % Integrate the signals from this orientation, such that everything is 
 % mapped in that frame.
-rotMatHat = math.intOmega(unitRotMat,gyroLocal',1/data.fs);
+rotMatHat = math.intOmega(unitRotMat,gyroLocal,data.fs);
 
 accLocal = (calibration.rotMatrix*data.filtAcc(indexes,:)')';
 

+math/intOmega.m

-function rotMat = intOmega(initRotMat, omega, ts)
+function rotMat = intOmega(initRotMat, omega, fs)
 % intOmega.m - Calculates orientation matrix by integrating gyroscope signal
 %
 % Inputs: 
 % initRotMat        Initial orientation matrix
 % omega             Angular velocity (rad/s)
-% ts                Sample time
+% fs                Sample frequency
 %
 % Outputs: 
 % rotMat               Orientation matrix [Nsamples x 3 x 3]
@@ -29,7 +29,7 @@ for i=2:N
     R = permute(rotMat(i-1, :, :),[2 3 1]);
     
     Rdot = R*permute(omegaMatrix(i,:,:),[2 3 1]);   % Integrate R
-    R = R + ts.*Rdot;
+    R = R + (1/fs).*Rdot;
     
     [A,~]=qr(R);                                 % create proper rotation matrix
     rotMat(i,:,:) = sqrt(A.*A).*sign(R);            % get correct sign

README.MD

+# Foot progression angle estimation
+
+Uses csv files from Movella DOT exporter to calculate foot progression angles assuming that you provide one calibration trial, see for details also the [publication](https://doi.org/10.1186/s12984-021-00816-4).
+
+The calibration trial should be performed with close to 0 degrees of FPA.
+
+The example files include:
+- calibration
+- toe-in walking
+- toe-out walking
+
+Be aware that `settingsFile.m` refers to the data path to use. When specified just run `main.m` to obtain a structure with the processed files.
\ No newline at end of file

getCalibration.m

@@ -16,7 +16,7 @@ function dataStruct = getCalibration(filePath, fCutOff)
 
         % Get the current file path and trial name.
         currFilePath = [calibFiles(i).folder '\' calibFiles(i).name];
-        trialName = ['trial_' strrep(extractBefore(calibFiles(i).name, '.csv'),' ', '_')];
+        trialName = [extractBefore(calibFiles(i).name, '.csv')];
 
         % Load in the actual Movella Dot CSV file.
         dataStruct.(trialName) = readDotCsv(currFilePath);

readDotCsv.m

@@ -10,7 +10,7 @@ function dataStruct = readDotCsv(filePath)
 
     % Store the data in a useable format.
     dataStruct.acc = table2array(currentData(:,{'Acc_X', 'Acc_Y', 'Acc_Z'}));
-    dataStruct.gyr = table2array(currentData(:,{'Gyr_X', 'Gyr_Y', 'Gyr_Z'}));
+    dataStruct.gyr = table2array(currentData(:,{'Gyr_X', 'Gyr_Y', 'Gyr_Z'}))*pi/180;
     dataStruct.mag = table2array(currentData(:,{'Mag_X', 'Mag_Y', 'Mag_Z'}));
     dataStruct.time = table2array(currentData(:,'SampleTimeFine')- ...
         currentData(1,'SampleTimeFine'))/1000000;

settingsFile.m

 %% This file contains all the required settings.
 
 % Specify the main direction for the subject data files.
-fileFolder = "C:\Measurements\FPA-measurements\Subject2";
+fileFolder = "C:\Measurements\20230912 - FPA";
 
 % Specify where the calibration folder is, has to be placed inside the 
 % subject folder.