Emg Gesture Segmentation Issues

I keep having an error with line 32,

Nd = cellfun( @str2double, regexp(Files, '\d+', 'match') );

What is wrong with this function?

Please help,

Thanks

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% This code is used for the segmentation of the sEMG signals in the dataset titled                %%%
%%% "Dataset for multi-channel surface electromyography (sEMG) signals of hand gestures"            %%%                                                            
%%% Mendeley Repository: http://dx.doi.org/10.17632/ckwc76xr2z.2                                    %%%
%%%                                                                                                 %%%
%%% Written by Mehmet Akif Ozdemir.                                                                 %%%
%%% Izmir Katip Celebi University                                                                   %%%
%%% Department of Biomedical Engineering                                                            %%%
%%% [e-mail]                                                                       %%%
%%% 21/12/2021                                                                                      %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

clear all
close all
clc


fs = 2000; % sampling rate "Hz"

%% DESIRED sEMG SEGMENTS LENGTH as second
signal_segment_starting=0; % indicate the desired beginning of segment as sec (usually 0 or 1)
signal_segment_ending=6; %indicate the desired ending of segment as sec (usually 5 or 6)
%ATTENTION: signal_segment_long=signal_segment_ending-signal_segment_starting; % max segment long is 6
%if you want to use sEMG segments which gestures are not beginning you can change the signal_segment_starting like -1

%% Get sEMG Records directory:
current_folder= '../'; %  !!!change with current folder!!!
addpath(genpath(current_folder))
Base  = strcat(current_folder,'/sEMG-dataset/filtered/mat'); % filtered recommended, change with raw or filtered
List  = dir(fullfile(Base, '**', '*.mat'));
Files = fullfile({List.folder}, {List.name});
Nd = cellfun( @str2double, regexp(Files, '\d+', 'match') );
[~,I] = sort(Nd);
Files = Files(I);

%%Using for automated segmentation of all participant sEMG data to sEMG gesture segment.
for iFile = 1:numel(Files) %40 participants, each sEMG data channel consist 1280000=640 sec* 2000 fs data point

    load(Files{iFile}) % load .. sEMG data of participants
    % Each File consists of : "data"        : discrete 4 ch sEMG signals
    %                         "fs"          : sampling rate as "2000"
    %                         "iD"          : participant iD as " 1 to 40"
    %                         "isi"         : sampling interval as "0.5"
    %                         "isi_units"   : sampling interval unit as "ms"
    %                         "labels"      : current channels' labels
    %                         "start_sample": start time of the signal recording as "0"
    %                         "units"       : sEMG data units as "mV"


    for rep=0:4 % 5 repetition, one cycle took 104 sec + 30 sec resting time, total 134 second fifth cycye only took 104 sec

        if rep==0
            rep_coeff=4; % first cycle: first REST start at fourth second and this cycle took 134 sec
        elseif rep==1
            rep_coeff=138; % second cycle: REST start at 138 sec= 104 sec (first cycle) + 30 sec (long rest) + 4 sec (begening rest)
        elseif rep==2
            rep_coeff=272; % third cycle: REST start at 272 sec= 268 sec (first two cycles) + 4 sec (begening rest)
        elseif rep==3
            rep_coeff=406; % fourth cycle: REST start at 406 sec= 402 sec (first three cycles) + 4 sec (begening rest)
        elseif rep==4
            rep_coeff=540; % fifth cycle: REST start at 540 sec= 536 sec (first four cycles) + 4 sec (begening rest)
        end % end is 640 sec


        for gesture =0:9 % a total of 10 hand gesture
            %0: X = REST
            %1: E = EXTENSION
            %2: F = FLEXION
            %3: U = ULNAR DEVIATION
            %4: R = RADIAL DEVIATION
            %5: G = GRIP
            %6: B = ABDUCTION
            %7: D = ADDUCTION
            %8: S = SUPINATION
            %9: P = PRONATION

            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

            %%%USE THE CODE BELOW FOR YOUR MULTI-CHANNEL ANALYSIS%%%
            multi_channel_sEMG_data=data((signal_segment_starting+rep_coeff+(gesture*10))*fs+1:...
                ((rep_coeff+(gesture*10))+signal_segment_ending)*fs,:);
            % It provides 6 seconds sEMG data of a single gesture belonging to 4-channel sEMG data.


            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
            %%%                 USE HERE "multi_channel_sEMG_data" TO ANALYZE               %%%                                                                      %%
            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


            switch gesture
                case 0%0: X = REST
                    %% Do something in here for REST segment i.e. save the multi-channel signal segment or
                    % make the multivariate anaylsis of the multi-channel segment, etc.
                    % Rest_signal_multiCH=multi_channel_sEMG_data;
                    % Example= plot(Rest_signal_multiCH);
                case 1%1: E = EXTENSION

                case 2%2: F = FLEXION

                case 3%3: U = ULNAR DEVIATION

                case 4%4: R = RADIAL DEVIATION

                case 5%5: G = GRIP

                case 6%6: B = ABDUCTION

                case 7%7: D = ADDUCTION

                case 8%8: S = SUPINATION

                case 9%9: P = PRONATION

            end %gesture swtich

            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

            %%%USE THE CODE BELOW FOR YOUR CHANNEL BASED ANALYSIS%%%
            for channel=1:4 % 4 ch sEMG data
                single_channel_sEMG_data=data((signal_segment_starting+rep_coeff+(gesture*10))*fs+1:...
                    ((rep_coeff+(gesture*10))+signal_segment_ending)*fs,channel);
                % The above code lines loops through all the repetitions, all the channels,
                % and all the gestures of all the participants, respectively, with the for loops.
                % It provides 6 seconds sEMG data of a single gesture belonging to a single channel.


                %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
                %%%                 USE HERE "single_channel_sEMG_data" TO ANALYZE              %%%                                                                      %%
                %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


                switch gesture
                    case 0%0: X = REST
                        %% Do something in here for REST segment i.e. save the single-channel signal segment or
                        % take the STFT of the single-channel segment, etc.
                        % Rest_signal_singleCH=single_channel_sEMG_data;
                        % Example= plot(Rest_signal_singleCH);
                    case 1%1: E = EXTENSION

                    case 2%2: F = FLEXION

                    case 3%3: U = ULNAR DEVIATION

                    case 4%4: R = RADIAL DEVIATION

                    case 5%5: G = GRIP

                    case 6%6: B = ABDUCTION

                    case 7%7: D = ADDUCTION

                    case 8%8: S = SUPINATION

                    case 9%9: P = PRONATION

                end %gesture swtich
                %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

            end%channel for

        end%gesture for

    end%repetition for

end%participants for

Answer 1

[Ramtej]

Hi Tanguy,

It seems like you might be facing an issue with file paths in your script.

To resolve this, please follow these steps:

1. Make sure that your script is running in the correct directory relative to your files, because the path to your files is relative to the current working directory in MATLAB.
2. Ensure that the path you're using to access the files is correct. Usually the current folder path is "./" instead of "../" which you have used in your code.

Hope this helps in your case!!