Auto create patches and extract glcm of the patches from multi-image file

hi.. im working on image processing using matlab. actually i'm sorry, it's the first time im working on matlab. i tried to do to get the pathes of multi-image file and also extract the glcm of every patch of those image. i want to do it automatically. i have following this code and add code for extracting glcm from each patch. but i think i still make mistakes coz still get error report in :

     Error in GLCM1 (line 53)
        baseFileName = ca(k).name;

if u guys could guide me it realt means a lot for me, please. here's the code that i was trying to create :

        folder = fullfile('D:\Program Files\MATLAB\R2017a\bin\DATABC1\Train\G1');
        fileNames = dir(fullfile(folder, '*.tif'));
        baseFileName1 = '6a.tif';
        fullFileName = fullfile(folder, baseFileName1); 
        if ~exist(fullFileName, 'file') 
  fullFileName = baseFileName1; 
  if ~exist(fullFileName, 'file') 
        errorMessage = sprintf('Error: %s does not exist.', fullFileName);
        uiwait(warndlg(errorMessage));
  return;
  end
        end

        h=zeros(28,4);%row->no. of image, column->no. of feature 

        % Create blocks
        rgbImage = imread(fullFileName);
        gr = rgb2gray(rgbImage);
        imshow(gr);
        set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
        drawnow;
        [rows, columns, numberOfColorBands] = size(gr);

        blockSizeR = 100; % Rows in block.
        blockSizeC = 100; % Columns in block.
        % The size of each block in rows. 
        wholeBlockRows = floor(rows / blockSizeR);
        blockVectorR = [blockSizeR * ones(1, wholeBlockRows), rem(rows, blockSizeR)];
        % The size of each block in columns. 
        wholeBlockCols = floor(columns / blockSizeC);
        blockVectorC = [blockSizeC * ones(1, wholeBlockCols), rem(columns, blockSizeC)];
        % Create the cell array
        % Divided up into blocks.
        if numberOfColorBands > 1
  
  ca = mat2cell(gr, blockVectorR, blockVectorC, numberOfColorBands); 
        else
  ca = mat2cell(gr, blockVectorR, blockVectorC);
        end

        % Display all the blocks.
        plotIndex = 1;
        numPlotsR = size(ca, 1);
        numPlotsC = size(ca, 2);
        for r = 1 : numPlotsR
        for c = 1 : numPlotsC
        for k = 1:length(ca)
        baseFileName = ca(k).name;
        I = imread(baseFileName);
        fprintf('plotindex = %d, c=%d, r=%d\n', plotIndex, c, r, I);
        subplot(numPlotsR, numPlotsC, plotIndex);
  rgbBlock = ca{r,c,I};
        imshow(rgbBlock);

        GLCM  = graycomatrix(rgbBlock,'Offset', [0 1;-1 1;-1 0;-1 -1],'NumLevel', 8,'Symmetric',true); 
        stats = GLCM_Features1(GLCM,'Contrast, Correlation, Energy, Homogeneity');
        h(k,1)= stats.contr(1);%contrast    
        h(k,2)= stats.corrp(1);%Correlation
        h(k,3)= stats.homom(1);%Homogeneity 
        h(k,4)= stats.energ(1);%Energy

        [rowsB, columnsB, numberOfColorBandsB] = size(rgbBlock);
        caption = sprintf('Block #%xzd of %d\n%d rows by %d columns', ...
        plotIndex, numPlotsR*numPlotsC, rowsB, columnsB);
  title(caption);
  drawnow;
  plotIndex = plotIndex + 1;
        end
        end
        end

what should i do ? i realy need your help, please.