Averaging the values of grayscale intensity for each image?

Is there a way in my script to just get each individual image's ControltoTest without overwriting it every time it analyzes an image for a value and just do the average mean of the values?

        RC = input('Are all the images cropped already? Y/N','s');
          if strcmpi(RC, 'y')
              uncropped=1;
          else
              uncropped=0;
          end

          %Asks user to select the folder containing the calibration set inside.
          CalFolder = uigetdir('Please select the calibration folder containing the images to calibrate.');
          if ~isdir(CalFolder)
            errorMessage = sprintf('Error: The following folder does not exist:\n%s', CalFolder);
            uiwait(warndlg(errorMessage));
            return;
          end

          %Adds the folder pathname to the top of the MATLAB search path list so it can find it first.
          addpath(CalFolder);

          %Returns a string containing the full file pathname and then shows the
          %filenames of the pictures inside the folder.
          calfilePattern = fullfile(CalFolder, '*.jpg');
          caljpegFiles = dir(calfilePattern);

          %Creates a cell array with the dimensions of: the quantity of pictures in
          %the folder by 1
          LFAcalarr=cell(length(caljpegFiles),1);

          %Stores the filenames of the pictures to use in the script.
          for i=1:length(caljpegFiles)
             LFAcalarr{i}=caljpegFiles(i).name; 
          end
          %Insert file names (without extensions) into LFAfile for processing needs
          %all images in folder.
          for m=1:length(LFAcalarr)

              %Add the file extension and look for the file
                  LFACalibration = imread(LFAcalarr{m});

                  %Uncropped set to 0 means that the image must still be manually
                  %cropped
                  if(uncropped==0)
                  %Image will appear in upper panel.
                  %Manually crop by drawing a box around the test and control lines
                  %Make sure the control line is in the left half of the crop window
                  %and the test line is in the right half of the crop window
                      subplot(3,1,1);
                      LFAGrayCal = imcrop(rgb2gray(LFACalibration));        
                      close all;

                  else
                      LFAGrayCal = rgb2gray(LFACalibration);    
                  end 

                  %Get the number of pixels along the x axis
                  CropWidthCal = size(LFAGrayCal,2);

                  %Convert to 1-Dimension by averaging along the columns
                  %In Grayscale, low values correspond to dark and high values to white
                  %Take complement and add 255 so dark values correspond to high signals
                  LFA1DCal=imcomplement(mean(LFAGrayCal,1))+255;

                  %Split the left matrix containing control line
                  %Split right matrix containing test line
                  LFAControlCal = LFA1DCal(1:fix(0.5*CropWidthCal));
                  LFATestCal = LFA1DCal(fix(0.5*CropWidthCal)+1:CropWidthCal);

                  %Locate the control line by finding the maximum and get value
                  [CalControlLineMax, CalControlLineLocation] = max(LFAControlCal);

                  %Calibration is on
                      %Locate test line by finding the maximum and get value
                      [TestLineMaxCal,TestLineLocationCal] = max(LFATestCal);
                      TestLineLocationCal = TestLineLocationCal + fix(.5*CropWidthCal);

                      %Calculate distance between control and test line
                      ValControlToTest=TestLineLocationCal-CalControlLineLocation;
                      ControlToTest = mean(ValControltoTest);
          end 
_

Answer 1

[Image Analyst]

Make it an array

ControlToTest(m) = ..................

[Bryant]

Thanks for the response Image Analyst, I got this error

Undefined function 'ControltoTest' for input arguments of type 'double'.

    Error in Calibration_Script (line 78)
               ControlToTest = mean(ControltoTest(m));

[Image Analyst]

?Huh? Why is it not

ControlToTest(m) = mean(ValControltoTest);