Automatic Mask for multiple Images

My goal is to have my code generate a mask around a cell automatically. Right now I have to create the mask using
hFH = drawassisted() maskImage = hFH.createMask();. 
Is there a way for me to generate this mask automatically for different images based on a range of pixel values? This is my current code

myFolder = 'C:\Users\x\Desktop\images';

if ~isdir(myFolder)

errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);

uiwait(warndlg(errorMessage));

return;

end

filePattern = fullfile(myFolder, '*.jpg');

theFiles = dir(filePattern);

for k = 1 : length(theFiles)

baseFileName = theFiles(k).name;

fullFileName = fullfile(myFolder, baseFileName);

fprintf(1, 'Now reading %s\n', fullFileName);

I = rgb2gray(imread(fullFileName));

subplot(1, 2, 1);

imshow(I);

title('Original Image', 'FontSize', fontSize);

subplot(1, 2, 2);

imshow(I);

title('Draw Region Of Interest', 'FontSize', fontSize);

set(gcf, 'units','normalized','outerposition',[0 0 1 1]);

set(gcf,'name','Analysis of Texture Features of Cervical Cells','numbertitle','off')

subplot(1, 2, 2);

hFH = drawassisted()

maskImage = hFH.createMask();

subplot(1, 2, 2);

blackMaskedImage = I;

blackMaskedImage(~maskImage) = NaN;

imshow(blackMaskedImage);

title('Masked Image', 'FontSize', fontSize);

maskedImage = I.* cast(maskImage, class(I));

glcm_maskedImage=graycomatrix(maskedImage);

stats_maskImage = graycoprops(glcm_maskedImage)

f = figure;

uit = uitable(f);

d = {'Contrast',stats_maskImage.Contrast;'Correlation',stats_maskImage.Correlation;'Energy',stats_maskImage.Energy,;'Homogeneity',stats_maskImage.Homogeneity;};

uit.Data = d;

uit.Position = [20 20 258 78];

if stats_maskImage.Energy<0.8700

imshow(blackMaskedImage)

title('Abnormal', 'FontSize', fontSize)

elseif(0.9600<stats_maskImage.Energy)

imshow(blackMaskedImage)

title('Error! Please Try Drawing Mask Again', 'FontSize', fontSize)

else

imshow(blackMaskedImage)

title('Normal','FontSize', fontSize)

end

pause(10)

end

[Gaurav Garg]

Hey Donnell,

Can you upload your sample image as image masking techniques vary from image to image?