I want to convert all images in an image set to grayscale. Can anyone help me??

trainingData=imageSet('E:\wallpaper','recursive');

%% Display classnames and counts tbl=trainingData(1,1).Count; [test_set_a,training_set_a] = partition(trainingData(1,1),194); aeroTrain=training_set_a.Count; aeroTest=test_set_a.Count;

tbl2=trainingData(1,2).Count; [test_set_c,training_set_c] = partition(trainingData(1,2),5); carTrain=training_set_c.Count; carTest=test_set_c.Count;

%% Converting images to grayscale for a = 1:aeroTrain grayScaleAero= rgb2gray(training_set_a.ImageLocation(1,a)); end

% for c= 1:carTrain % grayScaleCar=rgb2gray(training_set_c); % end

if true
  % code
end