morphological operations in matlab

hcsc = vision.ColorSpaceConverter;
 hcsc.Conversion = 'RGB to intensity';
 hautothresh = vision.Autothresholder;
 hdilate = vision.MorphologicalDilate('Neighborhood', ones(5,5));
 x1 = step(hcsc, a);
 x2 = step(hautothresh, x1);
 y = step(hdilate, x2);
 figure;
 subplot(3,1,1),imshow(a); title('Original image');
 subplot(3,1,2),imshow(x2); title('Thresholded Image');
 subplot(3,1,3),imshow(y); title('Dilated Image');