Trial and error to follow SegNet-Tutorial(3) 
(link: http://mi.eng.cam.ac.uk/projects/segnet/tutorial.html)

5. training SegNet using Cityscapes dataset
number of labels in Cityscapes dataset: 34 (id 0 to 33)
re-grouping labels into 11+1 classes ( sky, building, pole, road, pavement, tree, signsymbol, fence, car, pedestrian, bicyclist, unlabelled )

(to-be-updated)