How do you get the ground truth from the dataset about brain-tumor-segmentation HOT 1 CLOSED

How to get ground truth from the dataset? How did you use as a parameter?
Example :
def binary_dice3d(s,g):
#dice score of two 3D volumes
num=np.sum(np.multiply(s, g))
denom=s.sum() + g.sum()
if denom==0:
return 1
else:
return 2.0*num/denom

def sensitivity (seg,ground):
#computs false negative rate
num=np.sum(np.multiply(ground, seg ))
denom=np.sum(ground)
if denom==0:
return 1
else:
return num/denom

from brain-tumor-segmentation.