Update README.md

Plotting_3_levels.py

+import numpy as np
+import open3d as o3d
+import copy
+
+# Read .ply file
+input_file = "tata_filtered.ply"
+pcd = o3d.io.read_point_cloud(input_file) # Read the point cloud
+
+# Visualize the point cloud within open3d
+# o3d.visualization.draw_geometries([pcd]) 
+
+# Convert open3d format to numpy array
+# Here, you have the point cloud in numpy format. 
+Pc = np.asarray(pcd.points)
+#Sf for surface
+Sf = copy.deepcopy(Pc)
+#Legnth of Points cloud Pc
+L = len(Pc)
+iter = 1
+#Limits that will define the division between the 3 levels
+M1 = 3.16287333
+M2= 3.18335667
+#Loop to arrange the values to their corresponding height from -1 to 1
+while iter<= L:
+    for i in range (0,L):
+        for j in range (2, 3):
+            if Pc[i,j]<=M1:
+                Sf[i,j]=-1
+            elif Pc[i,j]<=M2:
+                 Sf[i,j]=0
+            else:
+                 Sf[i,j]=1
+                 iter+=1
+#Treatment of coordinate to convert them from measurements to coordinates value for a 2D plane.
+Dt =  copy.deepcopy(Sf)
+for i in range (0,L):
+    for j in range (1,2):
+        Dt[i,j]= -int((Sf[i,j]+21.8168)/0.0052)
+#For X
+for i in range (0,L):
+    for j in range (0,1):
+        Dt[i,j]= -int((Sf[i,j]+8.445706367)/0.005214)
+#Order the array of values Y axis from mayor to minor.
+data_3 = np.flip(Dt, axis=0)
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