Update RGBD/readme.md

RGBD/readme.md

@@ -4,7 +4,11 @@ RGBD File Processing
 
 ## Description
 
-Two ways to get the depth from a depth image
+Two ways to get the depth from a depth image:
+
+1) Use Point Cloud PLY file to get depth directly
+
+2) Use Point Cloud PLY file to get the depth from RGB value and convert into depth
 
 ## Getting Started