How to use kinect to update occupancy grid

edit

I have a robot which already using Lidar to for SLAM and it seems to function well. Now, I would like to add Kinect to help improving final map. Kinect can get x,y,z of these obstacles with respect to the camera frame. Now, I want to use x,y to update the occupancy grid along with Lidar already doing. How can this be done? Any hint would be appreciated. I am using ROS Indigo with Ubuntu x86-64.