Kinect invalid flag less than 0.4 m

edit

Hello, I came to know from this , kinect gives a invalid flag on for depth value less than 40cm distance. My question was how using ROS, I can read the invalid flag within the blind zone(less than 40 cm). I wrote a publisher which read from /camera/depth/points as PCL2 and then calculated the ibstacle distacle. It publishes data to another topic. But for moving objects which suddenly came in front of kinect in les the 40 cm then it cannot detect obstacle. Can anyone please help me regarding this? thank you.