Pointcloud visualisation blinking when using Velodyne VLP16 dual return mode

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Hi Tohoku, I was having the same problem, but I could find a solution.

First, you have to find the file "driver.cc". In there you will find some packet configuration for different types of velodyne lidars, and in some part you'll find the next:

else if (config_.model == "VLP16") { packet_rate = 754; // 754 Packets/Second for Last or Strongest mode 1508 for dual (VLP-16 User Manual) model_full_name = "VLP-16"; }

So, you have to change the packet rate to 1508, which is the packet rate for dual returns. This will solve the problem.

Now, there is another issue, the classification of the last return and the strongest/2nd strongest return, because now they are indistinguishably. If someone have an idea of how to do the classification, I'll be very grateful for the help!

The basic ROS sensor_msgs/LaserScan was supplemented with a similar sensor_msgs/MultiEchoLaserScan to handle multi-echo devices.

I know of no similar sensor_msgs/PointCloud2 enhancement, nor have I heard from any other developers with similar needs. I suppose there are various approaches one could take.

I recommend opening a discussion about it on the ros-sig-drivers mailing list. Perhaps we can develop a consensus on the best way to handle 3D multi-echo devices.