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It looks like your wall is closer than the one-meter min_range. All the cloud nodelet does with points nearer than that is throw them away.

What happens if you set min_range really small, like 0.02?

I have no personal experience with using the device indoors with close-up readings.

It looks like your wall is closer than the one-meter min_range. All the cloud nodelet does with points nearer than that is throw them away.

What happens if you set min_range really small, like 0.02?

I have no personal experience with using the device indoors with close-up readings.

It looks like your wall is closer than the one-meter min_range. All the cloud nodelet does with points nearer than that is throw them away.

What happens if you set min_range really small, like 0.02?

I have no personal experience with using the device indoors with close-up readings.

UPDATE: the more-distant points may be some generic LIDAR phenomenon with some reflections being bounced around before returning to the sensor. Perhaps the white wall is more reflective, making it more noticeable.

I'm just making up hypotheses here, because your use case is outside my experience with the device. I hope other LIDAR users may be able to help.

$ rosrun velodyne_driver velodyne_node _npackets:=696 _rpm:=300

It looks like your wall is closer than the one-meter min_range. All the cloud nodelet does with points nearer than that is throw them away.

What happens if you set min_range really small, like 0.02?

I have no personal experience with using the device indoors with close-up readings.

UPDATE: the more-distant points may be some generic LIDAR phenomenon with some reflections being bounced around before returning to the sensor. Perhaps the white wall is more reflective, making it more noticeable.

I'm just making up hypotheses here, because your use case is outside my experience with the device. I hope other LIDAR users may be able to help.

UPDATE2: I don't know if this explains all the problems you are seeing, but there is a bug in the driver's handling of 64E S2 and S2.1 models (ros-drivers/velodyne#11). That issue was recently fixed in velodyne-1.1.1, released to Hydro, but it still exists in Fuerte.

Fortunately, there is a work-around you can use with earlier versions on the driver. It appears from your bag that your device is running at 300 RPM (5Hz). If so, the work-around in the answer to this question should be adjusted slightly, as follows:

$ rosrun velodyne_driver velodyne_node _npackets:=696 _rpm:=300

The result of this bug is was that the driver is publishing slightly less than half-scans at twice the actual 5Hz scan rate. That makes the data difficult to view. It probably does not explain the problem you are seeing, but it does make it harder to diagnose.

It looks like your wall is closer than the one-meter min_range. All the cloud nodelet does with points nearer than that is throw them away.

What happens if you set min_range really small, like 0.02?

I have no personal experience with using the device indoors with close-up readings.

UPDATE: the more-distant points may be some generic LIDAR phenomenon with some reflections being bounced around before returning to the sensor. Perhaps the white wall is more reflective, making it more noticeable.

I'm just making up hypotheses here, because your use case is outside my experience with the device. I hope other LIDAR users may be able to help.

UPDATE2: I don't know if this explains all the problems you are seeing, but there is a bug in the driver's handling of 64E S2 and S2.1 models (ros-drivers/velodyne#11). That issue was recently fixed in velodyne-1.1.1, released to Hydro, but it still exists in Fuerte.

Fortunately, there is a work-around you can use with earlier versions on the driver. It appears from your bag that your device is running at 300 RPM (5Hz). If so, the work-around in the answer to this question should be adjusted slightly, as follows:

$ rosrun velodyne_driver velodyne_node _npackets:=696 _rpm:=300

The result of this bug was that the driver is publishing slightly less than half-scans at twice the actual 5Hz scan rate. That makes the data difficult to view. It probably does not explain the problem you are seeing, but it does make it harder to diagnose.

The minimum return distance for the sensor is approximately 3 feet (0.9 meters). Ignore returns closer than this.

It looks like your wall is closer than the one-meter min_range. All the cloud nodelet does with points nearer than that is throw them away.

What happens if you set min_range really small, like 0.02?

I have no personal experience with using the device indoors with close-up readings.

UPDATE: the more-distant points may be some generic LIDAR phenomenon with some reflections being bounced around before returning to the sensor. Perhaps the white wall is more reflective, making it more noticeable.

I'm just making up hypotheses here, because your use case is outside my experience with the device. I hope other LIDAR users may be able to help.

UPDATE2: I don't know if this explains all the problems you are seeing, but there is a bug in the driver's handling of 64E S2 and S2.1 models (ros-drivers/velodyne#11). That issue was recently fixed in velodyne-1.1.1, released to Hydro, but it still exists in Fuerte.

Fortunately, there is a work-around you can use with earlier versions on the driver. It appears from your bag that your device is running at 300 RPM (5Hz). If so, the work-around in the answer to this question should be adjusted slightly, as follows:

$ rosrun velodyne_driver velodyne_node _npackets:=696 _rpm:=300

The result of this bug was that the driver is publishing slightly less than half-scans at twice the actual 5Hz scan rate. That makes the data difficult to view. It probably does not explain the problem you are seeing, but it does make it harder to diagnose.

UPDATE3: The 64E S2 manual says:

The minimum return distance for the sensor is approximately 3 feet (0.9 meters). Ignore returns closer than this.

So, I would set min_range to 0.9, which would presumably give results similar to your 1.0 example.