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Why the raw data detected by lidar are very small?

asked 2019-10-27 09:16:14 -0500

PhaTracer gravatar image

updated 2019-10-27 09:27:58 -0500

In fact,my lidar data structure just look like this,I can see that the ranges column data is very small and not realistic, as if it were surrounded by a circle.:

seq: 25
stamp:
secs: 78
nsecs: 777000000
frame_id: "hokuyo_link"
angle_min: -1.57079994678
angle_max: 1.57079994678
angle_increment: 0.0175508372486
time_increment: 0.0
scan_time: 0.0
range_min: 0.0
range_max: 10.0
ranges: [0.05088043585419655, 0.032888345420360565, 0.00824850331991911, 0.03751131519675255, 0.037233006209135056, 0.016207106411457062, 0.029215959832072258, 0.02978556416928768, 0.019236300140619278, 0.025845319032669067, 0.008902770467102528, 0.026326626539230347, 0.023051125928759575, 0.03724529221653938, 0.031686700880527496, 0.00010798007133416831, 0.024950098246335983, 0.019893385469913483,  0.044057343155145645, 0.046771299093961716, 0.03137718886137009, 0.024098888039588928, 0.03176361322402954, 0.021393034607172012.......]enter code here

If I am not mistaken, the data in the ranges should represent the corresponding [angle, distance], thus ranging, the data should be like this:

seq: 25
stamp:
secs: 78
nsecs: 777000000
frame_id: "hokuyo_link"
angle_min: -1.57079994678
angle_max: 1.57079994678
angle_increment: 0.0175508372486
time_increment: 0.0
scan_time: 0.0
range_min: 0.0
range_max: 10.0
ranges: [10.0, 10.0, 10.0, 10.0,10.0, 10.0,10.0, 10.0, 10.0, 10.0,10.0, 10.0,10.0, 10.0, 10.0, 10.0,10.0, 10.0, 10.0, 10.0, 10.0, 10.0,10.0, 10.0,8.0, 8.0, 8.0, 8.0,8.0, 8.0,8.0, 8.0,8.0, 8.0,8.0, 8.0, 8.0, 8.0, 8.0, 8.0,8.0, 8.0,8.0, 8.0,8.0, 8.0,8.0, 8.0,.....]

My lidar settings are as follows:
Configured as:
<gazebo reference="hokuyo_link">
    <sensor type="ray" name="head_hokuyo_sensor">
 <pose>0 0 0 0 0 0</pose>
 <visualize>true</visualize>
 <update_rate>60</update_rate>
 <ray>
   <scan>
     <horizontal>
       <samples>180</samples>
       <resolution>1</resolution>
       <min_angle>-1.570796</min_angle>
       <max_angle>1.570796</max_angle>
     </horizontal>
   </scan>
   <range>
     <min>0</min>
     <max>10.0</max>
     <resolution>0.01</resolution>
   </range>
   <noise>
     <type>gaussian</type>
     <mean>0.0</mean>
     <stddev>0.01</stddev>
   </noise>
 </ray>
 <plugin name="gazebo_ros_head_hokuyo_controller" filename="libgazebo_ros_laser.so">
   <topicName>/autonomous_car/laser/scan</topicName>
   <frameName>hokuyo_link</frameName>
 </plugin>
</sensor>
</gazebo>

The data I get here is very small distance data, but the upper limit is 10m, which prevents me from getting distance information from the original data.And I am sorry that I can't upload an image.

How can I modify it to get normal lidar data?Thanks for your help!

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Comments

3

Is there something in your simulation model that is occluding the lasers field of view? This could be hitting the mesh of the robot.

stevemacenski gravatar image stevemacenski  ( 2019-10-27 17:19:23 -0500 )edit

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answered 2019-10-28 03:21:14 -0500

duck-development gravatar image

I think you gazebo model see some obstacles.

Do you see the beams in the gazebo simulation do this look like expected?

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Asked: 2019-10-27 09:16:14 -0500

Seen: 97 times

Last updated: Oct 28 '19