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octomap_sever color changing

asked 2013-05-05 20:33:54 -0500

elva gravatar image

Hi, i am using octomap to construct 3D mapping with a tilt laser scanner.The color of the octomap_sever is correct at the first scan however if the laser remains in the same place,after a while the color of different height tend to change to same color.btw ,the parameter "height_map" i have set it to true, what should i do to solve this problem? thank you!

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answered 2013-05-05 21:06:46 -0500

The MarkerArray for visualization of the octomap is colored based on the z value of the lowest and highest cell in your octomap. So when you start, let's say your octomap has cells from 0.2m to 0.6m height. The color range is adjusted so 0.2m appears blue and 0.6m appears red (or something like that). As you move your robot around, the robot also sees cells in a height from 0.1m to 1.6m. The coloring then is changed so it spans the whole 1.5m range, explaining why previous cells change color. What is "correct" of course depends entirely on your use case.

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thank you for the reply,your example make it easier for me to understand but my problem is : the laser tilts horizontally , the first scan can detect the ground and ceiling already,so the z value doesn't change. and i didn't move the robot ,btw i use laser_assemble to collect the point cloud:)

elva gravatar image elva  ( 2013-05-05 22:01:24 -0500 )edit

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Asked: 2013-05-05 20:33:54 -0500

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Last updated: May 05 '13