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Original question:

Compiler/IWR1443BOOST: Change the Intensity Information into Velocity in Rviz

Compiler/IWR1443BOOST: change settings of rviz Point cloud

rnaxi
Prodigy 50 points
Part Number: IWR1443BOOST

Tool/software: TI C/C++ Compiler

Hello,

sorry for the next question,

Like in this thread I made the changes in the code.

The problem is, that I don´t see a negative doppler index.

Is there a solution, that I can see postive and negative velocities in diferrent colours, but in contrast to the zone occupancy demo i need a better resolution of the velocity and only 2d?

Thank you.

  • 0
    TI__Mastermind 30405 points
    Hello,

    Can you please confirm which version of the ROS driver lab are you running? Please also confirm the version of SDK Out of Box demo firmware running on the EVM.

    Note:

    The definition of Doppler index was changed to a signed value and the latest versions do return a signed Doppler index with negative values for objects moving towards the sensor as mentioned in the structure definition given below:

    file:///C:/ti/mmwave_sdk_01_02_00_05/packages/ti/demo/xwr16xx/mmw/docs/doxygen/html/struct_mmw_demo__detected_obj__t.html

    The mmWaveDemoVisualizer converts the Doppler index to velocity in meters/sec using the following formula:

    velocity in m/s = doppler index * ( speed of light(3e8) / (2 * (startFreq * 1e9) * ((idleTime + rampEndTime) * 1e-6) * numChirpsPerFrame) )
    where the parameter names startFreq (GHz), idleTime (us) and rampEndTime (us) above are described in CLI's profile configuration. and numChirpsPerFrame is the total number of physical chirps in one frame [the quantity (idleTime + rampEndTime) * numChirpsPerFrame therefore represents the total chirping duration in a frame].

    Regards
    -Nitin
  • 0 in reply to Nitin Sakhuja
    Prodigy 50 points
    My version of the ROS driver lab is 1.4 and the version of the SDK is 1.2.0.5.
  • 0 in reply to rnaxi
    Prodigy 50 points

    Hello,

    I read, that rviz can´t show negative value of intensity. 

    Can I manipulate the source code of rviz in a way, that negative doppler information gets displayed in the plot?

    And is it possible to give the intensity information specific colours, e.g. that intensity = 0 is always white?

    Thank you.

  • 0 in reply to rnaxi
    TI__Mastermind 30405 points

    Hello,

    That is correct. TI mmWave ROS driver uses the PointXYZI point cloud structure which defines intensity as a float and doesn't allow negative values. It believe that it should be possible to define a new point cloud type or extend an existing one to include Doppler values but we have not explored this.  Please refer to the Point Cloud Library documentation at http://wiki.ros.org/pcl/Overview.

    For your second question, you can change the color scheme in RVIZ by selecting intensity as the Color Transformer under the PointCloud2 Topic as shown in the picture below. Then you can configure the desired colors by changing the Min and Max color values under it.

    Thanks

    -Nitin

  • 0 in reply to Nitin Sakhuja
    Prodigy 50 points
    Thanks,

    Do you have a tool to extract the position and doppler indexof the points to see the points e.g in excel?
    I´m new to ROS and C++, I think it would take a long time to define a new point cloud and its settings.


    rnaxi
  • 0 in reply to rnaxi
    TI__Mastermind 30405 points

    Hello,

    We have a beta mmWave Demo Visualizer which allows you to save the point cloud information in a csv file. You can run the web version or download an offline version of it from dev.ti.com/gallery as shown in the snapshot below:

    Please mark the thread answered otherwise get back if you have more questions on this subject.

    Thanks

    -Nitin