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# rotation angles in fovis odometry

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I am going to use fovis to do visual odometry. The obtained geometry information will be used for 2D mapping.

For 2D mapping, what I want is the horizontal rotation, ie the rotation along y-axis(downward). In fovis, I obtain the 3d rotation, but I am confused.

I ran the example program in libfovis with kinect, these codes return the odometry information: Eigen::Vector3d xyz = cam_to_local.translation(); Eigen::Vector3d rpy = cam_to_local.rotation().eulerAngles(0, 1, 2);

I am not sure about the type of rotation of rpy is. As I tested with kinect, I guess rpy(1) gives me the horizontal rotation angle, but its range is just +/- 90 degrees. What kind of transformation I need if I want the range to be +/- 180 degrees? Thanks.

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There is the example program I ran: http://fovis.googlecode.com/git/libfovis/examples/fv-example-openni/ . The codes I quoted is in main.cpp

( 2013-02-14 06:56:55 -0500 )edit

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rpy represents the roll, pitch and yaw angles. Assuming that the x axis points forward, the y axis to the left and the z axis upwards, then roll is rotation about the x axis, pitch is rotation about the y axis and yaw is rotation about the axis. In your case you want the pitch angle. a pitch angle of 90 degrees means your pointing the camera upwards, and -90 means its pointing downwards.

May I ask, are you using the fovis_ros wrapper? If so, how did you get it to work with the Kinect (because aparently the fovis_ros wrapper does not support the kinect yet but only stereo vision)?

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( 2013-02-14 17:59:48 -0500 )edit

Actually, there is description about the axis in fovis: +Z pointing along the camera look vector, +X to the right, and +Y down. But there is no description about the angles.

( 2013-02-14 18:07:11 -0500 )edit

Then roll angle is about the Z axis, pitch angle is about the X-axis and yaw angle about the Y-axis.Thanks for your answer on my other question. I will give it a try.

( 2013-02-14 18:56:43 -0500 )edit

Since yesterday fovis_ros supports kinect RGBD input in fovis_ros wrapper.

( 2013-02-14 20:10:08 -0500 )edit

Thanks Miquel, I will give a try.

( 2013-02-15 01:31:32 -0500 )edit