Set up help with lsd-slam about ethzasl_msf HOT 3 OPEN

@henn1001 several points that you should take a close look at:

• you do need to provide the IMU to camera transformation. What the framework expects here is the position and orientation of the camera w.r.t. the IMU frame of reference, expressed in the IMU frame of reference. This is the first and most important part to fix.
• absolute measurements refers to the fact that your measurements are not a relative quantity but denote the position of the camera system wrt. some global base-frame. You will need to switch this parameters to true
• don't fix the scale factor. Set pose_sensor/pose/fixed_scale to false (also you have this setting twice in your yaml, so you need to clean these up too)
• pose_sensor/pose_measurement_world_sensor needs to be double checked. If LSD slam provides the position/orientation of the camera wrt. a "world" frame of reference then this must be set to true. If LSD slam provides the position/orientation of a "world" frame expressed in the camera frame of reference, then this must be set to false.
• Yes, if the covariance of LSD is not set, then you should use the fixed-covariance setting in the estimator.
• The dropouts on the IMU you are seeing are probably due to your PC being too slow or your IMU node having in fact dropouts. If this is just about single messages, then it should work still fine.

from ethzasl_msf.

Thanks for your reply and your help - really appreciate that

• Yeah i understand this part. Since my Imu is sitting directly under my camera and the frames are already aligned, i wont have to rotate anything right? so i should be good with 1,0,0,0 / w,x,y,z ? i'm not that good with quaternions : )
• OK so if i set my position/vslam sensor as a absolute measurement - the thing that will be wrong is the scale. that's why i shouldn't use a fixed scale and where "pose_initial_scale:" comes into play. But over time the scale should automatically converge to a metric scale right?
• "pose_measurement_world_sensor: false" should be correct - same as ptam
• i fixed the imu dropouts -> had to set up a queue in my publisher node

Also i did some testing:

This is the position output from lsd_slam. after the initialization i moved it back and forth ~40 cm (x axis) and then to the side ~60 cm (y axis)

MSF output with absolute measurements = true

and here with a initial_scale = 0.5

from ethzasl_msf.

Hi, @henn1001 Have you managed to get your implementation of msf setup to work?

from ethzasl_msf.