I'm trying to follow the example 'Build a Map from Lidar Data Using SLAM' from the computer vision toolbox.
In the function helperComputeInitialEstimateFromINS, there are three lines that I really tried to understand but without sucess.
My problem is not in the theory but in this particular implementation. Here are the lines
insToLidarOffset = [0 -0.79 -1.73];
Tnow = [-insData.Y(end), insData.X(end), insData.Z(end)].' + insToLidarOffset';
Tbef = [-insData.Y(1) , insData.X(1) , insData.Z(1)].' + insToLidarOffset';
- The DATAFORMAT.txt file says that the transform from IMU to lidar is [0.79 0 1.73]. Why is it not implemented this way then?
- Why are X and Y coordinates inverted and negative in Tnow and Tbef? It is clear in the DATAFORMAT.txt that the X coordinates is front, Y coordinates is left and Z coordinates is up
What makes even less sense to me is that the transformation to insToLidarOffset (i.e.: switching X,Y then put them negative) and the transformation to Tnow and Tbef (i.e.: switching X,Y then just put Y negative) is not even the same.
I appreciate the time you take to answer this question,