使用点云库将点云转换为世界坐标

Question

I searched through all around the internet, this was suppose to be easy. But its getting harder to get one straight answer. I need to transform the point cloud to world coordinate system. Before the transformation the Z-axis(kinect sensor) will be pointing towards the object, x-axis to the bottom and Y-axis to the left. or any other orientation of kinect sensor. After the transformation, X-axis towards the object, Y-axis to the left and Z-axis to the top ie is the fixed world coordinates. Simplest way to achieve it?.

This is what I tried so far. I tried to find viewpoint of the cloud, Thinking it would give me orientation wrt World coordinate system. But it takes kinect as the origin. So I get Non-transformed Matrix. i,e Identity rotation matrix and unit translation vector.

Please can anyone give me a clue?.

Answer 1

The kinect coordinate will be Z-axis facing object, x-axis to the bottom and y-axis to right. So this transform should work.

double thetha=M_PI/2;
Eigen::Affine3f transform_2 = Eigen::Affine3f::Identity();

// Define a translation of 2.5 meters on the x axis.

transform_2.translation() << 0.0, 0.0, 0.0;     

// The same rotation matrix as before; thetha radians arround Z axis.

transform_2.rotate (Eigen::AngleAxisf (-theta, Eigen::Vector3f::UnitZ()) * Eigen::AngleAxisf (-theta, Eigen::Vector3f::UnitX()));