How to get accurate inital ros_x, rot_y, rot_z?

[oaix]

The precision of inital ros_x, rot_y, rot_z will impact final rotation matrix.

qlidarToCamera = Eigen::AngleAxisd(config.initialRot[2], Eigen::Vector3d::UnitZ()) *
                   Eigen::AngleAxisd(config.initialRot[1], Eigen::Vector3d::UnitY()) *
                   Eigen::AngleAxisd(config.initialRot[0], Eigen::Vector3d::UnitX());
lidarToCamera = qlidarToCamera.matrix();
Eigen::Matrix3d final_rotation = rotation_avg * lidarToCamera;

[xinwf]

Can we have a communication about this project? I can't get any result, when the window pop up, there is no any dots on it, just a black window, I don't know what should I do

[oaix]

• First of all, you should make sure your point cloud on cardboard can be seen in the view of camera, which is impacted by the initial ros_x, rot_y and rot_z.
• Second, edge points of cardboard should be detected. If it is successful, it will show in cloud window as below.
• Then you can draw a quadrilateral around the line being marked. Click and press a key (any key you like) to confirm the corner of the quadrilateral. In the polygon window you will see as below.

[xinwf]

@oaix , hi, I can't get the point cloud in the camera's view, our lidar is also VLP16, and the camera towards to the forward direction with lidar, so I haven't modified the rotation matrix ros_x, ros_y and ros_z, is there any problem about this setting? Can you give me some help? How can I get the coordinate of the camera and then get the rotation rad from lidar to camera? And another question is if I set the limits of visible area of point cloud to a large value, can I see many points in the window? Or I can't see anything if the rotation matrix is wrong?

[oaix]

@xinwf 如果你用的是velodyne的雷达，那么坐标系和源码中是一致的，只要你的相机雷达和标定板的位置和文中一致，就可以用他们的初始化旋转角。

[XinWenfei]

@oaix ,标定板位置是一致的，标定的marker也是一样的，但是激光雷达和camera的位置摆放不一样，在同一个中轴线上，但是有一个大约30cm的高度差，前后距离大概还有60cm左右，激光雷达在后，摄像头在前，弹出来的cloud的窗口只有标定板的上面一部分，不知道这个高度差还有前后的距离差是不是对标定程序有严重影响，这个代码里面也没有可以设置激光雷达到相机相对距离的地方，是不是这个程序要求摄像头和激光雷达必须在同一水平面啊

[xinwf]

@oaix, 说错了，高度差大概有80cm

[oaix]

@xinwf 你给一个平移量就可以了，源码里面给的[0, 0, 0]，也就是下面的x, y, z的值 transform(board_edge_cloud, x, y, z, config.initialRot[0], config.initialRot[1], config.initialRot[2]);

[xinwf]

@oaix ,非常感谢！不过再多问一些啊，这里的x，y，z应该怎么样取值呢，首先，这个校准是激光雷达到相机，所以应该以相机为原点，xyz是雷达到相机的平移量，对吧？第二个就是，xyz取值问题，是距离量还是坐标量，距离量就都是正的，坐标量就会有正负，如果是坐标量的话，是激光雷达在相机坐标系中的坐标吗，还是坐标取反表示平移量，例如，雷达在相机坐标系（Z向前，Y向下，X向右）中的坐标为（0，-0.8，-0.5），那么平移量就是[0, -0.8, -0.5]还是[0, 0.8, 0.5]

[ailovejinx]

@oaix ,非常感谢！不过再多问一些啊，这里的x，y，z应该怎么样取值呢，首先，这个校准是激光雷达到相机，所以应该以相机为原点，xyz是雷达到相机的平移量，对吧？第二个就是，xyz取值问题，是距离量还是坐标量，距离量就都是正的，坐标量就会有正负，如果是坐标量的话，是激光雷达在相机坐标系中的坐标吗，还是坐标取反表示平移量，例如，雷达在相机坐标系（Z向前，Y向下，X向右）中的坐标为（0，-0.8，-0.5），那么平移量就是[0, -0.8, -0.5]还是[0, 0.8, 0.5]

hi, xinwf, I also met this problem. Have you figured out the problem?