tform without checkerboard calibration

Hello,

I am trying to project lidar onto 2D image.

https://www.mathworks.com/help/lidar/ref/projectlidarpointsonimage.html?searchHighlight=projecting%20lidar%20&s_tid=srchtitle_projecting%20lidar%20_1

I need intrinsic parameters and transformation matrix. To create an intrinsics file, I need cameraintrinsics

https://www.mathworks.com/help/vision/ref/cameraintrinsics.html

I don't have any checkerboard planes to apply that. Because of that, I can't use Lidar Camera Calibrator either.

I have attached calibration files from a self-calibrated camera and lidar system. I try to create my own transformation matrix so I can implement for lidar projection in Matlab. Is there any way to create it without any checker board planes?

https://www.mathworks.com/help/images/ref/rigidtform3d.html

https://www.mathworks.com/help/lidar/ref/estimatelidarcameratransform.html#mw_a7a69912-e72d-42cd-9dad-f6ecf2795607

Thank you,

-Gizem

Answer 1

[Maneet Kaur Bagga]

Hi Gizem Karslioglu,

To create a transformation matrix for lidar projection without using checkerboard planes, please refer to the following steps:

• Load the calibration files from the camera and the lidar system into MATLAB Workspace.
• Extract the intrinsic parameters of the camera from the Camera Calibration File. The "cameraParameters" object can be used to store the intrinsic, extrinsic and lens distortion parameters of a camera.
• Extract the extrinsic parameters of the camera from the Camera Calibration File to determine the transformation matrix between the lidar and the camera coordinate system.
• Create a tform parameter for projection using the "rigidtform3d" object from the rotation and translation matrices obtained from the calibration file.
• Using the "projectLidarPointsOnImage" function, project the lidar points onto the 2D image using the intrinsic parameters and the tform object.

For better understanding please refer to the following MATLAB Documentations provided below:

cameraParameters

https://www.mathworks.com/help/vision/ref/cameraparameters.html

rigidtform3d

https://www.mathworks.com/help/images/ref/rigidtform3d.html

projectLidarPointsOnImage

https://www.mathworks.com/help/lidar/ref/projectlidarpointsonimage.html

I hope this helps!

Thank You

Maneet Bagga