Step 2- Camera calibration old method vs new method

[bitasd]

Hi, Thank you so much for providing us with your codes.
I am a bit confused about the output of step 2, the old method, which produces a Projection Matrix (3 x4) and the newer version which produces a Homography Matrix (3x3).
Since the projection matrix is fed into the code in the speed estimation step, I was wondering how the homography matrix could be converted into the projection matrix.

I really appreciate your response,
Bita

[zhengthomastang]

Hi Bita. The homography matrix cannot be converted into a projection matrix, but a projection matrix can be converted into a homography matrix. Since the homography is just a transformation from one plane to the other plane (ground plane to image plane), this is all you need for estimating the speed if the ground plane is flat (approximately). But you may need to modify the code of speed estimation to change the projection part.