Why is the unit of focal length in pixel when you multiply mm and pixel?

I calibrated my stereo camera with matlab and extracted the focal length.

Now if I look to the documentation in which unit the focal lenght is, it shows me the calculation f = F*s.

F is in mm and s is in pixel so the unit of f should be in mm*pixel but ist says it is in pixel.

Why?

Answer 1

[Image Analyst]

Where is that documentation you're referring to? I don't know why you'd multiply those two things. What do they represent? But in general the units of a product are the product of the units, so if F is in mm and s is in pixels, then y-F*s will have units of (mm*pixels).

Answer 2

[George Abrahams]

Hi @sinan saglam. I'm assuming that you're referring to the cameraIntrinsics documentation. At the time of writing, it describes the FocalLength property as follows:

Please reread this carefully. and are actually in . Therefore, the units of and are .