Where is the center reference of depth measurement

Hardware ZED2
1

Hello,
I am currently testing depth measurement with ZED2i. I would like to know the center reference of depth measurement. The phase center of the left camera? Or the screw hole at the bottom?

If it is based on the phase center of the camera, how can I verify the accuracy of the depth? I can get the depth from the point I want to measure to the screw hole, but I think if it is based on the phase center of the left camera, then there is a gap between the two depths. I am not sure if my understanding is wrong.

2

Hi @hhp
Depth information is typically calculated relative to the left optics of ZED cameras.
The camera’s frame origin is located where the optical axis meets the CMOS sensor, 2 cm behind the front panel in the case of the ZED 2i camera.

More information here: Coordinate Frames - Stereolabs

3

Hi，@ Myzhar
Thank you very much.
And the optical axis is about 3 cm from the left edge, right? This is my visual estimate. Can you give a definite value?

4

This is not correct. I recommend you use the 3D model for precise measurements.

5

thx,@ Myzhar
I’ll search for the information and learn more.