Efficient Ways to Obtain Camera Parameters for Accurate Size Measurement

Hello
I’m currently working with a ZED 2i camera for a project where accurate measurement of object sizes in images is crucial. I understand that the ZED 2i comes with factory-calibrated intrinsic and extrinsic parameters. I’m wondering if I need to obtain these parameters anew for each photo I take, or can I rely on the factory calibration? Additionally, is there a recommended software or tool for efficiently acquiring these parameters for each shot, especially if recalibration is needed?

Another point of clarification: for measuring the real-world size of an object using the depth map from the ZED 2i, do I need both intrinsic and extrinsic parameters, or are the intrinsic parameters sufficient? Any insights into how best to utilize these parameters for accurate size measurements would be greatly appreciated.

Thank you in advance for any tips or shared experiences!

Hi @code_lover
camera parameters are always available at runtime by using the ZED SDK API functions:

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Thank you. could you please advise how I can convert the pixel size of an object to the real world size, while I have the depth image and camera intrinsic parameters as below? are they enough or I need more information?

LEFT_CAM_VGA]
fx=478.7125
fy=478.87
cx=331.095
cy=185.6975
k1=-0.070943
k2=-0.0129377
p1=-0.00076779
p2=-0.000106157
k3=-0.0576469

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Thank you. The issue is that I want to know given an object in the image what is the real world size of that object. I came across the below Github which mentions pixel size. Could you guide me on how to find the physical pixel size for the ZED 2i camera?

This post refers to the pixel size of a single cell of the CMOS sensor.

To calculate the size of an object you can extract the coordinates of the boundaries of the object and calculate the Euclidean distance between the points on the boundaries.

Thank you but I suppose by this approach still I am measuring the size of the object in the pixel unit, not real wold unit (like meters, centimeters…).