# Forum

### Author Topic: The meaning of accuracy of rotation and translation on referencing cameras  (Read 708 times)

• Newbie
• Posts: 9
##### The meaning of accuracy of rotation and translation on referencing cameras
« on: June 10, 2022, 04:11:13 AM »
I am use the following part of code for adding the reference for camera alignment. What I am not sure is the definition of the location_accuracy and the rotation_accuracy. Does it mean the feasible range of the solution should be within the giving reference location (+- 0.1) for example? If so then what is the unit of it? it means percentage or millimeter?

for cam in chunk.cameras:
ref = cam.reference
ref.location = cam.transform.translation()
ref.location_accuracy = (0.1, 0.1, 0.1)
ref.location_enabled = True
ref.rotation = Metashape.Utils.mat2ypr(cam.transform.rotation())
ref.rotation_accuracy = (5, 5, 5)
ref.rotation_enabled = True

Thanks a lot !

#### Paulo

• Hero Member
• Posts: 1100
##### Re: The meaning of accuracy of rotation and translation on referencing cameras
« Reply #1 on: June 10, 2022, 08:26:52 PM »

the reference location accuracy will give the estimated accuracy for each camera. The higher the accuracy, then the more tightly constrained will be camera position  during adjustment. For example a camera with accuracy 0.1 will have a weight in adjustment 100 times higher than camera with accuracy 1.

By the way, I think that location_accuracy units are in meters and rotation_accuracy in degrees....
« Last Edit: June 10, 2022, 08:30:01 PM by Paulo »
Best Regards,
Paul Pelletier,
Surveyor

• Newbie
• Posts: 9
##### Re: The meaning of accuracy of rotation and translation on referencing cameras
« Reply #2 on: June 10, 2022, 09:07:20 PM »
Paulo,

Thanks very much! So basically the accuracy serves as an inverse weighting on the position constraint during the bundle adjustment? The unit don't really matters. For a specified system, the best way is to do experiments for finding the suitable number? Or could you share more information on how to define the such accuracy?

#### Paulo

• Hero Member
• Posts: 1100
##### Re: The meaning of accuracy of rotation and translation on referencing cameras
« Reply #3 on: June 10, 2022, 09:14:55 PM »
`ref.location.accuracy = Metashape.Vector((0.05,0.05,0.1))`here the camera reference location accuracy is set at 0.05 m in XY and 0.10 m in Z