Get your Calibration File
The ZED and the ZED mini are stereovision-based depth cameras meaning two cameras, displaced from one another are used to obtain two different views of a scene. By comparing these two images, the relative depth information can be obtained.
The calibration file contains information about the precise position of the right and left cameras and their optical characteristics. This file is key in the depth estimation process and guarantees its quality.
This file is generated during our manufacturing process and is automatically downloaded by the ZED SDK or any application.
Calibrations files are stored in the following locations and named according to the serial number of the camera:
- On Windows: C:\ProgramData\Stereolabs\settings
- On Linux: /usr/local/zed/settings/
- On Windows (SDK ≤ 2.2.0):C:\Users\YOUR_USER_NAME\AppData\Roaming\Stereolabs\settings\
You can also download it manually by following these instructions: calib.stereolabs.com
When using the ZED SDK, you can access these parameters from getCameraInformation(). This returns the parameters from the file* (named raw), along with the parameters of the rectified images.
* By default, a self-calibration runs at each camera initialization to optimize the parameters from the file. The returned parameters are the optimized one which will be used by the SDK.
The ZED calibration file contains intrinsic parameters for both left and right sensors at each resolution. Here is an example:
[LEFT_CAM_HD] fx=700.819 fy=700.819 cx=665.465 cy=371.953 k1=-0.174318 k2=0.0261121
- fx and fy are the focal length in pixels.
- cx and cy are the optical center coordinates in pixels.
- k1 and k2 are distortion parameters.
These data are matching the pinhole camera model.
The stereo parameters, also called extrinsic parameters, represent the relation between the left and right sensors. More precisely, the position of the right sensor from the left sensor with the center of rotation being the right sensor itself.
[STEREO] Baseline=120 CV_2K=0.00958521 CV_FHD=0.00958521 CV_HD=0.00958521 CV_VGA=0.00958521 RX_2K=0.00497864 RX_FHD=0.00497864 RX_HD=0.00497864 RX_VGA=0.00497864 RZ_2K=-0.00185401 RZ_FHD=-0.00185401 RZ_HD=-0.00185401 RZ_VGA=-0.00185401
- Baseline is the distance between the optics in mm (120 for the ZED and 63 for the ZED Mini)
- CV_*** also called RY_*** measures the optical convergence.
- RX_*** and RZ_*** are the other rotation axis describing the transformation between both sensors. Rotations are represented in the Rodrigues notation.