（4）Basic calibration

• Connect the lens and play, open the settings, select "Recording Settings", and enable the black - and - white video mode.

• Put the L calibration rod into the field, switch to the 2D view, open the device panel, and adjust the brightness and threshold of each camera so that the camera can stably capture the four points of the L rod.

• Click the "Calibration" button at the top of the software interface to open the calibration floating - window panel. After setting the calibration parameters in the panel, select "Basic Calibration".
• Next, perform L calibration. Place the selected L - shaped rod in the center of the field and confirm the coordinate orientation (when the Z - axis is upward, the long - side direction of the L - rod is the positive X - axis direction, and the short - side direction is the positive Y - axis direction; when the Y - axis is upward, the long - side direction of the L - rod is the positive Z - axis direction, and the short - side direction is the positive X - axis direction). After confirming that the numbers in the brackets at the lower - left corner of each lens in the 2D view are stably 4, click the "L Calibration" button at the bottom of the calibration panel. If the calibration is successful, the "T Calibration" button will be displayed below the window. If the L - shaped calibration fails, a pop - up window will prompt that the calibration has failed, and the "T Calibration" button will not appear.

The L calibration results are divided into three cases:

• All passed: All lenses are calibrated successfully, and the calibration result icon shows green.
• Only when all or part of the calibrations are passed can the T calibration be continued. Otherwise, the L calibration needs to be continued until it passes.

• Perform T calibration. In the basic calibration T calibration window, "rod length" refers to the distance between the reflective marker points at both ends of the T-shaped rod used. You can input the number marked on the label of the T-shaped rod. The "duration" is the calibration time, usually 60 - 120 seconds. After setting, click the "Next" button. The person swinging the rod holds the T-shaped calibration rod and waves it repeatedly within the capture area. When the lens collects valid data, the corresponding area will turn gray. Ensure that each lens has enough valid data, that is, as the amount of collected data increases for each lens, the color changes from light to dark.

• During T calibration, a progress bar is displayed. The progress bar moves forward gradually with the time of swinging the rod. When the progress bar reaches 50%, the background color of T calibration will change from orange-yellow to green. Swing the T-shaped rod to cover every corner visible to the camera as much as possible. In the 2D view of all cameras, at most three markers of the T-shaped rod can be seen (that is, the number in the lower left corner of the 2D view of all cameras is less than or equal to 3. Try to make the numbers of as many cameras as possible equal to 3). During the calibration process, the area swept by the calibration rod is displayed on the 2D interface, and the available data volume and impurity situation can be displayed in real time. When the dialog box shows that the number of frames has been reached, that is, when the progress bar is 100%, a calculation button appears below the floating window. Click "Calculate", and the software enters the calculation process. After the calculation is completed, the software will feedback the calibration result (evaluated as poor / ordinary / good / perfect). Different icons will also be displayed on the right side of T calibration according to the calibration result. (If the calibration result shows "poor", it is recommended to recalibrate. For others, it can be saved and used normally). Click "Save Calibration File", enter the file and click "Finish".
• Switch the video mode back to color, then switch to the 3D view. Have the model stand within the visible area of the AI camera. Twenty-two Marker points of the Markerless human body will be displayed on the 3D view. At this point, you can create a Markerless human body and start using the software.