Efficient calibration of the scale and orientation of the 3 D real scene model of the rock mass

The use of a 3D real-scene rock mass model for measurement tasks can significantly improve measurement efficiency and reduce safety risks for survey personnel. Efficient and accurate calibration of the orientation and scale of the 3D real-scene rock mass model is a prerequisite for achieving high-efficiency and safe rock mass measurement. To address the challenge of efficiently calibrating the scale and orientation of 3D real-scene rock mass models, this study investigated a method for reconstructing a 3D real-scene rock mass model based on the SFM (Structure from Motion) + MVS (Multi-View Stereo) algorithm. A calibration method combining three target points and a three-axis gyroscope was proposed to adjust the orientation and scale of the rock mass model. A foldable three-point calibration device was developed, and a data acquisition APP based on the Bluetooth communication protocol was designed for rapid data collection from the calibration device. Additionally, an interactive real-scene model calibration software system was developed using OpenGL graphics library technology. Taking a surface rock slope as an example, efficient data acquisition and calibration of the rock mass model were conducted, and the self-developed SlopeRMI software was employed to achieve efficient measurement of the rock mass structure. The results demonstrate that the proposed calibration method, device, and software system can effectively calibrate the orientation and scale of the rock mass model, showing promising application prospects.