High-accuracy calibration method for an underwater one-mirror galvanometric laser scanner.

Three-dimensional (3D) perception of deep-sea targets is the key to autonomous operation of underwater equipment (e.g., underwater robots).

Vision measurement system for geometric parameters of tubing internal thread based on double-mirrored structured light.

Geometric parameter measurement of tubing internal thread is critical for oil pipeline safety. In response to the shortcomings of existing methods for measuring internal thread geometric parameters, such as low efficiency, poor accuracy, and poor accessibility, this paper proposes a vision system for measuring internal thread geometric parameters based on double-mirrored structured light. Compared to previous methods, our system can completely reproduce the internal thread tooth profiles and allows multi-parameter measurement in one setup.

Single-lens multi-mirror laser stereo vision-based system for measuring internal thread geometrical parameters.

Oilfield pipes with out-of-tolerance internal thread can lead to failures, so the internal thread geometric parameters need to be measured. To tackle the problem of the low efficiency, poor accuracy, easy wear, and poor accessibility of existing methods, a single-lens multi-mirror laser stereo vision-based system for measuring geometric parameters of the internal thread is proposed, which allows the measurement of three parameters in one setup by completely reproducing the three-dimensional (3D) tooth profiles of the internal thread. In the system design, to overcome the incomplete representation of imaging parameters caused by insufficient consideration of dimensions and structural parameters of the existing models, an explicit 3D optical path model without a reflecting prism is first proposed.

Spatial light path analysis and calibration of four-mirror-based monocular stereo vision.

The feasibility and accuracy of four-mirror-based monocular stereo vision (FMSV) are related to the system layout and calibration accuracy, respectively. In this study, a spatial light path analysis method and a calibration method are proposed for an FMSV system. As two-dimensional light path analysis cannot fully characterize the imaging parameters, a spatial light path model is proposed, which allows refinement of the system design.