Shape-from-Shading Measurement with Global-Local Surface Registration

The patent combines two different optical measuring methods (triangulation and shape-from-shading) into a single integrated measuring system. The triangulation sensor provides robust 3D surface data while the shape-from-shading sensor delivers high-resolution surface normal information. By merging these complementary methods, the system achieves superior measurement precision that neither method could achieve alone, while maintaining manageable system complexity through integrated hardware and software architecture.

The patent creates a composite measuring system that integrates multiple sensor types with different measurement characteristics. Similar to how composite materials combine different materials to achieve superior properties, this system combines triangulation and shape-from-shading sensors to achieve measurement precision and sensitivity that exceeds individual methods, capturing both geometric accuracy and fine surface details.

The patent merges the functionality of multiple cameras and light sources into two integrated sensor units. Rather than using numerous separate components, the triangulation sensor and shape-from-shading sensor are combined into compact assemblies that achieve high measurement precision through coordinated operation of multiple optical elements within each sensor, reducing overall system complexity while maintaining accuracy.

The patent applies different measurement approaches to different spatial scales: the triangulation sensor captures global surface geometry with appropriate lighting, while the shape-from-shading sensor focuses on local surface normals with dedicated light sources. This local optimization allows each sensor to use precisely the number of cameras and light sources needed for its specific function, avoiding unnecessary complexity.

The patent segments the measurement function into two specialized sensors: a triangulation sensor optimized for capturing global surface geometry with wide field of view, and a shape-from-shading sensor optimized for high-resolution local surface normal measurement. This segmentation allows each sensor to excel at its specific function—the triangulation sensor provides broad coverage while the shape-from-shading sensor delivers detailed local resolution—without requiring a single sensor to compromise between the two requirements.

The patent adds a complementary measurement dimension by introducing the shape-from-shading sensor that measures surface normals in addition to the triangulation sensor's 3D coordinates. This additional dimensional information (surface orientation) enhances local resolution without requiring the triangulation sensor to increase its field of view, effectively adding information depth rather than just spatial coverage.

The patent merges data from triangulation and shape-from-shading sensors through an integrated processing pipeline that automatically registers the two data sets using feature matching and coordinate transformation algorithms. This unified approach combines the complete 3D geometric information from triangulation with the high-resolution surface normal data from shape-from-shading, achieving information completeness while managing processing complexity through automated registration rather than manual alignment.

The patent implements self-service data registration where the system automatically identifies corresponding features between the two sensor data sets and performs coordinate transformation and merging without external intervention. The processing unit autonomously handles the complex task of aligning and integrating the complementary information streams, reducing the burden on operators and minimizing information loss through automated, consistent registration.