Smart Scanning Sensors are being integrated into manufacturing processes in increasing numbers to provide real-time dimensional control. For the more complex applications where the scan target is larger than a single sensor’s field of view, or has a complex shape, multi-view scanning and processing needs to be applied to capture the complete geometry of the part.
Multi-view scanning and data processing can be used to:
- Cover larger fields of view while maintaining high resolution
- See more of the part (360º ring layout or opposing layout to measure thickness)
- See past occlusions (undercuts, gaps, steep edges etc)
- Perform absolute measurement between two or more features separated by a large distance (where both sensors must be calibrated to a world coordinate system)
The LMI Gocator is unique among 3D sensors as it contains a built-in multi-view 3D scanning and processing capability. Gocator sensors can be configured as multiple networked sensors to scan different views of a part to build a fully digitized 3D model or by using a single sensor on an XY positioning stage or robot to scan and stitch multiple views into a single surface. Gocator multi-sensor operation is supported by built-in connection and streaming logic and uses a web browser to connect to the “main” sensor with additional sensors simply added-on with each sensor assigned a location in a layout and its physical to logical mapping recorded.
Aligning to a Common Coordinate System and Data Transformation
All sensors in a network are usually aligned to a common coordinate system in order to stitch sensor data into a single 3D model or perform absolute measurement. The LMI Gocator sensor offers built-in alignment that scans a known shape, where each sensor “sees” one of the vertices of the polygon and creates a transformation from sensor to world coordinates. With Gocator, data merging and resampling is built-in. The smart sensor applies 6 DOF transformations from the alignment process to convert sensor coordinates to a common coordinate system. Overlapping sensor data is intelligently merged and the final 3D cross section is resampled to the desired resolution.
Point Cloud Processing
360° cross sectional profiles from laser profilers are synchronized to an encoder and collected to build 3D point clouds. Point clouds are aligned and projected to height maps for fast 3D feature or profile measurement. Anchoring is used to adjust measurement position for high repeatability. Data acquisition from multiple sensors requires accurate synchronization so each sensor exposes at exactly the same time (based on time, discrete triggering, or encoder).
Merging Separate 3D Scans into a Single 3D Model
Stitching a scan is carried out with the built-in Surface Stitch tool in the Gocator sensor, which combines multiple scans from one snapshot sensor into a single 3D height map. The stitched 3D scan is ready to use as input by any other native tool requiring a surface to carry out advanced measurement.
Accelerated Inline Inspection
When the need is to process large data sets, such as those generated from multiple-views, at production speed users can choose to accelerate the inspection cycle times using a smart vision accelerator. The LMI GoMax Smart Vision Accelerator instantly adds massive data processing power to a sensor or sensor network for faster inspection cycle times and improved overall inspection performance in applications where multi-view processing is required.
Multi-View 3D Scanning and Processing with Gocator
Unlike standard sensor solutions, Gocator 3D smart sensors offer extensive, built-in support for multi-view scanning and processing. This capability is becoming increasingly important as engineers are tasked with inspecting larger and more complex manufactured parts travelling at high speeds.
For more information: www.lmi3d.com