Optical Triangulation Error Models under Dynamic Printed Circuit Board Warpage
Dynamic substrate distortion induces height shifts in optical triangulation systems, requiring real-time surface mesh interpolation to prevent false deposit rejects.
Multi Projection Triangulation
Imaging Geometry
Optical measurement technique employing several light sources from different angles overcomes the limitations of single side illumination during three dimensional inspection. By using multi projection triangulation, a system can view the same feature from multiple perspectives simultaneously. This approach reduces the impact of component shadows and provides a more complete profile of complex shapes.
Shadow Mitigation
Elimination of blind spots occurs when the multi projection triangulation system captures data from directions that would otherwise be blocked by tall components. Each projector casts a fringe pattern or a light stripe onto the assembly. The sensors then record the deformation of these patterns from their respective angles.
Overlapping multiple views creates a map of the entire board surface including the areas between tightly packed chips.
Data Reconstruction
Combining the disparate images requires a high degree of spatial alignment and computational power. In a multi projection triangulation setup, the software must correlate the height data from each camera to resolve a single z value for every pixel. Discrepancies between the projectors are resolved through weighted averaging or best fit algorithms.
Reconstruction is essential for inspecting mirrored surfaces or steep vertical walls on solder fillets. High resolution results from this method enable the detection of subtle defects like lifted leads or insufficient heel fillets.