Inspection Method for PCB Distortion Compensation

The patent applies preliminary action by pre-defining feature blocks with specific shape patterns at known locations on the board before inspection. These feature blocks serve as reference markers that are captured in images, allowing the system to pre-calculate transformation relationships and distortion compensation parameters before actual circuit element inspection begins. This preliminary setup enables accurate inspection area positioning without adding complex real-time processing during inspection.

The patent introduces feature blocks as intermediary reference objects between the camera system and the actual circuit elements. These feature blocks with distinct shape patterns act as mediators that bridge the theoretical design coordinates and the actual distorted board positions. By capturing and analyzing these intermediary feature blocks, the system can calculate transformation matrices that compensate for board distortion, thereby accurately positioning the inspection area without directly measuring the distorted circuit elements themselves.

The system performs preliminary capture of feature blocks and pre-calculates transformation relationships between design coordinates and actual positions. This preliminary action includes defining feature blocks with specific shape patterns, capturing their positions in the image, and computing distortion compensation parameters before actual inspection begins. This upfront preparation reduces measurement errors while minimizing time loss during the actual inspection process.

The patent creates a transformed copy of the design coordinates system that accounts for board distortion. By capturing feature blocks and calculating transformation matrices, the system generates a corrected coordinate mapping that copies the theoretical design positions to their actual distorted positions on the board. This copied transformed coordinate system is then used to accurately locate circuit elements without requiring repeated measurements.

The patent applies segmentation by dividing the board into distinct feature blocks with unique shape patterns. Each feature block is treated as an independent identification target with its own characteristic pattern. This segmentation allows the system to individually recognize and locate each feature block even when similar patterns exist adjacent to each other, by analyzing the specific shape characteristics and spatial relationships of each segmented feature block separately.

The patent employs asymmetry by designing feature blocks with non-symmetric or distinctive shape patterns that differ from adjacent feature blocks. By introducing asymmetric characteristics in the shape patterns (such as different orientations, unique geometric configurations, or varied pattern arrangements), the system can reliably distinguish between adjacent feature blocks with similar patterns. This asymmetric design prevents confusion during automatic identification and enables accurate location determination even in densely packed areas.