关键词: 表面组装技术, 焊点, 三维质量信息, 非接触式提取, 阴影恢复形状, 光照模型

Abstract: A novel 3D quality information non-contact extraction approach for Surface Mount Technology(SMT)solder joint of chip components was proposed based on Shape From Shading(SFS). To improve the reconstruction accuracy, an improved illumination model, which was proposed before, was used in SFS. To solve the problem that the 3D shape reconstructed by SFS could not be determined, a gauge block was used to determine the ratio of pels to height of a point in the solder joint image. And the ratio was used to determine the 3D shape of SMT solder joint. As a result, 3D quality information of volume, section area, wetting angle was obtained after constructing 3D entity model via ANSYS. The implementation method and steps were introduced with practical examples. Results illustrated that the improved illumination model could obtain a better extraction accuracy comparing to the conventional models.

Key words: surface mount technology, solder joint, three-dimensional quality information, non-contact extraction, shape from shading, illumination model