In today’s manufacturing environment, automatic vision inspection has been widely applied in many different industries including semiconductor, electronics, food and beverage, pharmaceutical packaging, automotive, and many others. Within vision inspection, applications can be categorized into measurement, absence/presence, robotic guidance, flaw detection, identification such as 1D/2D, and optical character recognition (OCR) reading. Conventional 2D algorithms are typically good at tackling applications in which certain features are clear and well-defined for the detection to be robust. In other words, the features of interest must be stable and consistently presented in order to be detected and read reliably.
However, like life, vision inspection is not without its challenges. Some surfaces have a natural texture or a highly reflective finish. In other cases, parts are grinded or stamped during the manufacturing process which may result in a curved or textured surface. Some objects include embossed characters or features are impressed or indented, such as stamped and engraved markings—these all make inspection very challenging. Conventional 2D algorithms and preprocessors often fail to find reliable ways to solve these problems. Shape from Shading technology has been proven a more reliable method to tackle such challenging inspections.