This invention discloses a method for detecting the appearance of planar objects. First, a set of detection parameters, including imaging parameters, acquisition strategies, and threshold rules, is obtained based on the object information. Then, camera imaging calibration and pixel-to-actual-
size ratio calibration are performed, establishing a
coordinate mapping between pixels and the stage. Initial images are acquired to obtain object
pose parameters and perform
rotational alignment. Multi-view or rotational scanning is performed for synchronous
image acquisition according to the imaging parameters and acquisition strategy.
Image quality is evaluated frame by frame; if unqualified, parameters are adjusted and images are re-acquired. For qualified images, illumination normalization and
standardization preprocessing are performed to extract the final
region of interest, generate defect candidate regions, and extract
grayscale, shape, and texture features for identification and classification. The defect category, confidence level, and actual size are output. Finally, a qualified or unqualified result is determined based on preset threshold rules. This invention eliminates misjudgments caused by low-quality images at the source, significantly enhances detection robustness, and has good adaptability to various objects.