RETRO-REFLECTIVE IMAGING

摘要

Methods, systems, and apparatus for imaging a substrate through the use of retro- reflective optics and detecting any defects and patterns therein. Through the use of optical imaging, optical focusing is adjusted to capture optical effects of interest in the substrate with enhanced size, precision, clarity and image quality. Imaging data obtained from these images may then be analyzed. Both bright field image data and dark field image data are captured and analyzed to provide accurate and reliable imaging results. The invention is suitable for use in on-line, real-time detection of visual defects and pattern recognition or off-line for non-production use.