Open Access Conference Proceedings

Metallographic images mapping metal surfaces, including their chemical composition, were obtained with sizes up to 1 Gpix (2×3 mm2) and a digital pixel size of 75 nm, well below the theoretical limit of the optical microscope. These images are part of a global priority discovery (Large-Area Digital Optical Microscopy - LADOM). A new prototype of functional microscope was also built, integrating all the knowledge gained and addressing all existing technical requirements. In metallographic practice, large-scale images of 1 mm2 are acquired by combining many individual images. That implies the use of algorithms that compensate for mechanical imprecision, optical non-idealities, and smooth image edges. These processes irreversibly destroy the original information, and a true spectral response of the surface may not be obtained. To a large extent, this objection applies to all images stored by conventional algorithms and to all images of larger areas composed of smaller images, including those from electron microscopy. LADOM does not suffer from this problem. We demonstrate the use of LADOM in the metallographic practice of steel analysis using various etching procedures.

Keywords: Optical microscope, large field of view, spectral resolution

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