The rapid analysis provided by the Large Area Scan Macroscope with a resolution of 5 μm has proven to be an essential tool for inspecting the microstructures of e.g. ice cores, both in the field and in the laboratory.
Line Scan Camera
Time-consuming inspection using a microscope can be replaced by using the specially developed Large Area Scan Macroscope (LASM) with a monochrome Line Scan Camera.The Large Area Scan Macroscope consists of a Line Scan Camera, a high resolution lens as well as an illumination unit. The sample is imaged in reflection with a resolution of 5 μm (5080 dpi). The measuring width is 41 mm with a maximum scan length of 600 mm.
Bright-field illumination
In order to capture the relevant microstructures, brightfield illumination is used. The light directed at the sample is reflected by surfaces parallel to the sensor. Light reflected from structured areas and edges is reflected away from the sensor and appears dark. For images obtained with this method, as a consequence the grain boundaries appear as dark lines and gas inclusions appear as dark bubbles or spots.
Undisturbed, High Quality Images in Much Less Time
While for the image acquisition technique using a conventional microscope, thousands of images have to be stitched to form a complete picture, only two or three scans are necessary using the Large Area Scan Macroscope depending on sample dimensions. This reduces the imaging time considerably and obviates the alignment and matching of the many individual images of these sections, which requires significant computing time. Since the microscope method takes a long time, for scanning ice cores, all images are additionally taken with slightly different contrast due to the ongoing sublimation process, which also needs to be corrected for. In order to stitch the complete picture, the images also have to be corrected for vignetting and distortion. Using the Large Area Scan Microscope, a shading correction done prior to scanning allows for evenly illuminated images that also do not show significant signs of distortion due to an excellent correction of the field of curvature. Since only two or three images are necessary to cover the whole sample the time required for stitching is severely reduced.
One of many applications: Ice core inspection
The LASM is available for ice core research.The figure on the right shows the scan of a ice cores sample.The ice core image from 60 m depth shows well defined grain boundaries (dark lines) and pores.
