![]() The system takes images of a single drawer in a sequential order as determined by the controlling unit. Typically, these effects are caused by direct, punctual lighting when photographing insects with strongly sculptured and shining, in particular metallic, surfaces. The indirect lighting reduces the risk of blown-out highlights caused by reflections from insects with smooth surfaces and exceedingly high contrast. The flashes are directed toward the side and top panels to achieve an even and non-reflective illumination of specimens. ![]() The white inner surfaces of the top and side panels, and the white front curtain are highly reflective and allow for maximum lighting efficiency. As light sources we use two studio flash lights that are placed inside the scanner compartment. Our current system comprises a Nikon D300 DSLR camera equipped with a 12 megapixel APSC sensor, attached to a Voigtländer 90 mm Apo-Lanthar macro lens. In addition, mirrorless cameras employing electronic shutter mechanisms avoid the wear that can be significant when using a DSLR for creating large numbers of images. Currently the best option includes a digital single-lens reflex (DSLR) camera, although the recent introduction of mirrorless system cameras with interchangeable lenses and comparatively large sensors will increase the range of suitable optical equipment. A wide range of different camera systems can be adapted to work with the DScan, provided that the camera has remote control capability because the shutter release needs to be triggered by the control unit. OpticsĬhoice and selection of the optical components of the drawer scanning system are largely unconstrained by the mechanics of the positioning components of the DScan mechanism. The front is closed by a curtain with a reflective inner surface that is closed during scan operations. The system is operated by a PC-controlled console (netbook) with ProNC software (DNC Software Ltd, The left and right sides and back of the scanner are covered by white panels. Effective travel ranges are 600 × 600 mm horizontally (x- and y-axis) and 200 mm vertically (z-axis). Servo drives and precision ball screw spindles allow a minimum step distance of 0.02 mm at a maximum speed of 100 mm/s. 1, and YouTube video under youtu.be/zyT7l-CZego). Mechanics of the drawer scanning systemĭScan is made of a sturdy, industrial standard aluminium frame (LWH = 1080 × 1080 × 1500 mm) with linear units as used by Computer Numerical Control (CNC) positioning machines ( Fig. The level of detail can be adjusted as required, for instance in relation to the size of the insect specimens, and, is in most cases sufficient for specialists to recognize the taxon at genus or even species level. The resulting images allow inspection of insect specimens at high resolution without the need to access the collection itself physically. Because the contents of and arrangement of specimens within drawers will change if they are part of an active research collection, re-scanning of drawers needs to be as fast and as easy as possible. Our primary aim is the optimisation of this system for on-demand-digitisation requirements. Our aim is to use innovative approaches to develop new methods for the rapid digitisation of entomological collection drawers, and the subsequent extraction of relevant metadata from drawer images.ĭScan is a prototype scanning machine and the foundation of a digitisation system that allows fast and efficient digitisation of entomological drawers. However, these solutions need to be developed. Technical solutions have the potential to aid our digitisation efforts by reducing the need for extensive human resources. This is partly due to a regrettable lack of personnel, a situation that is not going to change in the foreseeable future. Moreover, digitisation of natural history specimens is labour-intensive and usually proceeds at a very slow pace. However, the level of documentation of entomological collections is very low, and even basic data about specimens or metadata about collections are often completely missing ( Brake and Lampe 2004). Natural history collections are indispensable scientific resources that play a central role in biodiversity research ( Wheeler et al. The material deposited in natural history collections like the ZSM is principally held and intended to support research purposes. About 90% of the collection are insects, including 10 million Lepidoptera, 3-4 million Coleoptera, and about three million Hymenoptera, stored in about 100,000 standard sized drawers (51 × 42 cm). ![]() The Zoologische Staatssammlung in Munich, Germany (ZSM) holds about 25 million zoological objects. About 80 million objects are deposited in German natural history collections alone, including about 65 million insects ( Brake and Lampe 2004). Natural history collections are nature’s treasure houses.
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