期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2004
卷号：XXXV Part B1
页码：48-52
出版社：Copernicus Publications
摘要：High performance scanning is a routine part of the digital photogrammetric production workflow. Modern scanners offer geometric precision similar to analytical plotters and high quality CCD sensors capable of faithfully capturing the information in the aerial pho- tograph at 12 bits per channel to provide excellent dynamic range and tonal set-up. Modern practice is typically based on scanning positive or negative roll films. One of the critical requirements of the best scanners is high optical resolution at very high speed, mo- tivated by the desire to complete roll-film scans overnight. Currently this can be done on the Leica DSW600 Digital Scanning Work- station for black and white photography owing to its industry fastest scan times of 2 minutes per 23 x 23 cm frame. No scanner can yet do this for a 500 foot colour roll. Recent improvements attempt to extend this performance on the DSW to colour, while at the same time improving image quality and control. Leica Geosystems has undertaken a number of innovations aimed at these goals, in- cluding: large format 12-bit sensor; novel LED illumination system, to increase amount and uniformity of light, enlarge the illumi- nated area to maximize scanning speed, reduce cost and improve reliability; coatings on stage plate and cover glass to eliminate Newton Rings; higher performance linear encoders to optimise geometric integrity; software refinements, including ease-of-use fea- tures and JPEG2000. These advances are incorporated in a new model, the DSW700, but most are available to users of existing scanners by means of a well defined upgrade program
