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Development of a high quality film duplication system using a laser digitizer: Comparison with computed radiography
Author(s) -
Yoshimura Hitoshi,
Xu XinWei,
Doi Kunio,
MacMahon Heber,
Hoffmann Kenneth R.,
Giger Maryellen L.,
Montner Steven M.
Publication year - 1993
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597061
Subject(s) - computed radiography , radiography , laser , optics , digital radiography , materials science , gene duplication , image quality , image resolution , computer science , computer vision , physics , medicine , radiology , image (mathematics) , biochemistry , chemistry , gene
A high quality film‐duplication system was developed in order to improve the image quality of duplicated radiographs and to recover improperly exposed films. The system consists of a laser film digitizer, a laser film printer, a workstation, and a magneto‐optical disk. Radiographs are digitized by the laser digitizer, processed by the computer for image enhancement, and then printed on a film by the laser printer. A nonlinear density‐correction technique is employed in recovering improperly exposed radiographs using the H&D curve of the screen‐film system. Using the new duplication system in our department, the average recovery rate was over 80% for chest and abdominal films rejected due to over‐ or underexposure. The basic imaging properties of the duplication system were compared with those of a Computed Radiography (CR) system and a conventional screen‐film system. For low spatial frequencies, the MTF of the CR system is superior to that of the digital duplication system; however, for high spatial frequencies, the MTF of the duplication system is superior. The noise in the duplication system is about half of that in the CR system.