title: Evaluation of imaging properties of a laser film digitizer.
abstract: In this paper we provide a quantitative assessment of the basic imaging properties of a laser film digitizer. The characteristic curve of the digitizer was determined in terms of the relationship between input optical density and output pixel value. Spatial resolution of the laser digitizer was characterized using the presampling modulation transfer function (MTF), which was measured using a curve fitting technique with an angulated slit. For the noise analysis, we compared the Wiener spectra of uniformly exposed film samples before and after digitization. The effects of different sampling distances and scanning directions were investigated. Our results show that the characteristic curve of the laser digitizer was linear. The presampling MTFs of the digitizer were similar at different sampling distances and were substantially greater in the vertical scanning direction than in the horizontal direction. The noise of the digitized film sample was mainly affected by the presampling MTF and structure noise of the digitizer.
authors.affiliation: Kurt Rossmann Laboratories for Radiologic Image Research, Department of Radiology, University of Chicago, IL 60637.
authors.forename: F F
authors.initials: FF
authors.lastname: Yin
authors.forename: M L
authors.initials: ML
authors.lastname: Giger
authors.forename: K
authors.initials: K
authors.lastname: Doi
authors.forename: H
authors.initials: H
authors.lastname: Yoshimura
authors.forename: X W
authors.initials: XW
authors.lastname: Xu
authors.forename: R M
authors.initials: RM
authors.lastname: Nishikawa
mesh_terms: D005069:Evaluation Studies as Topic; D006801:Humans; D007834:Lasers; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D014962:X-Ray Film