35-mm film scanner as an intraoral dental radiograph digitizer. II: Effects of brightness and contrast adjustments.

Typical 35-mm slide scanners use a photodiode array and software that allows for digital and analog controls that are manually adjustable. The digital controls provide brightness and contrast adjustments, whereas corresponding analog controls adjust the exposure time and black level that determines the clamping level of the charge-coupled device for the maximum black in the image. The objective of this study was to determine the effects of these controls on the radiometric data of intraoral dental radiograph images, to establish recommended settings, and to set specific standard guidelines for the digitization process. Three approaches were used. The results of this study demonstrate that brightness and contrast control alterations on the digitizer produces different optical densities and modulation transfer function values. The impact of these results is unresolved yet must be considered in analysis on quantitative radiometric studies.

[1]  T Wada,et al.  Digital image processing of periapical radiographs. , 1988, Oral surgery, oral medicine, and oral pathology.

[2]  E Sonnabend,et al.  Presentation and physical evaluation of RadioVisioGraphy. , 1989, Oral surgery, oral medicine, and oral pathology.

[3]  T. Southard,et al.  Quantitative features of digitized radiographic bone profiles. , 1992, Oral surgery, oral medicine, and oral pathology.

[4]  M W Vannier,et al.  35-mm film scanner as an intraoral dental radiograph digitizer. I: A quantitative evaluation. , 1993, Oral surgery, oral medicine, and oral pathology.

[5]  G. Seward,et al.  Oral Radiology: Principles and Interpretation , 1982 .

[6]  H. Gröndahl,et al.  Detectability of artificial marginal bone lesions as a function of lesion depth. A comparison between subtraction radiography and conventional radiographic technique. , 1988, Journal of clinical periodontology.

[7]  U E Ruttimann,et al.  An experimental study of new diagnostic methods for the examination of osseous lesions in the temporomandibular joint. , 1992, Oral surgery, oral medicine, and oral pathology.

[8]  W D McDavid,et al.  Digital subtraction radiography in artificial recurrent caries detection. , 1992, Dento maxillo facial radiology.

[9]  R L Morin,et al.  A practical method to measure the MTF of CT scanners. , 1982, Medical physics.

[10]  M W Vannier,et al.  Quantitative evaluation of digital dental radiograph imaging systems. , 1990, Oral surgery, oral medicine, and oral pathology.

[11]  Razzano Mr,et al.  RadioVisioGraphy: video imaging alters traditional approach to radiography. , 1990 .

[12]  K. Kornman,et al.  Computer-assisted densitometric image analysis (CADIA) for the assessment of alveolar bone density changes in furcations. , 1989, Journal of clinical periodontology.

[13]  S. Dunn,et al.  Diagnosing periapical bone lesions on radiographs by means of texture analysis. , 1992, Oral surgery, oral medicine, and oral pathology.

[14]  E Hausmann,et al.  Usefulness of Subtraction Radiography in the Evaluation of Periodontal Therapy. , 1985, Journal of periodontology.

[15]  U Brägger,et al.  Computer-assisted densitometric image analysis in periodontal radiography. A methodological study. , 1988, Journal of clinical periodontology.

[16]  T. Southard,et al.  Comparison of digitized radiographic alveolar features between 20- and 70-year-old women. A preliminary study. , 1992, Oral surgery, oral medicine, and oral pathology.

[17]  R. Langlais,et al.  Textbook of Dental Radiology , 1984 .

[18]  R T Droege.  A practical method to routinely monitor resolution in digital images. , 1983, Medical physics.