title: Evaluation of a Mathematical Model for Digital Image Enhancement.
abstract: The purpose of this study is to compare the detected number of holes on a stepwedge on images resulting from the application of the 5th degree polynomial model compared to the images resulting from the application of linear enhancement. Material and Methods : A 10-step aluminum step wedge with holes randomly drilled on each step was exposed with three different kVp and five exposure times per kVp on a Schick33(®) sensor. The images were enhanced by brightness/contrast adjustment, histogram equalization and with the 5th degree polynomial model and compared to the original non-enhanced images by six observers in two separate readings. Results : There was no significant difference between the readers and between the first and second reading. There was a significant three-factor interaction among Method, Exposure time, and kVp in detecting holes. The overall pattern was: "Poly" results in the highest counts, "Original" in the lowest counts, with "B/C" and "Equalized" intermediate. Conclusion : The 5th degree polynomial model showed more holes when compared to the other modalities.
authors.affiliation: The University of Texas Health Science Center, San Antonio, United States.
authors.forename: Hassem
authors.initials: H
authors.lastname: Geha
authors.affiliation: Department of Oral and Maxillofacial Radiology, Lebanese University, Beirut, Lebanon.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Nasseh
authors.affiliation: The University of Texas Health Science Center, San Antonio, United States.
authors.forename: Marcel
authors.initials: M
authors.lastname: Noujeim
keywords: Contrast; digital imaging; histogram; image enhancement