The influence of ambient lighting on the detection of small contrast elements in digital dental radiographs
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The aim of this study was to evaluate the effect of ambient light on the detection of contrast elements in digital dental radiographs.
Materials and methods
A high-contrast standardized digital radiograph of an aluminum step wedge containing 32 boreholes of different depth was cut into 40 isometric images. Images were presented at random on a 17-in cathode ray tube (CRT) monitor at different ambient background illuminations of 0, 50, 200, and 500 lx. Twenty observers stated twice their blinded decision whether or not they could perceive a dark spot on a five-point confidence scale. Areas (Az) under receiver operating characteristic curves were calculated and compared between the four different ambient illuminations using the Friedman test. Statistical significance was set at p < 0.05. Overall agreement was estimated determining the intraclass correlation coefficient.
The Az values (0.735 for 0 lx, 0.728 for 50 lx, 0.735 for 200 lx, and 0.788 for 500 lx) did not significantly differ (p = 0.796) between the four ambient lighting levels.
The detection of small contrast features in digital dental radiographs on a CRT monitor seems to be comparable over a wide range of ambient background illumination.
The ambient light in dental offices of <500 lx may not negatively impact the diagnostic performance of digital dental radiographs.
KeywordsRadiography Digital images Image perception Visual perception Light conditions
Conflict of interest
The authors declare that they have no conflict of interests.
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