Revisiting dynamic range and image enhancement ability of contemporary digital radiographic systems

Abstract

Objectives: To assess the dynamic range and enhancement ability of radiographs acquired with contemporary digital systems. Methods: Five repeated periapical radiographs of human mandibles with an aluminium step-wedge were acquired using two sensor-based and three phosphor plate-based (PSP plate-based) systems and an X-ray unit at ten exposure times 0.020, 0.032, 0.063, 0.080, 0.100, 0.200, 0.320, 0.400, 0.500, and 0.630 s. All images had their brightness and contrast enhanced by two experienced oral and maxillofacial radiologists in consensus and were exported as both the original and enhanced file formats. Mean grey values were obtained from the aluminium steps and tabulated with their corresponding thicknesses for each exposure time, digital radiographic system, and file format. Images with saturated steps were excluded and the mean grey values from the remaining images were averaged to assess image brightness and the angular coefficient of the linear trendlines was generated from the relationship between mean grey values and their corresponding aluminium thicknesses to assess image contrast. Brightness and contrast values were compared using two-way ANOVA with post-hoc Tukey (α = 0.05). Results: PSP plate-based digital radiographic systems had a broader dynamic range. Longer exposure times produced original images with lower brightness and variable contrast (p < 0.05). Subjective enhancement significantly increased or reduced brightness and/or contrast in some systems (p < 0.05). Conclusions: Contemporary digital radiographic systems present different dynamic ranges and exposure-related brightness and contrast. Image enhancement may be a valuable tool at slightly suboptimal exposure times.

Artificial Intelligence through Wireless Sensors Applied in Restorative Dentistry: A Systematic Review

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DICOM file format has better radiographic image quality than other file formats: an objective study

“…Due to the difference in exposure time recommended by each manufacturer, Digora Toto used a shorter time for image acquisition, which should have a lower signal-to-noise ratio than the Express system and could interfere with image quality. A previous objective analysis proved that longer exposure times produce images of significantly lower brightness using intraoral digital radiographic systems, including Express and Digora Toto systems 16 . Also, the different spatial resolutions may be another factor to justify the statistically significant difference observed between the tested digital radiographic systems.…”

Comparison of the Effect of the Time Under the Three Primary Color Lighting of Led Production Before Scanning of Phosphorus Plates

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“…The digital sensors were irradiated for 10 distinct exposure times, and the PSP systems were reported to provide a broader dynamic range. 7 Galvão defined automatic exposure compensation (AEC) as "a non-linear enhancement of the image histogram that detects the lowest and highest pixel values and modifies the greyscale to increase image contrast". 21 Presence of high-density dental materials is suggested as a factor influencing the overall grey values and the image contrast.…”

“…Moreover, doping the alkali halides with Eu 2+ enhances the PSL properties of the material. 5,7 PSPs consist of a polymer base coated with europium-activated alkali halide emulsion. BaFBr:Eu 2+ is a common phosphor compound used in medical imaging, and an Argon ion laser (514 nm), a frequency doubled YAG:Nd 3+ laser (532 nm) or a He-Ne laser (633 nm) can be used in the scanner.…”