Image quality characteristics of handheld display devices for medical imaging.
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Date
2013-11-15
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Abstract
Handheld devices such as mobile phones and tablet computers have become widespread with thousands of available software applications Recently handhelds are being proposed as part of medical imaging solutions especially in emergency medicine where immediate consultation is required However handheld devices differ significantly from medical workstation displays in terms of display characteristics Moreover the characteristics vary significantly among device types We investigate the image quality characteristics of various handheld devices with respect to luminance response spatial resolution spatial noise and reflectance We show that the luminance characteristics of the handheld displays are different from those of workstation displays complying with grayscale standard target response suggesting that luminance calibration might be needed Our results also demonstrate that the spatial characteristics of handhelds can surpass those of medical workstation displays particularly for recent generation devices While a 5 mega pixel monochrome workstation display has horizontal and vertical modulation transfer factors of 0 52 and 0 47 at the Nyquist frequency the handheld displays released after 2011 can have values higher than 0 63 at the respective Nyquist frequencies The noise power spectra for workstation displays are higher than 1 2 10 5 mm 2 at 1 mm 1 while handheld displays have values lower than 3 7 10 6 mm 2 Reflectance measurements on some of the handheld displays are consistent with measurements for workstation displays with in some cases low specular and diffuse reflectance coefficients The variability of the characterization results among devices due to the different technological features indicates that image quality varies greatly among handheld display devices