Comparing Signal Detection Between Novel High-Luminance HDR and Standard Medical LCD Displays

DICOM specifies that digital data values should be linearly mapped to just-noticable differences (JNDs) in luminance. Increasing the number of JNDs available requires increasing the display´s dynamic range. However, operating over too wide a range may cause human observers to miss contrast in dark regions due to adaptation to bright areas or, alternatively, miss edges in bright regions due to scattering in the eye. Dolby Inc.´s high dynamic range (HDR) LCD display has a maximum luminance over 2000 cd/m²; bright enough to produce significant in-eye scatter. The display combines a spatially variable backlight producing a low-resolution 8-bit ldquobacklight imagerdquo with a high-resolution 8-bit LCD panel, approximating a 16-bit greyscale display. Alternatively, by holding the backlight constant at 800 cd/m², a standard medical LCD display can be simulated.We used two-alternative forced choice (2AFC) signal-detection experiments to quantify display quality. We explored whether the full-power HDR display´s optical characteristics (scattering and low resolution backlight) have a negative effect on signal detection in medical images compared with a standard LCD. We used 8-bit test images derived from high-field MRI data combined with synthetic targets and synthetic Rician noise. We suggest signal detection performance with the HDR display is comparable to a standard medical LCD.