High-dynamic-range dermoscopy imaging and diagnosis of hypopigmented skin cancers.

High-Dynamic-RangeDermoscopy Imaging andDiagnosis of Hypopigmented Skin Cancers Acquiringdigitaldermoscopy imageshasbecomeroutinepractice in the offices of many dermatologists around the world. While the main purposes of acquiring digital dermoscopy images are documentation and shortand long-term monitoring,1,2 these images can be enhanced to magnify features or sharpen contrast, making it easier to better visualize dermoscopic structures that are otherwise not as conspicuous.3,4 The photographic technique known as highdynamic-range (HDR) imaging, a digital technique that produces a greater dynamic range (DR) of luminosity across the image than standard imaging, can enhance some dermoscopic structures. Indigital photography,DRdescribes the ratiobetween the maximum and minimum of detectable light intensities. It is measured in exposure value (EV) differences (knownas stops) between thebrightest anddarkestpartsof the image that show detail. An increase of 1 EV represents a doubling of the light intensity. The DR of the human eye is 6.5 EVs. Modern digital cameras have a DR up to 14 EVs, which is far superior to that of the human eye. High-dynamic-range imagesarenormallyproducedbycapturingmultiplestandardphotographsatdifferentexposuresettings: One image is taken underexposed (too dark), another with normal exposure, and a third overexposed (too bright). These images are subsequently combined to forma single image with a broader tonal range. Dermoscopyattachments formobilephonesarenowreadily available andare alreadywidelyused for routinedocumentation purposes. While HDR image acquisition was previously relegated to only high-end digital single-lens-reflex cameras, the new generation ofmobile phones is now able to acquire good-quality HDR images. Thus, it is now possible to effortlessly captureHDR imagesby simply turningon theHDR mode in the camera settings on their mobile phone.