Tone Adjustment of Underexposed Images Using Dynamic Range Remapping

摘要

We present a new method for automatically adjusting the tonal values of underexposed digital images. We make the most of the dynamic range of digital images, and adjust the tonal values through dynamic range remapping, with a specifically defined tone mapping operator. The operator comprises two concatenate terms. The first one is a global operator that adjusts the tonal values of underexposed image with a linear scale transformation as well as a nonuniform intensity reduction function. The second one is a local operator used for noise suppression and detail enhancement. With such operator, tone values of underexposed images are faithfully adjusted. Meanwhile, noises are suppressed without introducing noticeable artifacts into resulting images. Our method runs with high efficiency. Experimental results demonstrate its effectiveness.