High Dynamic Range Imaging for Digital Still Camera: An Overview

We present a collection of methods and algorithms able to deal with high dynamic ranges of real pictures acquired by digital engines e.g., charge-coupled device (CCD/CMOS) cameras. An accurate image acquisition can be challenging under difficult light conditions. A few techniques that overcome dynamic range limitations problems are reported. The presented methods allow the recovery of the original radiance values of the final 8-bit-depth image starting from differently exposed pictures. This allows the capture of both low- and high-light details by merging the various pictures into a single map, thus providing a more faithful description of what the real world scene was. However, in order to be viewed on a common computer monitor, the map needs to be compressed and requantized while preserving the visibility of details. The main problem comes from the fact that the contrast of the radiance values is usually far greater than that of the display device. Various related techniques are reviewed and discussed.