6 Dynamic Photo HDR1 HDR imagingWelcome to the exciting world of High dynamic range imaging.In computer graphics and photography, high dynamic range imaging (HDRI) is a set of
techniques that allow a far greater dynamic range of exposures (i.e. a large difference between
light and dark areas) than normal digital imaging techniques. The intention of HDRI is to
accurately represent the wide range of intensity levels found in real scenes ranging from direct
sunlight to the deepest shadows.The use of high dynamic range imaging in computer graphics was pioneered by Paul
Debevec. Debevec is thought to be the first person to create computer graphic images using
HDRI maps to realistically light and animate computer graphics objects. Gregory Ward
created the Radiance RGBE image file format in 1985, which was the first and still is the
most commonly used file format for high dynamic range imaging today.Tone mappingOne problem with HDR has always been in viewing the images. CRTs, LCDs, prints, and
other methods of displaying images only have a limited dynamic range. Thus various methods
of "converting" HDR images into a viewable format have been developed, generally called
"tone mapping".Early methods of tone mapping were simple. They simply showed a "window" of the entire
dynamic range, clipping to set minimum and maximum values. However, more recent
methods have attempted to show more of the dynamic range. The more complex methods tap
into research on how the human eye and visual cortex perceive a scene, trying to show the
whole dynamic range while retaining realistic colour and contrast.From Wikipedia, the free encyclopedia1.1 Introduction
The HDR imaging and tone mapping brought last couple of years a new excitement into the digital
photography. While HDR imaging has a very specific purpose for professional work (like CGI or image
recognition), its various tone-mapping processes can be also used to turn an ordinary digital photo into
a more dramatic and interesting work.