HDR processing in photography.

<p>(A) LDR photos taken at varying exposure times produce shifted characteristic curves (otherwise known as the digital conversion function <i>f</i>) that cover different ranges of irradiance. HDR processing merges the LDR characteristic curves to produce an HDR characteristic curve that covers a larger range of irradiance. The HDR characteristic curve is used to calculate object illumination to alleviate the issues of over- and under-exposure associated with conventional LDR photography. (B) An example showing the merger of 4 LDR photos (smaller photos) to a HDR photo (larger photo). In the HDR photo, the front wall showed no saturation from over-exposure while the poorly lit hallway remained visible. This was not achieved in any single LDR photo due to the limited dynamic range.