Abstract
The transition from traditional 24-bit RGB to high dynamic range
(HDR) images is hindered by excessively large file formats with
no backwards compatibility. In this paper, we demonstrate a
simple approach to HDR encoding that parallels the evolution of
color television from its grayscale beginnings. A tone-mapped
version of each HDR original is accompanied by restorative
information carried in a subband of a standard output-referred
image. This subband contains a compressed ratio image, which
when multiplied by the tone-mapped foreground, recovers the
HDR original. The tone-mapped image data is also compressed,
and the composite is delivered in a standard JPEG wrapper. To
naïve software, the image looks like any other, and displays as a
tone-mapped version of the original. To HDR-enabled software,
the foreground image is merely a tone-mapping suggestion, as the
original pixel data are available by decoding the information in
the subband. Our method further extends the color range to
encompass the visible gamut, enabling a new generation of
display devices that are just beginning to enter the market.