JPEG-HDR

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JPEG-HDR is an extension to the standard JPEG image file format allowing it to store high dynamic range images.

Overview[edit]

JPEG-HDR was created by Greg Ward and Maryann Simmons as a way to store high dynamic range images inside a standard JPEG file. This reduces the file size required to store HDR images compared to other HDR formats such as floating point TIFF and RGBE. It does this by first converting the image into a tone mapped version and storing a reconstructive multiplier image in APP11 markers in the same JPEG file. Ordinary viewing software will ignore the multiplier image allowing anyone to see the tone mapped version of the image. It was later updated by Ajit Ninan, Greg Ward, Arkady Ten and Wenhui Jia to support other features such as wide color support and the ability to use any tonemapper to create the base image. This updated version is currently being standardized as JPEG XT Part 2.

Support[edit]

Software programs that support JPEG-HDR's include Photosphere (by Greg Ward) and pfstools. A software encoder was available from BrightSide Technologies (formerly Sunnybrook Technologies, acquired by Dolby Laboratories in 2007). The new format that will be standardized will not support the old format headers.

Similar formats[edit]

Other formats that use similar ways of storing additional HDR information in a standard JPEG image include ERI from Kodak and XDepth from Trellis Management. The XDepth technology has been recently integrated into the upcoming JPEG XT standard for floating point HDR still images (Part 7 Profile B). This technology supports any tone mapping operator, a generic gamma curve and wide color gamut, meanwhile keeping its backward compatibility with the legacy JPEG decoder.

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