Comparison With Traditional Digital Images
Information stored in high-dynamic-range images typically corresponds to the physical values of luminance or radiance that can be observed in the real world. This is different from traditional digital images, which represent colors that should appear on a monitor or a paper print. Therefore, HDR image formats are often called scene-referred, in contrast to traditional digital images, which are device-referred or output-referred. Furthermore, traditional images are usually encoded for the human visual system (maximizing the visual information stored in the fixed number of bits), which is usually called gamma encoding or gamma correction. The values stored for HDR images are often gamma compressed (power law) or logarithmically encoded, or floating-point linear values, since fixed-point linear encodings are increasingly inefficient over higher dynamic ranges.
HDR images often do not use fixed ranges per color channel - other than traditional images - in order to represent many more colors over a much wider dynamic range. For that purpose, they do not user integer values to represent the single color channels (e.g. 0..255 in an 8 bit per pixel interval for red, green and blue) but a floating point representation. Common are 16-bit (half precision) or 32-bit floating point numbers to represent HDR pixels. However, when the appropriate transfer function is used, HDR pixels for some applications can be represented with as few as 10–12 bits for luminance and 8 bits for chrominance without introducing any visible quantization artifacts.
Read more about this topic: High Dynamic Range Imaging
Famous quotes containing the words comparison with, comparison, traditional and/or images:
“He was a superior man. He did not value his bodily life in comparison with ideal things. He did not recognize unjust human laws, but resisted them as he was bid. For once we are lifted out of the trivialness and dust of politics into the region of truth and manhood.”
—Henry David Thoreau (1817–1862)
“Intolerance respecting other people’s religion is toleration itself in comparison with intolerance respecting other people’s art.”
—Wallace Stevens (1879–1955)
“The traditional American husband and father had the responsibilities—and the privileges—of playing the role of primary provider. Sharing that role is not easy. To yield exclusive access to the role is to surrender some of the potential for fulfilling the hero fantasy—a fantasy that appeals to us all. The loss is far from trivial.”
—Faye J. Crosby (20th century)
“TV gives everyone an image, but radio gives birth to a million images in a million brains.”
—Peggy Noonan (b. 1950)