ColorToneMapping

ColorToneMapping[image]

applies a tone mapping to color values in image so as to make variations of luminance visible even in small intervals of the dynamic range.

ColorToneMapping[image,c]

maps colors by compressing the overall range of luminance values by a factor c.

ColorToneMapping[image,range]

applies a mapping only to colors whose initial luminance lies in the specified range.

ColorToneMapping[image,{range,c}]

takes the specified range of colors and compresses their overall luminance values by a factor c.

ColorToneMapping[image,{{range1,c1},{range2,c2},}]

uses different compression factors ci for different ranges rangei.

ColorToneMapping[image,spec,s]

uses the color compensation factor s to correct for saturation distortion introduced during tone mapping.

Details and Options

  • Tone mapping is typically used to represent a high dynamic range image on a low dynamic range screen. ColorToneMapping compresses the range of luminance values while preserving local spatial details.
  • ColorToneMapping works with grayscale and color images. Images with ColorSpace->Automatic are converted to "RGB".
  • The compression factor c ranges from 0 to 1. The default setting is c=1/2.
  • With c=0, minimal compression is performed. With c=1, extreme compression is performed, which typically results in a poorly contrasted, nonrealistic image.
  • Pixel luminance interval range can be in one of the following forms:
  • Allfull luminance interval (default)
    {min,max}interval ranging from min to max
    "Low"dark luminance values smaller than
    "Medium"intermediate luminance values ranging from to
    "High"high luminance values greater than
  • With overlapping ranges {rangei,ci} and {rangej,cj}, the maximum compression is used for the overlapping part. »
  • The color compensation factor s can be any non-negative value, with typical values being in the range from to .
  • The following are values and effects of the different values for s:
  • Automaticbased on compression factor and method (default)
    0completely desaturate colors, i.e. grayscale
    0<s<1desaturate colors
    1no effect
    s>1saturate colors
  • ColorToneMapping takes a Method option. Possible settings include:
  • "RGB"global mapping of RGB channels
    "Luminance"global mapping of luminance
    "LogLuminance"global mapping of luminance logarithm
    "DodgingAndBurning"local digital dodging and burning
    {"BaseLuminance",λ}local scaling of the base luminance, combined with details multiplied by λ (default)

Examples

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Basic Examples  (1)

Apply tone mapping to a high dynamic range image:

Scope  (8)

Tone map an image by compressing the luminance by a factor 0.2:

Tone map pixels in a luminance range specified by minimum and maximum values:

Use a named luminance interval:

Tone map two different sets of pixels:

Specify an amount of contrast compression:

Apply tone mapping in several ranges with several compression factors:

With overlapping ranges, the maximum compression is used for the overlapping part:

Specify a saturation correction:

Options  (3)

Method  (3)

The default mapping method is "BaseLuminance":

Specify a detail factor:

Compare the four methods based on some form of luminance compression:

Local methods typically yield crisper images:

Compare with global methods:

Global methods typically emphasize speed of computation:

Compare with local methods:

Use Method->"RGB" to highlight dark regions in a low dynamic range image:

More sophisticated methods typically yield unnatural results with low dynamic range images:

Applications  (1)

Lighten underexposed areas in a picture:

Wolfram Research (2015), ColorToneMapping, Wolfram Language function, https://reference.wolfram.com/language/ref/ColorToneMapping.html.

Text

Wolfram Research (2015), ColorToneMapping, Wolfram Language function, https://reference.wolfram.com/language/ref/ColorToneMapping.html.

BibTeX

@misc{reference.wolfram_2021_colortonemapping, author="Wolfram Research", title="{ColorToneMapping}", year="2015", howpublished="\url{https://reference.wolfram.com/language/ref/ColorToneMapping.html}", note=[Accessed: 25-September-2021 ]}

BibLaTeX

@online{reference.wolfram_2021_colortonemapping, organization={Wolfram Research}, title={ColorToneMapping}, year={2015}, url={https://reference.wolfram.com/language/ref/ColorToneMapping.html}, note=[Accessed: 25-September-2021 ]}

CMS

Wolfram Language. 2015. "ColorToneMapping." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ColorToneMapping.html.

APA

Wolfram Language. (2015). ColorToneMapping. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ColorToneMapping.html