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mathjax it up
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edit approved Nov 3, 2015 at 14:47
ratchet freak
edit approved Nov 3, 2015 at 14:47
ratchet freak
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If I get correctly what you are asking you basically just need to find the G in this equation:

enter image description here$$Image_{out} = Image_{in}^G$$

This could be easily solved as

enter image description here$$G = \frac{\log{Image_{out}}}{\log{Image_{in}}}$$

Because usallyusually gamma is applied in a uniform fashion on the image, you can just pick any two non zero pixel values (one for source and one for destination) to find out the gamma value applied.

EDIT: As @ChristianRau pointed out, if you don't actually know if the image has been modified with gamma correction, you have to take an higher amount of samples and trying to fit a gamma function on those. If a fit to a gamma function results in too many significant outliers, then probably gamma correction wasn't the function applied.

If I get correctly what you are asking you basically just need to find the G in this equation:

enter image description here

This could be easily solved as

enter image description here

Because usally gamma is applied in a uniform fashion on the image, you can just pick any two non zero pixel values (one for source and one for destination) to find out the gamma value applied.

EDIT: As @ChristianRau pointed out, if you don't actually know if the image has been modified with gamma correction, you have to take an higher amount of samples and trying to fit a gamma function on those. If a fit to a gamma function results in too many significant outliers, then probably gamma correction wasn't the function applied.

If I get correctly what you are asking you basically just need to find the G in this equation:

$$Image_{out} = Image_{in}^G$$

This could be easily solved as

$$G = \frac{\log{Image_{out}}}{\log{Image_{in}}}$$

Because usually gamma is applied in a uniform fashion on the image, you can just pick any two non zero pixel values (one for source and one for destination) to find out the gamma value applied.

EDIT: As @ChristianRau pointed out, if you don't actually know if the image has been modified with gamma correction, you have to take an higher amount of samples and trying to fit a gamma function on those. If a fit to a gamma function results in too many significant outliers, then probably gamma correction wasn't the function applied.

added 208 characters in body
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cifz
cifz
  • 2.6k
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  • 31

If I get correctly what you are asking you basically just need to find the G in this equation:

enter image description here

This could be easily solved as

enter image description here

Because usally gamma is applied in a uniform fashion on the image, you can just pick any two non zero pixel values (one for source and one for destination) to find out the gamma value applied.

EDIT: As @ChristianRau pointed out, if you don't actually know if the image has been modified with gamma correction, you have to take an higher amount of samples and trying to fit a gamma function on those. If a fit to a gamma function results in too many significant outliers, then probably gamma correction wasn't the function applied.

If I get correctly what you are asking you basically just need to find the G in this equation:

enter image description here

This could be easily solved as

enter image description here

Because usally gamma is applied in a uniform fashion on the image, you can just pick any two non zero pixel values (one for source and one for destination) to find out the gamma value applied.

If I get correctly what you are asking you basically just need to find the G in this equation:

enter image description here

This could be easily solved as

enter image description here

Because usally gamma is applied in a uniform fashion on the image, you can just pick any two non zero pixel values (one for source and one for destination) to find out the gamma value applied.

EDIT: As @ChristianRau pointed out, if you don't actually know if the image has been modified with gamma correction, you have to take an higher amount of samples and trying to fit a gamma function on those. If a fit to a gamma function results in too many significant outliers, then probably gamma correction wasn't the function applied.

Source Link
cifz
cifz
  • 2.6k
  • 18
  • 31

If I get correctly what you are asking you basically just need to find the G in this equation:

enter image description here

This could be easily solved as

enter image description here

Because usally gamma is applied in a uniform fashion on the image, you can just pick any two non zero pixel values (one for source and one for destination) to find out the gamma value applied.