Transformations of Gray Levels in an Image

transformation

logarithmic

power

σ

1.×

-6

10

γ

1

This Demonstration shows how the contrast of a grayscale image can be modified by applying the common gray level transformations found in typical image processing textbooks, that is, the logarithm and the

γ

transformations.

Details

The logarithm and the

γ

(power-law) transformations are useful in varying the dynamic range of the darker or lighter parts of the gray levels in an image. In this Demonstration, the logarithm transformation is defined by

y=clog(1+(

σ

e

-1)x)

and the power law by

y=c

γ

x

,

in which the constant

c

is scaled to set the maximum output of the transformation to the maximum gray level (in an 8-bit grayscale image this value is 255).

Varying the parameters

σ

or

γ

(depending on the transformation chosen), we can modify the contrast in the image and highlight details not seen in the original.

Permanent Citation

José A. Díaz

"Transformations of Gray Levels in an Image"
http://demonstrations.wolfram.com/TransformationsOfGrayLevelsInAnImage/
Wolfram Demonstrations Project
Published: October 13, 2011