adjust-sigmoid

adjust_sigmoid

skimage.exposure.adjust_sigmoid(image, cutoff=0.5, gain=10, inv=False) [source]

Performs Sigmoid Correction on the input image.

Also known as Contrast Adjustment. This function transforms the input image pixelwise according to the equation O = 1/(1 + exp*(gain*(cutoff - I))) after scaling each pixel to the range 0 to 1.

Parameters:

image : ndarray

Input image.

cutoff : float

Cutoff of the sigmoid function that shifts the characteristic curve in horizontal direction. Default value is 0.5.

gain : float

The constant multiplier in exponential’s power of sigmoid function. Default value is 10.

inv : bool

If True, returns the negative sigmoid correction. Defaults to False.

Returns:

out : ndarray

Sigmoid corrected output image.

See also

adjust_gamma

References

[R84] Gustav J. Braun, “Image Lightness Rescaling Using Sigmoidal Contrast Enhancement Functions”, http://www.cis.rit.edu/fairchild/PDFs/PAP07.pdf
doc_scikit_image
2017-01-12 17:20:03
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