# AsinhStretch¶

class astropy.visualization.AsinhStretch(a=0.1)[source]

An asinh stretch.

The stretch is given by:

$y = \frac{{\rm asinh}(x / a)}{{\rm asinh}(1 / a)}.$
Parameters
afloat, optional

The a parameter used in the above formula. The value of this parameter is where the asinh curve transitions from linear to logarithmic behavior, expressed as a fraction of the normalized image. a must be greater than 0 and less than or equal to 1 (0 < a <= 1). Default is 0.1.

Attributes Summary

 inverse A stretch object that performs the inverse operation.

Methods Summary

 __call__(values[, clip, out]) Transform values using this stretch.

Attributes Documentation

inverse

A stretch object that performs the inverse operation.

Methods Documentation

__call__(values, clip=True, out=None)[source]

Transform values using this stretch.

Parameters
valuesarray_like

The input values, which should already be normalized to the [0:1] range.

clipbool, optional

If True (default), values outside the [0:1] range are clipped to the [0:1] range.

outndarray, optional

If specified, the output values will be placed in this array (typically used for in-place calculations).

Returns
resultndarray

The transformed values.