ZScaleInterval

class astropy.visualization.ZScaleInterval(n_samples=1000, contrast=0.25, max_reject=0.5, min_npixels=5, krej=2.5, max_iterations=5)

Bases: BaseInterval

Interval based on IRAF’s zscale.

https://iraf.net/forum/viewtopic.php?showtopic=134139

Original implementation: spacetelescope/stsci.numdisplay

Licensed under a 3-clause BSD style license (see AURA_LICENSE.rst).

Parameters:

n_samplesint, optional

The number of points in the array to sample for determining scaling factors. Defaults to 1000.

Changed in version 5.2: n_samples replaces the deprecated nsamples argument, which will be removed in the future.

contrastfloat, optional

The scaling factor (between 0 and 1) for determining the minimum and maximum value. Larger values decrease the difference between the minimum and maximum values used for display. Defaults to 0.25.

max_rejectfloat, optional

If more than max_reject * npixels pixels are rejected, then the returned values are the minimum and maximum of the data. Defaults to 0.5.

min_npixelsint, optional

If there are less than min_npixels pixels remaining after the pixel rejection, then the returned values are the minimum and maximum of the data. Defaults to 5.

krejfloat, optional

The number of sigma used for the rejection. Defaults to 2.5.

max_iterationsint, optional

The maximum number of iterations for the rejection. Defaults to 5.

Attributes Summary

nsamples

Deprecated since version 5.2.

Methods Summary

get_limits(values)

Return the minimum and maximum value in the interval based on the values provided.

Attributes Documentation

nsamples

Deprecated since version 5.2: The nsamples attribute is deprecated and may be removed in a future version. Use n_samples instead.

Methods Documentation

get_limits(values)

Return the minimum and maximum value in the interval based on the values provided.

Parameters:

valuesndarray

The image values.

Returns:

vmin, vmaxfloat

The mininium and maximum image value in the interval.