Ring2DKernel

class astropy.convolution.Ring2DKernel(radius_in, width, **kwargs)

Bases: astropy.convolution.Kernel2D

2D Ring filter kernel.

The Ring filter kernel is the difference between two Tophat kernels of different width. This kernel is useful for, e.g., background estimation.

Parameters:

radius_in : number

Inner radius of the ring kernel.

width : number

Width of the ring kernel.

mode : str, optional

One of the following discretization modes:

• ‘center’ (default)

  Discretize model by taking the value at the center of the bin.

• ‘linear_interp’

  Discretize model by performing a bilinear interpolation between the values at the corners of the bin.

• ‘oversample’

  Discretize model by taking the average on an oversampled grid.

• ‘integrate’

  Discretize model by integrating the model over the bin.

factor : number, optional

Factor of oversampling. Default factor = 10.

See also

Gaussian2DKernel, Box2DKernel, Tophat2DKernel, MexicanHat2DKernel, Ring2DKernel, AiryDisk2DKernel, Moffat2DKernel

Examples

Kernel response:

import matplotlib.pyplot as plt
from astropy.convolution import Ring2DKernel
ring_2D_kernel = Ring2DKernel(9, 8)
plt.imshow(ring_2D_kernel, interpolation='none', origin='lower')
plt.xlabel('x [pixels]')
plt.ylabel('y [pixels]')
plt.colorbar()
plt.show()

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