Source code for astropy.convolution.kernels

# Licensed under a 3-clause BSD style license - see LICENSE.rst

import math

import numpy as np

from astropy.modeling import models
from astropy.modeling.core import Fittable1DModel, Fittable2DModel
from astropy.utils.decorators import deprecated

from .core import Kernel, Kernel1D, Kernel2D
from .utils import KernelSizeError, has_even_axis, raise_even_kernel_exception

__all__ = ['Gaussian1DKernel', 'Gaussian2DKernel', 'CustomKernel',
           'Box1DKernel', 'Box2DKernel', 'Tophat2DKernel',
           'Trapezoid1DKernel', 'RickerWavelet1DKernel', 'RickerWavelet2DKernel',
           'AiryDisk2DKernel', 'Moffat2DKernel', 'Model1DKernel',
           'Model2DKernel', 'TrapezoidDisk2DKernel', 'Ring2DKernel']


def _round_up_to_odd_integer(value):
    i = math.ceil(value)
    if i % 2 == 0:
        return i + 1
    else:
        return i


[docs]class Gaussian1DKernel(Kernel1D): """ 1D Gaussian filter kernel. The Gaussian filter is a filter with great smoothing properties. It is isotropic and does not produce artifacts. The generated kernel is normalized so that it integrates to 1. Parameters ---------- stddev : number Standard deviation of the Gaussian kernel. x_size : int, optional Size of the kernel array. Default = ⌊8*stddev+1⌋. 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 linearly interpolating 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. Very slow. factor : number, optional Factor of oversampling. Default factor = 10. If the factor is too large, evaluation can be very slow. See Also -------- Box1DKernel, Trapezoid1DKernel, RickerWavelet1DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import Gaussian1DKernel gauss_1D_kernel = Gaussian1DKernel(10) plt.plot(gauss_1D_kernel, drawstyle='steps') plt.xlabel('x [pixels]') plt.ylabel('value') plt.show() """ _separable = True _is_bool = False def __init__(self, stddev, **kwargs): self._model = models.Gaussian1D(1. / (np.sqrt(2 * np.pi) * stddev), 0, stddev) self._default_size = _round_up_to_odd_integer(8 * stddev) super().__init__(**kwargs) self._truncation = np.abs(1. - self._array.sum())
[docs]class Gaussian2DKernel(Kernel2D): """ 2D Gaussian filter kernel. The Gaussian filter is a filter with great smoothing properties. It is isotropic and does not produce artifacts. The generated kernel is normalized so that it integrates to 1. Parameters ---------- x_stddev : float Standard deviation of the Gaussian in x before rotating by theta. y_stddev : float Standard deviation of the Gaussian in y before rotating by theta. theta : float or `~astropy.units.Quantity` ['angle'] Rotation angle. If passed as a float, it is assumed to be in radians. The rotation angle increases counterclockwise. x_size : int, optional Size in x direction of the kernel array. Default = ⌊8*stddev + 1⌋. y_size : int, optional Size in y direction of the kernel array. Default = ⌊8*stddev + 1⌋. 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 -------- Box2DKernel, Tophat2DKernel, RickerWavelet2DKernel, Ring2DKernel, TrapezoidDisk2DKernel, AiryDisk2DKernel, Moffat2DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import Gaussian2DKernel gaussian_2D_kernel = Gaussian2DKernel(10) plt.imshow(gaussian_2D_kernel, interpolation='none', origin='lower') plt.xlabel('x [pixels]') plt.ylabel('y [pixels]') plt.colorbar() plt.show() """ _separable = True _is_bool = False def __init__(self, x_stddev, y_stddev=None, theta=0.0, **kwargs): if y_stddev is None: y_stddev = x_stddev self._model = models.Gaussian2D(1. / (2 * np.pi * x_stddev * y_stddev), 0, 0, x_stddev=x_stddev, y_stddev=y_stddev, theta=theta) self._default_size = _round_up_to_odd_integer( 8 * np.max([x_stddev, y_stddev])) super().__init__(**kwargs) self._truncation = np.abs(1. - self._array.sum())
[docs]class Box1DKernel(Kernel1D): """ 1D Box filter kernel. The Box filter or running mean is a smoothing filter. It is not isotropic and can produce artifacts when applied repeatedly to the same data. The generated kernel is normalized so that it integrates to 1. By default the Box kernel uses the ``linear_interp`` discretization mode, which allows non-shifting, even-sized kernels. This is achieved by weighting the edge pixels with 1/2. E.g a Box kernel with an effective smoothing of 4 pixel would have the following array: [0.5, 1, 1, 1, 0.5]. Parameters ---------- width : number Width of the filter kernel. mode : str, optional One of the following discretization modes: * 'center' Discretize model by taking the value at the center of the bin. * 'linear_interp' (default) Discretize model by linearly interpolating 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 -------- Gaussian1DKernel, Trapezoid1DKernel, RickerWavelet1DKernel Examples -------- Kernel response function: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import Box1DKernel box_1D_kernel = Box1DKernel(9) plt.plot(box_1D_kernel, drawstyle='steps') plt.xlim(-1, 9) plt.xlabel('x [pixels]') plt.ylabel('value') plt.show() """ _separable = True _is_bool = True def __init__(self, width, **kwargs): self._model = models.Box1D(1. / width, 0, width) self._default_size = _round_up_to_odd_integer(width) kwargs['mode'] = 'linear_interp' super().__init__(**kwargs) self._truncation = 0 self.normalize()
[docs]class Box2DKernel(Kernel2D): """ 2D Box filter kernel. The Box filter or running mean is a smoothing filter. It is not isotropic and can produce artifacts when applied repeatedly to the same data. The generated kernel is normalized so that it integrates to 1. By default the Box kernel uses the ``linear_interp`` discretization mode, which allows non-shifting, even-sized kernels. This is achieved by weighting the edge pixels with 1/2. Parameters ---------- width : number Width of the filter kernel. mode : str, optional One of the following discretization modes: * 'center' Discretize model by taking the value at the center of the bin. * 'linear_interp' (default) 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, Tophat2DKernel, RickerWavelet2DKernel, Ring2DKernel, TrapezoidDisk2DKernel, AiryDisk2DKernel, Moffat2DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import Box2DKernel box_2D_kernel = Box2DKernel(9) plt.imshow(box_2D_kernel, interpolation='none', origin='lower', vmin=0.0, vmax=0.015) plt.xlim(-1, 9) plt.ylim(-1, 9) plt.xlabel('x [pixels]') plt.ylabel('y [pixels]') plt.colorbar() plt.show() """ _separable = True _is_bool = True def __init__(self, width, **kwargs): self._model = models.Box2D(1. / width ** 2, 0, 0, width, width) self._default_size = _round_up_to_odd_integer(width) kwargs['mode'] = 'linear_interp' super().__init__(**kwargs) self._truncation = 0 self.normalize()
[docs]class Tophat2DKernel(Kernel2D): """ 2D Tophat filter kernel. The Tophat filter is an isotropic smoothing filter. It can produce artifacts when applied repeatedly on the same data. The generated kernel is normalized so that it integrates to 1. Parameters ---------- radius : int Radius of the filter 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, RickerWavelet2DKernel, Ring2DKernel, TrapezoidDisk2DKernel, AiryDisk2DKernel, Moffat2DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import Tophat2DKernel tophat_2D_kernel = Tophat2DKernel(40) plt.imshow(tophat_2D_kernel, interpolation='none', origin='lower') plt.xlabel('x [pixels]') plt.ylabel('y [pixels]') plt.colorbar() plt.show() """ def __init__(self, radius, **kwargs): self._model = models.Disk2D(1. / (np.pi * radius ** 2), 0, 0, radius) self._default_size = _round_up_to_odd_integer(2 * radius) super().__init__(**kwargs) self._truncation = 0
[docs]class Ring2DKernel(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. The generated kernel is normalized so that it integrates to 1. 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, RickerWavelet2DKernel, TrapezoidDisk2DKernel, AiryDisk2DKernel, Moffat2DKernel Examples -------- Kernel response: .. plot:: :include-source: 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() """ def __init__(self, radius_in, width, **kwargs): radius_out = radius_in + width self._model = models.Ring2D(1. / (np.pi * (radius_out ** 2 - radius_in ** 2)), 0, 0, radius_in, width) self._default_size = _round_up_to_odd_integer(2 * radius_out) super().__init__(**kwargs) self._truncation = 0
[docs]class Trapezoid1DKernel(Kernel1D): """ 1D trapezoid kernel. The generated kernel is normalized so that it integrates to 1. Parameters ---------- width : number Width of the filter kernel, defined as the width of the constant part, before it begins to slope down. slope : number Slope of the filter kernel's tails 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 linearly interpolating 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 -------- Box1DKernel, Gaussian1DKernel, RickerWavelet1DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import Trapezoid1DKernel trapezoid_1D_kernel = Trapezoid1DKernel(17, slope=0.2) plt.plot(trapezoid_1D_kernel, drawstyle='steps') plt.xlabel('x [pixels]') plt.ylabel('amplitude') plt.xlim(-1, 28) plt.show() """ _is_bool = False def __init__(self, width, slope=1., **kwargs): self._model = models.Trapezoid1D(1, 0, width, slope) self._default_size = _round_up_to_odd_integer(width + 2. / slope) super().__init__(**kwargs) self._truncation = 0 self.normalize()
[docs]class TrapezoidDisk2DKernel(Kernel2D): """ 2D trapezoid kernel. The generated kernel is normalized so that it integrates to 1. Parameters ---------- radius : number Width of the filter kernel, defined as the width of the constant part, before it begins to slope down. slope : number Slope of the filter kernel's tails 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, RickerWavelet2DKernel, Ring2DKernel, AiryDisk2DKernel, Moffat2DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import TrapezoidDisk2DKernel trapezoid_2D_kernel = TrapezoidDisk2DKernel(20, slope=0.2) plt.imshow(trapezoid_2D_kernel, interpolation='none', origin='lower') plt.xlabel('x [pixels]') plt.ylabel('y [pixels]') plt.colorbar() plt.show() """ _is_bool = False def __init__(self, radius, slope=1., **kwargs): self._model = models.TrapezoidDisk2D(1, 0, 0, radius, slope) self._default_size = _round_up_to_odd_integer(2 * radius + 2. / slope) super().__init__(**kwargs) self._truncation = 0 self.normalize()
[docs]class RickerWavelet1DKernel(Kernel1D): """ 1D Ricker wavelet filter kernel (sometimes known as a "Mexican Hat" kernel). The Ricker wavelet, or inverted Gaussian-Laplace filter, is a bandpass filter. It smooths the data and removes slowly varying or constant structures (e.g. Background). It is useful for peak or multi-scale detection. This kernel is derived from a normalized Gaussian function, by computing the second derivative. This results in an amplitude at the kernels center of 1. / (sqrt(2 * pi) * width ** 3). The normalization is the same as for `scipy.ndimage.gaussian_laplace`, except for a minus sign. .. note:: See https://github.com/astropy/astropy/pull/9445 for discussions related to renaming of this kernel. Parameters ---------- width : number Width of the filter kernel, defined as the standard deviation of the Gaussian function from which it is derived. x_size : int, optional Size in x direction of the kernel array. Default = ⌊8*width +1⌋. 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 linearly interpolating 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 -------- Box1DKernel, Gaussian1DKernel, Trapezoid1DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import RickerWavelet1DKernel ricker_1d_kernel = RickerWavelet1DKernel(10) plt.plot(ricker_1d_kernel, drawstyle='steps') plt.xlabel('x [pixels]') plt.ylabel('value') plt.show() """ _is_bool = True def __init__(self, width, **kwargs): amplitude = 1.0 / (np.sqrt(2 * np.pi) * width ** 3) self._model = models.RickerWavelet1D(amplitude, 0, width) self._default_size = _round_up_to_odd_integer(8 * width) super().__init__(**kwargs) self._truncation = np.abs(self._array.sum() / self._array.size)
[docs]class RickerWavelet2DKernel(Kernel2D): """ 2D Ricker wavelet filter kernel (sometimes known as a "Mexican Hat" kernel). The Ricker wavelet, or inverted Gaussian-Laplace filter, is a bandpass filter. It smooths the data and removes slowly varying or constant structures (e.g. Background). It is useful for peak or multi-scale detection. This kernel is derived from a normalized Gaussian function, by computing the second derivative. This results in an amplitude at the kernels center of 1. / (pi * width ** 4). The normalization is the same as for `scipy.ndimage.gaussian_laplace`, except for a minus sign. .. note:: See https://github.com/astropy/astropy/pull/9445 for discussions related to renaming of this kernel. Parameters ---------- width : number Width of the filter kernel, defined as the standard deviation of the Gaussian function from which it is derived. x_size : int, optional Size in x direction of the kernel array. Default = ⌊8*width +1⌋. y_size : int, optional Size in y direction of the kernel array. Default = ⌊8*width +1⌋. 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, Ring2DKernel, TrapezoidDisk2DKernel, AiryDisk2DKernel, Moffat2DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import RickerWavelet2DKernel ricker_2d_kernel = RickerWavelet2DKernel(10) plt.imshow(ricker_2d_kernel, interpolation='none', origin='lower') plt.xlabel('x [pixels]') plt.ylabel('y [pixels]') plt.colorbar() plt.show() """ _is_bool = False def __init__(self, width, **kwargs): amplitude = 1.0 / (np.pi * width ** 4) self._model = models.RickerWavelet2D(amplitude, 0, 0, width) self._default_size = _round_up_to_odd_integer(8 * width) super().__init__(**kwargs) self._truncation = np.abs(self._array.sum() / self._array.size)
[docs]class AiryDisk2DKernel(Kernel2D): """ 2D Airy disk kernel. This kernel models the diffraction pattern of a circular aperture. The generated kernel is normalized so that it integrates to 1. Parameters ---------- radius : float The radius of the Airy disk kernel (radius of the first zero). x_size : int, optional Size in x direction of the kernel array. Default = ⌊8*radius + 1⌋. y_size : int, optional Size in y direction of the kernel array. Default = ⌊8*radius + 1⌋. 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, RickerWavelet2DKernel, Ring2DKernel, TrapezoidDisk2DKernel, Moffat2DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import AiryDisk2DKernel airydisk_2D_kernel = AiryDisk2DKernel(10) plt.imshow(airydisk_2D_kernel, interpolation='none', origin='lower') plt.xlabel('x [pixels]') plt.ylabel('y [pixels]') plt.colorbar() plt.show() """ _is_bool = False def __init__(self, radius, **kwargs): self._model = models.AiryDisk2D(1, 0, 0, radius) self._default_size = _round_up_to_odd_integer(8 * radius) super().__init__(**kwargs) self.normalize() self._truncation = None
[docs]class Moffat2DKernel(Kernel2D): """ 2D Moffat kernel. This kernel is a typical model for a seeing limited PSF. The generated kernel is normalized so that it integrates to 1. Parameters ---------- gamma : float Core width of the Moffat model. alpha : float Power index of the Moffat model. x_size : int, optional Size in x direction of the kernel array. Default = ⌊8*radius + 1⌋. y_size : int, optional Size in y direction of the kernel array. Default = ⌊8*radius + 1⌋. 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, RickerWavelet2DKernel, Ring2DKernel, TrapezoidDisk2DKernel, AiryDisk2DKernel Examples -------- Kernel response: .. plot:: :include-source: import matplotlib.pyplot as plt from astropy.convolution import Moffat2DKernel moffat_2D_kernel = Moffat2DKernel(3, 2) plt.imshow(moffat_2D_kernel, interpolation='none', origin='lower') plt.xlabel('x [pixels]') plt.ylabel('y [pixels]') plt.colorbar() plt.show() """ _is_bool = False def __init__(self, gamma, alpha, **kwargs): # Compute amplitude, from # https://en.wikipedia.org/wiki/Moffat_distribution amplitude = (alpha - 1.0) / (np.pi * gamma * gamma) self._model = models.Moffat2D(amplitude, 0, 0, gamma, alpha) self._default_size = _round_up_to_odd_integer(4.0 * self._model.fwhm) super().__init__(**kwargs) self.normalize() self._truncation = None
[docs]class Model1DKernel(Kernel1D): """ Create kernel from 1D model. The model has to be centered on x = 0. Parameters ---------- model : `~astropy.modeling.Fittable1DModel` Kernel response function model x_size : int, optional Size in x direction of the kernel array. Default = ⌊8*width +1⌋. Must be odd. 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 linearly interpolating 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. Raises ------ TypeError If model is not an instance of `~astropy.modeling.Fittable1DModel` See also -------- Model2DKernel : Create kernel from `~astropy.modeling.Fittable2DModel` CustomKernel : Create kernel from list or array Examples -------- Define a Gaussian1D model: >>> from astropy.modeling.models import Gaussian1D >>> from astropy.convolution.kernels import Model1DKernel >>> gauss = Gaussian1D(1, 0, 2) And create a custom one dimensional kernel from it: >>> gauss_kernel = Model1DKernel(gauss, x_size=9) This kernel can now be used like a usual Astropy kernel. """ _separable = False _is_bool = False def __init__(self, model, **kwargs): if isinstance(model, Fittable1DModel): self._model = model else: raise TypeError("Must be Fittable1DModel") super().__init__(**kwargs)
[docs]class Model2DKernel(Kernel2D): """ Create kernel from 2D model. The model has to be centered on x = 0 and y = 0. Parameters ---------- model : `~astropy.modeling.Fittable2DModel` Kernel response function model x_size : int, optional Size in x direction of the kernel array. Default = ⌊8*width +1⌋. Must be odd. y_size : int, optional Size in y direction of the kernel array. Default = ⌊8*width +1⌋. 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. Raises ------ TypeError If model is not an instance of `~astropy.modeling.Fittable2DModel` See also -------- Model1DKernel : Create kernel from `~astropy.modeling.Fittable1DModel` CustomKernel : Create kernel from list or array Examples -------- Define a Gaussian2D model: >>> from astropy.modeling.models import Gaussian2D >>> from astropy.convolution.kernels import Model2DKernel >>> gauss = Gaussian2D(1, 0, 0, 2, 2) And create a custom two dimensional kernel from it: >>> gauss_kernel = Model2DKernel(gauss, x_size=9) This kernel can now be used like a usual astropy kernel. """ _is_bool = False _separable = False def __init__(self, model, **kwargs): self._separable = False if isinstance(model, Fittable2DModel): self._model = model else: raise TypeError("Must be Fittable2DModel") super().__init__(**kwargs)
class PSFKernel(Kernel2D): """ Initialize filter kernel from astropy PSF instance. """ _separable = False def __init__(self): raise NotImplementedError('Not yet implemented')
[docs]class CustomKernel(Kernel): """ Create filter kernel from list or array. Parameters ---------- array : list or array Filter kernel array. Size must be odd. Raises ------ TypeError If array is not a list or array. `~astropy.convolution.KernelSizeError` If array size is even. See also -------- Model2DKernel, Model1DKernel Examples -------- Define one dimensional array: >>> from astropy.convolution.kernels import CustomKernel >>> import numpy as np >>> array = np.array([1, 2, 3, 2, 1]) >>> kernel = CustomKernel(array) >>> kernel.dimension 1 Define two dimensional array: >>> array = np.array([[1, 1, 1], [1, 2, 1], [1, 1, 1]]) >>> kernel = CustomKernel(array) >>> kernel.dimension 2 """ def __init__(self, array): self.array = array super().__init__(self._array) @property def array(self): """ Filter kernel array. """ return self._array @array.setter def array(self, array): """ Filter kernel array setter """ if isinstance(array, np.ndarray): self._array = array.astype(np.float64) elif isinstance(array, list): self._array = np.array(array, dtype=np.float64) else: raise TypeError("Must be list or array.") # Check if array is odd in all axes if has_even_axis(self): raise_even_kernel_exception() # Check if array is bool ones = self._array == 1. zeros = self._array == 0 self._is_bool = bool(np.all(np.logical_or(ones, zeros))) self._truncation = 0.0
@deprecated('4.0', alternative='RickerWavelet1DKernel') class MexicanHat1DKernel(RickerWavelet1DKernel): pass @deprecated('4.0', alternative='RickerWavelet2DKernel') class MexicanHat2DKernel(RickerWavelet2DKernel): pass