ImageProfile

class gammapy.estimators.ImageProfile(table)

Bases: object

Image profile class.

The image profile data is stored in Table object, with the following columns:

• x_ref Coordinate bin center (required).

• x_min Coordinate bin minimum (optional).

• x_max Coordinate bin maximum (optional).

• profile Image profile data (required).

• profile_err Image profile data error (optional).

Parameters

tableTable

Table instance with the columns specified as above.

Attributes Summary

profile	Image profile quantity.
profile_err	Image profile error quantity.
x_max	Max.
x_min	Min.
x_ref	Reference x coordinates.

Methods Summary

normalize([mode])	Normalize profile to peak value or integral.
peek([figsize])	Show image profile and error.
plot([ax])	Plot image profile.
plot_err([ax])	Plot image profile error as band.
smooth([kernel, radius])	Smooth profile with error propagation.

Attributes Documentation

profile

Image profile quantity.

profile_err

Image profile error quantity.

x_max

Max. x coordinates.

x_min

Min. x coordinates.

x_ref

Reference x coordinates.

Methods Documentation

normalize(mode='peak')

Normalize profile to peak value or integral.

Parameters

mode[‘integral’, ‘peak’]

Normalize image profile so that it integrates to unity (‘integral’) or the maximum value corresponds to one (‘peak’). Default is “peak”.

Returns

profileImageProfile

Normalized image profile.

peek(figsize=(8, 4.5), **kwargs)

Show image profile and error.

Parameters

figsizetuple

Size of the figure. Default is (8, 4.5).

**kwargsdict, optional

Keyword arguments passed to ImageProfile.plot_profile().

Returns

axAxes

Axes object.

plot(ax=None, **kwargs)

Plot image profile.

Parameters

axAxes, optional

Axes object. Default is None.

**kwargsdict, optional

Keyword arguments passed to plot.

Returns

axAxes

Axes object.

plot_err(ax=None, **kwargs)

Plot image profile error as band.

Parameters

axAxes, optional

Axes object. Default is None.

**kwargsdict, optional

Keyword arguments passed to fill_between.

Returns

axAxes

Axes object.

smooth(kernel='box', radius='0.1 deg', **kwargs)

Smooth profile with error propagation.

Smoothing is described by a convolution:

\[x_j = \sum_i x_{(j - i)} h_i\]

Where \(h_i\) are the coefficients of the convolution kernel.

The corresponding error on \(x_j\) is then estimated using Gaussian error propagation, neglecting correlations between the individual \(x_{(j - i)}\):

\[\Delta x_j = \sqrt{\sum_i \Delta x^{2}_{(j - i)} h^{2}_i}\]

Parameters

kernel{‘gauss’, ‘box’}

Kernel shape. Default is “box”.

radiusQuantity, str or float

Smoothing width given as quantity or float. If a float is given it is interpreted as smoothing width in pixels. If an (angular) quantity is given it is converted to pixels using xref[1] - x_ref[0]. Default is “0.1 deg”.

kwargsdict, optional

Keyword arguments passed to uniform_filter (‘box’) and gaussian_filter (‘gauss’).

Returns

profileImageProfile

Smoothed image profile.