lentil.radiometry.Spectrum.bin#

Spectrum.bin(wave, interp_method='simps', ends='symmetric', preserve_power=True, sample_method='linear', fill_value=0, waveunit='nm')[source]#

Compute a binned representation of the Spectrum data at a given array of central wavelengths.

The general algorithm computes bin edges, sampling the Spectrum values at these edges, and numerically integrating within the edges of each bin. For \(n\) bins (centered at the wavelength values in the wave array), there will be \(n+1\) edges. The edges at each bin centered at \(\lambda_k\) are given by

\[ \begin{align}\begin{aligned}e_{\mbox{left}} = \lambda_k - \frac{\lambda_k - \lambda_{k-1}}{2}\\e_{\mbox{right}} = \lambda_k + \frac{\lambda_{k+1} - \lambda_k}{2}\end{aligned}\end{align} \]

Special treatment is required for the first and last edges (\(\lambda_k =\) wave[0] and \(\lambda_k =\) wave[-1]) since \(\lambda_{k-1}\) and \(\lambda_{k+1}\) are undefined, respectively.

Two different first/last bin edge methods are available:

../../_images/spectrum_bin.png

ends

Left edge for wave[0]

Right edge for wave[-1]

symmetric

\(\lambda_1-\frac{\lambda_2-\lambda_1}{2}\)

\(\lambda_{\mbox{end}}+\frac{\lambda_{\mbox{end}}-\lambda_{\mbox{end}-1}}{2}\)

inside

\(\lambda_1\)

\(\lambda_{\mbox{end}}\)
Parameters:

  • wave (array_like) – Central wavelength set for binning. At least two wavelengths must be provided.

  • interp_method ({'simps', 'trapz'}, optional) – Numerical integration method. ‘simps’ (default) is better for smooth data while ‘trapz’ is better for linear data.

  • ends ({'symmetric', 'inside'}, optional) – Method for handling the first and last bin edge value. Default is ‘symmetric’. See the notes below for details on the available methods.

  • preserve_power (bool, optional)

  • sample_method ({'linear', 'quadratic', 'cubic'}, optional) –

    • ‘linear’ uses linear interpolation (default)

    • ’quadratic’ uses second order spline interpolation

    • ’cubic’ uses third order spline interpolation

  • fill_value (float or array_like, optional) –

    • If a float, this value will be used to fill in requested points outside of the data range.

    • If a two-element array, the first element is used to fill value_new < value[0] and the second element is used for value_new > value[-1].

    • If not provided, the default is 0.

Returns:

value – The binned values, same shape as wave.

Return type:

ndarray

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