Wavelength Adjusted Data Control

A wavelength adjuster is a construct that is used to manage wavelength dependence and adjustment of optical coefficients. The most common case is simply adjusting scattering, absorption, or extinction coefficients from their native wavelengths to some other targets. Another example usage is generating Ångström exponents from pairs of neighboring wavelengths in the data. The adjuster also provides optional smoothing of the inputs before calculation of the output.

When generating output values, the adjuster has the concept of "valid distance". This is the number of nanometers that a given input value can be interpolated or extrapolated to a target wavelength. So, if the target wavelength exceeds the valid distance from all available inputs, the output is returned as unavailable or invalid. This allows inputs to only provide nearby values if they are approximating to limit the uncertainty of the approximation.

The wavelength adjuster consists of input classes an their parameters. The first class of inputs is the dynamically controlled ones. These inputs are specified by a match of potentially many variables and take their input wavelengths from the metadata of the associated variable. The configuration for dynamic inputs is on the top level of the wavelength adjuster hash configuration.

The next set of inputs are single channels at controlled wavelengths. These inputs do not incorporate the available metadata but the actual input value may be overridden. The structures of these inputs are as unique identifiers under the Fixed hash in the top level of the adjuster.

In addition to the optical coefficient inputs, the adjuster can also have direct Ångström exponent inputs. The first set of these are defined by unique identifiers under the Angstrom hash in the top level of the adjuster. These Ångström exponents are preferred for interpolation and explicit calculations if they are provided and within the valid distance. That is, if a value is provided here, the adjuster will attempt to use it before calculating one from any available inputs.

The final set of inputs are fallback Ångström exponents. These are Ångström exponents used only when the calculation from calculation from the optical coefficients fails. For example, the fall back Ångström exponent can be used when only a single coefficient is available or when channels are negative. The configuration for fallback Ångström exponents are located as unique identifiers under the AngstromFallback hash in the top level of the adjuster.