photobiology (version 0.11.4)

convertTfrType: Convert the "Tfr.type" attribute

Description

Function to set the "Tfr.type" attribute and simultaneously convert the spectral data to correspond to the new type.

Usage

convertTfrType(x, Tfr.type = NULL)

Value

x if possible, with the value of the "Tfr.type" attribute modified and the values stored in the Tfr variable converted to the new quantity.

Arguments

x

a filter_spct, object_spct, filter_mspct or object_mspct object.

Tfr.type

character One of "internal" or "total".

Details

Internal transmittance, \(\tau\), uses as reference the light entering the object while total transmittance, \(T\), takes the incident light as reference. The conversion is possible only if total reflectance, \(\rho\), is known. Either as spectral data in an object_spct object, a filter_spct object that is "under-the-hood" an object_spct, or if a fixed reflectance factor applicable to all wavelengths is stored in the filter.properties attribute of the filter_spct object.

Conversions are computed as:

$$\tau = \frac{T - \rho}{1 - \rho}$$

and

$$T = \tau * (1 - \rho) + \rho$$

For the conversion to take place the object passed as argument to x, must contain a column with transmittance data, named Tfr. Any necessary conversion from absorbance A or from Afr into transmittance, must be done before calling convertTfrType().

See Also

setTfrType, filter_spct

Examples

getTfrType(polyester.spct)
filter_properties(polyester.spct)
convertTfrType(polyester.spct, Tfr.type = "internal")