Читать книгу Introduction to the Physics and Techniques of Remote Sensing - Jakob J. van Zyl - Страница 29

Any wave can be considered as being composed of a number of sinusoidal component waves or spectral components, each carrying a part of the radiant flux of the total wave form. The spectral band over which these different components extend is called the spectral width or bandwidth of the wave. The manner with which the radiation quantities are distributed among the components of different wavelengths or frequencies is called the spectral distribution. All radiance quantities have equivalent spectral quantities that correspond to the density as a function of the wavelength or frequency. For instance, the spectral radiant flux Φ(λ) is the flux in a narrow spectral width around λ divided by the spectra width:

To get the total flux from a wave form covering the spectral band from λ₁ to λ₂, the spectral radiant flux must be integrated over that band:

(2.34)

Figure 2.11 Spectral luminous efficiency V(λ).