Light intensity deconvolution

It has been noted that deconvolution methods, most of which were linear, had a propensity to produce solutions that did not make good physical sense. Prominent examples were found when negative values were obtained for light intensity or particle flux. As noted previously, the need to eliminate these negative components was generally accepted. Accordingly, Gold (1964) developed a method of iteration similar to Van Cittert s but used multiplicative corrections instead of additive ones. 

Aerosols can be analysed using techniques that are based on the interactions between particles and light The examination of a scattered beam of light by a detector after hitting a particle is the basis for many optical instruments. For example, the number of scattered light pulses is a measure of particle number. Furthermore, the intensity and spatial scattering pattern can also be used for determination of particle size and particle shape, respectively. Optical methods are sensitive and easy to use. These methods are classified into four categories (1) optical particle counter, (2) laser diffractometer, (3) phase Doppler system and (4) intensity deconvolution system. 

The measured data was corrected for group velocity dispersion by comparison with white light generated in water under the same configuration, yielding in the end a two dimensional array of the fluorescence intensity as a function of frequency and time. Singular value decomposition and deconvolution of the obtained decays was used to reconstruct the spectral decay which would correspond to delta pulse excitation. S(t) was calculated from this processed data. 

Although the molar absorptivities of these bands tend to be rather small, the instrumental state of the art, combined with superior data deconvolution routines, has progressed to the point where their measurement is relatively straightforward.78 The most important experimental requirements are the use of high-intensity stable light sources, low-noise sensitive detectors, and efficient methods for collection of the diffuse reflectance of the measurement. 

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