©2017 Remote Sensing Geoscience and Engineering Consulting
LiDAR & Satellite Incorporated Application(14)
A Studied Case
Hyperspectral sampling points vs.LiDAR Points(2)
Figure 4
Figure 5
Table 1
Note that the wavelengths shown in Table 1 are only parts of data yielded from LiDAR within NIR band in terms of source intensities, others are also selectable within this range but each sampling point is fixed and same as the ones demonstrated. To effectively and professionally use them, for example, to find out the corresponding reflectance of one observed substance in landscape and then identify it by means of the known reflectance for one substance stored in any experimentally approved library, it must be combined with the corresponding hyper-spectra given in Figure 1 in this section. An Example of identifying one sampled substance is given in Figure 6.
Figure 6
An Example of Identifying Sampled Substance
In order to demonstrate how the substance sampled from hyper-spectra is identified by the known spectrum of one substance from a library. An example is offered as follows in Figure 6. In this case, it is clearly seen that the sampled substance belongs to leaf of bush in comparison with the spectrum of black bush existing in the spectral library: ASPEN-Leaf-B supplied by NASA JPL. The procedure of judgment is given as follows:
1. As seen from Figure 6, in the section of the cell structure thus in NIR band, two spectra are quite closely met.
2. According to plant physiology, the spectral feature of cell structure in a plant can be used to distinguish the catalogue of vegetation.
3. The contents of leaf pigments, chlorophyll and water prominently affect the reflectance of leaf. The primary absorption occurs in chlorophyll and water of leaf. However, the amount of chlorophyll and water existing in a plant varies with season change. That results in there is a relative large magnitude of change being shown by the corresponding reflectance in VIS and SWIR band respectively.
Similar judgment can be applied to any sampling because any substance has its own spectrum as long as its absolute temperature is larger than or equal to zero (K).
