Principle Component Analysis for Crop Discrimination using Hyperspectral Remote Sensing Data

Crop discrimination is still very challenging issue for researcher because of spectral reflectance similarity captured in non-imaging data. The objective of this research work is to focus on crop discrimination challenge. We have used ASD FieldSpec4 Spectroradiometer for collection of leaf samples of four crops Wheat, Jowar, Bajara and Maize. We used vegetation indices and some spectral reflectance band for featuring our dataset. We applied Principle Component Analysis (PCA) for discrimination and it has been observed that when we use first and second principle component, it will give poor result but if third principle component is used then we get accurate and fine results.

EXTENSION OF HIGH REFLECTANCE BAND WIDTH FOR FAR INFRARED SPECTRAL REGION : (1)

Extension of bandwidth for high reflectance zone for the spectral region (8-14pm) was studied adapting the concept of contiguous and overlapping high reflectance stacks. Computations was carried out using the modified characteristic matrix theory restricted to near-normal incidence of light on dielectric , homogenous and isotropic symmetrical stack. Certain precautions must be taken in the choice of stacks to avoid deep —reflectance minima from developing within the extended high reflectance region. Results illustrate that the techniques of extending the high reflectance regions are applicable not only to mirrors , but also to short-and long-edge filter and to narrow band pass filters.

Omnidirectional reflectance and optical gap properties of Si/SiO2 Thue-Morse quasicrystals

Aperiodic one dimensional Si/SiO2 Thue-Morse (T-M) multilayer structures have been fabricated, for the first time, in order to investigate both the band-gap behavior, with respect to the system size (band-gap scaling), and the omnidirectional reflectance of the fundamental optical band-gap. Variable angle reflectance data have experimentally demonstrated a large reflectance band-gap in the optical spectrum of a T-M quasicrystal, in agreement with transfer matrix simulations. We have explained the physical origin of the T-M omnidirectional band-gap as a result of periodic spatial correlations in the self-similar T-M structure, as revealed by Fourier Transform and Wavelet analysis. The unprecedented degree of structural flexibility showed by T-M systems can provide an attractive alternative to photonic crystals for the fabrication of photonic devices.