2D Perovskite Narrowband Photodetector Arrays

2021 ◽  
Author(s):  
Haizhen Wang ◽  
Lu Li ◽  
Jiaqi Ma ◽  
Junze Li ◽  
Dehui Li
Keyword(s):  
Spectral Range ◽  
Artificial Vision ◽  
Digital Cameras ◽  
Narrow Spectral Range ◽  
Photodetector Arrays

Narrowband photodetectors, which are capable of detecting light within a narrow spectral range, have important applications in the fields of digital cameras, biosensing and artificial vision. In particular, 2D layered...

scholarly journals Determination of the OB Stellar Population of IZw18 on the Basis of its Hγ and Hδ Absorption lines

1999 ◽  
Vol 194 ◽  
pp. 444-447
Author(s):  
A. Sinanyan ◽  
D. Kunth ◽  
J. Lequeux ◽  
G. Comte ◽  
A. Petrosian
Keyword(s):  
Spectral Range ◽  
Stellar Population ◽  
Dwarf Galaxy ◽  
Absorption Lines ◽  
Spectroscopic Observations ◽  
Narrow Spectral Range ◽  
Blue Compact Dwarf Galaxy

On the basis of new spectroscopic observations of the blue compact dwarf galaxy IZw18 in the narrow spectral range between 4000Å and 4500Å absorption components of Hγ and Hδ lines were discovered. Equivalent widths of Hγ and Hδ lines have been measured. From available data the OB population of IZw18 was analyzed.

A macroscopic theory of interference and diffraction of light from finite sources, I. Fields with a narrow spectral range

1954 ◽  
Vol 225 (1160) ◽  
pp. 96-111 ◽  
Keyword(s):  
Spectral Range ◽  
Correlation Factor ◽  
Macroscopic Theory ◽  
Fourier Frequency ◽  
Degree Of Coherence ◽  
Special Cases ◽  
Diffraction Of Light ◽  
Narrow Spectral Range ◽  
Huygens Principle ◽  
Typical Point

A macroscopic theory of interference and diffraction of light in stationary fields produced by finite sources which emit light within a finite spectral range is formulated. It is shown that a generalized Huygens principle may be obtained for such fields, which involves only observable quantities. The generalized Huygens principle expresses the intensity at a typical point of the field in terms of an integral taken twice independently over an arbitrary surface, the integral involving the intensity distribution over the surface and the values of a certain correlation factor, which is found to be the ‘degree of coherence’ previously introduced by Zemike. Next it is shown that under fairly general conditions, this correlation factor is essentially the normalized integral over the source of the Fourier (frequency) transform of the spectral intensity function of the source, and that it may be determined from simple interference experiments. Further, it is shown that in regions where geometrical optics is a valid approximation, the coherence factor itself then obeys a simple geometrical law of propagation. Several results on partially coherent fields, established previously by Van Cittert, Zernike, Hopkins and Rogers, follow as special cases from these theorems. The results have a bearing on many optical problems and can also be applied in in ­ vestigations concerned with other types of radiation.

UPT Chaos-Based Encryption Characteristic Analysis for Speech Signal

2015 ◽  
Vol 713-715 ◽  
pp. 1456-1459
Author(s):  
Hong Chen ◽  
Cheng Chen ◽  
Shu Bin Gu
Keyword(s):  
Spectral Range ◽  
Speech Signal ◽  
Low Frequency ◽  
Chaotic Signal ◽  
Characteristic Analysis ◽  
Simulation Experiments ◽  
Chaotic Signals ◽  
Before And After ◽  
Narrow Spectral Range ◽  
Signal Encryption

In chaotic speech signal encryption, masking is the most direct and convenient method. But the chaotic signals usually have a narrow spectral range in low frequency region. In order to overcome the disadvantage that the higher frequency signals can not be completely covered up, UPT is used to conduct a nonlinear transformation to chaotic signal. After UPT, chaotic types are increased, chaotic characteristics are improved and spectral range is widened. Simulation experiments are done respectively from frequency domain and spectrogram perspectives. The chaos before and after transformation are used to mask speech signal. Decoding experiment is taken on the speech encrypted by transformed chaos. Experiment results show that, after UPT, the encryption effect of speech signal is improved obviously. This method has a high security and a strong anti-attack ability.

scholarly journals COLOR PERCEPTION WITH THE DIGITAL CAMERAS

2019 ◽  
Vol 4 (1) ◽  
pp. 19-27
Author(s):  
Irina Palchikova ◽  
Evgenii Smirnov
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Spectral Sensitivity ◽  
Spectral Range ◽  
Spectral Dependence ◽  
Color Perception ◽  
Color Difference ◽  
Digital Cameras ◽  
Color Gamut ◽  
Color Chart

An experimental installation, based on the multi-purpose monochromator “UM-2”, was created. It allows to get the monochromatic color stimuli with a controlled width of the spectrum. The color chart of monochromatic stimuli was created. The monochromatic stimuli were used to demonstrate the test spectral sensitivity of any camera’s RGB sensors in the experiment. The method for finding out the camera’s color gamut has been developed. The mathematical modeling and calculation by the experimental data are showed both the spectral dependence of the color resolution of the camera, and the same dependence for the full delta E color difference. The inability to set the same delta E value for the full spectral range is shown. Plants of the same species that were grown in different conditions show a different saturation.

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