Hyperspectral Reconstruction with Redundant Camera Spectral Sensitivity Functions

2020 ◽  
Vol 16 (2) ◽  
pp. 1-15
Author(s):  
Xian-Hua Han ◽  
Yinqiang Zheng ◽  
Jiande Sun ◽  
Yen-Wei Chen
Keyword(s):  
Spectral Sensitivity ◽  
Sensitivity Functions ◽  
Camera Spectral Sensitivity

scholarly journals Measurement and Estimation of Spectral Sensitivity Functions for Mobile Phone Cameras

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4985
Author(s):  
Shoji Tominaga ◽  
Shogo Nishi ◽  
Ryo Ohtera
Keyword(s):  
Mobile Phone ◽  
Spectral Sensitivity ◽  
Imaging System ◽  
Monochromatic Light ◽  
Estimation Method ◽  
Principal Component ◽  
Estimation Accuracy ◽  
Spectral Features ◽  
Sensitivity Functions ◽  
Camera Spectral Sensitivity

Mobile phone cameras are often significantly more useful than professional digital single-lens reflex (DSLR) cameras. Knowledge of the camera spectral sensitivity function is important in many fields that make use of images. In this study, methods for measuring and estimating spectral sensitivity functions for mobile phone cameras are developed. In the direct measurement method, the spectral sensitivity at each wavelength is measured using monochromatic light. Although accurate, this method is time-consuming and expensive. The indirect estimation method is based on color samples, in which the spectral sensitivities are estimated from the input data of color samples and the corresponding output RGB values from the camera. We first present an imaging system for direct measurements. A variety of mobile phone cameras are measured using the system to create a database of spectral sensitivity functions. The features of the measured spectral sensitivity functions are then studied using principal component analysis (PCA) and the statistical features of the spectral functions extracted. We next describe a normal method to estimate the spectral sensitivity functions using color samples and point out some drawbacks of the method. A method to solve the estimation problem using the spectral features of the sensitivity functions in addition to the color samples is then proposed. The estimation is stable even when only a small number of spectral features are selected. Finally, the results of the experiments to confirm the feasibility of the proposed method are presented. We establish that our method is excellent in terms of both the data volume of color samples required and the estimation accuracy of the spectral sensitivity functions.

APB differentially affects the cone contributions to the zebrafish ERG

2002 ◽  
Vol 19 (4) ◽  
pp. 521-529 ◽  
Author(s):  
SHANNON SASZIK ◽  
AMBER ALEXANDER ◽  
TIMOTHY LAWRENCE ◽  
JOSEPH BILOTTA
Keyword(s):  
Glutamate Receptors ◽  
Spectral Sensitivity ◽  
Visual Processing ◽  
Short Wavelength ◽  
Wavelength Region ◽  
Wave Component ◽  
Adult Zebrafish ◽  
Short Wavelength Region ◽  
Long Wavelength ◽  
Sensitivity Functions

APB (DL-2-amino-4-phosphonobutyric acid) has been found to affect the retinal processing of many vertebrate species as evidenced by the suppression of the b-wave component of the electroretinogram (ERG). The present study examined the effects of APB on the cone contributions to the ERG response of adult zebrafish (Danio rerio). ERG responses were obtained from light-adapted adult zebrafish following intravitreal injection of either saline alone or saline with various concentrations of APB ranging from 10 μm to 500 μM. Visual stimuli were 200-ms flashes of various wavelengths and irradiances. Spectral sensitivity functions were calculated from the irradiance versus response amplitude functions of the a-, b-, and d-wave components of the ERG response. Saline had no effects on the ERG response. However, APB had differential effects on the sensitivity of the b- and d-wave components. The effects of APB on the b-wave component were most apparent in the ultraviolet and short-wavelength portions (320–440 nm) of the spectral sensitivity function, although the b-wave was not completely eliminated at these wavelengths. APB-treated subjects were found to possess the same cone mechanisms (L-M and M-S) in the middle- and long-wavelength areas of the spectrum as saline injected subjects, although absolute sensitivity was lower for the APB-injected subjects. Spectral sensitivity based on the d-wave response was affected by APB but only in the short-wavelength region. All results appear to be independent of the APB dose. These results support the notion that glutamate receptors play a specific role in zebrafish visual processing. In addition, the effects of APB support recent anatomical evidence that the zebrafish retina may possess different types of glutamate receptors.

scholarly journals 3D color charts for camera spectral sensitivity estimation

2017 ◽  
Author(s):  
Rada Deeb ◽  
Damien Muselet ◽  
Mathieu Hebert ◽  
Alain Tremeau ◽  
Joost van de Weijer
Keyword(s):  
Spectral Sensitivity ◽  
Sensitivity Estimation ◽  
Camera Spectral Sensitivity
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