scholarly journals A Novel Illumination Compensation Technique for Multi-Spectral Imaging in NDVI Detection

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1859
Author(s):  
Rui Jiang ◽  
Pei Wang ◽  
Yan Xu ◽  
Zhiyan Zhou ◽  
Xiwen Luo ◽  
...  
Keyword(s):  
Light Source ◽  
Radiation Intensity ◽  
Near Infrared ◽  
Imaging System ◽  
Red Light ◽  
Spectral Imaging ◽  
Constant Current ◽  
Infrared Light ◽  
Ndvi Index ◽  
Led Arrays

To overcome the dependence on sunlight of multi-spectral cameras, an active light source multi-spectral imaging system was designed and a preliminary experimental study was conducted at night without solar interference. The system includes an active light source and a multi-spectral camera. The active light source consists of four integrated LED (Light Emitting Diode) arrays and adjustable constant current power supplies. The red LED arrays and the near-infrared LED arrays are each driven by an independently adjustable constant current power supply. The center wavelengths of the light source are 668 nm and 840 nm, which are consistent with that of filter lens of the Rededge-M multi-spectral camera. This paper shows that the radiation intensity measured is proportional to the drive current and is inversely proportional to the radiation distance, which is in accordance with the inverse square law of light. Taking the inverse square law of light into account, a radiation attenuation model was established based on the principle of image system and spatial geometry theory. After a verification test of the radiation attenuation model, it can be concluded that the average error between the radiation intensity obtained using this model and the actual measured value using a spectrometer is less than 0.0003 w/m2. In addition, the fitting curve of the multi-spectral image grayscale digital number (DN) and reflected radiation intensity at the 668 nm (Red light) is y = −3484230x2 + 721083x + 5558, with a determination coefficient of R2 = 0.998. The fitting curve with the 840 nm (near-infrared light) is y = 491469.88x + 3204, with a determination coefficient of R2 = 0.995, so the reflected radiation intensity on the plant canopy can be calculated according to the grayscale DN. Finally, the reflectance of red light and near-infrared light can be calculated, as well as the Normalized Difference Vegetation Index (NDVI) index. Based on the above model, four plants were placed at 2.85 m away from the active light source multi-spectral imaging system for testing. Meanwhile, NDVI index of each plant was measured by a Greenseeker hand-held crop sensor. The results show that the data from the two systems were linearly related and correlated with a coefficient of 0.995, indicating that the system in this article can effectively detect the vegetation NDVI index. If we want to use this technology for remote sensing in UAV, the radiation intensity attenuation and working distance of the light source are issues that need to be considered carefully.

scholarly journals Photothermal Therapy Using Gold Nanorods and Near-Infrared Light in a Murine Melanoma Model Increases Survival and Decreases Tumor Volume

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mary K. Popp ◽  
Imane Oubou ◽  
Colin Shepherd ◽  
Zachary Nager ◽  
Courtney Anderson ◽  
...  
Keyword(s):  
Light Source ◽  
Gold Nanorods ◽  
Photothermal Therapy ◽  
Near Infrared ◽  
Tumor Volume ◽  
Infrared Light ◽  
Led Light ◽  
Murine Melanoma ◽  
Nir Light ◽  
Melanoma Model

Photothermal therapy (PTT) treatments have shown strong potential in treating tumors through their ability to target destructive heat preferentially to tumor regions. In this paper we demonstrate that PTT in a murine melanoma model using gold nanorods (GNRs) and near-infrared (NIR) light decreases tumor volume and increases animal survival to an extent that is comparable to the current generation of melanoma drugs. GNRs, in particular, have shown a strong ability to reach ablative temperatures quickly in tumors when exposed to NIR light. The current research tests the efficacy of GNRs PTT in a difficult and fast growing murine melanoma model using a NIR light-emitting diode (LED) light source. LED light sources in the NIR spectrum could provide a safer and more practical approach to photothermal therapy than lasers. We also show that the LED light source can effectively and quickly heatin vitroandin vivomodels to ablative temperatures when combined with GNRs. We anticipate that this approach could have significant implications for human cancer therapy.

scholarly journals Growth of quantum three-dimensional structure of InGaAs emitting at ~1 µm applicable for a broadband near-infrared light source

2017 ◽  
Vol 477 ◽  
pp. 230-234 ◽  
Author(s):  
Nobuhiko Ozaki ◽  
Shingo Kanehira ◽  
Yuma Hayashi ◽  
Shunsuke Ohkouchi ◽  
Naoki Ikeda ◽  
...  
Keyword(s):  
Light Source ◽  
Near Infrared ◽  
Three Dimensional ◽  
Infrared Light ◽  
Dimensional Structure ◽  
Near Infrared Light ◽  
Three Dimensional Structure

scholarly journals Behavioural red-light sensitivity in fish according to the optomotor response

2021 ◽  
Vol 8 (8) ◽  
pp. 210415
Author(s):  
Megumi Matsuo ◽  
Yasuhiro Kamei ◽  
Shoji Fukamachi
Keyword(s):  
Spectral Sensitivity ◽  
Fish Species ◽  
Near Infrared ◽  
Red Light ◽  
Light Sensitivity ◽  
Visual Sensitivity ◽  
Infrared Light ◽  
Optomotor Response ◽  
Optokinetic Response ◽  
Cone Opsin

Various procedures have been adopted to investigate spectral sensitivity of animals, e.g. absorption spectra of visual pigments, electroretinography, optokinetic response, optomotor response (OMR) and phototaxis. The use of these techniques has led to various conclusions about animal vision. However, visual sensitivity should be evaluated consistently for a reliable comparison. In this study, we retrieved behavioural data of several fish species using a single OMR procedure and compared their sensitivities to near-infrared light. Besides cavefish that lack eyes, some species were not appropriate for the OMR test because they either stayed still or changed swimming direction frequently. Eight of 13 fish species tested were OMR positive. Detailed analyses using medaka, goldfish, zebrafish, guppy, stickleback and cichlid revealed that all the fish were sensitive to light at a wavelength greater than or equal to 750 nm, where the threshold wavelengths varied from 750 to 880 nm. Fish opsin repertoire affected the perception of red light. By contrast, the copy number of long-wavelength-sensitive ( LWS ) genes did not necessarily improve red-light sensitivity. While the duplication of LWS and other cone opsin genes that has occurred extensively during fish evolution might not aid increasing spectral sensitivity, it may provide some other advantageous ophthalmic function, such as enhanced spectral discrimination.

Single red emission from upconverting ZnGa2O4:Yb,Er nanoparticles co-doped by Cr3+

2020 ◽  
Vol 8 (19) ◽  
pp. 6370-6379 ◽  
Author(s):  
Bhupendra B. Srivastava ◽  
Santosh K. Gupta ◽  
Yuanbing Mao
Keyword(s):  
Hydrothermal Method ◽  
Near Infrared ◽  
Red Light ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Red Emission ◽  
Co Doped

ZnGa2O4:Yb3+,Er3+,Cr3+ nanoparticles synthesized by a hydrothermal method and further annealing emit bright singular red light under 980 nm excitation and near-infrared light under 254 nm excitation.

scholarly journals PbS:Glass as broad-bandwidth near-infrared light source material

2013 ◽  
Vol 21 (2) ◽  
pp. 2287 ◽  
Author(s):  
Fangyu Yue ◽  
Jens W. Tomm ◽  
Detlef Kruschke ◽  
Peter Glas ◽  
Kazbek A. Bzheumikhov ◽  
...  
Keyword(s):  
Light Source ◽  
Near Infrared ◽  
Source Material ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Broad Bandwidth

scholarly journals Near-Infrared Transmittance Spectral Imaging for Nondestructive Measurement of Internal Disorder in Korean Ginseng

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 273 ◽  
Author(s):  
Lalit Mohan Kandpal ◽  
Jayoung Lee ◽  
Hyungjin Bae ◽  
Moon S. Kim ◽  
Insuck Baek ◽  
...  
Keyword(s):  
Near Infrared ◽  
Imaging System ◽  
Quality Measurement ◽  
Spectral Imaging ◽  
Cost Effective ◽  
Ginseng Root ◽  
Internal Quality ◽  
Infrared Transmittance ◽  
Significant Difference ◽  
Novel Strategy

The grading of ginseng (Panax ginseng) including the evaluation of internal quality attributes is essential in the ginseng industry for quality control. Assessment for inner whitening, a major internal disorder, must be conducted when identifying high quality ginseng. Conventional methods for detecting inner whitening in ginseng root samples use manual inspection, which is time-consuming and inaccurate. This study develops an internal quality measurement technique using near-infrared transmittance spectral imaging to evaluate inner whitening in ginseng samples. Principle component analysis (PCA) was used on ginseng hypercube data to evaluate the developed technique. The transmittance spectra and spectral images of ginseng samples exhibiting inner whitening showed weak intensity characteristics compared to normal ginseng in the region of 900–1050 nm and 1150–1400 nm respectively, owing to the presence of whitish internal tissues that have higher optical density. On the basis of the multivariate analysis method, even a simple waveband ratio image has the great potential to quickly detect inner whitening in ginseng samples, since these ratio images show a significant difference between whitened and non-whitened regions. Therefore, it is possible to develop an efficient and rapid spectral imaging system for the real-time detection of inner whitening in ginseng using minimal spectral wavebands. This novel strategy for the rapid, cost-effective, non-destructive detection of ginseng’s inner quality can be a key component for the automation of ginseng grading.

Ultrawide-band near-infrared light source over 1 mW by Sm3+,Pr3+-codoped glass phosphor combined with LED

2014 ◽  
Vol 7 (7) ◽  
pp. 072601 ◽  
Author(s):  
Shingo Fuchi ◽  
Yusuke Shimizu ◽  
Keita Watanabe ◽  
Hiroki Uemura ◽  
Yoshikazu Takeda
Keyword(s):  
Light Source ◽  
Near Infrared ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Glass Phosphor
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