scholarly journals Quantifying biologically essential aspects of environmental light

2021 ◽  
Vol 18 (177) ◽  
Author(s):  
Dan-E. Nilsson ◽  
Jochen Smolka
Keyword(s):  
Light Field ◽  
Elevation Angle ◽  
Spectral Composition ◽  
Image Sensor ◽  
Light Environment ◽  
Photon Flux ◽  
Small Subset ◽  
Interior Lighting ◽  
Environmental Light ◽  
Visual Ergonomics

Quantifying and comparing light environments are crucial for interior lighting, architecture and visual ergonomics. Yet, current methods only catch a small subset of the parameters that constitute a light environment, and rarely account for the light that reaches the eye. Here, we describe a new method, the environmental light field (ELF) method, which quantifies all essential features that characterize a light environment, including important aspects that have previously been overlooked. The ELF method uses a calibrated digital image sensor with wide-angle optics to record the radiances that would reach the eyes of people in the environment. As a function of elevation angle, it quantifies the absolute photon flux, its spectral composition in red–green–blue resolution as well as its variation (contrast-span). Together these values provide a complete description of the factors that characterize a light environment. The ELF method thus offers a powerful and convenient tool for the assessment and comparison of light environments. We also present a graphic standard for easy comparison of light environments, and show that different natural and artificial environments have characteristic distributions of light.

scholarly journals In search of the spectral composition of an effective light trap for the mushroom pest Lycoriella ingenua (Diptera: Sciaridae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sándor Kecskeméti ◽  
András Geösel ◽  
József Fail ◽  
Ádám Egri
Keyword(s):  
Light Intensity ◽  
Spectral Sensitivity ◽  
Fungal Pathogens ◽  
Light Trap ◽  
Spectral Composition ◽  
Wavelength Dependence ◽  
Crop Damage ◽  
Photon Flux ◽  
Compound Eyes ◽  
Behavioural Experiments

AbstractCertain fungus gnats, like Lycoriella ingenua are notorious pests in agriculture, especially in mushroom production. While larvae cause mainly direct crop damage, adults are vectors of several dangerous fungal pathogens. To promote the development of pesticide-free management methods, such as light trapping, we measured the spectral sensitivity of L. ingenua compound eyes with electroretinography and performed two different behavioural experiments to reveal the wavelength dependence of phototaxis in this species. The spectral sensitivity of the compound eyes is bimodal with peaks at 370 nm (UV) and 526 nm (green). Behavioural experiments showed that attraction to light as a function of wavelength depends on light intensity. In our first experiment, where the minimal photon flux (105–109 photons/cm2/s) needed for eliciting a phototactic response was determined wavelength by wavelength, phototaxis was strongest in the green spectral range (~526 nm). In the other behavioural experiment, where wavelength preference was tested under a higher but constant light intensity (~1013 photons/cm2/s), the highest attraction was elicited by UV wavelengths (398 nm). Our results suggest that both UV and green are important spectral regions for L. ingenua thus we recommend to use both UV (~370-398 nm) and green (~526 nm) for trapping these insects.

Research on Physical MPPT of Photovoltaic Array System Based on Image Processing

2013 ◽  
Vol 321-324 ◽  
pp. 1138-1144
Author(s):  
Chao Liu ◽  
Jing Hui
Keyword(s):  
Image Processing ◽  
Tracking Error ◽  
Elevation Angle ◽  
Image Sensor ◽  
Azimuth Angle ◽  
Field Of View ◽  
The Sun ◽  
Photovoltaic Array ◽  
Point Tracking ◽  
Power Point

Based on analyzing the development and the performance feature of existing solar tracker, we propose a solar Maximum Power Point Tracking (MPPT) strategy which combines photoelectric sensor and image processing. Firstly, photoelectric tracking mode positions the sun in the field of view of the image sensor. Then, the position of the sun image is captured by the image sensor. After that, we can find the coordinates of the sun spot in the field of view through image binarization processing. According to the number of steps of stepper motor rotation which is calculated by the deviation of coordinates, the controller drives the biaxial photosensitive (PV) array tracking device, making the sun spot always fall in the centre of the image. Tests show that the elevation angle and azimuth angle of the tracking range of the photovoltaic array are both 0～270°.The average tracking error of elevation angle is less than 0.7°, and the average tracking error of azimuth angle is less than 0.5°.

scholarly journals Acclimatization of symbiotic corals to mesophotic light environments through wavelength transformation by fluorescent protein pigments

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170320 ◽  
Author(s):  
Edward G. Smith ◽  
Cecilia D'Angelo ◽  
Yoni Sharon ◽  
Dan Tchernov ◽  
Joerg Wiedenmann
Keyword(s):  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Environmental Gradients ◽  
Red Light ◽  
Spectral Composition ◽  
Light Environment ◽  
Homogeneous Distribution ◽  
Red Fluorescent Proteins ◽  
Ecological Importance ◽  
Colour Morphs

The depth distribution of reef-building corals exposes their photosynthetic symbionts of the genus Symbiodinium to extreme gradients in the intensity and spectral quality of the ambient light environment. Characterizing the mechanisms used by the coral holobiont to respond to the low intensity and reduced spectral composition of the light environment in deeper reefs (greater than 20 m) is fundamental to our understanding of the functioning and structure of reefs across depth gradients. Here, we demonstrate that host pigments, specifically photoconvertible red fluorescent proteins (pcRFPs), can promote coral adaptation/acclimatization to deeper-water light environments by transforming the prevalent blue light into orange-red light, which can penetrate deeper within zooxanthellae-containing tissues; this facilitates a more homogeneous distribution of photons across symbiont communities. The ecological importance of pcRFPs in deeper reefs is supported by the increasing proportion of red fluorescent corals with depth (measured down to 45 m) and increased survival of colour morphs with strong expression of pcRFPs in long-term light manipulation experiments. In addition to screening by host pigments from high light intensities in shallow water, the spectral transformation observed in deeper-water corals highlights the importance of GFP-like protein expression as an ecological mechanism to support the functioning of the coral– Symbiodinium association across steep environmental gradients.

scholarly journals Radiative energy budget reveals high photosynthetic efficiency in symbiont-bearing corals

2014 ◽  
Vol 11 (93) ◽  
pp. 20130997 ◽  
Author(s):  
Kasper Elgetti Brodersen ◽  
Mads Lichtenberg ◽  
Peter J. Ralph ◽  
Michael Kühl ◽  
Daniel Wangpraseurt
Keyword(s):  
Energy Budget ◽  
Photosynthetic Efficiency ◽  
Light Field ◽  
Heat Dissipation ◽  
Spectral Composition ◽  
Light Energy ◽  
Low Energy ◽  
Radiative Energy ◽  
Gross Photosynthesis ◽  
Light Utilization

The light field on coral reefs varies in intensity and spectral composition, and is the key regulating factor for phototrophic reef organisms, for example scleractinian corals harbouring microalgal symbionts. However, the actual efficiency of light utilization in corals and the mechanisms affecting the radiative energy budget of corals are underexplored. We present the first balanced light energy budget for a symbiont-bearing coral based on a fine-scale study of the microenvironmental photobiology of the massive coral Montastrea curta . The majority (more than 96%) of the absorbed light energy was dissipated as heat, whereas the proportion of the absorbed light energy used in photosynthesis was approximately 4.0% under an irradiance of 640 µmol photons m −2 s −1 . With increasing irradiance, the proportion of heat dissipation increased at the expense of photosynthesis. Despite such low energy efficiency, we found a high photosynthetic efficiency of the microalgal symbionts showing high gross photosynthesis rates and quantum efficiencies (QEs) of approximately 0.1 O 2 photon −1 approaching theoretical limits under moderate irradiance levels. Corals thus appear as highly efficient light collectors with optical properties enabling light distribution over the corallite/tissue microstructural canopy that enables a high photosynthetic QE of their photosynthetic microalgae in hospite .

scholarly journals Far-red and Blue Light Synergistically Mitigate Intumescence Injury of Tomato Plants Grown Under Ultraviolet-deficit Light Environment

HortScience ◽  
2016 ◽  
Vol 51 (6) ◽  
pp. 712-719 ◽  
Author(s):  
Tomomi Eguchi ◽  
Ricardo Hernández ◽  
Chieri Kubota
Keyword(s):  
Blue Light ◽  
Stem Elongation ◽  
Light Treatment ◽  
Light Environment ◽  
Photon Flux ◽  
Physiological Disorder ◽  
Tomato Plants ◽  
Light Emitting ◽  
Number Of Leaves ◽  
Percent Number

Intumescence injury is an abiotic-stress-induced physiological disorder associated with abnormal cell enlargement and cell division. The symptom includes blister- or callus-like growths on leaves, which occur on sensitive cultivars of tomato when they are grown under ultraviolet (UV)-deficit light environment, such as light-emitting diodes (LEDs). Previous studies suggest that intumescence can be reduced by increasing far-red (FR) or blue light. In the present study, effects of end-of-day FR (EOD-FR) light and high blue photon flux (PF) ratio during the photoperiod on intumescence injury were examined using ‘Beaufort’ interspecific tomato rootstock seedlings (Solanum lycopersicum × Solanum habrochaites), a cultivar highly susceptible to intumescence injury. Our study showed that EOD-FR light treatment moderately suppressed intumescence injury. Using EOD-FR light treatment, the percent number of leaves exhibiting intumescences was reduced from 62.0–70.7% to 39.4–43.1%. By combining high blue PF ratio (75%) during the photoperiod and EOD-FR light treatment, the percent number of leaves exhibiting intumescences was further suppressed to 5.0%. Furthermore, the combination of high blue PF ratio and EOD-FR light treatment inhibited undesirable stem elongation caused by EOD-FR light treatment. We found that high blue PF ratio during the photoperiod combined with a small dose of EOD-FR lighting (≈1 mmol·m−2·d−1 provided by 5.2 µmol·m−2·s−1 FR PF for 3.3 minutes) could inhibit the problematic intumescence injury of tomato plants grown under LEDs without negatively influencing growth or morphology.

scholarly journals Influence of different light sources on the production process of tomato in intensive photoculture

2021 ◽  
pp. 65-70
Author(s):  
T. E. Kuleshova ◽  
O. R. Udalova ◽  
I. T. Balashova ◽  
L. M. Anikina ◽  
P. Yu. Kononchuk ◽  
...  
Keyword(s):  
Thin Layer ◽  
Radiation Spectrum ◽  
Spectral Composition ◽  
Emission Spectra ◽  
Fruit Weight ◽  
Light Environment ◽  
Light Sources ◽  
Lower Productivity ◽  
Spectrum Intensity

Introduction. The development of ideas about the influence of the light environment - the radiation spectrum, intensity and duration of exposure, on the physiology of plants, serves as the basis for the creation of effective light sources for protected ground.Purpose. Comparative test of the influence of a light environment with different spectral composition on the productivity and quality of tomatoes in conditions of intensive photo culture.Methods. Investigations were made under controlled conditions of intensive photoculture when growing dwarf tomatoes of the variety Natasha selections of the “Federal Scientific Vegetable Center” on thin-layer soil analogs with the supply of a nutrient solution to the plant roots through a slit capillary in vegetative light installations developed at the ARI. The light sources were high-pressure sodium lamps and LED lamps SD1, SD2, and SD3 with different emission spectra. Results. Tomatoes of the Natasha variety, illuminated during development with HPS lamps, formed almost the same yield with an average fruit weight of 42.5 kg/m2 per layer per year. Natasha tomato grown under LED lamps showed a tendency to lower productivity by 29% under SD1 and by 8% under SD2 and higher by 19% under underSD3 compared to that under HPS lamps. A comparative assessment of the biochemical composition of tomato fruits indicates their high quality under all tested light sources.Conclusion. Cultivation of dwarf tomato varieties on thin-layer soil analogs showed the best results in terms of productivity with good quality plant products under LED lamps SD3 with a radiation spectrum close to sunlight.

Digital Correction of Registration Error for the Micro Lens Array and Image Sensor in Plenoptic Camera

2014 ◽  
Vol 687-691 ◽  
pp. 1091-1094
Author(s):  
Peng Liu ◽  
Ru Min Zhang ◽  
Di Jun Liu
Keyword(s):  
Light Field ◽  
Image Sensor ◽  
Reconstructed Image ◽  
Lens Array ◽  
Digital Correction ◽  
Registration Error ◽  
Registration Errors ◽  
Plenoptic Camera ◽  
Micro Lens Array ◽  
Micro Lens

Plenoptic camera provides us with the capability of refocusing photographs after exposure and extended depth of field. But the registration error for the micro lens array and image sensor influences on the quality of extracted 4D light field and thus leads to a degradation of the reconstructed image. The paper discusses two type of registration errors based on the structure of focused plenoptic camera and proposes a correction algorithm to acquire accurate light field from the sensor data. The simulation shows that registration errors deteriorate the reconstructed image and the artifact will be reduced significantly after using the algorithm.

A Light-Field Image Sensor in 180 nm CMOS

2012 ◽  
Vol 47 (1) ◽  
pp. 257-271 ◽  
Author(s):  
Albert Wang ◽  
Alyosha Molnar
Keyword(s):  
Light Field ◽  
Image Sensor ◽  
Light Field Image
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