scholarly journals Extending Camera’s Capabilities in Low Light Conditions Based on LIP Enhancement Coupled with CNN Denoising

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7906
Author(s):  
Maxime Carré ◽  
Michel Jourlin
Keyword(s):  
Exposure Time ◽  
Visual Image ◽  
Light Conditions ◽  
Low Light ◽  
Lighting Conditions ◽  
Correct Information ◽  
Logarithmic Image Processing ◽  
Precise Simulation ◽  
Color Preservation

Using a sensor in variable lighting conditions, especially very low-light conditions, requires the application of image enhancement followed by denoising to retrieve correct information. The limits of such a process are explored in the present paper, with the objective of preserving the quality of enhanced images. The LIP (Logarithmic Image Processing) framework was initially created to process images acquired in transmission. The compatibility of this framework with the human visual system makes possible its application to images acquired in reflection. Previous works have established the ability of the LIP laws to perform a precise simulation of exposure time variation. Such a simulation permits the enhancement of low-light images, but a denoising step is required, realized by using a CNN (Convolutional Neural Network). A main contribution of the paper consists of using rigorous tools (metrics) to estimate the enhancement reliability in terms of noise reduction, visual image quality, and color preservation. Thanks to these tools, it has been established that the standard exposure time can be significantly reduced, which considerably enlarges the use of a given sensor. Moreover, the contribution of the LIP enhancement and denoising step are evaluated separately.

scholarly journals Controllable phycobilin modification: an alternative photoacclimation response in cryptophyte algae

2021 ◽  
Author(s):  
Leah Spangler ◽  
Mina Yu ◽  
Philip Jeffrey ◽  
Gregory Scholes
Keyword(s):  
Light Harvesting ◽  
Protein Structures ◽  
Green Light ◽  
Beta Subunits ◽  
Light Conditions ◽  
Low Light ◽  
Pump Probe ◽  
Light Harvesting Complex ◽  
Probe Spectroscopy

Cryptophyte algae are well known for their ability to survive under low light conditions through the use of their auxiliary light harvesting antennas, phycobiliproteins. Mainly acting to absorb light where chlorophyll cannot (500-650 nm), phycobiliproteins also play an instrumental role in helping cryptophyte algae respond to changes in light intensity through the process of photoacclimation. Until recently, photoacclimation in cryptophyte algae was only observed as a change in the cellular concentration of phycobiliproteins; however, an additional photoacclimation response was recently discovered that causes shifts in the phycobiliprotein absorbance peaks following growth under red, blue, or green light. Here, we reproduce this newly identified photoacclimation response in two other species of cryptophyte algae, P. sulcata and H. pacifica, and elucidate the origin of the response on the protein level. We compare isolated native and photoacclimated phycobiliproteins for these two species using spectroscopy and mass spectrometry, and we report the x-ray structures of the PC577 light harvesting complex and corresponding photoacclimated complex. We find that neither the protein sequences, nor the protein structures are modified by photoacclimation. We conclude that cryptophyte algae change a chromophore in one site of their phycobiliprotein beta-subunits as part of the photoacclimation response to changes in the spectral quality of light. Ultrafast pump-probe spectroscopy shows that the energy transfer is weakly affected by the photoacclimation.

scholarly journals Functional Asplund metrics for pattern matching, robust to variable lighting conditions

2020 ◽  
Author(s):  
Guillaume Noyel ◽  
Michel Jourlin
Keyword(s):  
Image Processing ◽  
Pattern Matching ◽  
Mathematical Morphology ◽  
Exposure Time ◽  
Low Contrast ◽  
Lighting Conditions ◽  
Logarithmic Image Processing ◽  
Robust To Noise ◽  
Complete Framework ◽  
Functional Metrics

In this paper, we propose a complete framework to process images captured under uncontrolled lighting and especially under low lighting. By taking advantage of the Logarithmic Image Processing (LIP) context, we study two novel functional metrics: i) the LIP-multiplicative Asplund metric which is robust to object absorption variations and ii) the LIP-additive Asplund metric which is robust to variations of source intensity or camera exposure-time. We introduce robust to noise versions of these metrics. We demonstrate that the maps of their corresponding distances between an image and a reference template are linked to Mathematical Morphology. This facilitates their implementation. We assess  them in various situations with different lightings and movement. Results show that those maps of distances are robust to lighting variations. Importantly, they are efficient to detect patterns in low-contrast images with a template acquired under a different lighting.

scholarly journals Postharvest Handling of Cut Campanula medium Flowers

HortScience ◽  
2002 ◽  
Vol 37 (6) ◽  
pp. 954-958 ◽  
Author(s):  
Theresa Bosma ◽  
John M. Dole
Keyword(s):  
Sucrose Concentration ◽  
High Light ◽  
Deionized Water ◽  
Vase Life ◽  
Light Conditions ◽  
Low Light ◽  
Storage Duration ◽  
Light Levels ◽  
Postharvest Handling

Various postharvest treatments were evaluated for effect on longevity and quality of cut Campanula medium L. `Champion Blue' and `Champion Pink' stems. Stems stored at 2 °C either wet or dry had no difference in vase life or percent flowers opened; however, flowers stored dry had a slightly greater percentage of senesced flowers at termination. Increasing storage duration from 1 to 3 weeks decreased vase life. Stems pretreated for 4 hours with 38 °C floral solution (deionized water amended to pH 3.5 with citric acid and 200 mg·L-1 8-HQC) or a 1-MCP pulse followed by a 5% sucrose pulse solution produced the longest vase life (10.3 or 10.4 days, respectively). Flowers opening after treatments commenced were paler than those flowers already opened and a 24-hour pretreatment with 5% or 10% sucrose did not prevent this color reduction. Stems had an average vase life of only 3.3 days when placed in floral vase foam but lasted 10.0 days without foam. Optimum sucrose concentration was 1.0% to 2.0% for stems placed in 22 °C floral vase solution without foam and 4% for stems placed in foam. High (110 μmol·m-2·s-1) or low (10 μmol·m-2·s-1) light levels did not affect postharvest parameters, but the most recently opened flowers were paler under low light conditions than under high light conditions. Chemical names used: 8-hydroxyquinoline citrate (8-HQC); 1-methylcyclopropene (1-MCP).

scholarly journals Recognition of vehicle make and model in low light conditions

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Aymen Fadhil Abbas ◽  
Usman Ullah Sheikh ◽  
Mohd Norzali Haji Mohd
Keyword(s):  
Image Quality ◽  
Image Enhancement ◽  
Operating Conditions ◽  
Light Conditions ◽  
Low Light ◽  
Lighting Condition ◽  
Front View ◽  
Recognition Model ◽  
Lighting Conditions ◽  
Model Recognition

This paper presents a method for vehicle make and model recognition (MMR) in low lighting conditions. While many MMR methods exist in the literature, these methods are designed to be used only in perfect operating conditions. The various camera configuration, lighting condition, and viewpoints cause variations in image quality.  In the presented method, the vehicle is first detected, image enhancement is then carried out on the detected front view of the vehicle, followed by features extraction and classification. The performance is then examined on a low-light dataset. The results show around 6% improvement in the ability of MMR with the use of image enhancement over the same recognition model without image enhancement.

scholarly journals Age Related Visual Pathologies among Nursing Home Residents: An Evaluation of Light Conditions and Recording in Client Files

2014 ◽  
Vol 1 (2) ◽  
pp. 136 ◽  
Author(s):  
Marianne M. Sinoo ◽  
Mirjam Van Tilborg ◽  
Jos M. G. A. Schols ◽  
Helianthe S. M. Kort
Keyword(s):  
Nursing Homes ◽  
Nursing Home Residents ◽  
Light Conditions ◽  
Eye Care ◽  
Lighting Conditions ◽  
Age Related ◽  
High Prevalence ◽  
Visual Problems ◽  
Poor Lighting

<p><strong><em>Objective:</em></strong><em> Reflection on visual problems in nursing homes.</em></p> <p><strong><em>Data Sources: </em></strong><em>Eye examinations, documented visual problems and illuminance levels. </em></p> <p><strong><em>Study design:</em></strong><em> The optometric examinations and recorded visual problems were combined with illuminance data.</em></p> <p><strong><em>Data collection:</em></strong><em> In seven nursing homes, 259 residents underwent an optometric examination. Their client records were analyzed for information regarding visual functioning. The illuminance data were ranked to set the quality of the lighting conditions.</em></p> <p><strong><em>Principal findings:</em></strong><em> 50% of the referred residents had problems with cataracts, retinal problems (21%), suspected glaucoma (13%), and other pathologies (16%). The information was not current</em><em> in 56% of the records. The quality of lighting conditions was low or moderate. </em></p> <strong><em>Conclusion:</em></strong><em> The finding of poor lighting conditions in nursing homes in combination with a high prevalence of visual problems (with cataract found to be the most common age related pathology), stretches the need of enhanced awareness of eye care by professional caregivers.</em>

scholarly journals Extreme Low-Light Image Enhancement for Surveillance Cameras Using Attention U-Net

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 495 ◽  
Author(s):  
Sophy Ai ◽  
Jangwoo Kwon
Keyword(s):  
Computer Vision ◽  
Image Enhancement ◽  
Light Conditions ◽  
Low Light ◽  
Convolutional Network ◽  
Surveillance Camera ◽  
Light Image ◽  
Lighting Conditions ◽  
Challenging Tasks ◽  
Significant Performance

Low-light image enhancement is one of the most challenging tasks in computer vision, and it is actively researched and used to solve various problems. Most of the time, image processing achieves significant performance under normal lighting conditions. However, under low-light conditions, an image turns out to be noisy and dark, which makes subsequent computer vision tasks difficult. To make buried details more visible, and reduce blur and noise in a low-light captured image, a low-light image enhancement task is necessary. A lot of research has been applied to many different techniques. However, most of these approaches require much effort or expensive equipment to perform low-light image enhancement. For example, the image has to be captured in a raw camera file in order to be processed, and the addressing method does not perform well under extreme low-light conditions. In this paper, we propose a new convolutional network, Attention U-net (the integration of an attention gate and a U-net network), which is able to work on common file types (.PNG, .JPEG, .JPG, etc.) with primary support from deep learning to solve the problem of surveillance camera security in smart city inducements without requiring the raw image file from the camera, and it can perform under the most extreme low-light conditions.

scholarly journals Effect of Light Regulation on the Quality of Sweetpotato Sprouts

HortScience ◽  
2021 ◽  
Vol 56 (3) ◽  
pp. 374-379
Author(s):  
Zunfu Lv ◽  
Simeng Zhang ◽  
Guoquan Lu
Keyword(s):  
Light Intensity ◽  
Light Regulation ◽  
High Light Intensity ◽  
Light Conditions ◽  
Low Light ◽  
Technical Parameters ◽  
Texture Characteristics ◽  
Set Up ◽  
Effect Of Light

Sweetpotato sprouts are buds or young shoots formed under dark or low-light conditions that can be eaten directly by people. This study was conducted to investigate the effects of light intensity and photoperiod on the quality and yield of sweetpotato sprouts and to identify the most suitable production conditions to provide a theoretical basis and technical parameters for the production of these vegetables. Four treatments involving different light intensities and photoperiods were set up: WL-1, WL-2, SL-1, and SL-2. The leaf color, nutritional quality, antioxidant capacity, texture characteristics, and yield of the sweetpotato sprouts were analyzed using Duncan’s new complex range method. The results demonstrated the following: 1) an increase in photoperiod improved leaf brightness and enhanced the appearance of the product, whereas light intensity had little effect on these parameters; and 2) low light intensity increased the yield of sweetpotato sprouts, whereas high light intensity reduced their yield. Under weak light conditions, the quality and yield of sweetpotato sprouts were improved, and their taste was unaffected. Therefore, the condition of 750 μmol·m−2·s−1 for 2 hours/day was chosen to produce crispy, high-quality, and high-yielding sweetpotato sprouts.

A cross-linguistic study of metacommunication in online hotel reviews

2020 ◽  
Vol 17 (4) ◽  
pp. 445-470
Author(s):  
Irene Cenni ◽  
Patrick Goethals ◽  
Camilla Vásquez
Keyword(s):  
Hospitality Industry ◽  
Service Providers ◽  
Mother Tongue ◽  
Service Failure ◽  
Specific Form ◽  
Service Encounter ◽  
Service Encounters ◽  
Correct Information ◽  
Linguistic Patterns

AbstractIn this study, we focus on a specific form of metacommunication found in an emerging digital genre: Hotel reviews posted on TripAdvisor. In particular, we investigate how tourists represent their service encounter interactions. The main goal of the present study is to identify what these digital metacommunicative practices reveal about communicative norms and expectations among groups of reviewers writing in three different languages. We analyzed a multilingual dataset of 1800 reviews written in English, Dutch, and Italian. The results reveal that reviewers commented upon a broad range of aspects when evaluating service encounters interactions, for instance, describing the quality of the interaction (e.g. polite, correct), or a lack of communication when a specific type of communication is expected (e.g. absence of greetings, or apologies after a service failure). Further, we found similar cross-linguistic patterns, such as appreciation for being able to communicate in one’s mother tongue during the hotel-guest encounter. At the same time, a few differences across languages emerged, such as the preference for precise and correct information within British reviews. Since service interactions are of fundamental importance for customer satisfaction, our findings contribute not only to the current research on metacommunication in digital contexts, but may also be significant for service providers in the hospitality industry.

Changes in the Stoichiometry of Photosystem II Components as an Adaptive Response to High-Light and Low-Light Conditions during Growth

1986 ◽  
Vol 41 (5-6) ◽  
pp. 597-603 ◽  
Author(s):  
Aloysius Wild ◽  
Matthias Höpfner ◽  
Wolfgang Rühle ◽  
Michael Richter
Keyword(s):  
Photosystem Ii ◽  
Functional Organization ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Molar Ratio ◽  
Light Conditions ◽  
Low Light ◽  
Pigment System ◽  
Transport Chain ◽  
The One

The effect of different growth light intensities (60 W·m-2, 6 W·m-2) on the performance of the photosynthetic apparatus of mustard plants (Sinapis alba L.) was studied. A distinct decrease in photosystem II content per chlorophyll under low-light conditions compared to high-light conditions was found. For P-680 as well as for Oᴀ and Oв protein the molar ratio between high-light and low-light plants was 1.4 whereas the respective concentrations per chlorophyll showed some variations for P-680 and Oᴀ on the one and Oв protein on the other hand.In addition to the study of photosystem II components, the concentrations of PQ, Cyt f, and P-700 were measured. The light regime during growth had no effect on the amount of P-700 per chlorophyll but there were large differences with respect to PQ and Cyt f. The molar ratio for Cyt f and PQ between high- and low-light leaves was 2.2 and 1.9, respectively.Two models are proposed, showing the functional organization of the pigment system and the electron transport chain in thylakoids of high-light and low-light leaves of mustard plants.

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