scholarly journals Light-switchable deposits from evaporating drops containing motile microalgae

Soft Matter ◽  
2021 ◽  
Author(s):  
Marius R. Bittermann ◽  
Daniel Bonn ◽  
Sander Woutersen ◽  
Antoine Deblais
Keyword(s):  
Light Source ◽  
Incident Light ◽  
Evaporating Drops

In this study, we show how deposits from evaporating drops containing motile microalgae can be tuned by changing parameters of the incident light source.

Relighting with real incident light source

2008 ◽  
Author(s):  
Yifan Chen ◽  
Xubo Yang ◽  
Shuangjiu Xiao ◽  
Xiaodong Ding
Keyword(s):  
Light Source ◽  
Incident Light

scholarly journals Colour Constancy for Image of Non-Uniformly Lit Scenes

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2242
Author(s):  
Md Akmol Hussain ◽  
Akbar Sheikh-Akbari ◽  
Iosif Mporas
Keyword(s):  
Light Source ◽  
State Of The Art ◽  
Incident Light ◽  
Digital Camera ◽  
Input Image ◽  
Absolute Difference ◽  
Light Sources ◽  
Colour Constancy ◽  
Adjustment Factors ◽  
Camera Sensors

Digital camera sensors are designed to record all incident light from a captured scene, but they are unable to distinguish between the colour of the light source and the true colour of objects. The resulting captured image exhibits a colour cast toward the colour of light source. This paper presents a colour constancy algorithm for images of scenes lit by non-uniform light sources. The proposed algorithm uses a histogram-based algorithm to determine the number of colour regions. It then applies the K-means++ algorithm on the input image, dividing the image into its segments. The proposed algorithm computes the Normalized Average Absolute Difference (NAAD) for each segment and uses it as a measure to determine if the segment has sufficient colour variations. The initial colour constancy adjustment factors for each segment with sufficient colour variation is calculated. The Colour Constancy Adjustment Weighting Factors (CCAWF) for each pixel of the image are determined by fusing the CCAWFs of the segments, weighted by their normalized Euclidian distance of the pixel from the center of the segments. Results show that the proposed method outperforms the statistical techniques and its images exhibit significantly higher subjective quality to those of the learning-based methods. In addition, the execution time of the proposed algorithm is comparable to statistical-based techniques and is much lower than those of the state-of-the-art learning-based methods.

scholarly journals Application of Microspectral Imaging in Motor and Sensory Nerve Classification

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Du Xu
Keyword(s):  
Feature Extraction ◽  
Light Source ◽  
Motor Nerve ◽  
Incident Light ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Correction Algorithm ◽  
Fast Speed ◽  
Motor Nerves ◽  
Better Than

Objective. It aimed to explore the application of the microscopic hyperspectral technique in motor and sensory nerve classification. Methods. The self-developed microscopic hyperspectral acquisition system was applied to collect the data of anterior and posterior spinal cord sections of white rabbits. The joint correction algorithm was employed to preprocess the collected data, such as noise reduction. On the basis of pure linear light source index, a new pixel purification algorithm based on cross contrast was proposed to extract more regions of interest, which was used for feature extraction of motor and sensory nerves. Besides, the ML algorithm was employed to classify motor and sensory nerves based on feature extraction results. Results. The joint correction algorithm was adopted to preprocess the data collected by the microscopic hyperspectral technique, so as to eliminate the influence of the incident light source and the system and improve the classification accuracy. The axon and myelin spectrum curves of the two kinds of nerves in the stained specimens had the same trend, but the values of all kinds of spectrum of sensory nerves were higher than those of motor nerves. However, the myelin sheath spectrum curves of motor nerves in the unstained specimens were greatly different from the curves of sensory nerves. The axon spectrum curves had the same trend, but the axon spectrum values of sensory nerves were higher than those of motor nerves. The ML algorithm had high accuracy and fast speed in motor and sensory nerve classification, and the classification effect of stained specimens was better than that of unstained specimens. Conclusion. The microscopic hyperspectral technique had high feasibility in sensory and motor nerve classification and was worthy of further research and promotion.

scholarly journals Quantitative evaluation of osteogenesis through infrared light

2017 ◽  
Vol 4 (2) ◽  
Author(s):  
Pedro Alejandro Lomelí Mejía ◽  
Pablo Alfonso González Lomelín ◽  
Hugo Lecona Butrón ◽  
René Domínguez Rubio ◽  
Saúl Renan León Hernández ◽  
...  
Keyword(s):  
Light Source ◽  
Quantitative Evaluation ◽  
Incident Light ◽  
Good Choice ◽  
Infrared Light ◽  
External Fixators ◽  
Bone Consolidation ◽  
Photo Sensor ◽  
New Zealand White Rabbits ◽  
Dental Acrylic

Veterinaria México OA ISSN: 2448-6760Cite this as:Lomelí Mejía PA, González Lomelín PA, Lecona Butrón H, Domínguez-Rubio R, León-Hernández SR, Luna-Valdéz IX, Domínguez-Hernández V. Quantitative evaluation of osteogenesis through infrared light. Pilot study. Veterinaria México OA. 2017;4(2). doi: 10.21753/vmoa.4.2.410.Different methods are available to evaluate the degree of bone healing. A good choice involves employing optical techniques with infrared light to eval-uate the progress of bone consolidation. Because infrared light is absorbed in liquids and reflected in solids, it is possible to assess bone consolidation progress using an incident light source and a coupled photo sensor. We used a 940-nm light source that is capable of reaching bone to determine the degree of bone consolidation. Five New Zealand White rabbits were used according to the NOM-062-ZOO99 standard. In each animal, a fracture was generated in the left tibia, and the fragments were fixed using an external fixator constructed with Kirschner nails and dental acrylic cement. Progress in bone consolidation was evaluated at days 7, 23, and 34 after surgery. A linear dependence was observed between the days elapsed and the reflection of the infrared light.Figure 2. Reduction of tibia by external fixators made with Kirschner nails 0.045 inch in diameter and methylmethacrylate cement.

On-Site Measurement of the Spectral Transmittance of a Stripe Filter

2017 ◽  
Vol 870 ◽  
pp. 3-8
Author(s):  
Ho Lin Tsay ◽  
Po Han Huang ◽  
Kun Huan Wu ◽  
Ting Ming Huang
Keyword(s):  
Thin Film ◽  
Light Source ◽  
Incident Light ◽  
Test Sample ◽  
Spot Size ◽  
Measuring Instrument ◽  
Spectral Transmittance ◽  
Band Pass ◽  
The Difference ◽  
Single Data

A simple on-site transmittance measurement setup that is easy to move and install is proposed in this study. It is especially suitable for those cases when laboratory instruments are not applicable. Ordinarily, witness samples are measured since the uniformity is good enough inside the thin film coator and the size of the sample is proper for the facilities to measure. When the spot size of the measuring instrument is too large for the filter or the size of the test sample is too large to fit into the instrument. The proposed setup is shown to work well for this measurement. An application for this setup is also presented. The test target was a stripe filter, which has five band-pass thin films and nominal dimensions of 120 x 3.6 mm each film. Distance between neighboring films is 3.85 mm. The width of each film is so narrow and the size the stripe filter is large such that the traditional method for spectral transmittance is not applicable. The proposed measurement setup consists of a light source, integration sphere and spectrophotometer. The setup was installed inside a dark room. It shows that the setup can provide as accurate results as those data measured by an accreditated instrument. The difference between the present setup and accreditated instrument was found within 7% for high radiance. When the radiance of the incident light is low the accuracy decreases, which can be compensated by stronger light source. In addition, since the measurement spot size is estimated as 1.5 x 2.1 mm it can provide local transmittance data along the stripe thin film rather than a single data represented by the witness sample.

scholarly journals Domain multiplexed computer-generated holography by embedded wavevector filtering algorithm

PhotoniX ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Lin Wu ◽  
Ziyang Zhang
Keyword(s):  
Light Source ◽  
Computational Methods ◽  
Incident Light ◽  
Plane Waves ◽  
Filtering Algorithm ◽  
Spherical Waves ◽  
Computer Generated Holography ◽  
Arbitrary Intensity ◽  
Speckle Suppression

AbstractComputer-generated holography can obtain the wavefront required for constructing arbitrary intensity distributions in space. Currently, speckle noises in holography remain an issue for most computational methods. In addition, there lacks a multiplexing technology by which images from a single hologram and light source can be switched by a lens. In this work, we first come up with a new algorithm to generate holograms to project smoother images by wavevector filtering. Thereupon, we propose a unique multiplexing scheme enabled by a Fourier lens, as the incident light can be decomposed either by a superposition of spherical waves or plane waves. Different images are obtained experimentally in the spatial and wavevector domains, switchable by a lens. The embedded wavevector filtering algorithm provides a new prospective for speckle suppression without the need for postprocessing. The multiplexing technology can double the capacity of current holographic systems and exhibits potential for various interesting display applications.

scholarly journals Domain Multiplexed Computer-generated Holography by Embedded Wavevector Filtering Algorithm

2020 ◽  
Author(s):  
Lin Wu ◽  
Ziyang Zhang
Keyword(s):  
Light Source ◽  
Computational Methods ◽  
Incident Light ◽  
Plane Waves ◽  
Filtering Algorithm ◽  
Spherical Waves ◽  
Computer Generated Holography ◽  
Arbitrary Intensity ◽  
Speckle Suppression

Abstract Computer-generated holography can obtain the wavefront required for constructing arbitrary intensity distributions in space. Currently, speckle noises in holography remain an issue for most computational methods. In addition, there lacks a multiplexing technology by which images from a single hologram and light source can be switched by a lens. In this work, we first come up with a new algorithm to generate holograms to project smoother images by wavevector filtering. Thereupon, we propose a unique multiplexing scheme enabled by a Fourier lens, as the incident light can be decomposed either by a superposition of spherical waves or plane waves. Different images are obtained experimentally in the spatial and wavevector domains, switchable by a lens. The embedded wavevector filtering algorithm provides a new prospective for speckle suppression without the need for postprocessing. The multiplexing technology can double the capacity of current holographic systems and exhibits potential for various interesting display applications.

scholarly journals Eye/Photophore Coordination and Light-following in Krill, Euphausia Superba

1988 ◽  
Vol 134 (1) ◽  
pp. 61-77 ◽  
Author(s):  
A. D. GRINNELL ◽  
P. M. NARINS ◽  
F. T. AWBREY ◽  
W. M. HAMNER ◽  
P. P. HAMNER
Keyword(s):  
Light Source ◽  
White Light ◽  
Antarctic Krill ◽  
Incident Light ◽  
Euphausia Superba ◽  
Control Signal ◽  
Eye Rotation ◽  
The Antarctic ◽  
Antarctic Krill Euphausia Superba

Eight of the 10 photophores of the Antarctic krill, Euphausia superba, are located at the ends of muscular stalks and exhibit coordinated orientation responses to incident white light; light emitted from the photophores is directed away from the incident light. Moreover, eye rotation occurs synchronously with photophore movement. Immobilization of one or both eyes eliminated the photophore light-following response in 40% of the trials, but in the remaining 60%, photophores continued to exhibit oriented, but less stable responses. In the presence of a stationary light source the eyes could be passively rotated without affecting photophore position. Furthermore, eye removal or covering the head with an opaque hood eliminated coordinated photophore movement. We conclude that vision is necessary for light-following responses by the photophores. In addition, the control signal for that movement is CNS-derived, may occur spontaneously or may be lightinduced, and appears to be accompanied by a parallel signal governing eye rotation. Subtle differences in photophore response when krill were oriented other than horizontally imply that krill may have a gravity sense that could help them orient in darkness.

Miniaturized Optimal Incident Light Angle-fitted Dark Field System for Contrast-enhanced Real-time Monitoring of 2D/3D-projected Cell Motions

2021 ◽  
Author(s):  
Yeongseok Jang ◽  
Seungbeom Han ◽  
Chulgyu Song ◽  
Jinmu Jung ◽  
Jonghyun Oh
Keyword(s):  
Real Time ◽  
Light Source ◽  
Incident Angle ◽  
Incident Light ◽  
Dark Field ◽  
High Contrast ◽  
Real Time Monitoring ◽  
Contrast Imaging ◽  
Field System ◽  
Cell Monitoring

Abstract In the field of biology, dark field microscopy provides superior insight into cells and subcellular structures. However, most dark field microscopes are equipped with a dark field filter and a light source on a 2D-based specimen, so only a flat sample can be observed in a limited space. We propose a compact cell monitoring system with built-in dark field filter with an optimized incident angle of the light source to provide real-time cell imaging and spatial cell monitoring. 2D/3D projected darkfield images are optimized for 2D/3D samples as they rely on darkfield filters, and incident light. 2D projection imaging was implemented using a modular condenser lens to acquire high-contrast images. This enabled the long-term monitoring of cells, and the real-time monitoring of cell division and death. This system was able to image, by 2D projection, cells on the surface thinly coated with multi-walled carbon nanotubes, as well as living cells that migrated along the surface of glass beads and hydrogel droplets with a diameter of about 160 μm. The Optimal incident light angle-fitted dark field system combines high-contrast imaging sensitivity and high spatial resolution to even image cells on three-dimensional surfaces.

The response of squid and fish to changes in the angular distribution of light

2003 ◽  
Vol 83 (4) ◽  
pp. 849-856 ◽  
Author(s):  
Lydia M. Mäthger
Keyword(s):  
Angular Distribution ◽  
Light Source ◽  
Incident Light ◽  
Vertical Plane ◽  
The Body ◽  
Horse Mackerel ◽  
Trachurus Trachurus ◽  
Light Reflex

This paper describes the responses of a squid (Alloteuthis subulata) and a fish (Trachurus trachurus) to changes in the angular distribution of light.  An apparatus was made that simulated the angular distribution of daylight in the sea. The apparatus enabled the direction of the brightest light to be changed and the positions of the animals in response to these changes were observed. Squid viewed head-on were observed to roll by a maximum of 20° when the incident light source was at angles between 20° and 90° (where 0° is vertically downwards). When viewed laterally, i.e. in the pitch plane, the squid were observed to position themselves more closely with respect to the angle of the light source, they swam in a near vertical plane when the incident light source was at an angle of 90°. Swimming movements in the roll and pitch plane became more horizontal with positions of the light source between 90 and 180°. Horse mackerel, in contrast, inclined their dorsal surfaces to almost perfectly match the angle of the incident light source, even swimming upside-down when light came from below. These experiments also revealed that squid display a counter-shading chromatophore pattern (‘Flexible Countershading’) in response to light coming from the sides, which involves darkening the side of the body facing the brightest light. The use of chromatophores in this way may explain why the dorsal light reflex in squid is so weak compared to that of fish.

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