Light Detection Method Research Articles

Upsampling method for sparse light detection and ranging using coregistered panoramic images

We present a method to upsample low-resolution light detection and ranging (LiDAR) data using coregistered panoramic images collected in urban environments. The context is a mobile mapping vehicle equipped with a LiDAR scanner and spherical camera system, where the goal is to recover a three-dimensional model of the built environment. What makes this problem challenging is that as LiDAR samples become sparse, interpolation becomes difficult as connectivity between points can become ambiguous. The idea behind this paper is to use structural context and information in the associated panoramic images to determine the location of surfaces in the scene, and by inference, the surface membership of the LiDAR samples. With the latter determined, surfaces can then be reconstructed via interpolation using a function appropriate to the task at hand. We show that this method is effective in recovering details that are not apparent in the initial dataset. In the event that images are either uninformative or not available, we introduce a fallback method for surface segmentation that infers depth discontinuities from the properties of the surface triangulation. Experimental results are presented showing the performance of both methods on data acquired from an urban setting.

교통 신호등과 비전 센서의 위치 관계 분석을 통한 이미지에서 교통 신호등 검출 방법

In this paper, a robust traffic light detection method is proposed by using vision sensor and DGPS(Difference Global Positioning System). The conventional vision-based detection methods are very sensitive to illumination change, for instance, low visibility at night time or highly reflection by bright light. To solve these limitations in visual sensor, DGPS is incorporated to determine the location and shape of traffic lights which are available from traffic light database. Furthermore the geometric relationship between traffic light and vision sensor is used to locate the traffic light in the image by using DGPS information. The empirical results show that the proposed method improves by 51% in detection rate for night time with marginal improvement in daytime environment.

Photon-counting 1.0 GHz-phase-modulation fluorometer.

We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method.

Novel cyanine dyes and homodimeric styryl dyes as fluorescent probes for assessment of lactic acid bacteria cell viability

Innovations in labeling techniques and in the design and synthesis of dye structures are closely related to the development of service equipment such as light sources and detection methods. Novel styryl homodimers and monomethine cyanine dyes were synthesized and their staining abilities for discrimination between live and dead lactic acid bacterial cells were investigated. The dyes were combined in pairs based on their excitation and emission maxima and the capacity to penetrate through cell membranes of viable bacterial cells. The absorption maxima in the same region and the large Stocks shifts of the styryl derivatives allowed viability analysis to be done with epifluorescent microscope with a very basic configuration – one light source about 480nm and one filter for the fluorescent emissions. A staining protocol was developed and applied for live/dead analysis of Bulgarian yoghurt starters. The live cells quantification by the fluorescence dyes coincided well with the results of the much more time-consuming tests by plate counting. Thus, the proposed dye combinations are appropriate for rapid viability estimation in small laboratories that may have conventional equipment.

A Remarkably Small Species ofUroplectesPeters, 1861 (Scorpiones: Buthidae), Endemic to the Succulent Karoo of South Africa

The scorpion fauna of southern Africa is very diverse, especially in the arid western half of the subcontinent. New species continue to be discovered as the region is surveyed with ultraviolet light detection methods. The present contribution describes Uroplectes ansiedippenaarae sp. n., which is endemic to the Succulent Karoo Biome in the Northern Cape and Western Cape provinces of South Africa. The new species appears to be most closely related to U. variegatus (C.L. Koch, 1844), which is endemic to the Fynbos Biome in the Western Cape Province. Uroplectes ansiedippenaarae sp. n. is the smallest species of Uroplectes Peters, 1861, and among the smallest scorpion species in southern Africa, with adults ranging from 16–20 mm in total length. The addition of this new species raises the number of Uroplectes species and subspecies in South Africa to 19, and the number of endemics to 10.

비전 기반 주간 LED 교통 신호등 인식 및 신호등 패턴 판단에 관한 연구

비전 기반 주간 LED 교통 신호등 인식 및 신호등 패턴 판단에 관한 연구

A New Method for Determining the Emulsion Stability Index by Backscattering Light Detection

AbstractIn the present study, the Δbackscattering (ΔBS) method was developed as a simple and sensitive tool for determining the emulsion stability index (ESI) by backscattering light detection. The backscattering light detection method uses emulsion‐scanning technology to monitor physical behavior in an emulsion as a function of storage time. Emulsions were prepared by the homogenization (8,000 rpm for 2 min at 25C) of distilled water and perilla oil containing Tween 60, and the sample was quiescently incubated in a vial at 25C for 11 h. To confirm this new methodology, the sum of ΔBS at the clarified layer, obtained from the backscattering flux profiles over the storage period, was compared with the ESI determined by the volumetric method. Our backscattering light detection method was compared with the volumetric method based on the emulsifier content. The sum of ΔBS at the clarified layer decreased as the ESI decreased, with a correlation of 0.999, 0.993, 0.998 and 0.998 for emulsions stabilized with 200, 300, 400 and 500 μmol of emulsifier, respectively. Regardless of the emulsifier content in the emulsion, the R2 values for the fit curve, calculated by plotting the sum of ΔBS at the clarified layer against the ESI determined by the volumetric method, revealed strong linear relationship (R2 = 0.953). Our results suggest that the backscattering light detection method is a new tool for the quantitative determination of the ESI in an emulsion system.Practical ApplicationsThe acceptable way for the emulsion characterization is the determination of emulsion stability by measuring creaming rate and/or oil droplet diameter. Although the determination of oil droplet diameter provides the various information on the emulsion stability, it needs the expensive instruments based on dynamic light scattering or laser diffraction analysis. On the other hand, creaming is monitoring the change in the height of the boundary between the creamed and serum layers with naked eyes. In many cases, however, the condition of emulsions (such as their color, viscosity, and oil content, etc) prevents the clear reading of the boundary. The backscattering light detection described in this study could be a promising method which enables the accurate analysis of emulsion stability regardless of the limitations mentioned above.

Development and Validation of a Bioanalytical Method for Quantification of 2,6-Bis-(4-hydroxy-3-methoxybenzylidene)-cyclohexanone (BHMC) in Rat Plasma

A sensitive and accurate high performance liquid chromatography with ultraviolet/visible light detection (HPLC-UV/VIS) method for the quantification of 2,6-bis-(4-hydroxy-3-methoxybenzylidene)-cyclohexanone (BHMC) in rat plasma was developed and validated. BHMC and the internal standard, harmaline, were extracted from plasma samples by a simple liquid–liquid extraction using 95% ethyl acetate and 5% methanol. Plasma concentration of BHMC and internal standard were analyzed by reversed phase chromatography using a C18 column (150 × 4.6 mm I.D., particle size 5 µm) and elution with a gradient mobile phase of water and methanol at a flow rate of 1.0 mL/min. Detection of BHMC and internal standard was done at a wavelength of 380 nm. The limit of quantification was 0.02 µg/mL. The calibration curves was linear (R2 > 0.999) over the concentration range of 0.02–2.5 µg/mL. Intra- and inter-day precision were less than 2% coefficient of variation. The validated method was then applied to a pharmacokinetic study in rats by intravenous administration of BHMC at a single dose of 10 mg/kg. Pharmacokinetic parameters such as half-life, maximum plasma concentration, volume of distribution, clearance and elimination rate constant for BHMC were calculated.

Real-Time Computer Vision/DGPS-Aided Inertial Navigation System for Lane-Level Vehicle Navigation

Many intelligent transportation system (ITS) applications will increasingly rely on lane-level vehicle positioning that requires high accuracy, bandwidth, availability, and integrity. Lane-level positioning methods must reliably work in real time in a wide range of environments, spanning rural to urban areas. Traditional positioning sensors such as the Global Navigation Satellite Systems may have poor performance in dense urban areas, where obstacles block satellite signals. This paper presents a sensor fusion technique that uses computer vision and differential pseudorange Global Positioning System (DGPS) measurements to aid an inertial navigation system (INS) in challenging environments where GPS signals are limited and/or unreliable. To supplement limited DGPS measurements, this method uses mapped landmarks that were measured through a priori observations (e.g., traffic light location data), taking advantage of existing infrastructure that is abundant within suburban/urban environments. For example, traffic lights are easily detected by color vision sensors in both day and night conditions. A tightly coupled estimation process is employed to use observables from satellite signals and known feature observables from a camera to correct an INS that is formulated as an extended Kalman filter. A traffic light detection method is also outlined, where the projected feature uncertainty ellipse is utilized to perform data association between a predicted feature and a set of detected features. Real-time experimental results from real-world settings are presented to validate the proposed localization method.

水面溢油可见/近红外偏振光检测方法研究

水面溢油可见/近红外偏振光检测方法研究

Three Dimensional Modeling of a Forested Area Using an Airborne Light Detection and Ranging Method

Preserving forests and their value to us is indispensable to human life. When making forest preservation plans and managing forests efficiently, it is necessary to use three dimensional (3D) models of the forest regions. Apart from the traditional and photogrammetric methods used for producing these maps, the LIght Detection and Ranging (LIDAR) measurement technique with its various advantages has been used in recent years. This paper explains the principle of the operation of the LIDAR measurement system and discusses the determination of digital elevation models (DEM) of forest areas and their usage in 3D models. This test study aims to convert the scattered distributed 3D datasets obtained from airborne LIDAR technology to a digital elevation model with a regular grid format. One of the most significant aspects of this process, the interpolation method, which affects the quality of the final product when generating the digital elevation model, is examined with respect to data density and distribution, grid size interval and terrain type.

The detection of food soils and cells on stainless steel using industrial methods: UV illumination and ATP bioluminescence

Open food contact surfaces were subjected to organic soiling to provide a source for transfer of microbial cells. Rapid industrial methods used for the detection of residual cells and soil e.g. ATP (adenosine triphosphate) bioluminescence and an ultraviolet (UV) light detection method were assessed for their ability to detect organic soils, or organic soil–cell mix on surfaces. A range of soils (complex [meat extract, fish extract, cottage cheese extract]; oils [cholesterol, fish oil, mixed fatty acids]; proteins [bovine serum albumin, fish peptones casein]; carbohydrates [glycogen, starch, lactose]); was used. Under UV, oily soils, mixed fatty acids, cholesterol and casein were detected at low concentrations, with detection levels ranging from 1% to 0.001% for different substances. Glycogen was the most difficult substance to detect at lower concentrations. Using UV wavelength bands ( λ) of 330–380 nm, 510–560 nm and 590–650 nm, wavelength bands of 330–380 nm, illuminated most of the soils well, whilst the wavelength band of 510–560 nm illuminated the fish extract, cholesterol and fatty acids; the 590–650 nm wavelength band illuminated the lactose. Soils at all concentrations were detected by the ATP bioluminescence method; the complex soils gave the highest readings. When complex soils were combined with Listeria monocytogenes Scott A or a non-pathogenic Escherichia coli O157:H7, ATP measurements increased by 1–2 logs . For UV illumination, the L. monocytogenes and cheese combination was the most intensely illuminated, with E. coli and meat the least. UV illumination is a simple well established method for detecting food soil, with little change in findings when microorganisms are included. Performance can be enhanced in certain circumstances by altering the wavelength. ATP bioluminescence is a proven system for hygienic assessment being especially useful in the presence of microorganisms rather than organic soil alone.

Visualizing Method of Colon Cancer Marking-clip using Near-infrared Light During Laparscopic Surgery

This paper presents a near-infrared light detection method of colon cancer lesion using a marking-clip, which is applied to laparoscopic surgery. In this method, the near-infrared light backscattering from colon tissue and marking-clip is captured on the abdomen side by an endoscope. In this study, irradiating 700 nm near-infrared light, the visualizing experimentation was demonstrated using a colon phantom. The marking-clip can be imaged as decreasing and increasing intensity regions, i.e. cold spot and hot spot. Monte Carlo simulation was carried out to compare with the experimental results and evaluate the system parameters, e.g. irradiating wavelength. Cold and hot spots could be simulated as an image of marking-clip and their contrasts were related to reflectance of marking-clip and irradiating wavelength. Consequently, cold spot was considered to be visualized due to the non-transparent volume of marking-clip, according to the shield of light scattered by medium and reflecting light on marking-clip. The dynamic range of proposed detection can be enhanced in an irradiating condition of 1000 nm.

Particle identification using the de/dx and the Cherenkov light detection methods in high energy physics

This paper deals with two particle identification methods: dE/dx and Cherenkov detection. The dE/dx method is the most common technique used in conjunction with tracking in gaseous detectors. We systematically compare existing dE/dx data with various predictions available in the literature and judge the overall consistency. To my knowledge, this comparison was not done to date. There are two Cherenkov light emission detection techniques: the threshold and the Ring imaging methods. We want to discuss the recent trend in these techniques.

Multichannel mode-filtered light detection based on an optical fiber for small-volume chemical analysis

A novel mode-filtered light detection method is described in which an unjacketed optical fiber is inserted into a transparent capillary tube and three or more detection channels are set on the capillary side for different distances from the port of the fiber. This new method is the basis of synchronization of separation and analysis, with which a modern multidimensional analysis apparatus will be constructed. For samples of different concentration, the more close to the laser incidence port of the fiber the detector has been set up, the greater the change of the intensity profile of mode-filtered light (deltaI(F)) that is obtained. Vice versa, if a parameter alpha = I0/In is established and, instead of a mode-filtered light signal, the reversed alteration trend of deltaalpha is found in comparison with the alteration trend of deltaI(F), the reason is that the background rapidly lowers with the increasing distance to the laser incidence port of the fiber; moreover, the mode-filtered light signal decreases slowly with it. With the present method and apparatus, glucose and glycerol have been determined, with good reproducibility and stability and a small sample volume. Furthermore, a real sample of glucose injection is measured for a detection volume of 5 microL, and an acceptable result is observed.

Advances in Detector Systems for Imaging Single Molecule Fluorescence

Advances in Detector Systems for Imaging Single Molecule Fluorescence

Developments in light sources and detectors for atomic absorption spectroscopy

In a tribute to the contributions of Sir Alan Walsh to atomic spectroscopy, and in particular to his pioneering efforts in conceiving and developing the technique of atomic absorption spectroscopy, a brief overview is given of some developments in light sources and detection methods that took place during his leadership of the spectroscopy group at the CSIRO Division of Chemical Physics, Melbourne, Australia. The topics covered include hollow-cathode lamps, high-intensity lamps, resonance detectors, selective modulation of resonance lines emitted by hollow-cathode sources and isotopic analysis.

Extraction of Quasi-Straightforward-Propagating Photons Through a Scattering Medium by Up-Conversion Method as a Coherent Light Detection Technique

Aiming at the realization of optical CT (computed tomography), the extraction of quasi-straightforward-propagating photons from optical pulses transmitting through a standard scattering medium of Intralipid-10% aqueous solution has been demonstrated by an up-conversion method (second harmonic generation). We have found that this operates as a coherent light detection method rather than a time-gate one and extends the dynamic range where the Lambert-Beer’s law holds to − 86 dB. We have also proposed improvements to obtain the largest possible dynamic range by such an up-conversion technique.

Immunoelectron microscopy identification of early proliferating cells in rat liver tissue during hyperplasia induced by lead nitrate.

Recent studies have suggested that hepatic stem cells may be involved in at least some forms of liver epithelial growth. To obtain further information on this controversial hypothesis, we treated rats with lead nitrate to induce liver growth and identified the cells undergoing early DNA synthesis by bromodeoxyuridine immunohistochemistry, using both light and electron microscopic detection methods. Eight hours after an intravenous injection of lead nitrate 100 mumol/kg, DNA synthesis was detected in a few scattered hepatocytes and in nonparenchymal cells in portal connective tissue. At the light microscopic level, identification of nonparenchymal cells was limited to bile duct epithelial cells. Other cell types were also labeled, but their identity could not be established. At the ultrastructural level, however, four types of nonparenchymal cells were identified as containing bromodeoxyuridine immunogold particles. These four types included bile duct epithelial cells, fibroblasts, macrophages and nondescript periductular cells. These periductular cells displayed certain ultrastructural features of bile duct cells but did not line a lumen or display microvilli on their apical membrane, nor did they reside within the bile duct basement membrane. Because proliferation of nonparenchymal cells in portal areas preceded that of hepatocytes, it is suggested that the former reaction reflects a direct mitogenic effect of lead nitrate and not an adaptive growth response secondary to parenchymal enlargement. However, whether DNA synthesis in periductular cells or bile duct cells reflects activation of hepatic stem cells cannot be established from the present morphological observations. If so, such a progenitor compartment must be dormant because it does not seem to play a functional role in this and other forms of adult liver epithelial growth.

A hydrophilic resin-embedding method for light and electron microscopic detection of tissue anionic sites with cationic colloidal iron: as applied to mouse Paneth cells.

A cationic colloidal iron method was introduced for electron microscopic detection of anionic sites in hydrophilic resin-embedded specimens, and the method was applied to Paneth cells of the mouse jejunum. Mouse jejunal blocks were embedded in hydrophilic acrylic resin (LR White), cut into ultrathin sections, stained with the diluted cationic colloidal iron, and exposed to osmium vapor. The jejunal tissues, including the Paneth cells, embedded in hydrophilic resin were reactive to the fine cationic colloidal iron. At pH value 1.5, fine electron dense colloidal iron deposited along the rims of the secretory granules and the Golgi apparatus of the Paneth cell. Colloidal particles distributed on the osmiophilic reticular structures in the rim and in dot-like fashion lined the border between the granular core and rim. At pH value 4.0, ribosomes reacted to cationic colloidal iron particles in addition to the granular rims and Golgi apparatus. At pH 7.0, even the cores of the secretory granules were stained. Semi-thin sections prepared from the LR White-embedded specimens and stained at pH 1.5 with the diluted (1:3 in volume) cationic colloidal iron showed sufficient Prussian blue reaction for light microscopy in the rims of Paneth granules and mucus of goblet cells. This method is therefore useful for correlative light and electron microscopic detection of tissue anionic sites, including sulfate, carboxyl and phosphate groups, at various pH values.