CCD Camera Research Articles

Development of a large-area alpha imaging detector for hand and foot monitors

— This paper describes the development of a large-area imaging detector capable of measuring the detailed distribution of alpha particles on hands and feet for use in entry/exit control monitors in decommissioning sites such as the Fukushima Daiichi Nuclear Power Plant. The detector was developed using a commercially available ZnS(Ag) scintillator and an electron multiplying CCD camera. The effectiveness of the detector was evaluated by measuring several types of radiation sources, and the results showed that it was possible to detect the position of alpha particles in a very short time, and contamination levels of up to 11 Bq/cm2 could be visualized. As a result of the minimal detectable surface activity concentration evaluations, 2.0 min or more is required to achieve 4 Bq/cm2, and 25.0 min or more is required to achieve 0.4 Bq/cm2. The field of view of the detector was also checked, and it was confirmed that the setup had a field of view that could cover most of the hand and the sole of the shoe. This detector is expected to be useful for preventing internal uptake and decontamination.

Continuous motion of an electrically actuated water droplet over a PDMS-coated surface

Electrically actuated linear motion of a water droplet over PDMS-coated single active electrode is analyzed from detailed experiments and modeling. In an experiment, continuous motion of the droplet is achieved when it is located over an active electrode with a horizontal ground wire placed just above in an open-electrowetting-on-dielectric configuration. Using a CCD camera, the instantaneous centroid position of the droplet is determined and its velocity is inferred by numerical differentiation. The edge-detected image is also used to determine the advancing and receding contact angles of the moving drop relative to the substrate. Motion of 2, 6, and 10 µl water droplets for voltages in the range of 170–270 V DC is examined to investigate the effect of drop volume and voltage on drop deformation and velocity. The motion of the droplet is initiated by Young-Lippmann spreading at the three-phase contact line, followed by a nonuniform electric force field distributed between the active electrode and the ground wire localized at the droplet-air interface. Simulations carried out using COMSOL© Multiphysics with full coupling between the electric field and hydrodynamics are in conformity with experiments. A contact angle model with pinning and friction leads to close agreement between simulations and drop motion over a bare PDMS layer, particularly in terms of the relevant timescales. When contact line friction is neglected, the fully coupled numerical solution shows a good match with experimentally determined drop movement over a silicone oil-coated PDMS layer. Over both surfaces, continuous motion of the water droplet is seen to be achieved in three stages, namely, initial spreading, acceleration, and attainment of constant speed.

Portable Particle Sizing Concept for Beach Sand Identification for Forensic Purposes:A Success Case Application of DLS/PCS

Abstract A cheap and simple experimental setup for executing particle sizing in water disperion by means of dynamic light scattering (DLS) and consequently the necessary software to evaluate the calculations of photon correlation spectroscopy (PCS) are described here in order to characterize beach sand by its source location according to the mean beach sand grain hydrodynamic diameter. Despite the existence of similar commercial particle sizing equipments, the innovation presented here consists of a portable measurements able to be used in the field. It consists of an easy handling apparatus composed by a solid-state laser pointer as light source and a smartphone CCD camera as detector for video acquiring. Correlation calculus of light intensity variations were performed in a software developed by the authors. The performance test of the proposed protocol was evaluated to characterize beach sand particles on aqueous solution determining its hydrodynamic diameter. The limitations of the technique were explored and comparison with optical microscopy results and literature were performed.

Feature Point Identification in Fillet Weld Joints Using an Improved CPDA Method

An intelligent, vision-guided welding robot is highly desired in machinery manufacturing, the ship industry, and vehicle engineering. The performance of the system greatly depends on the effective identification of weld seam features and the three-dimensional (3D) reconstruction of the weld seam position in a complex industrial environment. In this paper, a 3D visual sensing system with a structured laser projector and CCD camera is developed to obtain the geometry information of fillet weld seams in robot welding. By accounting for the inclination characteristics of the laser stripe in fillet welding, a Gaussian-weighted PCA-based laser center line extraction method is proposed. Smoother laser centerlines can be obtained at large, inclined angles. Furthermore, an improved chord-to-point distance accumulation (CPDA) method with polygon approximation is proposed to identify the feature corner location in center line images. The proposed method is validated numerically with simulated piece-wise linear laser stripes and experimentally with automated robot welding. By comparing this method with the grayscale gravity method, Hessian-matrix-based method, and conventional CPDA method, the proposed improved CPDA method with PCA center extraction is shown to have high accuracy and robustness in noisy welding environments. The proposed method meets the need for vision-aided automated welding robots by achieving greater than 95% accuracy in corner feature point identification in fillet welding.

Rapid scan white light pump–probe spectroscopy with 100 kHz shot-to-shot detection

We demonstrate a femtosecond pump–probe spectrometer that utilizes a white light supercontinuum as input and relies on mutual synchronization of the laser repetition rate, acousto-optical chopper, pump–probe delay stage, and the CCD camera to record shot-to-shot pump–probe spectra while the pump–probe delay is scanned synchronously with the laser repetition rate. The unique combination of technologies implemented here allows for electronically controllable and repetition-rate scalable detection throughput that is only limited by the camera frame rate. Despite high probe RMS fluctuations due to sample scatter (from ∼1.8% with solvent to 7.9% with sample scatter), a combination of fast and slow averaging with a fine sampling of pump–probe delay leads to reduction of RMS noise without multichannel referencing down to ∼0.4 mOD for a scattering nanotube sample. Throughput and limitations of the rapid versus stepwise scanning approaches are analyzed. Experimental comparison with stepwise scan shows ∼1.9x noise reduction in a significantly faster experiment, suggesting an additional suppression of 1/f noise enabled by rapid scan data collection. The particular combination of technologies implemented here makes our approach especially suitable for high throughput impulsive pump–probe micro-spectroscopy of highly scattering samples, without added cost and complexity of light sources, multichannel detection, or long sample exposure.

Optimization of parameters for portable X-ray diffraction/X-ray fluorescence combined analysis device (P-XRDF-CAD)

This paper aims to optimize the parameters of a portable device that combines X-ray diffraction (XRD) and X-ray fluorescence (XRF) analysis techniques. By using the same X-ray source and detector, the device enables the simultaneous acquisition of two-dimensional XRD and XRF information from a sample with the advantage of high analysis efficiency and consistency in the measurement points. The equipment and slit materials are discussed, including the selection of the X-ray source (Moxtek MAGNUM) and the detector (Andor CCD camera). We also explore two different slit designs (the bottom-hole and side-hole) and optimize their dimensions using rectangular holes instead of inclined trapezoidal holes. Considering the fluorescence X-rays of the filters in the X-ray tube spectra, a theoretical formula is derived for rapid and accurate calculation. The calculated results are compared with the experimental results of Al and Ni filters, demonstrating good agreement across various tube voltages and filter thicknesses. Furthermore, an XRD/XRF comprehensive analysis platform is established. The effects of tube voltage, tube current, exposure time, and pixel-binning on the single-pixel events of the CCD camera are investigated and can be used to guide the selection of appropriate device parameters. The effects of the frame and tube voltage on the XRD/XRF analysis efficiency are examined for several sample materials, including Al, α-Fe, Zn, and ZrO2(Y2O3).

Analysis of cable eccentric diameter measurement based on the production line

In order to meet the requirements of real-time monitoring and timely adjustment of cable diameter, a laser caliper is installed on the cable production line. Based on the laser diffraction measurement technology, the related laser diameter measuring instrument was developed. This equipment adopts a CCD array sensor and two mutually perpendicular pulse laser light sources, with a single exposure of only 0.1μs. It can identify the measuring objects with instantaneous changes, such as jittery workpieces, and obtain the outer diameter of the measured object through complex algorithm processing and relevant data calculation. The equipment is designed by relying on the laser diffraction measurement method and electromagnetic induction technology and using the CCD laser diffraction principle. In addition, the error can also be introduced into the linear array CCD image collector. TCD1703C is used for the linear array CCD, and the size length of each pixel is 7μm. If the measurement result is not processed by edge subdivision, the maximum measurement accuracy can only reach 7μm resolution.

Bayesian inference approach for Full Poincaré Mueller polarimetry

Full Poincaré Mueller Polarimetry is a new technique for characterizing samples by means of their Mueller matrix. The method is based on the use of a full Poincaré beam as a generator of polarization states. These beams present different polarization states, covering the entire Poincaré sphere surface, at different points in the beam cross section. To obtain the Mueller matrix, Stokes parameters are collected at both the entrance and the output of the sample. They are calculated from irradiance measurements at each pixel of a CCD camera for different configurations of the polarization state analyzer. These measurements can be processed in several ways. In this work, we propose to use Bayesian inference, in particular, Markov chain Monte Carlo methods, to obtain, without any prior knowledge of the sample, its Mueller matrix together with its uncertainties. The new approach is tested with experimental measurements of different samples and compared with the real theoretical Mueller matrices. Excellent agreement is observed between the experimental results and the theoretical ones for all the samples tested.

Effect of blending ratio on the compatibility and stability of konjac glucomannan/starch composite systems

A series of complex dispersions and films combining Konjac glucomannan (KGM) and starch in different ratios were prepared. The compatibility and stability of KGM/Starch composite (KS) systems were evaluated using a new horizontal casting device coupled with CCD camera system and Near-infrared (NIR) spectrometer and multiple conventional characterization techniques. The findings from the casting device revealed that when the KGM and starch were combined in a 7∶3 ratio, the dispersion demonstrated isotropic behavior, flowing and diffusing at a consistent speed from the central point to the surrounding area on the casting disc. Additionally, the scattered particles in the NIR reflectance spectrum were evenly distributed at every point, indicating excellent compatibility and uniformity within the dispersion. FTIR and XRD analyses indicated the existence of molecular interactions between the film components, and showed good compatibility between KGM and starch when the KGM content was greater than 50%. The best compatibility was obtained when the KGM content was 70%. The SEM results showed that the increase of KGM content contributed to a smoother and denser microstructure in the cross-section of the KS composite films, especially when the KGM content was 70% (w/w). The rheological results of the KS dispersion further confirmed the formation of a hybrid network structure between KGM and starch. Higher KGM content led to more hydrogen bonds and provided more opportunities for macromolecular chain entanglement. This work will contribute to a better understanding of the interaction mechanism between polysaccharides and starch, as well as provide a new perspective and novel characterization methods to deconstruct the compatibility and assembly structure stability between KGM and starch. It is beneficial for facilitate the application of KGM in the development of denatured food or starch materials, including food texture properties and emulsion stability, and establish a foundation for the diversification of food design tools.

Structural changes in the wall of the small intestine of rats under the conditions of action of Nikolsky’s viper (Vipera berus nikolskii) poison

The components of poisons of various living species cause a wide range of effects and symptoms in the victim’s body. The mechanisms of damage to various organs and systems of animals and humans under the influence of specific components of their toxins remain open. The mechanisms of damage to various organs and systems of animals and humans under the influence of specific components of toxins of the venom of vipers remain open. Therefore, the study of the mechanisms of action of viper venom, as well as the development and implementation of a set of measures to reduce the negative impact of their poison on the mammalian organism, remain relevant. The study of the ecological and biological aspects of the violation of the homeostasis of the rat organism under the conditions of the action of viper venom is a complex and multifaceted process that covers various scientific areas. The aim of the study is to identify signs of damage to the small intestine of rats under the conditions of the poison of Nikolsky’s viper (Vipera berus nikolskii). The experiment was conducted on 20 white male rats. In the study, rats were divided into two groups — control and experimental. The poisoning was simulated by administering Nikolsky’s viper venom to rats of the experimental group intra-abdominally at a dose of ED50 of 0.972 μg/g. Histological preparations were examined under the SEO SCAN light microscope; the images were processed using the Vision CCD Camera with an existing system for displaying images on a computer monitor. It was found that severe intoxication of the body with the venom of the Nikolsky’s viper causes extensive destructive-dystrophic changes in the wall of the empty intestine, along with significant stromalvascular disorders. Poisonous hemotoxins increase vascular wall permeability and change intravascular coagulation processes, which leads to disseminated intravascular coagulation (DVS syndrome) and irreversible degeneration of small bowel structures in experiment.

Laser-Induced breakdown spectroscopy and Energy-Dispersive X-ray analyses for green mineral fluorite (CaF2)

Laser-induced breakdown spectroscopy (LIBS) technique was utilized to investigate the green mineral fluorite (CaF2) samples. The LIBS experiment was implemented by using Nd: YAG Laser system and a linear array CCD detector coupled with an Avantes spectrometer in an air atmosphere. The emission spectra of ten various fluorite samples were studied. The molecular bands correspond to the green B2Σ+-X2Σ+ and orange A2Π-X2Σ systems of diatomic CaF-molecule, specifically at Δν = -1, 0, +1 sequences and the CaO diatomic molecule between 618 nm and 630 nm were detected. It was observed that the CaF-diatomic molecular emission bands exhibited stronger optical emission compared to the fluorine (F) atomic lines. Chemical composition (wt.%) analysis was acquired using CF-LIBS methodology under optically thin and local thermodynamic equilibrium (LTE) conditions. Our CF-LIBS studies revealed that Ca (50–60%) and F (30–40%) were the major elements, while C (3–5%) and O (2–5%) were minor elements present in all samples. For comparison, we employed energy-dispersive X-ray (EDX) technique to study the essential elemental composition (wt.%). The results achieved from CF-LIBS were found to be in good agreement to that obtained from the EDX technique. To validate CF-LIBS results, the calibration curve method was employed using the validated samples (S3, S5, and S7). Furthermore, we utilized a principal component analysis (PCA) technique on the LIBS spectral data to classify the fluorite samples.

Fast neutron radiography detector with polyethylene converter and MCP: development and performance evaluation

We present a new position-sensitive fast neutron detector for 14 MeV fast neutron radiography, comprising a high-density polyethylene converter, a micro-channel plate (MCP), a P43 phosphor screen, a reflection mirror, and a CCD camera. Experimental tests are conducted using a DT neutron generator at CIAE, with different samples and a knife-edge measurement used to determine overall image resolution. Results show that the detector is feasible for fast neutron radiography, producing a fast neutron image with a neutron flux of ∼ 3.22 × 104 n · s-1 · cm-2 and 120 s exposure time. Our study demonstrates the potential of this detector for use in fast neutron radiography applications.

An Improved Crack Identification Method for Asphalt Concrete Pavement

The results of high-precision asphalt concrete pavement crack identification can provide help for pavement maintenance. Therefore, methods of image feature enhancement and crack identification of asphalt concrete pavement cracks are proposed. First of all, we used an industrial CCD camera mounted on a vehicle to collect an asphalt concrete pavement crack image. Then, after using the NeighShrink algorithm to denoise the acquired image, a fractional differential image enhancement algorithm was designed based on image feature blocks to enhance the image features. On this basis, crack characteristics were segmented and processed by watershed algorithm. Through crack direction identification and crack parameter extraction, crack distribution direction, crack length and width and other parameters of asphalt concrete pavement were obtained in order to achieve accurate identification of asphalt concrete pavement cracks. The experiment found that this method can effectively remove noise information from asphalt concrete crack images; after applying this method, the image entropy value of each image was improved, with a minimum improvement of 0.38 and a maximum improvement of 1.98. The time consumed by this method in identifying cracks in asphalt concrete pavement varied between 1.4 s and 2.4 s. When identifying the length of cracks in asphalt concrete pavement, the maximum deviation value was only 0.47 mm; when identifying the width of cracks in asphalt concrete pavement, the maximum deviation value was only 0.31 mm. The above results indicate that by enhancing the image features of asphalt concrete cracks, this method achieves more accurate identification results for crack distribution direction, length and width values, with high identification efficiency and good application effect.

Three-Dimensional Shape and Deformation Measurements Based on Fringe Projection Profilometry and Fluorescent Digital Image Correlation via a 3 Charge Coupled Device Camera.

We propose a novel hybrid FPP-DIC technique to measure an object's shape and deformation in 3D simultaneously by using a single 3CCD color camera, which captures the blue fringe patterns and red fluorescent speckles within the same image. Firstly, red fluorescent speckles were painted on the surface of the specimen. Subsequently, 12 computer-generated blue fringe patterns with a black background were projected onto the surface of the specimen using a DLP projector. Finally, both the reference and deformed images with three different frequencies and four shifted phases were captured using a 3CCD camera. This technique employed a three-chip configuration in which red-green-blue chips were discretely integrated in the 3CCD color camera sensor, rendering independent capture of RGB information possible. Measurement of out-of-plane displacement was carried out through the implementation of Fringe Projection Profilometry (FPP), whereas the in-plane displacement was evaluated using a 2D Digital Image Correlation (DIC) method by leveraging a telecentric-lens-based optical system. In comparison to the traditional FPP-DIC hybrid methodology, the present approach showed a lower incidence of crosstalk between the fringe patterns and speckle patterns while also offering a corrective for the coupling of the in-plane displacement and out-of-plane displacement. Experimental results for the in-plane cantilever beam and out-of-plane disk comparisons with the traditional 3D-DIC method indicated that the maximum discrepancy obtained between FPP-DIC and 3D-DIC was 0.7 μm and 0.034 mm with different magnifications, respectively, validating the effectiveness and precision of the novel proposed FPP-DIC method.

Measuring Uncertainty Analysis of the New Leveling Staff Calibration System.

Besides precise levels, precise leveling staffs are a crucial part of the measuring equipment when carrying out geodetic (geometric) leveling measurements. The leveling staffs define the scale of the height reference system, so it is important to calibrate them periodically and when necessary. This paper shortly describes the development of the new method of calibrating leveling staffs in the Laboratory for Measurements and Measuring Technique of the Faculty of Geodesy, University of Zagreb. The existing horizontal comparator was upgraded by installing a servo-motorized positioning drive with a mounted CCD camera and telecentric lens that is used to record graduations of the leveling staffs. The software was developed to support the management of the comparator system, as well as for the analysis and processing of images and measurement data and, most importantly, giving the result in the form of a calibration report. The main subject of this paper is a detailed assessment of the measurement uncertainty of determining the position of the edges of the graduation lines and determining the scale of precise centimeter and coded leveling staffs. The estimates were confirmed by experimental measurements.

Fracture mechanism of 316L/BNi-2 brazed joints using experiment and microstructure-based model

Compact components are prone to failure at brazed joints. To ensure the reliability of brazed joints, it is vital to have a comprehensive understanding of the fracture mechanism of brazed joints which can be attributed to highly inhomogeneous microstructures and individual phase mechanical properties. This study measured the stress-strain curve of brazed joint micro-zone of 316L austenitic stainless steel with the BNi-2 filler alloy by a tensile testing machine equipped with a CCD camera. The instrumented indentation technique was used to determine the flow properties of individual phases in joints considering the size effect. Representative volume element (RVE) technology was applied to simulate the mechanical behavior of brazed joints, which was in good agreement with the tested. The fracture of brazed joints can be divided into ductile fracture and brittle fracture which includes the decohesion of the interface between the boride and the austenite matrix and the fragmentation of the boride in terms of the analysis of the morphology of cross-section and fracture surface in brazed joints. According to the stress and strain distribution in the brazing micro-zone, the plastic strain localization cause decohesion, and the stress concentration along the loading direction cause boride fragmentation.

Research on the Application of VIC-3D Technology in Civil Engineering

Digital image correlation method has been widely used in various research fields of civil engineering since it was proposed, because of its convenient and simple, full-field measurement, good environmental adaptability and other characteristics. It has become an important measurement method in various research fields. The CCD camera is used to match the position of the same pixel in the two speckle images before and after the surface deformation of the specimen to obtain the displacement vector of the pixel, and record the change of the speckle characteristics of the specimen surface. Combined with computer vision and digital image processing technology, the physical quantities such as the morphology, displacement and strain of the object surface can be accurately measured. Therefore, this paper introduces the application of VIC-3D technology in civil engineering in detail.

Astronomical Camera Based on a CCD261-84 Detector with Increased Sensitivity in the Near-Infrared

Herein, we describe the design, implementation and operation principles of an astronomical camera system, based on a large-format CCD261-84 detector with an extremely thick 200 μm substrate. The DINACON-V controller was used with the CCD to achieve high performance and low noise. The CCD system photometric characteristics are presented. A spatial autocorrelation analysis of flat-field images was performed to reveal the dependence of substrate voltage on the lateral charge spreading. The investigation of the dispersion index for the optimal choice of exposure time is discussed. Studies of the patterns of fringes were carried out in comparison with previous detectors. The amplitude of fringes with CCD261-84 was significantly lower, compared to previous-generation detectors. The results of using a new camera for imaging and spectral observations at the Russian 6 m telescope with the SCORPIO-2 multimode focal reducer are considered. The developed CCD camera system makes it possible to significantly increase the sensitivity in the 800–1000 spectral range.

Experimental and numerical studies on the interaction between two identical slot jet H2/CO diffusion flames

Hydrogen offers a unique opportunity in achieving a CO2-neutral future, but great challenges exist for the successful transition from conventional fossil fuels to H2, due to the great component variation and safety issues of H2 energy. The multiple-injection combustor concept effectively addresses these problems, with the merits of flexible nozzle distance satisfying the varying H2 content in the fuel and low flash-back risk comparable to diffusion flames. In such combustors, flame interaction plays an essential role in the performance of multiple-injection combustors. This work focused on the flame interaction behavior of two identical slot jet H2/CO diffusion flames. OH* chemiluminescence was captured by an intensified CCD camera and the flame temperature was measured using a type-B thermocouple. The combustion process was modeled using a Fortran flame code by incorporating the detailed thermal and transport properties as well as the chemical kinetic mechanism. With these experimental and numerical efforts, the effects of burner separating distance, fuel composition, and fuel velocity were parametrically studied. Results showed that flame interaction enables a more uniform temperature distribution. Increasing H2 content in the fuel decreases the flame length for the merged flames, but this effect is less distinguished for the merging and separated flames. In addition, flames with a higher H2 content merge more easily because of the enlarged flame radius, featured with a linear relationship between the merging distance and H2 content. When increasing the fuel flow rate, the twin flames contact and merge at farther separating distances, and this influence of fuel flow rate on flame interaction was observed to be fuel-composition-dependent. Increasing the burner separating distance lowers the flame length, which is attributed to the enhancement of CO oxidization rather than the H2 reactions. Moreover, burner separating distance plays a critical role in NO emissions, with a non-monotonical impact due to the combined effect of flame temperature and O2 concentration.

An intermediate water gravity wavelength and wave height measurement inside a large wave flume tank

This paper discusses an intermediate water gravity wavelength and wave height measurement method. Three methods were used to obtain wave height, wavelength, and period. Firstly, conventional methods used two Honeywell pressure sensors mounted at the bottom of the wave tank at two different locations. Secondly, using the transfer function of the flap wavemaker (the relationship between wave height and the wave paddle stroke). Thirdly, the Laser Sheet technique (PIV image processing technique). The significant wave height and period from pressure reading sensors of regular gravity waves were obtained from the Raleigh distribution and Zero up crossing technique. Wavelength was obtained indirectly by using a dispersion relationship that was solved by using the Newton Raphson numerical method from both the pressure sensors and the transfer function of the flap wavemaker. This experiment was focused on getting the direct value of wave measurements by developing an image processing technique in a clear large wave flume tank to replace the conventional methods and eliminate the error that may produce by using the numerical methods. The PIV setup with the CCD camera was used to capture wave images. The image processing technique based on Canny edge detection with constant threshold value was used to detect the edge of the waves. The experimental result showed a good agreement between the results obtained from these three methods, with the percent of error up to 8.683%.