Charge-coupled Device Camera Research Articles

Investigation of a non-thermal atmospheric pressure plasma jet in contact with liquids using fast imaging

An experimental diagnostic based on a nanosecond-intensified charged coupled device camera and optical emission spectroscopy (OES) are proposed to observe the interfacial region between the plasma plume and liquid surfaces. The study is simulating the investigations of using non thermal atmospheric pressure plasma jets for the eradication of bacterial biofilms. The spatially and temporally resolved images are focused on the contact region in the open air between the nozzle of the reactor and liquid targets. The emission intensity from one discharge cycle is captured and accumulated over several cycles to investigate the formation and the kinetic evolution of the plasma during the interaction. Moreover, the emission intensity of the helium plasma jet and plasma behaviour with different samples are observed. It is found that some dynamic of the plasma discharge has changed during the interaction with different targets. The method can be used to improve the need of understanding of the physics and chemistry of plasma jet during the interaction with liquid surfaces. Different types of species that arrived to the samples were studied and compared with the free jet mode using OES.

Experimental diagnosis of electron density and temperature in capacitively coupled argon plasmas: Triple-frequency discharges and two-dimensional spatial distributions

An approach combining optical emission spectroscopy with a collisional radiative model (OES-CRM) has been used to diagnose electron density and electron temperature in low pressure capacitively coupled argon plasmas. The electron density and electron temperature obtained by the OES-CRM show reasonable agreement with the results measured by a Langmuir probe. The method was first applied to diagnosis in triple-frequency (2, 13.56, and 27.12 MHz) plasmas. Compared with dual-frequency (2 and 27.12 MHz) discharges, it was found that in triple-frequency discharges, the high frequency source controls electron density more independently and with less influence on electron temperature as the intermediate frequency power increases. Next, the method was extended to a two-dimensional diagnosis based on the use of a charge coupled device camera and optical bandpass interference filters. The results showed that the axial and radial distributions of the electron density are more uniform at a lower radio frequency (RF) power. The axial uniformity of the electron density is better at a lower discharge frequency while the radial profiles of the electron temperature are flatter at a higher frequency. In all the cases, the electron temperature is highly uniform within the bulk plasma. Moreover, a mode transition from an α to a γ mode is observed at 13.56 MHz with the increasing RF power, and this is accompanied by a significant enhancement in electron density and a sharp reduction in electron temperature.

Measurement of magnetic field distribution produced by high-current pulse using Zeeman splitting of Na emission distributed by laser ablation.

Measurement of the magnetic field distribution in Z-pinch experiments remains an ongoing challenge. We present a method of measuring the radial distribution of the magnetic field around a copper rod using Zeeman splitting of sodium (Na) emission lines, in which an Na layer is formed by the laser ablation of NaCl crystals on a load surface. The load consists of a copper rod of 2mm diameter and is pre-covered on its surface by the NaCl crystals. An 8ns pulsed laser with an energy of 1J and wavelength of 532nm is focused on the crystals. The Na plasma is produced and expands from the surface of the copper rod into a vacuum. After applying a pulsed current with a peak value of 375 kA to the load, the Na 3s-3p doublet displays significant Zeeman splitting patterns. The self-luminosity of the Na plasma is recorded by a spectrometer coupled with an intensified charge-coupled device camera from an end-on view to eliminate the effects of different observing angles and Doppler shifts. We determine the magnetic field by fitting the measured spectra with the calculated results of the Voigt profile. The measurable range of radial position is 5-7mm, and the corresponding magnetic field is 5-15T. The averaged error of curve fitting is less than 12%.

Computational evaluation of sparse coding on off-axis electron holograms: comparison between charge-coupled device and direct-detection device cameras.

The effectiveness of sparse coding for image inpainting and denoising of off-axis electron holograms was examined computationally based on hologram simulations according to considerations of two types of electron detectors, namely charge-coupled device (CCD) and direct-detection device (DDD) cameras. In this simulation, we used a simple-phase object with a phase step such as a semiconductor p-n junction and assumed that the holograms recorded by the CCD camera include shot noise, dark-current noise and read-out noise, while those recorded by the DDD camera include only shot noise. Simulated holograms with various electron doses were sparsely coded. Even though interference fringes cannot be recognized in the simulated CCD and DDD holograms when subjected to electron doses (per pixel) equal to 1 and 0.01, respectively, both the corresponding sparse-coded holograms exhibit meaningful interference fringes. We demonstrate that a combination of the DDD camera and sparse coding reduces the requisite dose used to obtain holograms to values less than one-thousandth compared with the CCD camera without image postprocessing. This combination is expected to generate lower-dose and/or higher-speed electron holography.

Development of Conventional Controller Based on Image Processing for Monitoring and Controlling Burning Zone Temperature in a Cement Plant in Rotary Kiln Process Through IOT

In the cement factories, a rotary kiln is a pyro-processing device that is used to raise the temperature of the materials in a continuous process. Temperature monitoring is an essential process in the rotary kiln to yield high quality clinker and it has been implemented using various image processing techniques. In this paper we are measuring and controlling the temperature of rotational kiln in cement industry to get proper clinker ouput. Burning zone flame images are captured using CCD(Charge Coupled Device) camera and are processed using image processing with PID(Proportion Integration and Derivative) controller and which are programmed on raspberry pi card with the help of python language, also the captured images and attributes are transferred to authorized mobile/pc through Raspberry PI by selecting the IP address of mobile or PC. All the attributes received in the mobile in the form of web page the according to the object following data temperature controlled and object is ceaselessly followed to get the proper clinker output. Picture handling calculation with Open cv, as indicated by the calculation the edge estimation of the camera is settled. The frame value of the camera is set. Conversion from RGB color space to HSV color space is achieved and the reference color threshold value is determined. The range esteem estimated by the camera is contrasted and the reference esteem. In this study temp of rotational kiln is measured effectively using PID controller, this controller continuously control the temperature of revolving kiln by varying the i/p images of burning zone at finally fix one flame which is giving 1400degc.

Three-dimensional (3D) optical imaging of muon beam using a plastic scintillator plate in water

Although optical imaging of muon beams is a possible method for range determination, it has been limited to two-dimensional (2D) projection images. For the precise measurement of an optical image of a muon beam, three-dimensional (3D) imaging is desired. To measure a 3D optical image, we conducted optical imaging of muon beams using a plastic scintillator plate set in a water phantom. When this plate was immersed in the water phantom, irradiation with a positive muon beam was carried out from along the plate’s sides. Optical images of the scintillator plate were acquired using a charge-coupled device (CCD) camera from the side during irradiation with a positive muon beam. The imaging system was moved in 10-mm steps perpendicular to the beam direction to acquire a set of sliced optical images of the beam. These sliced images were stacked and interpolated to form a 3D optical image, and the depth and lateral profiles were evaluated. From the depth profiles derived from the 3D optical image, the Bragg peak position was estimated. The lateral profiles at the Bragg peak could also be derived. We confirmed that 3D imaging of muon beams is feasible and in fact a promising method for measuring sliced optical images at any position, which is a capability that is useful for research on muon beams as well as for future muon radiotherapy.

Wide-field photothermal reflectance spectroscopy for single nanoparticle absorption spectrum analysis

Abstract Photothermal imaging is useful for detecting individual nanoparticles and obtaining the absorption spectra. This study presents a wide-field photothermal reflectance spectroscopy technique achieved by incorporating a pump beam, a probe beam, and a charge-coupled device (CCD) camera into a commercial microscopic setup. The presented design does not require precise alignment between the pump and the probe beams and enables the observation of numerous individual nanoparticles during image acquisition. Despite the use of a simple imaging processing method, i.e., a four-bucket method using a CCD camera, sufficient sensitivity for the spectral imaging of a single gold nanorod (20 nm diameter and 84 nm length) is demonstrated. Numerous individual nanoparticles within a wide field of view (240 μm × 180 μm) are detected in an image captures at an imaging measurement speed of 0.02 mm2 min−1. Furthermore, the proposed photothermal reflectance spectroscopy technique can detect the variation in the absorption peak of the measured spectra depending on the aspect ratio of individual nanoparticles within a spectral resolution of 1 nm.

EXPERIMENTAL INVESTIGATION ON THE CREEP RESPONSE AND THERMAL EXPANSION OF PARALLEL STEEL WIRES AT ELEVATED TEMPERATURES

The thermal expansion at 15 different temperatures and the high temperature creep at multiple stress levels of 1670 MPa parallel steel wires, which are widely used in practical engineering, were experimentally investigated by a charge-coupled device camera (CCDC) system. The tensile strength of the specimens which experienced 2-hour’s high temperature creep investigation was measured at the ambient temperature. The curves of thermal expansion strain and high temperature creep strain of the parallel steel wires were obtained. The test results show that the thermal expansion strain of the parallel steel wires increased nonlinearly with the increase of the temperature and the microstructure changed at 750 ℃. Both the heating temperature and the stress level significantly affected the high temperature creep strain. At a higher temperature, the effect of the stress level on the residual tensile strength of the parallel steel wires was more significant. Compared with the 1860 MPa pre-stressed twisted steel wires, the 1670 MPa parallel steel wires had a lower creep strain at a high temperature. Based on the test data, the function of the thermal expansion coefficient of parallel steel wires with respect to the temperature and the high temperature creep model are proposed. The thermal expansion coefficient and the high temperature creep model proposed in this paper can benefit the mechanical response analysis of pre-stressed steel structures at elevated temperatures.

MEASUREMENT OF HALF-VALUE LAYER IN COMPUTED TOMOGRAPHY SCANNERS USING LUMINESCENCE OF POLYETHERSULFONE RESIN BY X-RAY IRRADIATION.

In this study, a method for estimating the half-value layer (HVL) and effective energy (Eeff) by imaging the luminescence from a polyethersulfone (PES) resin with rotating irradiation of X-rays in a computed tomography scanner was developed. The luminescence of the PES resin was imaged using a charge-coupled device camera. The PES-HVL was determined from the luminance attenuation profile corresponding to the X-ray attenuation within the resin. The PES-HVLs for tube potentials of 80-135 kVp were converted into Eeff values and were compared to those of a conventional lead-covered case method. The Eeff obtained using the proposed luminescence imaging method agreed within ~3.9% of that obtained using the conventional method. Moreover, dose simulations based on the X-ray spectrum calculated from the HVLs were performed using a poly(methyl methacrylate) phantom with a diameter of 16 cm. The simulated doses based on the luminescence imaging method agreed with the in-phantom dosimetry within ~9%.

Effects of pulse energy ratios on plasma characteristics of dual-pulse fiber-optic laser-induced breakdown spectroscopy

Laser-induced plasmas of dual-pulse fiber-optic laser-induced breakdown spectroscopy with different pulse energy ratios are studied by using the optical emission spectroscopy (OES) and fast imaging. The energy of the two laser pulses is independently adjusted within 0–30 mJ with the total energy fixed at 30 mJ. The inter-pulse delay remains 450 ns constantly. As the energy share of the first pulse increases, a similar bimodal variation trend of line intensities is observed. The two peaks are obtained at the point where the first pulse is half or twice of the second one, and the maximum spectral enhancement is at the first peak. The bimodal variation trend is induced by the change in the dominated mechanism of dual-pulse excitation with the trough between the two peaks caused by the weak coupling between the two mechanisms. By increasing the first pulse energy, there is a transition from the ablation enhancement dominance near the first peak to the plasma reheating dominance near the second peak. The calculations of plasma temperature and electron number density are consistent with the bimodal trend, which have the values of 17024.47 K, 2.75×1017 cm−3 and 12215.93 K, 1.17 × 1017 cm−3 at a time delay of 550 ns. In addition, the difference between the two peaks decreases with time delay. With the increase in the first pulse energy share, the plasma morphology undergoes a transformation from hemispherical to shiny-dot and to oblate-cylinder structure during the second laser irradiation from the recorded images by using an intensified charge-coupled device (ICCD) camera. Correspondingly, the peak expansion distance of the plasma front first decreases significantly from 1.99 mm in the single-pulse case to 1.34 mm at 12/18 (dominated by ablation enhancement) and then increases slightly with increasing the plasma reheating effect. The variations in plasma dynamics verify that the change of pulse energy ratios leads to a transformation in the dual-pulse excitation mechanism.

Automated Crystal Orientation Mapping by Precession Electron Diffraction-Assisted Four-Dimensional Scanning Transmission Electron Microscopy Using a Scintillator-Based CMOS Detector

The recent development of electron-sensitive and pixelated detectors has attracted the use of four-dimensional scanning transmission electron microscopy (4D-STEM). Here, we present a precession electron diffraction-assisted 4D-STEM technique for automated orientation mapping using diffraction spot patterns directly captured by an in-column scintillator-based complementary metal-oxide-semiconductor (CMOS) detector. We compare the results to a conventional approach, which utilizes a fluorescent screen filmed by an external charge charge-coupled device camera. The high-dynamic range and signal-to-noise characteristics of the detector greatly improve the image quality of the diffraction patterns, especially the visibility of diffraction spots at high scattering angles. In the orientation maps reconstructed via the template matching process, the CMOS data yield a significant reduction of false indexing and higher reliability compared to the conventional approach. The angular resolution of misorientation measurement could also be improved by masking reflections close to the direct beam. This is because the orientation sensitive, weak, and small diffraction spots at high scattering angles are more significant. The results show that fine details, such as nanograins, nanotwins, and sub-grain boundaries, can be resolved with a sub-degree angular resolution which is comparable to orientation mapping using Kikuchi diffraction patterns.

Observational equipment for asteroseismology at the Observatorio Astronómico Nacional San Pedro Mártir: white dwarfs

Here, we describe an implementation of an electron-multiplying charge-coupled device camera to search for seismological activity in white dwarfs (WD). The equipment was installed on the 2.12-m telescope at the Observatorio Astronómico Nacional San Pedro Mártir, Baja California, México. We have determined the proper operational regime to keep a very low noise while maintaining a high gain. We have also developed software for the instrument control system and data processing. Finally, we report the first results on the seismological activity of WD, obtained using photometry with one-second exposure. The results were compared to the known variables LAMOST J004628.31 + 343319.90 and GD 66. The WD 2255-001 showed very weak periodic activity with a dominant frequency of 67 mHz.

The Relationship between Tribo-Magnetization and Wear State during Reciprocating Sliding

In order to investigate the relationship between tribo-magnetization and wear phenomena, a series of sliding-friction tests were carried out using a pin-on-block reciprocator type device, which was specially designed to generate sliding friction and to detect magnetic fields. The tribological behavior was observed by a charge-coupled device (CCD) camera in real time, and the magnetic signal was detected by using a two-axis magnetic sensor. It was found that as the friction continues, both the tangential and the normal components of magnetic field on the material surface increase gradually, and that both the average value of the tangential magnetic field ΔH(x)mean and the peak-to-peak value of the normal magnetic field Vpp at the wear scar clearly reflect changes of the wear state. Furthermore, in order to better understand the tribo-magnetization phenomenon, the changes of surface morphology and wear debris in different wear stages were analyzed. Moreover, an improved magnetic dipole model that considered the distribution of magnetic charges on the worn surface was established. This model can successfully describe the tribo-magnetization phenomenon during the stable wear stage, and should be useful for characterizing frictional wear phenomena in the future.

Optical imaging of decayed positrons and muons with different collimators

Although optical imaging of decayed positrons and muons can provide promising methods, it has been attempted only for muons without a collimator, and the beam characteristics with collimators, such as peak position or beam spread in depth and lateral directions, have not yet been evaluated. Therefore, we conducted optical imaging of decayed positrons and muons with different collimators. For the imaging of decayed positrons, Cherenkov-light imaging in fluorescein (FS) water was used, while imaging of a plastic scintillator block was used for the imaging of muons. We conducted these imaging trials during irradiation with 84.5-MeV/c positive muons to an FS water phantom or a plastic scintillator block using a cooled charge-coupled device (CCD) camera with each collimator of a different diameter attached to the beam port. We could measure the Cherenkov-light images of FS water of decayed positrons and optical images of muons using the plastic scintillator block for all collimators. The depth profiles of the Cherenkov-light images were slightly wider for the muons with the collimators of larger diameters, although the estimated peak depths were nearly the same for all collimators. The lateral profiles of the Cherenkov light were wider for the muons when using collimators of larger diameters. Asymmetry in the directions of positron emissions from the muons was observed for all collimators. The depth profiles of the optical image of muons using a plastic scintillator block had nearly the same shape. The estimated lateral widths of the optical images of the plastic scintillator block were the same sizes as the collimator diameters within a 1.1-mm difference at a 10-mm depth of the scintillator block, and the widths were wider at the Bragg peak. With these measured optical images, we conclude that Cherenkov-light imaging of decayed positrons in water and optical imaging of muons using a plastic scintillator block with collimators are useful methods for determining not only peak position but also beam width as well as the asymmetry of the directions of positron emissions from the muons.

Electrical treeing behavior in XLPE insulation due to content AL2O3 nanoparticles

XLPE is currently commonly used in high voltage underground cables. Several researchers recently chose several nanofillers to improve the electric tree’s strength in the polymer matrix. Alumina AL2O3 nanofiller have been utilized to investigate the effects on the electrical treeing in XLPE. The percentage concentration were used as follows with different amounts “0.3wt.” % and “1wt.”% from weight of base material. The needle-plane electrodes were used in this investigation and gap selected between needle and plane earth is 3 mm. The growth and morphology of treeing in XLPE insulation have been observed by using charge coupled device camera CCDc and microscope system. Scanning of electron microscopes SEM has been investigated the nanoparticles spread in base material. The outcomes show the tree inception voltage TIV values 12.5, and 14.8 KV “0.3wt.” % and “1wt.”%, respectively in XLPE composites that is mean the TIV increase with increase concentration nanofiller, while the tree propagation time at 2mm length increase about 40 min and 2 hours in “0.3wt.” % and “1wt.”% AL2O3/XLPE, respectively compared with unfilled XLPE, as well as the breakdown time BDT enhancement by4.347% and 13.043% for 0.3wt% and 1 wt% nano AL2O3 composites compared with unfilled XLPE insulation. And showed pictures taken with a SEM Diffusion and accumulation of nanoparticles in the XLPE material.

Evaluation of SLE arthritis using frequency domain optical imaging

ObjectivesSystemic lupus erythematosus (SLE) affects the joints in up to 95% of patients. The diagnosis and evaluation of SLE arthritis remain challenging in both practice and clinical trials. Frequency domain...

An Integration Strategy to Develop Dual-State Luminophores with Tunable Spectra, Large Stokes Shift, and Activatable Fluorescence for High-Contrast Imaging

An Integration Strategy to Develop Dual-State Luminophores with Tunable Spectra, Large Stokes Shift, and Activatable Fluorescence for High-Contrast Imaging

First measured optical image of Cerenkov-light in water during irradiation of neutron beam from boron neutron capture therapy (BNCT) system

Optical imaging that detects Cerenkov-light or the luminescence of water is a promising method to measure dose distributions in radiotherapy due to its ability to provide high-resolution images in a short measurement time. However, it is unclear whether optical imaging is possible for neutron beams in water. Although neutrons do not emit light in water, prompt gamma photons or protons produced from the interaction between neutrons and water may emit light. To clarify this point, we measured the light distribution in water during irradiation of neutron beams from a boron neutron capture therapy (BNCT) system and compared the result with that calculated by Monte Carlo simulation. The light distribution was measured in a black box using a cooled charge-coupled device (CCD) camera during irradiation of neutrons to water for 5 s from a cyclotron-based clinical BNCT system. In the measured optical image in water, clear light distribution could be observed during neutron beam irradiation. The depth and lateral profiles of the optical images were well-matched with those calculated by simulation for produced Cerenkov-light by the secondary electrons from prompt gamma photons. The simulated Cerenkov-light was nearly identical to that of the dose for prompt gamma photons. We conclude that the optical imaging of a neutron beam is possible and that it might be used for the dose distribution measurements of prompt gamma photons produced by the nuclear interactions between neutrons and water in addition to the gamma photons from the port and collimator.

Luminescence imaging of non-uniform phantoms during irradiation of protons

Although luminescence imaging during irradiation of protons is a useful method for range and dose estimations, it has only been attempted for uniform phantoms. Since luminescence imaging inherently has high resolution, we will be able to measure the images with non-uniform phantoms. Therefore, we measured the luminescence images for a non-uniform structured acrylic block during irradiation of protons. Imaging was conducted using a cooled charge-coupled device (CCD) camera during the irradiation of 129-MeV protons to an acrylic block with a 10-mm diameter hole in which an acrylic rod, air, or a titanium rod was inserted. Under these three different conditions, we could obtain different luminescence images for protons. The luminescence images with the acrylic rod showed uniform Bragg peaks in the lateral direction. In the luminescence images with air, a part of the Bragg peak under the hole was elongated. In the luminescence images with the titanium rod, the part of the Bragg peak under the hole was shortened. The ranges estimated from the depth profiles of the measured images matched the simulated results within a 1-mm difference. We confirmed that the luminescence imaging of non-uniform phantoms was possible and that ranges could be estimated from the images. We conclude that luminescence imaging is promising not only for uniform phantoms but also non-uniform phantoms.

SAFFNet: Self-Attention-Based Feature Fusion Network for Remote Sensing Few-Shot Scene Classification

In real applications, it is necessary to classify new unseen classes that cannot be acquired in training datasets. To solve this problem, few-shot learning methods are usually adopted to recognize new categories with only a few (out-of-bag) labeled samples together with the known classes available in the (large-scale) training dataset. Unlike common scene classification images obtained by CCD (Charge-Coupled Device) cameras, remote sensing scene classification datasets tend to have plentiful texture features rather than shape features. Therefore, it is important to extract more valuable texture semantic features from a limited number of labeled input images. In this paper, a multi-scale feature fusion network for few-shot remote sensing scene classification is proposed by integrating a novel self-attention feature selection module, denoted as SAFFNet. Unlike a pyramidal feature hierarchy for object detection, the informative representations of the images with different receptive fields are automatically selected and re-weighted for feature fusion after refining network and global pooling operation for a few-shot remote sensing classification task. Here, the feature weighting value can be fine-tuned by the support set in the few-shot learning task. The proposed model is evaluated on three publicly available datasets for few shot remote sensing scene classification. Experimental results demonstrate the effectiveness of the proposed SAFFNet to improve the few-shot classification accuracy significantly compared to other few-shot methods and the typical multi-scale feature fusion network.