CCD Camera Research Articles

Characterization of OH species in kHz air/H2O atmospheric pressure dielectric barrier discharges

Abstract This work numerically studies densities and mechanisms of OH species generated in atmospheric-pressure air dielectric barrier discharges with the model validated by experiments. The power consumption is measured, and the number of microdischarges (MDs) generated within a half period is captured by an intensified CCD camera. The OH densities of cases with various H2O concentrations are measured using ultraviolet absorption spectroscopy. The numerical model integrating the 1.5D discharge fluid model and 3D background gas model (BGM) is adopted to predict the MD behavior and the generation of species related to OH generation. The simulated OH densities cover the range of 1.1×10^19 and 1.6×10^19 m-3 in the cases studied, agreeing with those measured. The simulated results show that most OH radicals are generated in MDs, while the reactive section contributes around 2% of the total OH generation. The detailed analysis shows that atomic oxygen (O(1D) and O) and O3 contribute most of the OH generation in the MDs. In contrast, the self-association reactions (i.e., 2OH + M → H2O2 + M and 2OH → O + H2O) and NOx species consume more than 64% of OH radicals generated in MDs. In the BGM, it is interesting to find that reactive species NOx play significant roles in both the OH generation and depletion in the reactive section. The distributions of species related to the OH species obtained by the BGM are presented to elucidate the detailed chemistry of OH species in the reactive section.

Static Mode Testing of S-20 Optical Streak Camera

The spectral response of the S-20 streak camera ranges from 350 to 850 nanometers. The streak camera consists of a streak tube and an image intensifier tube followed by a CCD camera. The optical streak camera can be operated in three modes viz. static mode, gated mode, and dynamic mode. In static mode, various electrodes are checked by applying suitable DC voltages For this purpose, a high-voltage biasing network is developed. Gated mode operation is introduced to improve signal-to-noise ratio. So, the Micro Channel Plate (MCP) of the image intensifier tube will be activated with the gated signal.

Vignetting Compensation Method for CMOS Camera Based on LED Spatial Array

To solve the problem of pixel light intensity information distortion caused by camera vignetting in optical devices such as CMOS or CCD cameras, existing studies mainly focus on small spatial light fields and point light sources and adopt an integrating sphere and function model for vignetting correction, but it is not suitable for large LED optical composite display devices. Under this background, this paper innovatively proposes a camera vigneting compensation method based on an LED spatial array, independently develops a two-dimensional translation device driven by a high-precision guide rail, uses spatial array technology to obtain the brightness distribution of the corrected display screen to quantify its camera vigneting distortion characteristics, and adopts systematic mathematical operations and iterative compensation strategies. Industry standard tests show that the brightness uniformity of the display has been improved by 5.06%. The above research results have been applied to mass production and industrialization.

Single shot depth-resolved imaging through dynamic turbid media

Guide star assisted wavefront shaping techniques have been exploited for focusing and imaging through turbid media by addressing a scatter inverse pattern. However, the turbid medium is required to be steady before finding the proper correction pattern, which limits applications in focusing and imaging through dynamic media, such as turbid water or blood. This study proposes a holography-based dual-polarization computational wavefront shaping method for imaging objects at variant depths behind dynamic turbid media. The orthogonal polarized output speckles of a point source (considered as a guide star) and an object are simultaneously recorded in holograms in separate regions of a single CCD camera. The holograms of the point source and object are subjected to the same distortion regardless of whether the media is static or dynamic. The hologram of the point source is used to determine the correction phase pattern for the distortion, while that of the object is used to record the complex scattered wavefront of the object. To reconstruct a clear object image, the wavefront of the scattered object is digitally corrected using the correction phase pattern and is then transferred to the image plane by calculating the transmission of the angular spectrum. Benefiting from the autofocusing feature of digital holography, objects at different depths can be recovered from a single shot hologram pair. The potential applications of the proposed method in diverse dynamic scattering media are demonstrated by imaging through a moving diffuser, turbid water, and pig blood with optical depth beyond 10.

Spexin Diminishes Atrial Fibrillation Vulnerability by Acting on Galanin Receptor 2.

G protein-coupled receptors play a critical role in atrial fibrillation (AF). Spexin is a novel ligand of galanin receptors (GALRs). In this study, we investigated the regulation of spexin and GALRs on AF and the underlying mechanisms. Global spexin knockout (SPX-KO) and cardiomyocyte-specific GALRs knockout (GALR-cKO) mice underwent burst pacing electrical stimulation. Optical mapping was used to determine atrial conduction velocity and action potential duration. Atrial myocyte action potential duration and inward rectifying K+ current (IK1) were recorded using whole-cell patch clamps. Isolated cardiomyocytes were stained with Fluo-3/AM dye, and intracellular Ca2+ handling was examined by CCD camera. A mouse model of AF was established by Ang-II (angiotensin II) infusion. Spexin plasma levels in patients with AF were lower than those in subjects without AF, and knockout of spexin increased AF susceptibility in mice. In the atrium of SPX-KO mice, potassium inwardly rectifying channel subfamily J member 2 (KCNJ2) and sarcolipin (SLN) were upregulated; meanwhile, IK1 current was increased and Ca2+ handling was impaired in isolated atrial myocytes of SPX-KO mice. GALR2-cKO mice, but not GALR1-cKO and GALR3-cKO mice, had a higher incidence of AF, which was associated with higher IK1 current and intracellular Ca2+ overload. The phosphorylation level of CREB (cyclic AMP responsive element binding protein 1) was upregulated in atrial tissues of SPX-KO and GALR2-cKO mice. Chromatin immunoprecipitation confirmed the recruitment of p-CREB to the proximal promoter regions of KCNJ2 and SLN. Finally, spexin treatment suppressed CREB signaling, decreased IK1 current and intracellular Ca2+ overload, which thus reduced the inducibility of AF in Ang-II-infused mice. Spexin reduces atrial fibrillation susceptibility by inhibiting CREB phosphorylation and thus downregulating KCNJ2 and SLN transcription by GALR2 receptor. The spexin/GALR2/CREB signaling pathway represents a novel therapeutic avenue in the development of agents against atrial fibrillation.

Building Height Extraction Based on Satellite GF-7 High-Resolution Stereo Image

Abstract. High-resolution remote sensing images can distinguish objects of smaller size, so as to more clearly express the texture features and structural information of objects, and provide a data source for the development of large-scale mapping, high-precision stereo measurement and other fields. The purpose of this paper is to complete the height estimation of the buildings by analyzing the stereoscopic observation formed by the front and rear view images of the Gaofen-7 line array CCD. After determining the roof profile of the building on the rear-view image, assuming a series of object elevations of the building, that is, searching for elevations with a certain step distance within a certain elevation search range, adopt the object-based image matching VLL algorithm, Through the RFM imaging model of the Gaofen-7 sensor, the rear-view contour is projected to the front-view image, and then the PSNR is selected as the similarity measure of the window, and the similarity of the image block area corresponding to the front- and rear-view contour is calculated. Corresponds to the hypothetical object elevation as the estimated height of the building. Under the technical route of this paper, the height of buildings on high-resolution images can be estimated to a level within 3 meters of accuracy.

Surface Defect Detection of Aluminum Profiles Based on Multiscale and Self-Attention Mechanisms.

To address the various challenges in aluminum surface defect detection, such as multiscale intricacies, sensitivity to lighting variations, occlusion, and noise, this study proposes the AluDef-ClassNet model. Firstly, a Gaussian difference pyramid is utilized to capture multiscale image features. Secondly, a self-attention mechanism is introduced to enhance feature representation. Additionally, an improved residual network structure incorporating dilated convolutions is adopted to increase the receptive field, thereby enhancing the network's ability to learn from extensive information. A small-scale dataset of high-quality aluminum surface defect images is acquired using a CCD camera. To better tackle the challenges in surface defect detection, advanced deep learning techniques and data augmentation strategies are employed. To address the difficulty of data labeling, a transfer learning approach based on fine-tuning is utilized, leveraging prior knowledge to enhance the efficiency and accuracy of model training. In dataset testing, our model achieved a classification accuracy of 97.6%, demonstrating significant advantages over other classification models.

Visible camera-based diagnostic to study negative ion beam profiles in ROBIN ion source

Ensuring ion beam quality is of prime importance concerning the design of large-size neutral beam injectors(NBIs). Homogeneity, divergence, and beam energy are three crucial parameters defining beam quality. ROBIN(RF-Operated Beam source in India for Negative ions) source is one such prototype for extracting H− ion beam from hydrogen plasma. The extracted beam interacts with background neutrals and emits photons. These emissions are proportional to current density and the visible range emissions are used to characterize the beam using CCD cameras. The observed vertical emission profiles depict Gaussian-type asymmetric wings with a tilted flat-top that suggest non-uniform beam groups from the two grid segments. Divergence data extracted from the camera decreases with the acceleration voltage sweep. A strong correlation of the camera divergence data with calorimeter measurements was observed. A numerical beam model is in development to provide more insight into this correlation and pave the way to study beam group interaction.

Time-resolved observation of 150 kHz high-power pulse burst high-frequency discharge using a high-speed video camera and an intensified charge coupled device camera

The discharge phase and time evolution of a 150 kHz high-power pulse burst discharge were observed. A vacuum chamber was constructed by connecting glass tubes on which a solenoid coil was wound. Burst pulses with a width of 1000 μs and a repetition rate of 10 Hz were applied to the solenoid coil. A high-speed video camera and an intensified CCD camera were used to record photographs of the discharges. Observation of the discharge phase using a high-speed camera showed that the discharge occurs at the time of 40 μs and propagates from the wall of the cylindrical reactor. Over time, the discharge pattern evolves, and a branched pattern appears. The number of the branches changes with time. The discharge blinks synchronize with the instantaneous power, which suggests that the discharge is generated and maintained by the electrostatic field generated by the sides of the coil. The propagation velocity calculated from downstream decreases with increasing pressure and increases with increasing power.

Clemastine as a Main Sedative Drug in Colonoscopy

Background: Colonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber-optic camera on a flexible tube passed through the anus. It can provide a visual diagnosis. Methods: In this study, clemastine plus fentanyl was compared with fentanyl plus midazolam in analgesia during colonoscopy. Patients were monitored for pain and hemodynamic changes. The mean age in the group treated with clemastine was 52 years and in the group treated with midazolam was 54 years. There were 56 males and 35 females in the study. There was no significant difference in gender in the two groups. Systolic blood pressure was 109.9 mmHg before and 109.35 mmHg after clemastine administration, which showed no significant difference. Results: Diastolic blood pressure was 72.2 mmHg before and 73.7 mmHg after clemastine administration, which showed no significant difference. No change in mean pulse rate (PR) was seen (84/min before and after clemastine administration). In the group receiving midazolam, systolic and diastolic blood pressure changes were not significant, but changes in PR and arterial oxygen saturation were significantly different. Meanwhile, the two groups had a significant lower pain level after colonoscopy in the group receiving clemastine compared to midazolam. Conclusion: Based on the results of the present study, clemastine can be used as a main drug for sedation during colonoscopy.

Real-time monitoring of the pH of white wine and beer with colorimetric sensor arrays (CSAs)

The real-time monitoring of the pH values of alcoholic beverages was performed with a compact wireless device based on a colorimetric detection method with the Hue (H) as the analytical signal working in a pH range of 2.50–6.50. This device represents the first colorimetric pH meter reported in the literature monitoring in real-time the pH value of colored solutions. This pH meter consists of I) a nitrocellulose membrane impregnated with a pH-sensitive gel; II) a CCD camera for color acquisition; III) an electronic board with the calibration profiles of H vs. pH, and IV) a display to read the measured pH. It was applied to the pH determination of a white wine, a prosecco white wine, and a double malt beer leading to the values of pHwine= 3.30, pHprosecco= 3.33, pHbeer = 4.29. The analytical performance is comparable to the glass electrode with an accuracy error ≤ 0.05 pH units.

Quality evaluation of eggs during shelf-life ambient storage by laser speckle technique

Laser speckle technique is non-destructive, cost-effective with a simple experimental setup, and has been used in the field of agriculture, food processing, medicines etc. A coherent laser source, CCD Camera, and a recording system are needed to record the speckle image. Our objective of this work is to both quantify and visualize the quality of chicken eggs using the non-destructive Laser speckle technique and also to verify the outcomes with other established destructive techniques such as calculation of Haugh Unit (HU), Yolk Index (YI), PH value etc. In this work, we have done the single exposure speckle image as well as the biospeckle activity analysis of eggs stored under ambient conditions at room temperature (29±3°C) for seven days of shelf-life storage. We have approached a new probabilistic method to quantify a single exposure speckle image and the Frequent Motion Image (FMI) method to construct the speckle activity map of the egg's internal constituents. As a result, we have found that the biospeckle activity of eggs decreased by 24–38% after seven days, its internal activity map changed significantly. An egg on the first day of storage shows high biospeckle activity compared to other days. For the single exposure speckle image, the calculated Average energy decreased by 40–60%, and Entropy increased by 10–15%, with significant differences for each day during seven days of shelf storage. The average HU decreases by around 15%, and the YI decreases by 10% during seven days of ambient storage.

Non-Destructive Single-Revolution Electron Beam Profilometer based on a CCD Camera

Non-Destructive Single-Revolution Electron Beam Profilometer based on a CCD Camera

Classification of laser beam profiles using machine learning at the ELI-NP high power laser system

The high power laser system at Extreme Light Infrastructure—Nuclear Physics has demonstrated 10 PW power shot capability. It can also deliver beams with powers of 1 PW and 100 TW in several different experimental areas that carry out dedicated sets of experiments. An array of diagnostics is deployed to characterize the laser beam spatial profiles and to monitor their evolution during the amplification stages. Some of the essential near-field and far-field profiles acquired with CCD cameras are monitored constantly on a large screen television for visual observation and for decision making concerning the control and tuning of the laser beams. Here, we present results on the beam profile classification obtained from datasets with over 14 600 near-field and far-field images acquired during two days of laser operation at 1 PW and 100 TW. We utilize supervised and unsupervised machine learning models based on trained neural networks and an autoencoder. These results constitute an early demonstration of machine learning being used as a tool in the laser system data classification.

Particle-resolved hyperspectral pyrometry of metal particles

We present temperature histories of individual combusting metal particles using hyperspectral pyrometry. This method gives an increase in accuracy over traditionally used two- or three-color pyrometry, while maintaining temporal and spatial resolution. Temperatures can be determined between 1800 to >3000 K with a precision of typically <1%. It is shown that the maximum temperature of the burning iron particles increases from 2760 K to 2840 K with an increasing mean particle size from 32 to 54 μm in air with 21 % oxygen. The relatively high temperatures and its dependence on particle size are possibly related to flow field properties of the current experimental setup. Opportunities for this method, as well as future work, are discussed.Novelty and Significance Statement: In this article, a method to use a CCD camera and spectrograph as a hyperspectral detector, gaining a wavelength dimension while maintaining two spatial dimensions, is demonstrated and validated. This method is applied to measure the temperature of iron particles, a carbon free and circular energy carrier. This method is then used to prove that there is a particle size dependence on the maximum temperature, an open question which is often disputed in literature. This work will also add a dataset that can be used for the validation of numerical models. There are only two such datasets available for iron at this moment. Our analysis suggests that the heat release of iron is dependent on the slip velocity, possibly due to a circulating flow inside of the particle.

An experimental platform for investigation of the Zeeman effect in strong magnetic fields.

An experimental platform is developed for the investigation of the Zeeman effect in strong magnetic fields. Mega-Gauss magnetic fields are generated by a 1 MA Zebra pulsed power machine using metal rod loads. A gas jet or CH oil on the load is the source of hydrogen. Excited hydrogen atoms are backlit by black body radiation from the rod load. Hydrogen absorption spectra are recorded with a grating spectrometer and intensified gated CCD camera. The experimental platform enables the observation of the quadratic Zeeman effect in hydrogen gas jets using the spectral shift of the central line in the Zeeman triplet. Other gases can be studied using the gas jet method.

Contrastive Analysis of Interferometric Techniques for Small Channel Temperature Measurements

This research employs a state-of-the-art digital interferometric technique to investigate the temperature distribution within a confined rectangular channel, with a hydraulic diameter of 3 mm. The experimental setup incorporates an optical glass channel, with nanofluids (Aluminium oxide) as the test fluid at 0.001% volume concentration. To induce controlled heating, a heater filament is strategically placed along the bottom wall of the channel. Simultaneously, a T-type thermocouple is carefully placed to measure the temperature along the upper wall. Two distinct interferometric methods, namely the Michelson interferometer and the Mach-Zehnder interferometer, are employed to capture the complex details of fringes resulting from the evolving temperature field within the test section. A high-resolution CCD camera is employed to capture these fringes, and sophisticated digital image processing techniques are subsequently applied for in-depth fringe analysis. The culmination of these efforts results in the origin of a comprehensive localized temperature distribution map within the small-sized channel. The obtained temperature profiles are meticulously compared, providing valuable insights into the effectiveness and reliability of the Michelson and Mach-Zehnder interferometric techniques in this specific experimental context. This detailed comparative analysis contributes to the broader understanding of interferometric methods for temperature measurements in confined fluidic systems.

Fresnel–Arago laws: an easily feasible demonstration and laboratory exercise for students

The basic premise of this work was to create a simple experimental setup for the demonstration of Fresnel–Arago laws and the realization of an experimental exercise. An Iceland calcite is used as a beam splitter, and by adding a diverging lens (commonly used to magnify the image), a large image of overlapping spots is obtained at a short distance, visible to a wide audience. Additionally, by placing a diverging lens at different distances from the calcite, the level of the spots overlapping can be changed. The interference image is photographed by a smartphone and processed by one of the available applications for quantitative image processing. The experiment was carried out using red and green laser light. The same setup, with a diverging lens, also allows the reconstruction of the original Fresnel and Arago experiment with a thin metal cylinder. Quick and easy construction, relatively simple processing of the interference image, without the use of expensive devices (CCD camera, beam splitter, beam expander), and the good agreement between the nominal and measured laser light wavelengths, make this setup very suitable for realization as a student exercise for undergraduate and master’s students.

Deep Learning-Based Inkjet Droplet Detection for Jetting Characterizations and Multijet Synchronization.

Inkjet printing is a powerful direct material writing process. It can be used to deposit microfluidic droplets in designated patterns at submicrometer resolution, which reduces materials usage. Nonetheless, predicting jetting characterizations is not easy because of the intrinsic complexity of the ink-nozzle-air interactions. Thus, inkjet processes are monitored by skilled engineers to ensure process reliability. This is a bottleneck in industry, resulting in high labor costs for multiple nozzles. To address this, we present a deep learning-based method for jetting characterizations. Inkjet printing is recorded by an in situ CCD camera and each droplet is detected by YOLOv5, a 1-stage detector using a convolutional neural network (CNN). The precision, recall, and mean average precision (mAP) at a 0.5 intersection over the union (IoU) threshold of the trained model were 0.86, 0.89, and 0.90, respectively. Each regression result for a detected droplet is accumulated in chronological order for each class of droplet and nozzle. The quantified information includes velocity, diameter, length, and translation, which can be used to synchronize multinozzle jetting and, eventually, the printed patterns. This demonstrates the feasibility of autonomous real-time process testing for large-scale electronics manufacturing, such as the high-resolution patterning of biosensor electrodes and QD display pixels while exploiting big data obtained from jetting characterizations.

Novel frameless LINAC radiosurgery solution for uveal melanoma.

Radiation treatment has replaced enucleation as an organ-preservation treatment for patients with uveal melanoma (UM). We developed a novel non-invasive, frameless LINAC based solution for fractionated stereotactic radiosurgery (fSRS) treatment. We designed and constructed the a stereotactic ocular localization box that can be attached and indexed to a stereotactic LINAC tabletop. It contains adjustable LED lights as a gaze focus point and CCD camera for monitoring of the patient's eye position. The device also has 6 infrared spheres compatible with the ExacTRAC IGRT system. Treatment plans were developed using iPLAN Dose version 4.5, with conformal dynamic arcs and 6MV photon beam in flattening filter free mode, dosed to 50Gy in 5 fractions. During treatment, patients were instructed to stare at the light when a radiation beam is prepared and ready for delivery. Eye movement was tracked throughout treatment. Residual setup errors were recorded for evaluation. The stereotactic ocular localization box was 3D-printed with polylactic acid material and attached to the stereotactic LINAC tabletop. 10 patients were treated to evaluate the feasibility, tolerability and setup accuracy. Median treatment time for each arc is 17.3 ± 2.4 seconds (range: 13.8-23.4). After ExacTRAC setup, the residual setup errors are -0.1 ± 0.3mm laterally, -0.1 ± 0.3mm longitudinally, and 0 ± 0.2mm vertically. The residue rotational errors are -0.1 ± 0.3 degree pitch, 0.1 ± 0.2 degree roll, and 0 ± 0.2 degree couch rotation. All patients received treatment successfully. We successfully developed a novel non-invasive frameless mask-based LINAC solution for SRS for uveal melanoma, or other ocular tumors. It is well tolerated with high set up accuracy. Future directions for this localization box would include a multi-center trial to assess the efficacy and reproducibility in the fabrication and execution of such a solution for UM therapy.