Fast Data Acquisition Research Articles

Fabrication of self-actuated piezoresistive thermal probes

The fabrication and characterization of the novel thermal sensitive probes presented here are established on a well-known physical effect of the electrical resistivity changes of a nanometric metal (Au or Pt) filament. The filament is fabricated from the high aspect ratio (1:4) silicon AFM cantilever tip (approximately 3–5μm high) covered by a metal layer (approximately 50nm thick), but keeping its tip diameter of about 20nm. Therefore, a focused ion beam (FIB) milling process is used to remove the silicon underneath the metal coating of the tip in order to increase the thermal and electrical resistance. Silicon is milled away very precisely with ion beam settings of only 69pA beam current and 30kV acceleration voltage. As a result, the electrical resistance of the metal filament increases in the order of 5–6 times in comparison to its original value (≈25Ω). The new probe tip is undergoing a vast resistance change with the slightest temperature fluctuations measured at the tip apex. Typical characteristic thermal sensitivity (SA) value of the sensor is measured to be SA=40±4nm/mW. In addition, AFM thermal probe has a full Wheatstone bridge integrated, which is used for an ultra-sensitive and non-optical deflection read out. Deflection sensitivity (SV) of the thermal probes is measured to be SV=9±0.5μV/nm. This self-sensing method allows recording simultaneously data about the topography, as well as the thermal properties of the sample’s surface. Therefore the probe is operating in a contact mode. Thermally-calibrated sensors are implemented in a measurement setup, which includes self-developed electronics connected to a lock-in amplifier for a fast data acquisition. The novel approach is the combination of CMOS technology, bulk and surface micromachining with advanced FIB milling processes to fabricate unique nanoprobes with a thermal resolution of 10−3K.

A cooled CCD camera-based protocol provides an effective solution for in vitro monitoring of luciferase

Luciferase assay has become an increasingly important technique to monitor a wide range of biological processes. However, the mainstay protocols require a luminometer to acquire and process the data, therefore limiting its application to specialized research labs.To overcome this limitation, we have developed an alternative protocol that utilizes a commonly available cooled charge-coupled device (CCCD), instead of a luminometer for data acquiring and processing. By measuring activities of different luciferases, we characterized their substrate specificity, assay linearity, signal-to-noise levels, and fold-changes via CCCD. Next, we defined the assay parameters that are critical for appropriate use of CCCD for different luciferases. To demonstrate the usefulness in cultured mammalian cells, we conducted a case study to examine NFκB gene activation in response to inflammatory signals in human embryonic kidney cells (HEK293 cells). We found that data collected by CCCD camera was equivalent to those acquired by luminometer, thus validating the assay protocol. In comparison, The CCCD-based protocol is readily amenable to live-cell and high-throughput applications, offering fast simultaneous data acquisition and visual and quantitative data presentation.In conclusion, the CCCD-based protocol provides a useful alternative for monitoring luciferase reporters. The wide availability of CCCD will enable more researchers to use luciferases to monitor and quantify biological processes.

LiDAR Strip Adjustment Using Multifeatures Matched With Aerial Images

Airborne light detecting and ranging (LiDAR) systems have been widely used for the fast acquisition of dense topographic data. Regrettably, coordinate errors always exist in LiDAR-acquired points. The errors are attributable to several sources, such as laser ranging errors, sensor mounting errors, and position and orientation system (POS) systematic errors, among others. LiDAR strip adjustment (LSA) is the solution to eliminating the errors, but most state-of-the-art LSA methods neglect the influence from POS systematic errors by assuming that the POS is precise enough. Unfortunately, many of the LiDAR systems used in China are equipped with a low-precision POS due to cost considerations. Subsequently, POS systematic errors should be also considered in the LSA. This paper presents an aerotriangulation-aided LSA (AT-aided LSA) method whose major task is eliminating position and angular errors of the laser scanner caused by boresight angular errors and POS systematic errors. The aerial images, which cover the same area with LiDAR strips, are aerotriangulated and serve as the reference data for LSA. Two types of conjugate features are adopted as control elements (i.e., the conjugate points matched between the LiDAR intensity images and the aerial images and the conjugate corner features matched between LiDAR point clouds and aerial images). Experiments using the AT-aided LSA method are conducted using a real data set, and a comparison with the three-dimensional similarity transformation (TDST) LSA method is also performed. Experimental results support the feasibility of the proposed AT-aided LSA method and its superiority over the TDST LSA method.

철강공정 배기가스로부터 가스 하이드레이트 형성에 미치는 촉진제의 영향

본 연구에서는 가스 하이드레이트 기술을 이용하여 철강 공정 배기가스로부터 <TEX>$CO_2$</TEX>를 분리하는데 사용하는 여러 촉진제의 성능을 조사하였다. 이 실험에서는 <TEX>$CO_2/N_2$</TEX> 혼합가스 (<TEX>$CO_2/N_2$</TEX>=20/80, 40/60)와 <TEX>$CO_2/N_2$</TEX> 이외에 CO, <TEX>$H_2$</TEX>가 첨가된 Blast furnace gas (BFG) 모델 가스를 대상 가스로 사용하였다. 촉진제로는 구조 II 하이드레이트를 형성한다고 알려진 tetrahydrofuran (THF), propylene oxide, 1,4-dioxane 를 사용하였으며, 각 가스에 대하여 촉진제를 농도별로 첨가했을 때 상평형점의 변화를 측정하였다. 상평형점은 "연속" Quartz crystal microbalance (QCM) 방식을 이용하였다. 또한, Powder X-ray diffraction (PXRD) 분석을 통하여 촉진제의 첨가가 가스 하이드레이트 구조에 미치는 영향을 알아보았다. In this work, the performance of various promoters was investigated used in <TEX>$CO_2$</TEX> separation from the gases emitted from steel-making process using gas hydrate technology. The studied promoters are tetrahydrofuran (THF), propylene oxide and 1,4-dioxane, which are all expected to form a structure II hydrate, and the target gases include <TEX>$CO_2/N_2$</TEX> mixed gases (<TEX>$CO_2/N_2$</TEX> = 20/80 and 40/60) and Blast Furnace Gas (BFG). The phase equilibrium points were measured when each promoter was added with various concentrations. For fast acquisition of abundant data, the "continuous" Quartz crystal microbalance (QCM) method was employed. In addition, the crystal structure of each gas hydrate was analyzed by Powder X-ray diffraction (PXRD).

Simulation Study on Iterative Reconstruction Method for Time-Correlation Magnetic Particle Imaging With Continuous Trajectory Scan

Magnetic particle imaging (MPI) is a medical imaging technology suitable for noninvasive diagnostics. However, in conventional image reconstruction methods, due to either noise or the reconstruction method itself, the reconstructed image quality degrades. In order to suppress this problem, we improved the time-correlation MPI method that we had previously proposed. Specifically, this method iteratively corrects image blurring by reducing the difference between the observed signals from magnetic nanoparticles and the analytically calculated waveforms for the reconstructed image generated with the time-correlation method. Using numerical simulation, we evaluate the effectiveness of this method in conjunction with the continuous scan technique, which makes fast data acquisition possible.

Data Collection and Processing Instrumentation for Time-of-Flight Mass Spectrometry and Ion Mobility Time-of-Flight Mass Spectrometry

Data processing characteristics can significantly affect reliability of obtained results. Here we discuss two recently developed data collection instruments based on analog-to-digital converters. The first instrument is based on three 500MHz 12 bit ADC and used for extended dynamic range measurements. Based on 667MHz 8 bit ADC the second one allows fast 3D data acquisition. The instruments were used for time-of-flight mass spectrometry and ion mobility TOF mass spectrometry fast data acquisition and processing.

Microwave Stepped Frequency Head Imaging Using Compressive Sensing With Limited Number of Frequency Steps

Compressive sensing (CS) can be used to recover sparse data (signal) from limited measurements by solving a constrained convex optimization problem. If this approach is applied on microwave stepped frequency imaging technique, the required number of frequency steps to get clear images can be significantly reduced resulting in simple systems with fast data acquisition and real time results. To that end, three different CS techniques are applied on head imaging systems aiming at the detection of brain injuries by utilizing the sparse characteristic of the correlated time domain scattered signals. The presented measured results using a head imaging system indicate that the time domain correlation signals are indeed sparse and thus can be recovered using a limited number of frequency steps. Those recovered signals are then used to successfully generate clear images that show brain injuries. A comparison between using the proposed and the traditional approaches using two quality metrics indicates superiority of the presented CS-based approach in not just the limited needed frequency steps, but also in the quality of the obtained images.

Photoacoustic microscopy by scanning mirror-based synthetic aperture focusing technique

Photoacoustic imaging with a synthetic aperture focusing technique (SAFT) is an effective method to improve the lateral resolution for out-of-focus regions in scanning microscopy systems, which commonly require a decent motorized scanning stage for a lateral scan of a transducer to obtain a cross-sectional image. In this study, we propose and test a photoacoustic imaging system with a scanning mirror-based SAFT (SM-SAFT) for simple and fast data acquisition, without the need for a physical scan of the transducer. Photoacoustic images of hair phantoms acquired by SM-SAFT are demonstrated, serving as a proof-of-concept experiment to show the feasibility and potential of the proposed approach.

Frontiers ofin situelectron microscopy

Abstract

Fatigue Testing of Continuous GFRP Composites Using Digital Image Correlation (DIC) Technique a Review

Usage of Glass Fiber Reinforced Polymeric (GFRP) composites is increasing drastically in many fields from Aerospace to Sporting good due to light weight and low cost. An effective design of GFRP composites requires detailed understanding of material and the way of testing. Fatigue is the single largest failure that occurs in composites suddenly without any warning, and this failure is catastrophic in nature. In the past years the composites were tested under fatigue loads so that the fatigue behavior can be identified. But this can’t detect the crack behavior of material at the time of testing which is a very important phenomena in identifying the stress concentration of the material. This paper discusses the application of Digital Image Correlation (DIC) technique for fatigue testing of GFRP material in order to capture anisotropic damage. DIC is a non-contact and non–destructive unique exploring full field optical method used to measure accurate displacement, surface strains usually called as speckle pattern for anisotropic material undergoing motion and deformation. In this paper we explained DIC by using Newton- Rapshon (NR) correlation analysis. DIC technique uses high speed, high resolution and accurate Charge-Coupled device (CCD) cameras for measuring displacement components on the surface of the testing material having speckle patterns. Images were captured at the time of testing at every stress cycle and these deformed patterns were correlated with a reference pattern and determining the displacements of the so called subsets. Because of fast data acquisition this technique is well suited for characterization of material properties.

Compressive Sensing: Real-time Data Acquisition and Analysis for Biosensors and Biomedical Instrumentation

The rapid growth of sensors for a vast number of applications have required that CPU and processors be applied as part of the data acquisition systems for a number of applications including communication, position tracking, health care monitoring, environmental changes, and transportation. In addition, the advances in nanometer electronic systems, compressive sensing (CS) [1-11] based information processing, and stream computing technologies provide great potential in creating novel hardware/software platforms and having fast data acquisition capability. Driven by these new technology developments, it is possible to develop a high speed “Adaptive Design for Information” (ADI) system that leverages the advantages of featurebased data compression, low power nanometer CMOS technology, and stream computing for biomedical instrumentation.

Degradation Assessment of Industrial Composites Using Thermography

Thermographic inspection is a relatively new technique for Non-Destructive Testing (NDT) which has been gathering increasing interest due to its relatively low cost hardware and extremely fast data acquisition properties. This technique is especially promising in the area of rapid automated damage detection and quantification. In collaboration with a major industry partner from the aerospace sector advanced thermography-based NDT software for impact damaged composites is introduced. The software is based on correlation analysis of time-temperature profiles in combination with an image enhancement process. The prototype software is aiming to a) better visualise the damages in a relatively easy-to-use way and b) automatically and quantitatively measure the properties of the degradation. Knowing that degradation properties play an important role in the identification of degradation types, tests and results on specimens which were artificially damaged have been performed and analyzed.

On-line visualization of multicolor chemical images with stimulated Raman scattering spectral microscopy.

We demonstrate multicolor, on-line visualization in label-free biomedical microscopy based on stimulated Raman scattering (SRS). Fast data acquisition of SRS spectral images and subsequent image generation are achieved. The loading vectors for the blind separation of chemical components are predetermined by multivariate analysis at a certain field of view (FOV) and are applied to execute on-line visualization of chemical images at other FOVs. We also show that the response time can be shortened by reducing the number of spectral data points. This on-line visualization system is expected to increase the usability of the Raman imaging system and the analytical throughput for screening.

Key Techniques of Fast Photographic Geological Logging in Exploration Tunnel

Because of the special geometric shape and narrow space of exploration tunnel, field geological logging in exploration tunnels has always been staying at manual drafting stage with low efficiency and low level of informatization. This paper studies the existing issues of photographic geological logging in exploration tunnel, including the control method, image acquisition method, geometric correction of original images and the generation of display images, etc. This paper realizes fast acquisition and processing of the image data of geological logging, meeting the accuracy requirement of photographic geological logging in exploration tunnels, filling the vacancy of photographic geological logging technologies in exploration tunnels, improving the efficiency, level of automation and informatization of geological logging in exploration tunnels.

Fast Data Acquisition of Aerial Images Using Unmanned Aerial Vehicle System

The present work discusses the technique and methodology of analysing the potential of fast data acquisition of aerial images using unmanned aerial vehicle system. This study utilizes UAV system for large scale mapping by using digital camera attached to the UAV. UAV is developed from the low-altitude photogrammetric mapping to perform the accuracy of the aerial photography and the resolution of the image. The Ground Control Points (GCPs) and Check Points (CPs) are established using Rapid Static techniques through GPS observation for registration purpose in photogrammetric process. The GCPs is used in the photogrammetric processes to produce photogrammetric output while the CP is employed for accuracy assessment. A Pentax Optio W90 consumer digital camera is also used in image acquisition of the aerial photograph. Besides, this study also involves image processing and map production using Erdas Imagine 8.6 software. The accuracy of the orthophoto is determined using the equation of Root Mean Square Error (RMSE). The final result from orthophoto is compared to the ground survey using total station to show the different accuracy of DEM and planimetric survey. It is discovered that root mean square errors obtained from UAV system are ± 0.510, ± 0.564 and ± 0.622 for coordinate x, y and z respectively. Hence, it can be concluded that the accuracy obtained from UAV system is achieved in sub meter. In a nutshell, UAV system has potential use for large scale mapping in field of surveying and other diversified environmental applications especially for small area which has limited time and less man power.

Investigation of the computational efficiency and validity of the surface response to excitation method

The Surface Response to Excitation (SuRE) method excites the surface of the structure with a piezoelectric element. The generated vibrations at critical points on the surface are measured with other piezoelectric elements, a laser vibrometer or other sensors. Then the magnitude of the transfer function between the excitation and the sensory signal is monitored. The performance of the SuRE method was evaluated using a low cost Digital Signal Processor (DSP) system, spectrum analyzer, and laser vibrometer. The accuracies of the Teager–Kaiser (TKA), Goertzel, RMS and average of the positive values algorithms were evaluated for magnitude estimation. The SuRE method was employed successfully for detection of compression loads by using the DSP system. Existence of composite coating was inspected using a spectrum analyzer. Finally, the method was used to detect localized loads on an aluminum plate with a laser vibrometer. The study indicated that the SuRE method may be used as a low cost alternative to impedance method. The inconvenience of using separate sensor(s) is the disadvantages of the SuRE method respect to the impedance method. The main advantages are requirement of simpler and cheaper instrumentation for data analysis, defect location estimation capability when multiple sensors are used, faster data acquisition at low noise environments, and allowing non-contact sensors such as laser vibrometers for measurement of surface response.

A system of detection and data acquisition for time-of-flight neutron diffraction setups

A simple system of neutron detection and data acquisition is considered. It is composed of sector sets of 3He counters, timing amplifiers-discriminators, 8-stop time-to-digital converters (TDCs), and a gate duration generator, as well as branch and crate controllers coupled to a computer. The system is used in neutron diffraction setups on the neutron spallation source at the Institute for Nuclear Research. The output pulse from the timing amplifier-discriminator is timed with the fast electron component of an avalanche in the detector. Neutron time-of-flight spectra are formed by a TDC in its embedded memory over the recording enable time ranging from 1 to 63 ms. The TDC time range has 4096 gradations with time step of 0.125–128 μs. Fast data acquisition is ensured by the Linux kernel driver. The data acquisition software based on the Qt4 library recognizes modules in the CAMAC crate and displays spectra with their preliminary processing.

Multilayer Thickness Determination Using Continuous Wave THz Spectroscopy

We present a multilayer thickness measurement system based on optoelectronic continuous wave THz spectroscopy. Due to its wide tuning range, high frequency resolution, and fast data acquisition the system combines micrometer precision with short measurement time. In addition, the presented system is not limited by the 2π uncertainty of previous continuous wave signals and is therefore capable of measuring thick layers. Thus, the presented system and measurement method are a cost effective alternative to THz time-domain systems in the field of thickness measurements.

Autostereoscopy-based three-dimensional on-machine measuring system for micro-structured surfaces.

Traditional off-line measuring systems find it difficult to measure micro-structured workpieces which have a large volume and heavy weight, such as micro-structured patterned precision roller drums. This paper proposes an autostereoscopy-based three-dimensional (3D) measuring method and develops an innovative measuring system for the 3D on-machine measurement of the micro-structured surfaces, an Autostereoscopy-based Three-Dimensional On-machine Measuring (ATDOM) system. The ATDOM system is compact and capable of fast data acquisition and high accuracy in 3D computational reconstruction of complex surfaces under different measuring environments. A prototype ATDOM system is experimentally verified through a series of measurement experiments conducted on a precision machine tool. The results indicate that the ATDOM system provides an important means for efficient and reliable on-machine measurement of micro-structured surfaces.

Raster Vs. Point Cloud LiDAR Data Classification

Abstract. Airborne Laser Scanning systems with light detection and ranging (LiDAR) technology is one of the fast and accurate 3D point data acquisition techniques. Generating accurate digital terrain and/or surface models (DTM/DSM) is the main application of collecting LiDAR range data. Recently, LiDAR range and intensity data have been used for land cover classification applications. Data range and Intensity, (strength of the backscattered signals measured by the LiDAR systems), are affected by the flying height, the ground elevation, scanning angle and the physical characteristics of the objects surface. These effects may lead to uneven distribution of point cloud or some gaps that may affect the classification process. Researchers have investigated the conversion of LiDAR range point data to raster image for terrain modelling. Interpolation techniques have been used to achieve the best representation of surfaces, and to fill the gaps between the LiDAR footprints. Interpolation methods are also investigated to generate LiDAR range and intensity image data for land cover classification applications. In this paper, different approach has been followed to classifying the LiDAR data (range and intensity) for land cover mapping. The methodology relies on the classification of the point cloud data based on their range and intensity and then converted the classified points into raster image. The gaps in the data are filled based on the classes of the nearest neighbour. Land cover maps are produced using two approaches using: (a) the conventional raster image data based on point interpolation; and (b) the proposed point data classification. A study area covering an urban district in Burnaby, British Colombia, Canada, is selected to compare the results of the two approaches. Five different land cover classes can be distinguished in that area: buildings, roads and parking areas, trees, low vegetation (grass), and bare soil. The results show that an improvement of around 10 % in the classification results can be achieved by using the proposed approach.